Dot sights

Can a fixed-barrel airgun have barrel droop?

by B.B. Pelletier

This report is in response to a comment Pyramyd Air got from a customer who doubts that fixed-barrel airguns can ever droop. His position is that they can only have droop if the barrel is heated in some way (as on a firearm that fires very fast) or if the gun is assembled in a shoddy fashion.

He said he believed barrel droop is only commonly found on breakbarrel airguns, which is why he said he would never own one. He thought that droop was mostly caused by the metallurgy of the barrel.

Today, I’d like to address the subject of barrel droop in detail. It can be caused by many things, but poor metallurgy isn’t one of them. Barrels do not bend from cocking, despite what some people may think. It is true that a barrel can be bent by human force, but the force required to do so is much greater than the heaviest cocking effort on the most powerful magnum airgun. So, poor metallurgy is not a contributor to barrel droop.

What is barrel droop?
I will explain what barrel droop is in detail later in this report. For now, I’ll just say that barrel droop is a condition in which an air rifle shoots so low that the scope cannot be adjusted to hit the target.

You must understand that most scopes cannot be adjusted all the way to their highest elevation settings and still operate correctly. This will differ from scope to scope, but generally most scopes do not work well when adjusted above three-fourths of their maximum elevation. It’s imperative that they get on target before reaching that height, and a drooping barrel can prevent that.

History
Throughout the first five decades of spring-piston air rifles, no one ever heard of barrel droop. It was a non-issue. That was because nobody bothered scoping their air rifles.

The sights on most breakbarrel guns are attached to the barrel, both at the front and rear, so they’re in line with the bore — as long as the bore is drilled straight through the barrel, which it seldom is. The amount of misalignment is usually measured in the thousandths of an inch — an amount the sights can easily account for.


With both the front and rear sight attached to the barrel, there’s less chance for misalignment.

In the 1960s, retailers began attaching scopes to airguns to sell more of them. Firearms had been using scopes for some time, and the general belief among shooters was that scopes extracted the maximum accuracy from any gun.

But scopes had a problem, as well. They were attached to the spring tube of the gun, which isn’t integral with the barrel on a breakbarrel airgun. For the first time, the alignment of the spring tube and barrel came into question.

It soon became known that most breakbarrel guns have a barrel that slants downward from the axis of the spring tube. In the 1960s and ’70s, breakbarrels were hand-selected for scope use when they exhibited less slant than other guns of the same model. You can read about this selection program in both the Air Rifle Headquarters and Beeman catalogs of the period.

What those catalogs didn’t address was the fact that fixed-barrel airguns can and do sometimes have the same barrel slanting problems. They didn’t address it because, at the time, scoping airguns was brand new and not that much was known about it. The people scoping the guns often installed simple fixes, such as shimming the rear ring, and didn’t even think about why they were doing it.

Why the barrel droops
The comment that prompted this blog went on to say that barrel droop was caused by poor metallurgy. Evidently, the writer thought that “droop” referred to a barrel that was curved (or bent) downward — which is not the case. The term “droop” doesn’t refer to a barrel that is somehow curved. It means a barrel that points in a direction away from the sight line, so the axis of the bore and the sight line are diverging. To correct for this droop, the scope has to be repositioned to align with the axis of the bore.

We all understand that a pellet starts falling the moment it leaves the muzzle. The farther from the muzzle it goes, the faster it falls; so the line of flight is actually an arc, rather than a straight line. To align the sight line of the scope with the axis of the bore, we have to align the scope to look downward through the line of flight. To be effective — that is to get any distance over which the pellet is on target — the sight line is made to pass through the arc of the pellet twice — once when the pellet is close to the gun and again when it’s farther away.


The scope is angled down through the pellet’s trajectory. This illustration is greatly enhanced for clarity. This alignment is done the same for firearms and airguns, alike.

But the question is, “Why does the barrel point downward?” With a breakbarrel, it’s usually because of how the breech locks up at a slight angle that causes the downward slant. Some guns, most notably target breakbarrels, overcome this with barrel locks that cam the breech tightly against the spring tube in a straight line. Most guns rely on the spring-loaded detent to both align and hold the barrel during firing. If there’s a weakness, it’s at this point. When a breakbarrel with an unlocked breech fires, the barrel tends to flex in the direction the barrel is hinged. If the barrel broke upward to cock, the problem would be reversed and we would have a barrel “climb” problem.


A breech lock like the one on this HW 55 ensures that the barrel always aligns with the sights — provided the rifle is designed that way.

Do you now understand that the barrels are perfectly straight, and it’s just the angle of the bore’s axis relative to the line of sight that creates the drooping problem? Good, because that’ll make the following easier to understand.

What about underlevers and sidelevers with fixed barrels?
How can a fixed-barrel rifle have droop? Easy — the barrel isn’t attached to the gun with the bore parallel to the line of sight. Presto! Automatic sighting problem. Or the scope base that’s attached to the spring tube may not be aligned with the axis of the bore. Or the bore may be drilled off-center; and although the outside of the barrel is parallel to the sight line, the bore’s axis isn’t. Any of these three things can happen.

Bore not drilled straight
This is very common. It’s extremely difficult to drill a deep (long) hole straight through a steel bar. The drill bit can wander off-axis as it bites its way through the steel, or it can be off-axis all the way through the bore if it isn’t correctly set into the holding fixture before the drilling begins. I’ve had barrels with bores as much as a quarter-inch off-axis with the outside. Granted that’s extreme and uncommon, but it demonstrates the possibility.

