Posts Tagged ‘trigger adjustment’

Diana 72 youth target rifle: Part 4

by Tom Gaylord, a.k.a. B.B. Pelletier

Part 1
Part 2
Part 3

Diana 72
Diana 72 is a youth target rifle from the late 20th century.

This report addresses:

• More on the trigger.
• Accuracy with various pellets.
• Why 5 shots?
• Accuracy with deep-seated pellets.
• Summary.

Today is accuracy day for the Diana model 72 target rifle. We had one extra report in this series, and that was on adjusting the trigger. I want to tell you some more of what I have learned about this trigger.

More on the trigger
During the accuracy test, the trigger failed to work two times. The first time I made a small adjustment and got it running again in a matter of a minute. The second time, however, I worked on it for 15 minutes without success. I finally read Part 3 of this report, to see where the two adjustment screws had been positioned when the trigger was working. The camera angle of that photo isn’t the best, so there was still some guesswork involved; but even then I couldn’t get the rifle to fire.

Then, I thought of something. I know this rifle has a very protective anti-beartrap mechanism, and I wonderd if it was a little too over-protective. So, I cocked the gun, again (it was still cocked and loaded from when the trigger had failed). I’ve had other spring-piston air rifles — most notably Weihrauchs and a few Dianas — that would seem to cock but wouldn’t quite go all the way. How many people have I talked through cocking their RWS Diana sidelevers because they had not pulled the lever all the way back, and the gun was stuck? Even my Whiscombe has done this often enough that I’m used to it.

When it happens to the 72, the rifle is cocked from the standpoint that the piston is back and the mainspring is compressed, but it also isn’t fully cocked in that the trigger isn’t in the right position to fire the gun. It’s a sort of limbo state that some spring rifles can get into. Think of it as a disagreement between the trigger and the anti-beartrap device, and the designers have allowed the anti-beartrap device to trump the trigger for safety reasons.

All you need to do when this happens is cock the rifle a second time, making sure that the cocking linkage goes all the way back. When I did this, the 72′s trigger began working immediately. So, if you ever get one of these rifles, keep this in mind.

Accuracy
I began this test not knowing where the sights were set. After all, this rifle had been through a complete rebuild, so those sights presumably came off. And the action has been out of the stock several times over the past 2 years. So, the gun needed to be sighted-in.

As a side note, the manufacturing date on the left rear of the spring tube is November 1989. That puts it near the end of the production cycle (1979-1993, according to the Blue Book of Airguns).

Sighting-in with H&N Finale Match Pistol
I started sighting-in with H&N Finale Match Pistol pellets. The first shot was lined up with the center of the bull, but it was too low. It landed at 6 o’clock. Since the sights are target apertures front and rear, I was not using a 6 o’clock hold, but centering the bull in the front aperture.

The first sight-in shot was interesting, but the second was even more so, for it would tell me if this was an accurate rifle or not. It hit above the first shot, in the same line but the 2 holes didn’t quite touch. That was good but not what I had hoped for. I had hoped to see a single hole that had barely enlarged with the second round.

Shot 3, however, went into the same hole as shot 2, and shot 4 joined them. So, the rifle was probably accurate, after all. I clicked the elevation up two clicks and proceeded to the first record target.

Shooting for the record
The first 5 shots went into a group that measures 0.221 inches between centers. It’s a group you would love to see out of most sporting rifles but not impressive coming from a 10-meter rifle. Just to make sure it wasn’t me, I shot a second group with this same Finale Match Pistol pellet. As I shot, I could hear the voices of the newer readers, asking why I only shot 5 shots. So, on just this one target, I put 10 into the next group, which measures 0.269 inches. That’s encouragingly close to what just 5 shots did, so it renewed my enthusiasm.

H&N Finale Match Pistol target 1
Five H&N Finale Match pellets went into 0.221 inches at 10 meters.

H&N Finale Match Pistol target 2
Ten H&N Match Targets made this 0.269-inch group. This is not that much larger than the 5-shot group.

RWS R10 Match Pistol pellet
Next up was the RWS R10 Match Pistol pellet. Five of those made a group that measures 0.244 inches. It’s in the same range as the H&N Finale Match pellet, so no cigar.

RWS R10 Match Pistol target
Five RWS R10 Match Pistol pellets went into 0.244 inches.

RWS Hobby
After that, I decided to give the RWS Hobby wadcutter pellet a try. Who knows what they might do? Well, that was a good decision this time, because 5 of them went into 0.194 inches between centers — the smallest group so far.

RWS Hobby target
Five RWS Hobby pellets went into 0.194 inches at 10 meters. This is a good group.

At this point, I’d noticed that all the groups were landing off to the left. There’s no scope involved, so I can hit the center of the target and not destroy the aim point. I dialed in 3 clicks of right adjustment into the rear sight and continued the test.

JSB Match
Next, I tried JSB Match pellets. Five went into 0.264 inches. That was the second-largest group in this test, so no joy there.

JSB Match target
Five JSB Match pellets made this 0.264-inch group. Not that good.

Why 5 shots?
Before someone asks why I shot 5-shot groups, I’ll tell you. Accuracy is the reason. Ten-meter guns are generally so accurate that there isn’t that much difference between 5 and 10 shots. You only have to look at the first 2 targets to see the truth of that.

H&N Match Pistol
Next, I shot 5 H&N Match Pistol pellets. They’re a lower-cost pellet than the Finale Match Pistol, and sometimes they produce good results. This was to be one of those times. Five pellets made a round group that measures 0.166 inches between centers. That’s the smallest group of the test; and because it was noticeably smaller, I shot a second group to see if the first was a fluke.

H&N Match Pistol target 1
Now, this is a group! Five H&N Match Pistol pellets went into 0.166 inches.

