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Diana 72 youth target rifle: Part 4

Posted on May 20, 2014 by B.B. Pelletier ↓ 42 Comments

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

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.

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

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.

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.

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.

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.

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.

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.

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.

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

Posted on May 12, 2014 by B.B. Pelletier ↓ 49 Comments

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

Part 1
Part 2

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.

Diana 72 youth target rifle: Part 2

Posted on May 7, 2014 by B.B. Pelletier ↓ 47 Comments

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

Part 1

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

This report addresses:

• Cocking effort
• Velocity
• Velocity and consistency comparisons, depending on how the pellet is loaded
• Firing behavior and cocking behavior after oiling
• Trigger-pull
• Impressions so far

Some topics resonate with more readers than others, and this is one of them. I heard from many Diana model 70 and 72 owners when Part 1 was published, and I hope to hear from more with this installment. New blog reader Harryholic from the UK had just received a new-old-stock model 72 when Part 1 was published. Searching for information on his new rifle, he stumbled across our blog.

His new rifle is one that hadn’t ever been fired, apparently. It was still in the original Diana packaging based the pictures he published online. Unfortunately, that means it has the old Diana piston seals that dry rot with age. His new gun heeded a resealing before he could even fire the first shot. While he’s arranging to have that done, I’ll test our 72 that was resealed last year. It should have pretty close to new-gun performance.

Cocking effort
This rifle is a converted air pistol — we learned that in the last report. I recall my Diana model 10 target pistol needing about 35 lbs. of force to cock. The old Air Rifle Headquarters reported the velocity of a broken-in model 10 as close to 500 f,.p.s. with lighter lead pellets. I will presume they mean something like RWS Hobbys.

A model 10 has the same poweplant as the model 6 pistol that on which this rifle is based, so I’ll use the cocking effort and velocity for the model 6, as well. I believe a model 6 in good shape should launch a Hobby pellet around 475 f.p.s. That would also be my guess for the model 72 rifle. We shall see.

As for the cocking effort, we learned last time that the 72 has a longer barrel shroud (13-3/4 inches, compared to the 7-inch barrel on the pistol) that extends the lever used to cock the rifle, so I expected the cocking effort to drop off to about 20 lbs. When I measured it on my bathroom scale, it was more like 16 lbs., though some stiffness in the cocking linkage did make the needle spike up to 20 at times. I think this will smooth out as the rifle wears in.

Velocity
I think I learn as much when I chronograph an airgun as I do when shooting it for accuracy. The things I learn aren’t always what I expect, though, and today’s test demonstrates that.

RWS Hobby
I started the test shooting the 7-grain RWS Hobby wadcutter pellet. I like using Hobbys because not only are they very light and give high velocity numbers, but they’re also well-made and often quite accurate.

On the first string, I noticed something remarkable. I’m going to print the string here, so you can see what I saw:

Shot Vel
1 438
2 406
3 391
4 387
5 377
6 366
7 362
8 349

After shot 8, I stopped to evaluate the gun’s performance. Each shot was going slower than the last. The 72 is a spring-piston rifle, and it honked a bit when cocked. So, I deduced the piston seal was dry. I oiled the seal with a few drops of RWS Chamber Lube and then returned to the string.

9 414
10 399

The average for this string is 389 f.p.s., but a lot of the reason for that is because of the velocity loss. This rifle was just rebuilt. It came back to my friend Mac just a few weeks before he passed away, so he never shot it. Therefore, I’m the first person to shoot it since it was rebuilt. I’m breaking it in.

After the first string, I oiled the chamber, again, with about twice as much oil as I used before. This time, I shot 10 Hobbys at an average 427 f.p.s. The spread was from 399 to 449, so 50 f.p.s. Obviously, the rifle needed to be oiled. And notice that my original estimate of the expected velocity was too high.

Next, I tried deep-seating the pellets with the Air Venturi Pellet Pen and Pellet Seater. This gave an average velocity of 424 f.p.s. The spread went from 401 to 461, so a total of 60 f.p.s. From this, I have to deduce that deep-seating Hobby pellets does not accomplish anything.

H&N Finale Match Pistol
Next, I tested the rifle with H&N Finale Match Pistol pellets. Seated deep, these averaged 393 f.p.s. The spread went from 376 to 405, so 29 f.p.s. That’s a lot tighter than the Hobbys.

I tried these same pellets seated flush. This time they averaged 456 f.p.s. The spread went from 450 to 462, so just 12 f.p.s. They’re both faster and more consistent when seated flush with the breech (not pushed into the barrel by a pellet seater).

RWS R10 Match Pistol
The last pellet I tried was the RWS R10 Match Pistol pellets. These weigh 7 grains, just like the Hobbys. Seated deep, they averaged 395 f.p.s., with a spread from 365 to 414. A max spread of 49 f.p.s. Seated flush, they averaged 429 f.p.s., and the spread went from 404 to 446. That’s a total of 42 f.p.s. Again, the pellet went faster and the spread was tighter when it was seated flush with the breech.