The only way a barrel-maker can ensure concentricity of the bore to the outside of the barrel is to machine the outside of the barrel after the gun is rifled.

Barrel isn’t aligned with the spring tube
This problem is also common. When the barrel is pressed into the spring tube (usually into a block that’s held in the front of the spring tube), the bore isn’t aligned with the spring tube. You might think that modern manufacturing processes make perfect things time after time, but the truth is that there’s always some variation.

Scope base on top of the spring tube is not aligned with the bore
Of all the problems with scope alignment, this one is the most common. Off-axis bores are usually held to just a few fractions of an inch for which the scope adjustments can easily compensate. The same is true for barrels that are bushed off-axis. But scope bases are both short as well as attached in such a way (by spot-welds and rivets) that precision is difficult to maintain. Because scope bases are short, any small deviation in their positioning is exaggerated when extended out to infinity by a scope’s sight line. This is the one place where firearms and certain brands of airguns have an advantage over other brands, because they machine their scope bases into the receiver (of a firearm) or scope tube, rather than riveting or spot-welding the base to the scope tube. If the tooling is set correctly, the machining process ensures alignment of the scope base.

Talking about the spot-welded and riveted scope bases brings us to a discussion of one well-known company that makes highly regarded spring-piston air rifles. This company stands head and shoulders above the others when it comes to having barrel droop — both with their breakbarrels and their fixed-barrel air rifles. That company is Diana. Historically, enough Diana air rifles have had barrel droop so severe that special corrective scope mounts have been made and successfully marketed for their models. Even RWS, who exports Diana airguns, has marketed such a corrective scope mount.

But even Diana can change. Their most recent breakbarrel is their 350 magnum model in all of its various forms, and this rifle is very noticeably immune to the drooping problem. Something has changed at Diana. I would think that, over time, we’ll see this change spread to all of their models.

Firearms also have droop
Drooping isn’t just an airgun problem. Firearms have droop, too. But because of how firearms were scoped in the early days, nobody noticed the problem.

When firearms were scoped back in the 1940s and ’50s, many of them did not have optional scope mounts available. It was very common back then for a gunsmith to drill-and-tap holes into the firearm to accept scope base screws. Naturally, when a gunsmith did the job, he would align the holes in the scope mounts so the axis of the barrel was in line with the sight line seen through the scope. If there was any barrel droop, it was corrected as the mounts were installed.

Do barrels only droop (slant down)?
Before someone asks the obvious question, I’ll address it. Yes, there are airguns with barrels that slant up, plus point to the left and to the right too much for the scope to compensate. They’re not encountered as often as droopers, but they’re not unheard of. The reasons for most of these problems are the same as for droopers except for one standout reason.

If a breakbarrel rifle has been fired with the barrel open, so the barrel was allowed to snap closed from the force of the mainspring, that rifle will have a bent barrel. The barrel will be bent upward at the point it emerges from the baseblock, which is the piece that holds the barrel in the action. It’s where the pivot bolt attaches. It’s the blocky-looking piece the barrel is coming out of in both photos of guns in this report.

For this type of problem, the solution is to bend the barrel straight again. Any qualified airgunsmith should be able to straighten a barrel that has this problem, and a number of owners have learned to straighten their own bent barrels..

Most airgun barrels don’t droop
To put this report into the proper perspective, I should mention that a drooping barrel isn’t that common. I have several air rifles whose barrels are okay for shooting with scopes as they came from the factory. And, of the hundreds of rifles I test, only a small percent have a drooping problem. So, it isn’t a given that your rifle will droop.

But you may get a drooper, and you can rest assured that there are plenty of solutions to rectify the situation should you encounter it. The things to remember are:

Not all breakbarrels droop. Only a small percentage do these days.

Rifles with fixed barrels can also have droop, for the reasons mentioned in this report. It is not as common to find a fixed barrel with droop, but any air rifle that has a separate scope base that’s either spot-welded or riveted in place is a likely candidate for droop.

Firearms have droop, just like airguns. But the amount of droop is small enough that it’s corrected by the scope or by the mounts that are supplied by the firearms manufacturers.

2012 SHOT Show: Part 2

by B.B. Pelletier

Photos by Earl “Mac” McDonald

Part 1

This is the second of my reports on the 2012 SHOT Show. There will certainly be at least one more after this, and perhaps even more, as there’s simply too much new information to pack into a single report.

The state of the airgun industry in 2012
Before I get to some specifics, I want to make a general observation. This year’s SHOT Show was different for me in a major way, because I saw for the first time that firearms shooters are beginning to understand airguns as never before. In the past, I always had to start my explanations with the cooling of the earth’s crust and then progress through the age of the dinosaurs because each firearms person I talked to thought of airguns as either toys or BB guns. This year, a lot of them were clued-in on what’s happening. They weren’t surprised by the accuracy we get, and they knew about big bores. A lot of them had some airgun experience and more than a few asked me the same kind of questions that I get from long-time readers of this blog.

That tells me the day of the airgun has finally dawned in the U.S. Instead of 25,000 to 50,000 active shooters (at best!), we will now see an influx from over 5 million active firearm shooters who are ready to augment their shooting experience with airguns. I’m already getting calls and emails from state departments of wildlife resources, asking about the issues of incorporating airguns into their hunting seasons.

It has been a long haul to get to this point, but we’re now seeing the start of the harvest of all the work that’s been done over the past 40 years — starting with Robert Beeman in the early 1970s. The job is now to manage this growth and provide useful information to the tens of thousands of new airgunners who are flooding in the doors.