It wasn’t a fluke at all, as you can see. The second group was a little larger, at 0.196 inches, but still one of the smaller groups fired in this test.

H&N Match Pistol target 1
This second group of H&N Match Pistol pellets was shot to confirm the first one. It measures 0.196 inches, which is larger but still one of the smaller groups of this session.

Seating the pellets deep
Now that I’d tested 4 different wadcutter pellets, three of them being designated as target pellets, I thought I would take the best 2 and test them by seating them deeply in the breech to see if there was any difference. For this, I used the Air Venturi Pellet Pen and Pellet Seater that was also used in the velocity test. We learned then that the 72 doesn’t like pellets to be seated deeply where velocity is concerned. Let’s see what it does for accuracy.

The first pellet I tested this way was the H&N Match Pistol that proved to be the most accurate in the entire test. When seated deeply, they gave a 5-shot group that measures 0.23 inches between centers. While that isn’t bad, it’s larger than either of the two groups that were seated flush. They measured 0.166 inches and 0.196 inches, respectively.

H&N Match Pistol target seated deep
When they were seated deeply, 5 H&N Match Pistol pellets went into 0.23 inches. It’s larger than either of the 2 groups made with the same pellet seated flush.

And the last pellet I tested was the RWS Hobby. When seated deeply, Hobbys group in 0.252 inches. Again, this was not as small as the one group of flush-seated Hobbys that went into 0.194 inches. That leads me to believe that this rifle likes its pellet seated flush much better.

RWS Hobbys seated deep
Five deep-seated RWS Hobby pellets went into 0.252 inches. This group appears smaller than it really is because some of the target paper has closed around the holes.

Summary
The RWS model 72 target rifle is a fine example of the quality and ingenuity that Diana can put out. They took a great informal target pistol — the model 6 — and turned it into a youth target rifle. They didn’t pour a lot of money into this airgun, with the rear target sight being a conventional, adjustable sight fitted with an aperture, but they did everything right. This is a youth target rifle to covet!

If you want one of these, you’d better start looking right away. There aren’t that many of them, and owners tend to hang on to them longer than they do most airguns.

This was a test of the recoilless model 72, but don’t forget there’s also a model 70 that’s based on the model 5 pistol that recoils. There are more of them to be found, and their recoil doesn’t amount to much since they were originally an air pistol. Either model is a great airgun that you should certainly look for if this sort of gun interests you.

Diana 72 youth target rifle: Part 3

by Tom Gaylord, a.k.a. B.B. Pelletier

Part 1
Part 2

Diana 72
Diana 72 is a youth target rifle from the late 20th century.

This report addresses:

• Examining the Diana model 72 trigger.
• Two trigger adjustments.
• Caution — you may not want to do this!
• Trigger adjustment directions.
• Blog reader Mikeiniowa.

Today, we’re going to look at how to adjust the Diana model 72 trigger. I know this report is needed; because when I searched for information on the Diana model 72 target rifle, this blog was at the top of the list! I wish I had an owner’s manual for this little rifle, as I’m sure clear trigger adjustment instructions are in there. Lacking that, let’s first look at the trigger.

The Diana 72 trigger
As you’ve learned, the Diana model 72 youth rifle is just a model 6 target pistol in a rifle stock. Most things remained the same, but the trigger is one feature that had to change. People will tell you this rifle trigger is identical to the pistol trigger, but the presence of the long linkage from the trigger blade to the sear adds complexity the pistol trigger doesn’t have.

Diana 72 trigger left
Kind of surprising, no? What looks like the trigger is nothing but an isolated lever. Under the large hole in the flat plate several inches to the left is where the actual trigger lies. The arrow points to the trigger adjustment screws.

Diana 72 trigger right
On the right side of the trigger mechanism, we see the trigger linkage (the flat bar above the trigger blade that connects it to the trigger mechanism on the right).

What you thought was the rifle’s trigger turns out to be just a lever sitting out by itself and connected to a lot of machinery located several inches away. The linkage that connects the blade to the rest of the trigger mechanism is long and springy. It’s why this trigger can never be set to operate as crisply as a true target trigger. But some small amount of adjustment is possible, and this trigger can be very nice.

You can see the trigger adjustment screws in both pictures, but it isn’t necessary to take the stock off to access them. The rifle has an oval cut in the bottom of the forearm, and both screws are exposed. Actually, I should say all three screws are exposed, because the adjustment screw is actually two screws — one inside the other. The other screw isn’t for adjustment — it’s there to lock the larger adjustment screw in place.

Diana 72 trigger adjustment screws
The trigger adjustment screws can be seen through an oval hole in the underside of the forearm when the rifle is assembled. There are three screws. The one on the right is actually 2 different screws. On the left is the locking screw that locks the large screw on the right. Notice the very large screw at the far left of this picture? That’s the stock screw and has nothing to do with the trigger adjustment.

Diana 72 trigger adjustment screws exposed
Here you can see the adjustment screws exposed. The screw on the right in this picture is actually two different screws — one inside the other. The small screw inside the large screw on the right will turn at all times. The single screw to the left of the two screws locks the larger screw in place. When you do that, the smaller screw inside can still be turned.

Two trigger adjustments
You can make 2 adjustments to the trigger. You can adjust the length of first-stage travel, and you can adjust the amount of second-stage letoff — which means the weight of the trigger-pull.

BUT — Please read this and believe it. These two screws — one inside the other — act in unison. As one is adjusted, it affects the other. It is extremely easy to adjust them OUTSIDE the safe range, in which case the trigger stops working altogether. When that happens the gun can be cocked, but cannot be fired!

To be safe, when that happened to me several times, I always broke open the action so the anti-beartrap would prevent the gun from firing. Then, I adjusted the 2 screws together until the gun worked once more. I did this several times to learn what each screw does. One time it took a full 10 minutes of working with both screws before I got the gun firing again!