Let me reflect on how the industry seems to be reacting to this trend. Some companies have been on board for many years and are poised to ride the new tidal wave of business as far as they can. Other companies are aware that airguns are very hot, but they’re foundering, trying to understand them. Let me say right now that it’s not as easy as you think!

The readers of this blog are among the most clued-in airgunners in the world. But they’re unique, and they do not represent the true market. The demographic of a new airgunner is a man (usually) in his late 20s to late 40s who is most likely a fan of AR-type rifles and Glock-type pistols. He wants repeaters, semiautos and he thinks that a five-shot group is the gold standard of any gun. Velocity impresses him, and he isn’t comfortable with the term kinetic energy.

Things like good triggers and good sights are not an issue with this customer until he experiences bad ones. His ARs have decent triggers off the rack, and he can choose from many drop-in triggers that are much better. When he encounters a spring-piston gun with a horrible trigger that cannot be easily modified, he’s surprised.

He does not use the artillery hold, and he equates all airguns to be alike in terms of performance. When he learns about precharged guns, he’s put off by the additional equipment he must buy. Spring-piston guns seem the best to him for their simple operation, and he doesn’t appreciate the fact that they’re also the most difficult airguns to shoot well.

That’s the customer who’s coming to airguns today, so that’s the person airgun manufacturers have to deal with. If you have wondered why many of the new airguns are what they are — this new-customer profile is the reason.

Okay, I’ve talked about those companies that get it and those that are struggling to understand. There’s one more type of company out there. I like to call them the “gloom and doom company” or the “zero sum company.” They’re firmly entrenched in the 1970s and cannot take advantage of this new windfall of business. They either fired their engineers years ago or they let them all retire, and now they couldn’t build a new airgun to save their lives. As far as they’re concerned, there are only 25,000 airgunners in the United States and it’s the NRA’s responsibility to identify and train them so these companies can sell them some guns.

They think of marketing in 1950′s terms, when a simple paint job and some sheet metal was enough to create a new product. Their “secret” business plan is to buy guns made by other manufacturers and have their name put on. If you’re a collector, better buy up the guns these guys sell because in 10 years their name will be a memory.

That’s enough of the big picture. Let’s see some more products.

More from Crosman
Many of you saw the list of new Crosman products Kevin posted last week, so the few that I show here are by no means all there is, but they’re the highlights. Crosman had about half the new airgun products at the entire SHOT Show.

New tan M4-177 and carry handle
The M4-177 multi-pump that I recently tested for you is going to be very popular this year. Crosman is also offering it as an M4-177 Tactical air rifle with a new carry handle that replaces the rear sight for improved sighting options. I think this gun will be in their lineup for many years to come.


The M4-177 now comes as this tactical model in tan with a carry handle.

I mentioned to Crosman’s Ed Schultz that this rifle looks like the A.I.R.-17 of the 1990s, but done better. He said he always wanted to update that design, and that is exactly what this is. So, what he said next came as no great surprise.

I shared my thoughts on a 2260 made as a multi-pump in .25 caliber, and Ed told me that was how the rifle was originally created (not in .25, however). The CO2 version was an afterthought that got put into production, while the multi-pump version languished in the Crosman morgue. I told him that I thought the time was ripe to bring it back as an upscale hunting rifle, and he seemed to agree. We can only hope.

Carbon fiber tank
As Crosman extends their capability into PCP guns, they know shooters are always looking for better options for their air supply. Besides the new butterfly hand pump I showed you last time, they’ll also be adding a long summer-sausage black carbon fiber tank with increased capacity over their current tanks. This is a 300-bar tank that has 342 cubic-inch capacity. It comes in a black nylon carrying case with sling for field transport.


More air for you! New Benjamin carbon fiber tank will help you take your PCPs further afield.

Benjamin Nitro Piston breakbarrel pistol
The Benjamin NP breakbarrel pistol certainly has people talking on the internet. This is the first commercial gas spring application in a pistol, I believe. The most distinctive feature is a cocking aid that can either be detached or left in place while shooting. That reminds us that this pistol is going to be hard to cock, but I’ll test one for you so we’ll all know just how hard.


New Benjamin Trail NP pistol is a breakbarrel with a gas spring. The cocking aid can be detached or left in place while shooting.

Crosman 1720T PCP pistol
Everybody was ready to jump down Crosman’s throat for creating the 1720T PCP pistol. They wondered with the .22-caliber Marauder pistol and the .177-caliber Silhouette PCP pistol already selling, why was this one needed? As Ed Schultz explained it to me — this one is for field target. It’s a .177 (naturally) that produces just under 12 foot-pounds through a shrouded Lother Walther barrel. It can be used for hunting, but field target was its primary purpose. They worried about the shot count with the Silhouette; but with this one, power was the criterion. Look for about 800 f.p.s. with a 7.9-grain Premier. And the trigger is the same as the Marauder, so excellent operation there.


The new Crosman 1720T PCP pistol is meant for field target competition. It will also work well for hunting.

Crosman MAR 177 PCP conversion
The Crosman MAR-177 PCP conversion is another new product that has a lot of people talking. This AR-15 upper converts your .223 semiauto into a .177 PCP repeating target rifle. Because it’s on an AR platform, almost everybody expects it to be semiautomatic — including those who should know better. This rifle is a bolt action that cocks and loads via a short pull on the charging handle.

This conversion is an Olympic-grade target rifle for a new official sport that Scott Pilkington and others have been promoting for several years. It will take the U.S. battle rifle back into the ranks of target shooting. However, the look of the gun has many shooters totally confused. I was even asked at the show if I thought Crosman should have come out with an “everyman’s” version of the gun first. That would be like asking whether Feinwerkbau missed the boat by not first making their 700 target rifle in a $300 version for casual plinkers.


The MAR-177 PCP conversion is an upper for your target-grade lower. Plan on investing about another $1,000 in a good lower if you hope to compete.

Crosman TT BB pistol
It’s all-metal and a good copy of the Tokarev pistol. The weight is good and the gun feels just right. This will be one to test as soon as possible.


Crosman’s TT Tokarev BB pistol is realistic and looks like fun.

Benjamin MAV 77 Underlever
The Benjamin MAV 77 underlever rifle is going to force Crosman to recognize spring-piston air rifles instead of just calling them all breakbarrels. This is the TX-200 copy from BAM that was once sold by Pyramyd Air. When the quality dropped off, it was discontinued. Hopefully, Crosman will watch the quality on this one.

They didn’t have a firm retail price yet, but hopefully it’ll be significantly under the TX. Otherwise, why buy it? I may test one for you, but I already know that BAM can make a great rifle when they want to. I think it all comes down to price.


Benjamin MAV-77 is an underlever spring-piston rifle that looks and, hopefully, performs like an Air Arms TX-200.

TR-77
The Crosman TR-77 is a conventional breakbarrel spring-piston rifle in an unconventional stock. It’s different enough that I want to test one for you. It appears to be a lower-powered rifle that probably sells at a bargain price because it’s branded under the Crosman banner rather than Benjamin. Mac photographed one in a sand-colored stock for you.


Crosman TR-77 breakbarrel in a sand-colored stock also comes in black.

There was a lot more at Crosman that I could have mentioned, but now let’s go over to the Leapers booth.

Leapers
I’ve watched Leapers grow from a relatively small company back in 1998 to a major player — blasting past older, entrenched companies as they grew. This year, they were playing a video about the company on a continuous loop in their booth. I was impressed to see their plant in Livonia, Michigan, where they build airsoft guns, tactical mounts, accessories and scopes right here in the U.S. The plant is filled with many CNC machining centers and testing facilities to keep close watch over their products during development.

American-made
Leapers owner David Ding told me he wants to get control over the production process so he can assure the quality of all of his products. In keeping with that goal, I was shown the new scope line for 2012 that now offers locking target knobs on all of the upscale models. Many of them feature etched glass reticles that are amazingly crisp and sharp.

Scopes
Mac was impressed by the reticle on the new 3-9x Bug Buster scope. He urged me to look through it; and when I did, I saw that the reticle is now fine and sharp — not the heavy black lines of the past.


David Ding shows me the new 3-9x Bug Buster scope (not out yet), with target knobs and a finer reticle.

But scopes were just the beginning at Leapers. Next, I was shown the whole line of tactical flashlights and lasers, including some mini lasers I will test on my M1911A1 for you. These are all made in the U.S. now and have more rugged internals, adjustments and optics than similar products from the Orient.

UTG 555 Long Range Light
One item I hope Pyramyd Air will consider stocking is a fantastic 500-lumen tactical light for law enforcement. It can be mounted on a rifle, handheld or even mounted on a bike! It comes with rechargeable lithium batteries and a smart charger…and believe me when I tell you it turns night into day!


The UTG Long Range light can go on your rifle, held in the hand or even mounted to your bike! The rechargeable lithium-ion battery pack will keep it shining at 500 lumens for 1.5 hours.

Fast Action Gun bag
Not all Leapers products are for airguns. They also make tactical and law enforcvement gear that rivals spec-built equipment but sells at a fraction the cost. As a result, many of their customers are ordering straight from the front lines of combat and from law enforcement agencies all over the country to get the products that their own supply lines cannot or will not furnish.

One of their latest developments is a Fast Action Gun bag that lets the wearer walk in public with a substantial firearm hidden from view. A quick pull of a strap, and the bag opens to reveal the weapon inside.


Leapers owner Tina Ding models their new Fast Action Gun bag. Here, it’s concealed; but she’s just pulled it over her shoulder from her back, where it looks like a tennis bag.


And in less than a second, the bag is open, giving instant access to the tactical shotgun or submachine gun inside.

11mm-dovetail-to-Picatinny adapter
Leapers has an entirely new range of quick-disconnect scope mounts coming this year, but there’s another innovation that I think you’ll find even more impressive. It’s an adapter that snaps into a Picatinny scope mount base, turning it into an 11mm dovetail. So, your conventional air rifle will now also accept Leapers Picatinny scope mounts with this adapter.

11mm-dovetail-to-Picatinny adapter is small and doesn’t raise the mount at all! This will be one to test!

Leapers is still the company to watch because the owners want to build a lasting corporation here in the U.S. They’re poised to move to the next level of quality in their optics, which gives me a lot of hope for the future — they’ve always been receptive to the needs of airgunners.

Whew! That’s a lot of products, and there are still many more to show. As I said in the beginning, there will be at least another report.

Crosman’s new M4-177 multi-pump air rifle: Part 4

by B.B. Pelletier

As you read this, I’m at the SHOT Show in Las Vegas. I’ll be there all week. In fact, today is Media Day, where the media gets to go to an outdoor shooting range in Boulder City and shoot the guns displayed by manufacturers, importers and distributors. Since I won’t be monitoring comments much of this week, I would appreciate it if our regular readers would help answer them. Edith will still monitor all the comments but may not have a chance to answer many more than she already does.