Caution: This is very difficult
If you’re afraid of how sensitive this adjustment is — good! Stay away from it! The large hollow screw has a very small range of adjustment and can get out of the range very easily. But if you want to try this, below are the instructions.

Adjustment directions
First adjust the length of first-stage travel (the small screw inside the large one). This can be done with the second-stage screw (the large hollow screw) locked in place. Turning the small screw out (counterclockwise) lengthens the first-stage travel. Turning it in (clockwise) shortens the first-stage travel. I tried to eliminate the first stage altogether because I know some people like it that way, but I was unable to get rid of the last little bit of travel. Formal target shooters use two-stage triggers almost exclusively, so perhaps Diana thought some travel was needed; but it also might be necessary to have some travel in this particular trigger for safe operation.

After you have the first stage where you want it, you can adjust the second stage. First, unlock it by loosening the locking screw to the left. I found the adjustment range of the large, hollow (second stage) screw extremely limited. It was possible to get out of the range with as little as one complete turn of the large, hollow screw.

I played and played with this adjustment mechanism and came to the conclusion that not only are the screw turns limited — the weight range of the trigger release is also very limited. That’s because this trigger blade is connected by a springy linkage.

The best I was able to do was reduce the release from 2 lbs., 1 oz. (33 oz.) to 1 lb., 8.5 oz. (24.5 oz.). The first stage takes up about the first pound of that weight, so stage 2 is very light and difficult to feel until you get accustomed to it. There’s also some travel in stage 2, but there’s no creep (moving and pausing at random points).

Mikeiniowa
If you search the internet for directions on how to adjust the Diana model 72 trigger, you’ll discover that a good many folks who are experts with vintage airguns avoid this job. Several of them recommend sending your rifle to our blog reader Mikeiniowa, who apparently knows this rifle quite well. I hope he reads this report and comments.

Status of the rifle
The model 72 is now ready for accuracy testing. Although the trigger isn’t match grade, it’s as good as it can get– and it isn’t that bad.

Octane combo from Umarex — trigger job: Part 5

by Tom Gaylord, a.k.a. B.B. Pelletier

Part 1
Part 2
Part 3
Part 4

Octane combo
Umarex Octane gas spring combo.

Today’s report is a guest blog from blog reader DMoneyTT. He promised to show us how to fine-tune the Octane trigger, and he’s provided some good photos to go along with his article.

If you’d like to write a guest post for this blog, please email me.

Over to you, DMoneyTT.

Umarex Octane trigger job

by DMoneyTT

As the cost and availability of firearm ammunition continues to keep many shooters from getting adequate trigger time, scores of shooters are turning to airguns to keep their skills honed. Often, new airgunners will be tempted to put down their hard-earned dollars on a rifle offering the highest advertised velocity. Airgun marketing tends to focus on this aspect of performance over all else; but experienced shooters know that accuracy is paramount, and it takes more than just a good barrel and powerplant to deliver tight groups. Proper fit and trigger control are critical considerations when attempting to extract the maximum potential from any rifle.

It’s no secret that the Chinese-manufactured airgun market has seen unparalleled growth and their products are steadily closing the gap between these affordable rifles and their more precise, yet costly, brethren manufactured in Germany, Russia, the United Kingdom and the United States (to name but a few). Many times the differences in quality of manufacturing may be ironed out by the end user. It’s not beyond the skills or tools of the average shooter to dramatically improve the performance of a budget Chinese airgun.

For the shooter who desires all the power of a magnum springer and wants the accuracy to make good use of the velocity but doesn’t want to spend a lot, there are a few good choices. In my humble opinion, the best of these is the Umarex Octane combo. I picked one up several months ago, and it’s been a real joy to plink with and should be excellent for hunting small game, as well. The only downside to this excellent rifle is the trigger-pull. Out of the box, the pull on my rifle registered almost 10 lbs. Others have reported slightly less, so I may have started with an abnormally high pull weight to begin with. There was very little creep (which is a result of minimal sear engagement), and the break was quite crisp. So, a trigger job was necessary, and lessening the pull weight was the only task required.

I would like to say that this does take a steady hand, and careful attention should be paid to the work done on these tiny parts. Any work you decide to do on your rifle should be done with care to maintain the original parts geometry, and it’s always a good idea to carefully test the rifle after any work has been performed. I suggest reading this article before beginning any work to decide if this is within your skill set.

Note from B.B.: Do not work on your gun’s trigger if you do not already have experience working on airguns or are not 100% confident that you can properly disassemble and reassemble the gun and trigger. If you decide to do any part of this trigger tune, you will void the gun’s warranty.

The necessary tools are few.

You will need:
• An Allen wrench that fits the forearm screws.
• A large Phillips screwdriver
• Some paste-type lubricant (synthetic open-gear lube worked well for me)
• A fine wet stone (300-600 grit is preferable)

Optional:
• A Dremel (or any other rotary tool) with a grey rubber polishing wheel may be used on contact points other than the primary sear and secondary sear interaction point because it’s too likely to round edges.
• A vise to hold the rifle while performing the work.
• Small needlenose pliers or hemostats.

So, let’s begin! Start by ensuring that the rifle is not cocked or loaded. The next task is to remove the stock from the rifle so the trigger group can be accessed. Use an Allen wrench to remove the two forearm screws that attach the action to the stock.

Octane combo forearm screws

Next, a large Phillips screwdriver is used to remove the screw found behind the triggerguard.