Part 1
Part 2
Part 3


Crosman’s new M4-177 is a smart-looking M4 battle rifle lookalike.

How many of you remember that I said I would come back to the Crosman M4-177 multi-pump air rifle and test it at longer range with a dot sight? Well, if everything went right, Mac and I are out at the range in Las Vegas at the SHOT Show Media Day today, but while we are seeing and shooting all the new guns you guys get one more look at this one.

As I mentioned in the last report, I mounted a dot sight on the rifle, to see how it performs at longer distance. I picked the 25-yard indoor range for this one. For the sight, I selected the BSA Optics red/green/blue dot sight that also has a laser and a tactical flashlight. It certainly looks right at home on this rifle, and the Weaver clamp fits the rifle’s Picatinny base. All I had to do was remove the open sights, front and rear, and put this one on the base.

The problem with optical sights on a multi-pump rifle is they get in the way of holding the gun during pumping. I had to hold the M4 at the buttstock extension tube because the sight sat right where I wanted to put my hand. Because of that, pumping was more difficult, and I wanted to pump the rifle 10 times per shot. So, I decided to shoot 5-shot groups until I found an accurate pellet, then shoot 10 shots with that one.

Accuracy testing
As I said, all testing was done at 25 yards off a rest. The rifle was pumped 10 times for every shot. Pay no attention to where the groups land, as I adjusted the sights several times to keep the pellets on the target.

I first tried the Crosman Premier Super Match pellet that had worked so well at 10 meters in Part 3. Once it was on target, I shot a group of 5 to see how they did. Unfortunately, at 25 yards, they didn’t do as well as I’d hoped. The group measures approximately 3.01 inches, but that’s not precise because the widest pellet didn’t land entirely on target. Suffice to say it was poor enough to disregard.


Crosman Super Match wadcutters didn’t give the performance I wanted.

I continued on, testing RWS Hobby pellets. They were better, with 5 going into 1.563 inches but not what I was looking for.

Next came 5 JSB Exact 8.4-grain domes. This was the first domed pellet I tried, and the group size shrank to 1.406 inches. The group was also very vertical, however, which leads me to an important point.


JSB Exact 8.4-grain domes did better.

By this point in the test, I noticed that this dot sight is not precise. The dot smears in all three colors at all three intensities. I’ve used quality dot sights that held the size of their dots very well, but with this one the dot smeared to the sides. I tried it both with my glasses and without, and the results were always the same. Maybe it’s me and not the sight, but I felt I wasn’t able to aim precisely enough with this sight.

The last pellet I tried was the Crosman Premier 7.9-grain dome. This one gave me 4 very tight shots, with No. 5 landing several inches away. Now, I had a quandary. Should I go with the JSBs or the Premier lites?


Four of five Premier lites made this tight group, but there’s that lone shot up to the left. What to do?

I decided to go with the Premiers, because of the tighter group of 4. So, I shot 10 more Premier lites at 25 yards.


And this is what I got. This “group” is pretty poor, and I don’t believe it represents what the M4 can do. It measures 3.358 inches between centers.

What now?
Well, I had been unhappy with the performance of the dot sight to this point. What if I replaced it with the original factory sights — a peep rear and a post front? Hey! Haven’t I read somewhere on the internet that those kind of sights can do a good job?

The dot sight came off and the factory sights went back on. It took 4 shots to sight in, and then I shot another 10-shot group. This time, the pumping was much easier because my hands could hold the rifle in the right places.


And that’s the same rifle, same pellet with factory peep sights. This group measures 1.546 inches between centers, with 8 of the 10 shots going into 0.923 inches. Clearly, the factory sights were better in this case.

Bottom line
Well, I’ve wrung out the M4-177 pretty thoroughly. It’s accurate and fun to shoot, and for my money you can use the sights that come with it. I know that the look of the gun begs for tactical accessories; but for me, accuracy is always the trump.

New BKL mount adjusts for barrel droop: Part 2

by B.B. Pelletier

Part 1

It’s been half a year since I did Part 1 of this report. I always meant to do today’s test, but other things seemed to crop up every time I was ready. I did make an excursion in another direction to test BSA’s 2×20 pistol scope using another mount on the Beeman P1 air pistol. Such is the tangled life of the airgun blogger!

New territory!
Today’s report takes me into fresh territory with my Slavia 631 breakbarrel rifle. I had earmarked it as a testbed rifle for testing the accuracy of lead-free pellets a long time ago, but the lack of a scope mount caused me to substitute the Whiscombe rifle at the last minute. You see, the Slavia air rifles all share a common problem when it comes to mounting scopes. They have dovetails that are among the very widest on the market. Most 11mm scope mounts will not expand wide enough to fit the 14mm dovetails (they are still called 11mm, which creates a world of confusion among buyers who try to scope their rifles) that are standard on all Slavia breakbarrels. Even for me — with a drawerful of specialized airgun mounts and prototypes — the Slavia remained a gun I could not scope until this new BKL mount hit the market.


Those dovetail grooves may be called 11mm, but they’re really 14mm apart. And that makes a huge difference. Almost no scope mounts will open that wide. Those three scalloped notches are for a specific type of scope stop that no longer exists in the U.S.

I’ve owned this 631 since back in the 1990s when I was still writing The Airgun Letter. I got it from Compasseco (now owned by Pyramyd Air) for a test and liked it so much I decided to keep it. Over the years, I’ve used it for other tests, such as testing the accuracy and penetration of round lead balls; but these tests were done with open sights. Today, I get to discover for the first time how the rifle shoots when a scope is mounted.

Just fit!
The BKL adjustable mount is a one-piece mount that just fits the length of the scope grooves on the 631. There isn’t a millimeter to spare on either end. As for the width, the fit is much easier, though I did have to spread the clamping rails to get it on the gun. For those who are unfamiliar with BKL mounts, they hold onto the airgun by clamping pressure, alone — there are no mechanical scope stops on any BKL mount. It’s often necessary to spread the mount base a little to get it onto the dovetails of the rifle. BKL has designed an ingenious way of doing this with the base screws applying reverse pressure to spread the base “jaws” just the right amount. It’s easy to do and takes only a minute or two extra. Once the mount is on the gun and the base screws are tightened, you have a scope mount that’s not going to move under recoil, no matter how severe.

Droop-compensating!
The second great thing about this new mount is that the rear scope ring elevates to compensate for barrel droop. Newer readers may wonder what droop is, so allow me to explain


The BKL is mounted on my Slavia 631 rifle. The mount is silver because it’s an unfinished preproduction model, not because it’s finished that way.

Barrel droop
Breakbarrel springers are notorious for having barrels that are angled downward from the sight plane. Because the manufacturers mount both the front and rear sight on the barrel, they remain in a fixed relationship that masks the droop or downward slant of the barrel. When you install a scope, it goes on the spring tube and the barrel droop becomes painfully obvious. You adjust the scope up as far as it will go to bring the strike of the round back up to the intersection of the crosshairs. Sometimes, you just barely get there, but other times you can’t even get that high before running out of adjustment. Either way, when a scope is adjusted all the way up as high as it will go, the internal springs relax and the point of aim starts moving all over the place. New shooters blame this on scope shift, but it’s really a different problem that’s completely correctable

You want to mount the scope in such a way that its vertical adjustment is about in the middle of the range or even closer to the low end. That’s where the droop-compensation scope mount, or “drooper” as it’s called, comes into play. With a droop-compensation scope mount you can slant the scope downward so it follows the line of the bore more closely.

And this new BKL is a drooper mount! But until I tried to sight in my Slavia 631, I had no way of knowing that it’s a breakbarrel with a droop problem. Once I confirmed that it is, I adjusted the rear of the BKL mount upward and got the scope dead-on at 25 yards! It took only one adjustment, and I had the scope back into the middle of its adjustment range again. Now, it was time to see how this rifle shot.

Twitchy
This is going to be a longer report, so I’m cutting to the chase right away. When I started shooting the 631 at 25 yards, I discovered that this rifle is twitchy. What does that mean? Well, if a breakbarrel is very powerful, it’s usually extremely difficult to hold for accuracy. It wants to spray its pellets all over the place — that’s what I call twitchy.

But lower-powered breakbarrel springers like this 631 aren’t usually twitchy. Usually, they lob all their shots to the same place. They’re also very tolerant of different types of pellets. But my Slavia 631 is none of those things. It’s twitchy. Allow me to show you what I mean. The first group I tried to shoot was with the Air Arms Falcon pellet.


This first target shot with Falcon pellets revealed a lot about the gun. Do you see that two pellets are close together in each of the three groups, but the point of impact moves? That’s due to very small changes in the hold. Four of the 10 pellets missed the target altogether!

The first group I attempted told me this rifle is twitchy. But sometimes that’s only with a couple pellets, so I pressed on.

Next, I tried shooting RWS Hobby pellets. They did better and were less twitchy but were not really that good.


Ten Hobbys went into a real group at 25 yards. It looks like only 6 shots landed because several went through the same holes. This is a better group, measuring 0.73 inches between centers, but it’s still not great.

I had to use every bit of technique, short of a scope level, to get that group. The differing points of impact were obviously the result of very subtle changes in the hold. This was obvious to me as I shot, because I was able to feel where the pellets wanted to go. But in spite of that, I did my best to shoot the tightest group I could.

I tried Crosman Premier lites next, but they were all over the place. Then, I tried the JSB Exact RS pellet that often proves best in rifles of this power level. This time, though, they were too hold-sensitive to do well.

Finally, I tried the BSA Wolverine pellet that’s also a medium weight JSB but is subtly different from the others of the same weight (8.44 grains). Like the Hobbys, I got a group of 10; but like the others, it’s interesting for being more of a cluster of several smaller groups.


Ten BSA Wolverine pellets gave this group, which measures 0.75 inches across. There’s a cluster of 6 in one hole, then 4 others below. The fourth shot lies between the two that are stacked vertically.

Bottom line
The BKL adjustable scope mount works as advertised. It’s easy to install and to adjust. And it has jaws that are wide enough for the widest 11mm air rifle dovetails. Just don’t try to use it on a Weaver base, because it isn’t that wide, nor is it configured for the proprietary shape of a Weaver dovetail. This mount is one elegant solution for a drooper.

The Slavia 631 is a twitchy breakbarrel that shoots at a mild level of power. If I hadn’t done this test, I never would have guessed that from the muzzle velocity, alone. That made me think of another report I can write — and probably should: What to do with a twitchy breakbarrel. It would be a collection of the tricks and techniques I would use when I encounter a twitchy breakbarrel. In my role as an airgun tester, I see a lot of them over time, so I’ve built up a bag of techniques I employ to deal with them when one comes along.

The 631 is also a great potential testbed for an adjustable muzzle weight to be used for tuning the harmonics of a spring gun. I’ll look into that.