Octane combo Phillips screw
The action can now be removed from the stock. It’s helpful to hold the rifle directly upside down, as the trigger pins fit very loosely and will fall out if the action is tilted to either side once the stock is removed. It’s wise to do all the work over a flat and clean surface that will easily allow dropped parts to be seen and recovered. I chose to mount my action in a vise to allow easy removal of the stock and to gain access to the components of the trigger group. It’s certainly easier to work on the rifle if both hands are free.

Here is the correct placement of the pins in the trigger housing.

Octane combo trigger pins

Each pin will now need to be removed, and the associated component will need to come out with it. I find that hemostats are very helpful for those with large hands like mine. To help organize the parts, it’s advised to lay them on a white sheet of paper according to their position as they’re removed.

To illustrate the internal layout of the parts, I assembled a jig to hold the pins in the same position they are within the trigger housing. Notice that the shorter leg of the V-shaped sear spring rests against the secondary sear. This is important to reproduce when assembling the trigger group.

Octane combo trigger parts
These parts are shown upside down. In the rifle, the trigger blade would be on the bottom of these parts.

Now that the components have been removed from the trigger housing, warm soapy water should be used to degrease all the parts. All contact points between the parts should also be deburred and polished. These areas are circled below in red. I first used a fine (500 grit) whetstone to debur and smooth any rough surfaces. I then polished these parts with a very fine (1000 grit) whetstone. Remove as little metal as possible to get the desired mirror finish and be careful not to round any of the sharp edges. The goal is to make the parts smooth and shiny so they’ll slide against each other with minimal friction but not alter the shape of the parts.

Octane combo trigger parts cocked

Like the previous photo, these parts are also shown upside down.

Octane combo trigger parts fired
Perhaps the most important part to refinish is the trigger adjustment screw. It comes from the factory with a very sharp point that digs into the tertiary sear where it touches. This galls the metal, and there’s significant drag produced when attempting to pull the trigger in its stock configuration. Simply removing this grub screw with a small Allen wrench and rounding and polishing the end that contacts the tertiary sear will reduce the pull weight by 2 or more pounds, depending on the severity of the galling.

I chucked this screw into my drill and spun it against my whetstone until it had a nice, smooth ball end instead of a sharp point. It should look like the image below when you’re done.

If you are not confident enough to tackle this full trigger job, the trigger adjustment screw can be removed from the rifle without any other parts being removed. That allows you to round and polish the end and install it in the trigger to realize a vastly improved trigger-pull with little work involved.

 

Octane combo trigger adjustment screw

The adjustment of this screw has very little effect on the pull weight or quality because it allows adjustment of the first stage only. This first stage is not a true first stage because the sears do not move as the trigger travels through this stage. The trigger return spring is just being compressed, much like a Gamo or Crosman trigger. Feel free to adjust this screw to whatever position you prefer. There’s no set rule except to not adjust the screw so far in that it eliminates the first stage. That will result in an unsafe rifle that may cause a bear-trap incident (where the piston releases without the trigger being pulled, allowing the barrel to snap shut unexpectedly).

Assembly of the trigger is fairly straightforward and is the reverse of disassembly. The use of a thick paste-type lubricant on the bearing surfaces of the parts will help decrease pull weight as well. I use Mobile One synthetic open gear lube, but most any paste-type lubricant should work. My Octane trigger group was bone-dry from the factory, which certainly contributed to the very stiff pull weight. Use the pictures to help install the parts and pins in their appropriate locations. The hemostats will come in handy again at this point. I installed washers to remove slop from my components but would not recommend it. The difference is hardly noticeable, and it makes assembly much more difficult.

The sum of these modifications should get the trigger-pull down to around 4 lbs. and make it much more smooth and consistent. After averaging the pull weight from 5 measurements, my trigger has settled down at a 3 lb., 2 oz. pull. It’s possible to go slightly lighter with some modifications of the secondary sear geometry; but because of the required precision and the possibility of dangerous results, I suggest stopping at this point. A 3.5-lb. trigger is quite good for a magnum springer and is ideal for accurate plinking and hunting. I know that my groups have improved dramatically, and I’m enjoying the fruits of my own labor when I feel a crisp trigger-break and see targets fall. I hope this helps you get the best from yourself and your rifle.

Please post any questions, comments or tips you have. I’m curious to see what you think.

Octane combo from Umarex: Part 4

by Tom Gaylord, a.k.a. B.B. Pelletier

Part 1
Part 2
Part 3

Octane combo
Umarex Octane gas spring rifle combo.

Today’s report is both interesting and a little different. I shot the .22-caliber Octane combo from Umarex at 25 yards and used the Umarex 3-9X40 scope that came in the package. I’ll talk about the scope and mounts first.

The scope is a variable with parallax adjustment from 10 yards to infinity. It features a duplex reticle and comes with 2-piece Weaver rings that have 4 screws per cap. The top of the rifle has a Picatinny adapter clamped on the 11mm dovetails that are cut directly into the spring tube, so the scope rings mounted quickly.

I found the scope to be clear and sharp, and the parallax adjustment to be close to the actual distance once the eyepiece was adjusted correctly. This is one of the nicest scopes I have seen bundled with a combo airgun. I don’t think you need to buy anything other than pellets — lots of pellets.

Sight-in
I sighted-in the gun at 12 feet with one shot, then backed up to 25 yards to refine the sight picture. Veteran readers know I’m purposely trying not to hit the center of the bull, as that erases the aim point.

I was finished sighting-in after 4 more shots and ready to start shooting for the record. The first pellet I selected was the .22 caliber 14.3-grain Crosman Premier that had done so well in the 10-meter test with open sights.

After the first 5 shots, I thought I had a slam-dunk accurate rifle, but I guess I got a little sloppy. Shot 6 went into the same hole, but shots 7 through 10 moved over to the left of the main group. Six consecutive shots went into 0.449 inches; but after 10 shots, the group measured 1.067 inches.