New BKL mount adjusts for barrel droop: Part 1

by B.B. Pelletier

Announcement: Due to a mix-up, the most recent Big Shot of the Week winner wasn’t announced last Friday. Jeffrey Aaron Demers is this week’s winner of Pyramyd Air’s Big Shot of the Week on their facebook page. He’ll receive a $50 Pyramyd Air gift card.


Jeffrey Aaron Demers is this week’s Big Shot of the Week. Congratulations!


The optional BKL bubble level is mounted on the left side of the new BKL adjustable scope mount. This view shows the rear of the mount raised up to compensate for this rifle’s barrel droop.

Today, I’m going to show you the new BKL adjustable scope mount that will soon be available. I mentioned this mount in the Part 3 test of the new RWS Diana T06 trigger last week, which is where the first picture comes from. I’ll show all the nuances of the new mount and discuss how it works.


Looking up from the underside of the mount’s rear ring, we see the two legs that slide up and down for elevation compensation. Note that the ring has two cap screws.


The front ring is captured, so all it can do is rotate as the rear ring goes up or down. This prevents stress on the scope tube.

These first two detail shots show how the mount works. The rear ring moves up and down on forked legs that are open on the bottom. Two screws on the sides of the legs jam the ring tight in position when the right elevation is achieved.

The front ring is captive and is only able to rotate when the rear ring moves up and down. This prevents stress on the scope tube.


The black elevation pad is a Delrin screw that the scope tube rests on. It’s located just ahead of the rear ring.

Another key feature of this mount is the elevation pad, located back by the rear ring. The scope tube rests on this pad, which is used to make very small adjustments to the elevation of the scope. A small Allen wrench inserted into one of the holes in the periphery of the elevation pad lets you turn it up or down like a capstan, providing tight control over the elevation changes made. When the scope rests on the pad, it provides additional support against random movement once the scope ring screws are properly locked down.

Does it work?
I tested this mount on an RWS Diana 34P that I’ve retained for tests just like this. The rifle in question has 21 inches of droop at 20 yards (the only sight-in distance I use, since the pellet strikes the same place as the 30-yard point of intersection when it crosses the line of sight for the second time), making it a severe case of barrel droop. When I developed the UTG droop-compensated scope bases for RWS Diana spring rifles, this rifle was the worst test case, against which the base for the RWS Diana 34 base was designed. If the BKL mount can fix the droop on this rifle, it can fix anything you’re ever likely to encounter.

And fix it, it did! With the mount adjusted about as far up as it could go and still be locked in position, the scope was sighted-in dead-on at 25 yards, which is in the center of the 20-30 yard sight-in distance. And, the scope was in the center of its click-adjustment range. This was an acid test that the BKL mount passed with flying colors.

Another factor I was watching was the BKL mount’s ability to hold its position on a heavy-recoilling spring rifle. When the mount was given to me for testing, it had already withstood the jackhammer recoil of a Hatsan 125, which is even harder on scopes and mounts than the UK-produced Webley Patriot. Indeed, the scope that had been in that test was destroyed, but this mount held fast.

On the RWS Diana 34P, the mount also held fast under two different scopes, the intial one that finally gave up the ghost during my test and the replacement scope. Hundreds of test shots were fired without a hint of scope mount movement or scope movement in the rings. Despite there being just two screws per scope cap, both scopes remained in place throughout the test.

Additional features
This mount also offers 11mm dovetails on both sides of its base. If you want to attach a laser, tactical flashlight or rangefinder, your base for them is built right into the scope mount. Because BKL recesses the Allen screw heads into the base, both sides of the scope base have this feature and can be used in this way.


Here you can see one of the two 11mm dovetails in the base of the BKL mount. There’s another one on the other side, and recessed screw heads make it accessible for this purpose, as well.

The final feature this scope mount offers is the facility to mount a bubble level to the base of the new mount. It attaches to one of the three spreader holes in the base, though I think you’ll choose the hole that’s farthest from your eye so you can focus on the bubble. I used this level in the test of the RWS Diana 34P, and it worked well.


An optional BKL scope level can be screwed into one of the three spreader holes (the center hole in each group of three) on the base of the new BKL scope mount.

Mounting
If you need to spread the base of the mount to get it on a gun, the ring screws also have to be loosened. Then, the base can be spread evenly by the three spreader screws.

The best part
I’ve saved the best for last. When this mount was shown to me at the BKL factory, I was told that the motivation for making it the way they did wasn’t an air rifle, but a popular air pistol! The cuts on the mount are specific to clear the front sight on the Beeman P1/HW 45 spring air pistol.


The profile of the new BKL adjustable rings was made to accommodate (to clear) the front sight of the Beeman P1 pistol.


The Beeman P1 was the inspiration for the new BKL adjustable scope mount.

Because this is the first mount I’ve seen that was made for the P1, I think I’ll order a BSA pistol scope and give it a test. Whatever scope you select has to fit into the two rings that measure 4.0625 inches apart on the outside. Because this is a one-piece scope mount, those rings cannot be moved, so pick your scopes accordingly.

BSA Stealth Tactical Dot Sight with laser and tactical flashlight: Part 1

by B.B. Pelletier


The BSA Stealth Tactical Dot Sight is a sexy-looking unit!

And now for something completely different. It’s not an airgun at all, but an optical sight system with a lot going for it! The BSA Stealth Tactical Red/Green/Blue Dot Sight with tactical flashlight and laser is a unique optical sight that gives more sighting options with greater innovation than I have ever seen. I will try to do it justice in this report.