Octane combo Premier group 1
The first 6 Crosman Premiers went into a tight 0.449 inches, but the remaining 4 shots opened the group to 1.067 inches at 25 yards.

After this group was finished I discovered the scope base screws were both loose. That made the scope loose, as well. I tightened them and checked them frequently throughout the remainder of the test.

The second group of Premiers opened to 1.382 inches. This one is very horizontal, but within it is a tight group of 4 shots that came early in the string. That group measures 0.188 inches between centers.

Octane combo Premier group 2
These 10 Premiers are not very impressive for 25 yards, at 1.382 inches between centers; but at the 9 o’clock position on the bull, 4 pellets went into a tight 0.188 inches!

Following this group, I noticed that both forearm screws had come loose. So they were tightened — a lot! And for the rest of the test, I monitored their tightness closely.

What’s happening?
The Octane recoils a lot, and you have to watch all the screws. Once they’re tight, they probably won’t back out for a long time; but the first time you use the gun, they probably need to be tightened just a bit more than normal. At least, watch for them to loosen.

This is nothing new. We have always been told to watch the screws on spring guns that recoil heavily. I just forgot it this time until it became obvious downrange.

JSB Exact Jumbo
Next I tried JSB Exact Jumbo pellets. They did very well for the first 6, then the last 4 wandered over to the right. And when I say “wandered,” I mean they really went places! The group measures 2.822 inches between centers, with 6 of those shots in 0.763 inches.

Octane combo JSB Exact Jumbo group
Interesting group! Six shots in a tight 0.763 inches, then the last 4 stretched it out to 2.822 inches. Go figure!

After this group, I played around with holding my off hand at different places under the forearm, and then some non-standard holds that included resting the rifle directly on the bag 2 different ways. By the time I was finished, I’d fired over 60 shots from a rifle that takes 39 lbs. of force to cock. I never reported that effort in Part 2, like I normally would, so now you know that the Octane is hard to cock — like all powerful gas spring airguns.

I suspected that I was tiring at this point. The term used in competition is I was “blowing up”! The Octane wanted to put them in the same place, but something prevented it. I shot one final group of Premiers — just to see if I could see what it was doing. But that group wasn’t worth reporting. I had clearly pushed past the point of fatigue, so the session was over.

Here’s what’s at stake. Priced at just $200 with a very good scope, the Octane is poised to take its place beside legendary air rifles like the RWS Diana 34 Striker Pro combo. It’s actually $100 less than the 34, yet offers the same power. If it also gives the same accuracy, the Octane suddenly becomes an important air rifle; and if the horribly heavy trigger has a workable solution that the average owner can follow, then folks, we have a winner. So, I want to give this air rifle every chance to compete. It seems to want to do well, so I need to find out what needs to be done.

Octane combo from Umarex: Part 3

by Tom Gaylord, a.k.a. B.B. Pelletier

Part 1
Part 2

Octane combo
Umarex Octane gas-spring rifle combo.

Today is the start of accuracy testing for the Octane combo air rifle, and I’m going to make some changes. For starters, I’m going to give you the summary now. The Octane is a smooth-shooting, accurate air rifle. It’s everything the manufacturer wants it to be, and a couple of things they probably didn’t think about, on top of that. The rest of this report will justify and explain my summary.

Another thing, the Octane is different from any gas spring I’ve ever tested. Gas springs always fire fast, as in instantaneously. When the sear releases, the shot is over, and you usually know it from the sharp crack of sound and the painful slap to your cheek. The Octane fires slowly in comparison. There’s a lot of forward recoil and almost no vibration, and the discharge is very quiet, as I noted in part 2. I attribute this behavior to the Reaxis gas-spring design that’s reversed from the norm, and to the SilencAir silencer on the muzzle. Both apparently work as advertised.

The test
I decided to just shoot 5 shots per pellet today, and to shoot the rifle with open sights at 10 meters. I wanted to get a good sense of how accurate it is before putting the walls of my house at risk. And what I discovered was that this rifle is fun to shoot! I normally don’t have much fun shooting a 20 foot-pound spring rifle, but the Octane is so civilized that it gave me a lot of confidence. By the time I’d fired the first 2 shots at the target, putting them into the same hole, by the way, I knew this day was going to be fun.

I held the rifle with an artillery hold, but the thumbhole stock makes you grip the gun harder than you normally might. So, I would have to call it a modified artillery hold. But the rifle cooperated, and there was noting to worry about. The muzzle heaviness holds the front sight steady on target once you’re dialed in.

The sights are fiberoptic, which destroy all attempts at precision, but by lighting the target brightly and sitting in a darker room to shoot, I could defeat the fiberoptic tubes and get a very sharp sight picture. When they don’t glow, the Octane’s sights offer a nearly ideal sight picture, and that was what made me decide to not mount the scope, yet. I wanted to have the fun of shooting with open sights since the rifle was cooperating.

The trigger is still quite heavy and very creepy, so I envy those who own their rifles and can modify them. If I could drop the release weight to under 4 lbs. and if there was a way to eliminate all the second-stage creep, this trigger would help accuracy greatly.

Beeman Kodiaks
The first target was shot with 5 Beeman Kodiak pellets. This was when I first noticed how slow the Octane’s gas piston is. It feels like an airgun equivalent of a 45-70 single-shot. You feel the recoil and the rifle bounces around, but you know the pellet got out of the muzzle before all that started and that accuracy wasn’t affected in the slightest.

As I said, the first 2 pellets cut the same hole, though each made a distinctive mark. Then I stopped watching through the spotting scope and just shot the next 3 pellets. In the end, the group is larger than I would have liked for 10 meters, at 0.581 inches, but this is with open sights. Still, it is just 5 shots instead of 10.

Octane combo 10-metr Kodiak target
Five Beeman Kodiaks at 10 meters with open sights measure 0.581 inches between centers. It’s a good start!

RWS Hobby
Next, I tried the RWS Hobby pellet. It felt good while loading because it fit the breech tight but not overly so. And, though the point of impact shifted up a bit, the Hobby was quite accurate — putting 5 pellets into 0.368 inches! I thought that was remarkable. I couldn’t wait to test some more pellets!

Octane combo 10-meter RWS Hobby target
Five RWS Hobbys at 10 meters with open sights measure 0.368 inches between centers. Now, the rifle was giving me confidence.

RWS Superdome
Next, I tried the RWS Superdome. Here’s where you’re going to see something significant. RWS makes both Hobbys and Superdomes in Germany, and presumably they use the same lead alloy for both. And domed pellets are generally regarded to be the most accurate. Yet look at how the Superdomes did! They grouped horizontally, to exactly 1 inch, while the Hobbys stayed together.

You might try to blame me for getting tired at this point in the test, but there’s group coming that will show that I was still shooting my best. That’s one benefit of these 5 shot groups. They don’t tire me as quickly.

Octane combo 10-meter RWS Superdome target
Five RWS Superdomes at 10 meters measure a long 1 inch between centers. When you compare this group to the one made by the Hobbys, you see that Superdomes are not suited for this Octane.

Predators
Now, for those of you who think I might have slipped up on the last group, I shot 5 Predator Polymag pellets next. They’re a recognized premium pellet, just like the Superdomes, and I’ve shown some great groups using them in recent tests. But not this time. Instead of the group stringing sideways, the Predator group were stringing vertically. Five went into 0.982 inches, so we won’t be seeing them in any future tests of the Octane.

Octane combo 10-meter Predator target
Five Predator Polymag pellets made this vertical 0.982-inch group.

If you have now decided that I’ve gotten tired and ho-hum, what’s so special about the Octane if this is the best that it can do — hold on! I saved the best for last. Actually, the Octane saved the best for last because the next group is the last one I shot on this day.

Crosman Premier
The 14.3-grain Crosman Premier pellet is sometimes the best pellet you can use in an airgun. And it is in the Octane test! Five Premiers went into a group measuring 0.245 inches between centers. It looks like only 3 pellets have passed through, but I did shoot all 5. This is very clearly and hands-down the most accurate pellet I tested in the Octane.

Octane combo 10-meter Premier target
Five Crosman Premiers made this beautiful 0.245-inch group. It was the last group of the test. Who says the groups open up as you go? This is the pellet for this rifle.

Summary
I already gave you the summary in the beginning of this report. Now you see the substantiation of what was said.

Several readers reported higher velocities than I got in the last test, and I was asked to change the breech seal. Well, I might do that, but frankly the rifle is shooting so nice right now that I don’t feel any urgency.

The Octane is unlike any gas-spring breakbarrel rifle I’ve ever tested. I wish the trigger was better, but it’s hard to argue with the accuracy or with the rifle’s firing behavior.

I will skip testing the rifle at 10 meters with the scope that comes in the package and go straight to 25 yards next time.

Benjamin Marauder .22 repeater with synthetic stock: Part 2

by Tom Gaylord, a.k.a. B.B. Pelletier

Benjamin Marauder .177 caliber Part 1
Part 2
Secrets of loading the Benjamin Marauder magazine
Part 3
Part 4
Part 5
Part 6
Fixing a Marauder magazine
Part 7
Benjamin Marauder .25 caliber Part 1
Benjamin Marauder .25 caliber Part 2
Part 3
Part 4
Benjamin Marauder .22 repeater with synthetic stock Part 1

Benjamin Marauder synthetic stock

New Benjamin Marauder with synthetic stock has all the features of the classic Marauder in a lighter, trimmer package.

Today is our second look at the .22-caliber Benjamin Marauder with synthetic stock. We have a new log reader who goes by the handle AirrifleRatHunter, and he just bought a synthetic Marauder and it’s his first PCP, so I want to help him with his rifle.

Baffled?
ARH said his rifle wasn’t as accurate as he thought it should be. We found that he was using substandard pellets and corrected that, but I also mentioned to him that the baffles inside the shroud could be involved. He asked me what baffles are, so I’m now showing them to everyone. The test Marauder has 7 Delrin washers (the baffles) that are shaped to strip away the compressed air behind the pellet once it leaves the rifle’s muzzle, which is buried deep within the shroud. I’ve laid out these parts for you to see how they work. If the pellet were to touch one of these baffles as it passes through, it would destroy accuracy.

Benjamin Marauder synthetic stock baffles
Here you see all the baffles that are held inside the shroud under spring tension, so they don’t rattle around.

Benjamin Marauder synthetic stock baffle detail
Looking at a single baffle shows that the compressed air that’s behind the pellet gets stripped to the sides by the shape of the baffle (on the left) as the pellet passes through its center. This happens 7 times in succession before the pellet leaves the gun. The end cap that pushes the baffles against the coiled spring at the back has an o-ring to keep the air from escaping around its threads.

One other accuracy tip is to ensure that the shroud is not touching the forward barrel band on any side. Mine was touching on one side when I got the rifle, so I loosened the 2 set screws on the bottom of the band and repositioned it.

Benjamin Marauder synthetic stock front barrel band
I have repositioned the front barrel band so it clears the barrel shroud around its entire circumference.

Today is setup day, where I will adjust the rifle to suit myself. The first thing I did was select a scope and mounts. Marauders have a low receiver, which means you need to select a higher scope mount if the objective bell of your scope is a large one. I chose a Leapers UTG 4-16X50 scope with illuminated reticle, but mine is an older model than the one I linked to. Nevertheless, it’s a big scope with a large objective bell that needs height to clear the barrel shroud.