It’s not cheap
The price of $136 is bound to put off a lot of potential buyers, but perhaps if I tell the whole story some will look a second time. And, a second look is warranted, for this is no bargain-bin dot sight. It’s a well-engineered system, containing a dot sight with three different-colored dots, a laser and a tactical flashlight in one comprehensive package. And, speaking of the package, let’s begin there, because the box this thing comes in is enough to warm the hearts of most shooters.

Ammo can
Inside the heavy card lithographed box is a metal container styled like a military ammo can. If you’ve ever served in a military organization, this container will seem familiar, because the military often packages expensive field equipment in rugged containers like this. The can opens like any ammo box ever produced, revealing the sight and its supporting parts inside. I know I would have lots of uses for that container after the sight was mounted on a gun.


The sight comes packed in a padded metal ammo can.

The sight is a unitized cluster that contains a three-color dot sight, a tactical flashlight and a red laser. The flashlight and laser run on button batteries, so don’t use them indiscriminately. They are there to be used, but the batteries don’t have the life of the much larger CR123A batteries found in standalone units.

Weaver base required
The unit includes an integral Weaver mount with locking crossbars to prevent movement under recoil. Factor that into your purchase plans. Because I’m still recovering from a hernia, I plan to test the sight on an AirForce Talon SS that has an 11mm to Weaver adapter, but the sight would also work perfectly on one of the new Benjamin Trail-series rifles that has a Weaver base built in. If I could cock a springer, I would have tested it on a benjamin Trail rifle that has the Weaver base built-in.

What is a dot sight?
A dot sight is like a scope, but with a few important differences. First, most dot sights do not magnify the target at all. Because they don’t, they have a wide field of view that’s well-suited to the quick acquisition of a target. Hunters love them for that.

Dot sights are similar to scopes, but instead of a vertical and horizontal crosshair they use a single dot located in the center of the optical package. The dot represents the intersection of a vertical and horizontal reticle. The motion of the erector tube moves the dot around so the sight can be zeroed, the same as it does for a scope. The dot is visible only inside the sight. No one other than the shooter can see it. It doesn’t project outside the unit like a laser light beam. A laser is like a flashlight with a coherent light; a dot sight is like a scope but with a dot instead of a crosshair.

Multiple colors
Dots can be any color, and by changing the color they may be more visible in certain light situations. This device has a choice of three different colors — red, green and blue. A single rotary knob lets you select the color you want and vary the intensity. The intensity is important because, as the dot gets brighter, it appears to grow in size. The larger it is, the less precise when aiming. With the BSA sight, each color has three levels of intensity, and there’s an “off” position between each color. As the knob is turned, you get a light in three levels, followed by an off, then a different color light followed by another “off” and so on. The knob can be rotated completely around without stopping.

Lens covers
The BSA sight has a unique set of lens covers, front and rear. They’re built right into the unit, so there’s nothing to lose or carry separately. Simply twist the outer ring on both ends of the sight, and an iris opens and closes to protect the lens. I like the convenience of this kind of lens cover, and I wish scopes had it, too.


The integral iris lens covers are always with the sight and never get in the way. I really like them!

The laser
Why put a laser on a gun? Well, it can be used as a close-range sight of sorts. You can align where the laser shines to where the pellet strikes and have a quick means of sighting. Simply put the dot on a target and pull the trigger. There’s been so much use of this in movies over the past 20 years that I don’t need to elaborate further.

To make this possible, you have to adjust the laser to the point of impact, and that can be a difficult thing to do. I’ll test this aspect of the sight in my report. I’ll attempt to adjust the laser to be on target at 10 yards, which is a perfect distance for it. You use a laser in conjunction with an optical sight by adjusting the laser for ranges at which the sight is not adjusted. So, I’ll zero the dot for a 20-yard first point of impact and the laser for a 10-yard had zero. In other words, the pellet will not be zeroed at any range other than 10 yards. That way, I’ll have the gun zeroed from about 8 yards out to 40 yards, because the amount the pellet will be off-target at the interim distances (the non-zeroed distances of 10 yards, 20 yards and perhaps 34 yards) will be a negligible pellet’s diameter away.

The tactical flashlight
This feature seems less valuable to me than the laser. I understand it’s there for the coolness factor, and that in a combat or tactical law enforcement situation a flashlight may be just the thing you want. For a hunter, it’s less useful. Yes, hunters need flashlights, but they don’t need flashlights that operate on button batteries and have a useful life of an hour or less. I’ll test this to find out what the life really is, because there’s no literature that comes with the sight. You need a flashlight that works with a beefy CR123A battery, so you have sufficient illumination time. Still, it’s there and I’ll test it.

Do we need a unit like this? Well, that’s more up to the individual shooter than it is to writers like me. To the man who wants a good dot sight for hunting, if this is a good one then, yes, he needs it. To the man who calculates the pennies he spends on pellets, I’d say this sight is a bit too pricey. Other dot sights might satisfy his itch just as well. I’ll be testing it for functionality, not for its “worth,” which only you can define.

Remote cables
You need remote switches to operate a sight like this. There are switches on the unit that can turn it on and off, but for the laser and flashlight there are also coiled cables that allow you to position a pressure-sensitive thumb switch to a spot on the gun stock where it’s more convenient to operate. It’s your choice to use the cables or the switches that come on the unit.


You can install these remote cables anywhere you like on your gun. They make operation of the laser and flashlight faster and easier.

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