Benjamin Marauder synthetic stock with scope mounted
See how close the objective lens comes to the barrel shroud — despite my using high mounts? Also note that the magazine needs clearance, so the scope mount must be 2-piece.

You have to either use a 2-piece mount or a cantilever 1-piece mount that will clear the magazine sticking up above the receiver, so keep that in mind when looking at mounts. I chose BKL one-inch mounts with double straps that are high enough for the gun and scope combination. The double straps mean that you don’t need to worry about the torque sequence when you tighten the screws in the scope caps because each strap is independent.

Benjamin Marauder synthetic stock scope cap detail
These clever BKL scope caps relieve you of the need to follow a torque procedure when tightening the cap screws.

Adjust the cheekpiece
Usually, I have to just adapt to whatever gun I’m testing because most of them don’t have any ergonomic features. But the new Marauder synthetic stock does have an adjustable cheekpiece. I was able to raise it up so my eye in in line with the scope’s exit pupil when I shoulder the rifle normally. What a convenience that is!

The new trigger
The Marauder’s trigger has been moved back in the receiver by about one-half inch, which brings the blade closer to the pistol grip. The result is a nicer feeling when you hold the rifle because your hand doesn’t have to stretch to reach the trigger. I never noticed it until I shouldered the new rifle the first time, but it certainly feels much better now.

Moving the trigger back meant that several internal trigger parts had to be redesigned. In essence, this trigger is the same one that’s always been on the Marauder, but there are small differences inside. So, the next thing I did was adjust the trigger.

To properly adjust the trigger, you remove the action from the stock. It’s only necessary to remove one stock screw for this, and the action comes right out.

As the rifle came from the box it had a heavy first stage pull of 2 lbs., 6 oz. This can be reduced by adjusting a screw counterclockwise to take tension off the trigger return spring. When I backed the screw out entirely so no spring tension remained, the first-stage pull dropped to just under 11 oz., so there’s another spring inside the trigger group that also helps return the trigger blade.

Benjamin Marauder synthetic stock trigger adjustment screws
The large round screw at the left adjusts the trigger-pull weight. Behind the trigger blade the two small screws adjust the first- and second-stage pull length. And the screw behind those 2 allows for slight repositioning of the trigger blade.

I put the adjustment screw back in the hole and tightened it just enough to keep it from falling out. That raised the first-stage pull to just over 14 oz., which is fine for a sporting rifle; but I must note that it’s heavier than the triggers in the other 2 Marauders I’ve tested. They both break at 11 oz., and this one has a first-stage pull greater than that.

Next, I adjusted the first-stage pull a little shorter, and the second-stage pull to start sooner. Those were 2 separate adjustments; but each affects the other, so the manual tells you to do them together. The owner’s manual also warns you that these screws adjust the amount of sear contact, so go slow and be careful to not get the trigger to the point that it won’t hold the sear or will only hold it dangerously close to firing. After making these adjustments, I assembled the action in the stock once more and cocked the rifle. Then, I bumped it hard from several directions, and the sear did not slip off and fire.

Before the adjustment, the rifle fired at 3 lbs., 4 oz. That’s pretty good for an air rifle trigger, given the lawyerly influences in companies these days; but a Marauder is not an average air rifle. After adjustment, it fired at 1 lb., 7 oz. but still had a bit of creep in stage 2, so I adjusted the stage-2 screw one last time. This time, I didn’t take the action out of the stock. The small Allen wrench used on these 2 screws (a .050-inch wrench is used for both stage-1 and stage-2 screws) is small enough to reach through the triggerguard and fit into the socket of the screw.

The final adjustment took another half-ounce off the pull and eliminated most of the creep. I wouldn’t call this trigger glass-crisp…but the way it’s adjusted now, it’s quite good!

Now the rifle is set up for me. Next, I’ll shoot it for velocity and decide whether to leave the fill limit at the factory-set 2,500 psi or increase it for more shots. And I may adjust the velocity, depending on what I find.

Octane combo from Umarex: Part 2

by Tom Gaylord, a.k.a. B.B. Pelletier

Part 1

Octane combo
Umarex Octane gas-spring rifle combo.

Just a word
Befoere I get started with today’s report, I want to say something about what happened this weekend. Friday’s airsoft report got a lot of comments. Among them are several questions about the technology of the guns. And some admissions that people didn’t think much of airsoft before they tried it, then they found their opinions changed drastically. That also happened to me, so I can relate to it.

But all you who don’t care for the subject don’t need to worry. This isn’t going to become an airsoft blog. I will continue to report on it at a low level, but I know this is an airgun blog, and that’s not going to change. I want to assure the readers for whom the subject of airsoft is not welcome that we are still going to talk about pellet guns and BBs guns for the most part. I will write a few reports on airsoft now and then, and I trust they won’t upset you too much.

Okay, that’s done. On to the topic of the day!

Today is our second look at the .22-caliber Octane combo from Umarex, and it’s velocity day. Before I get to that, there are a couple adjustments I wanted to make to the rifle. Let’s look at those now.

The first adjustment is the trigger. In the first report, I said the trigger is crisp but heavy. The adjustment screw adjusts only the length of the first-stage pull; so I adjusted it to be longer, and stage 2 decreased. Don’t go too far or the rifle will not cock at all because this adjustment does affect the area of sear contact.

I did go too far and had to call Umarex USA, where I learned that the Octane is supposed to come with a warning tag telling you not to turn in the adjustment screw more than one full turn. I went way past that, so all I had to do was turn the screw back out until the head stood even with the trigger blade — and the trigger was back to working again. For even greater contact, turn the screw so it stands proud of the trigger blade.

Dismantling tip
The second thing I wanted to adjust is the tension on the action forks because the barrel pivot was too loose. To do that, I normally take the barreled action out of the stock. But with this rifle, you need to be aware that the pins in the trigger are not held in and will fall out of the trigger if the action is tipped sideways. I didn’t know this, of course; and when the first pin fell out, it set me up for 45 minutes of work to get the trigger back together again. It seems that the trigger pins are held in place by the stock. Other airguns I’ve worked on have the same arrangement, and one solution is to put tape on one side of the trigger to hold the pins in place…and keep the trigger oriented straight up and down.

Octane combo trigger assembly
Each of the 6 free (not held by circlips or springs) trigger pins seen here is very loose in its hole and will fall out of the trigger if the gun is jostled or tipped to the side. They’re held in place by the stock. What appears to be a pin at the far right is actually a rivet.

Better still — what you can do (VERY CAREFULLY!) is remove both forearm screws and just LOOSEN the rear screw behind the triggerguard. Then the front of the action can be tipped up clear of the stock far enough to tighten the barrel pivot bolt and nut. I would advise against taking the action completely out of the stock. If you do, know how loose the trigger pins are and treat the rifle accordingly. When the pins fall out, the internal trigger parts start moving around. They’re fairly easy to align with their pin holes, except for the safety that takes a little fiddling since it’s a 2-piece assembly with an internal pivot. My advice is to leave the gun in the stock.

One final tip. When you tighten the stock screws, don’t tighten the rear stock screw (the one behind the triggerguard) too much or the trigger won’t function. It was not tight when I first took the action out of the stock; and I found that if I tightened it too much, the trigger would not work. Umarex told me the screw shouldn’t affect the trigger at all, but I’m just reporting on the behavior of my test rifle.

Now, let’s look at the velocity of the Octane. I’ve selected 3 popular lead pellets and one lead-free pellet.

JSB Exact Jumbo
The first pellet I tested was the 15.9-grain JSB Exact Jumbo. This is a popular and very accurate pellet in many airguns, and I think it may be accurate in the Octane. This pellet averaged 762 f.p.s. in the Octane. The low was 748 f.p.s., and the high was 787 f.p.s.; so the spread was 39 f.p.s. At the average velocity, this pellet produced 20.51 foot-pounds of muzzle energy.

This pellet loaded easily, perhaps too easily. I think it might be a little undersized for the Octane’s breech. That could affect the accuracy. We’ll see.

RWS Hobby
The RWS Hobby pellet weighs 11.9 grains in .22 caliber and is very tight in the Octane’s breech. It averaged 889 f.p.s. in the rifle with a low of 867 and a high of 902 f.p.s. So the spread was 35 f.p.s. At the average velocity, this pellet produces 20.89 foot-pounds of energy at the muzzle.

I don’t know how Hobbys will do in the Octane, but I suspect they’ll do well because of the tight fit in the bore. Of course, the Hobby is a wadcutter, so accuracy will fall off after about 25 yards.

Beeman Kodiak
The .22-caliber Beeman Kodiak dome weighs 21.14 grains, which makes it a very heavy pellet. In the Octane, Kodiaks averaged 682 f.p.s. with a range from 665 to 691 f.p.s. That’s a total spread of 26 f.p.s. At the maximum velocity, the Kodiak produces 21.84 foot-pounds at the muzzle.

My guess is that the Kodiak pellet might also be a good one for the Octane. If so, that’s great because it also produces the most energy of all the lead pellets tested.

RWS HyperMAX
Okay, the name of the game with pellet rifles these days is speed, and the RWS HyperMAX lead-free pellet at 9.9 grains is the way to get it. In the Octane, they averaged 1029 f.p.s. with a spread from 1022 to 1075 f.p.s. That’s a spread of 53 f.p.s., so the rifle is probably still burning a lot of fuel. At the average velocity, the HyperMAX pellet produced 23.28 foot-pounds of energy at the muzzle.

The HyperMAX pellet fit the breech very loosely. That’s probably where the extra velocity spread came from, as more dieseling was generated by less pellet resistance. I doubt this pellet will do very well in the Octane because of the loose fit.

Shooting behavior
The rifle recoils noticeably in both directions, but there’s no vibration, whatsoever. Nearly all rifles with gas springs have a sharp buzz that hits you in the cheek, but the Octane doesn’t. In fact, aside from the recoil, it’s a very smooth-shooting spring rifle.

Trigger-pull
Remember that I had to adjust the trigger for a very definite stage-2 let-off. That affected the trigger-pull a lot. I was able to adjust it back to a release of 7 lbs., 14 oz. with very little creep. It’s heavy, as I noted before, but I think it’s crisp enough to do good work. We shall soon see!

The Octane IS NOT LOUD!
When I first tested the rifle it was very loud. And the sound persisted for longer than I felt the dieseling of a new airgun would last. But during this test the rifle suddenly became MUCH quieter. Obviously, it had been dieseling and I didn’t know it.

I originally told Edith it was a 3.7 on the sound scale when I tested it, and she adjusted the loudness level on Pyramyd Air’s product page to 4. But now she can hear that the Octane is clearly a 3. I apologize to everyone who was mislead by my earlier report. The Octane is a normal-sounding breakbarrel air rifle.

Observations thus far.
I said in Part 1 that the Octane holds very well in the hands. The weight is biased forward toward the muzzle, and the stock is slender when the off hand rests. Add the smooth shooting to this, and I think the Octane might surprise us in the accuracy test.

I plan on shooting the rifle at 10 meters with its open sights first. That should give us an idea of which pellets it likes. Then, I’ll mount the scope and shoot those best pellets at 10 meters, again. That does 2 things. First, it confirms the pellets are as good as we think; and second, it allows me time to adjust the scope for the second accuracy test at 25 yards.

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