Note the velocities
A couple days ago, someone asked me if I ever experienced a heavier pellet going faster and with more consistency than a lighter pellet in the same gun. This test demonstrates that phenomenon. The 7-grain Hobbys went an average 424-427 f.p.s., while the 7.56-grain H&N Finale Match Pistol pellets averaged 393-456 f.p.s. When seated flush, these were the fastest pellets in this test, as well as the heaviest pellets.

Firing behavior and cocking effort revisited
I told you the rifle squeaked when cocked. At the end of the test, it still squeaked — but less than before. Also, the cocking effort seems to have smoothed out a bit. I measured it, again, and this time the needle deflected from 16 lbs. up to between 18 and 19 lbs., but it was so close I can’t tell if there has been a real reduction or not.

The rifle fires dead-calm regardless of which pellet is loaded or how it’s loaded. But flush seating seems to be best, so that’s what I’ll do.

Trigger-pull
The 72 trigger is 2-stage, but not as crisp as I remember the trigger of my model 10 pistol. Stage 1 stops at stage 2, but then stage 2 has movement that can be felt. The net feeling is a trigger that has no second stage, though I know this one does and can feel it if I really try. The trigger breaks at 33 oz. consistently.

There’s a good reason for this trigger to be mushy. The linkage is very long because this is a pistol in a rifle stock. I looked for trigger adjustment instructions on the internet and couldn’t find any, so in the next report I’ll show you the trigger and describe how to adjust it in detail.

Impressions so far
I like the little rifle — not quite as much as I thought I would, but perhaps I’m objecting to the stiffness of the rebuild that just needs to be broken in. Once I get the trigger where I want it — if that’s possible, I may warm to it some more.

Diana 72 youth target rifle: Part 1

Posted on April 29, 2014 by B.B. Pelletier ↓ 67 Comments

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

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

This report addresses:

• History of the rifle
• The Giss contra-recoil system
• General description and dimensions of the Diana model 72

Today, we’ll begin looking at an air rifle that I’ve been waiting 3 years to share with you. In 2011 my friend Mac and I were looking at his vintage air rifles to see which ones would be of interest. We actually did a report on his Diana 60 target rifle that was labeled a Hy Score model 810. The rifle needed to be rebuilt, so the velocity was low, but the accuracy was right on. The report was so successful that he decided to test his Diana model 72 youth target rifle next.

Alas, the seals were gone on that rifle, and it no longer worked. So, Mac packed it together with some other target rifles and sent them all to be resealed. What he didn’t count on was the repairs taking two years to complete! The repaired guns arrived back at his home when I was there sitting with him last April, three weeks before he passed away.

This report is for Mac. It completes the plan he and I formulated in the days before illness overtook him. He was proud of this little rifle, and he wanted to share its quirks with all of you. He purchased the rifle at the Damascus airgun show that used to run at the Damascus Izaak Walton League in Maryland. He paid a lot for it because it was complete in the box, and because the model 72 has always had a cachet that other target guns lacked.

I purchased this rifle from Mac’s son this year when I was back to visit after the Findlay airgun show. I’ve wanted to share it with you for a very long time.

Air pistol
The Diana models 70 and 72 youth target rifles are breakbarrel spring rifles based on Diana’s breakbarrel models 5 and 6 target pistols. The model 5 pistol/model 70 rifle are the recoiling versions and the models 6/72 are the recoilless versions of the same gun. All Diana did to make these rifles was install a longer barrel shroud over the pistol barrel and drop the pistol action into a shoulder stock. So, the cocking effort and velocity of both the models 70 and 72 are those of air pistols — not air rifles, which works perfectly for 10-meter target shooting by older youngsters.

The model 70 was made from 1979 to 1993, and the model 72 lasted one additional year — to 1994. The model 72 cost $205 at the end of the production cycle, while the model 70 sold for $130 — no doubt accounting for its more popular reception. Both rifles appear identical from the outside, with the exception of the gear trunnions on the model 72 that hold both pistons — the real one that compresses the air, and the fake one that counter-balances the recoil.

The rifles originally came with a set of front globe inserts and 3 stock spacers to adjust the length of pull. Mac’s rifle had all of these accessories when he bought it; but when I purchased it from his son, we were unable to locate anything other than the rifle and its box. I’ll make some stock spacers at some point (they are easy enough to make from wood), but, for now, I’ll shoot the rifle using its short 11-inch pull. Because this is a target rifle meant to be shot offhand, the pull length isn’t that important.

The buttpad screws are very long to accommodate all 3 spacers when needed. So, nothing but the spacers are required to change the length of pull by about 1.5 inches. Just back out the 2 screws and slide in as many spacers as you need — up to 3.

The barrel appears to measure 13-3/4 inches overall from the outside, but there’s about a 6-1/2-inch freebore (hollow tube without rifling) up front. The rifled barrel is actually the original pistol barrel with a length of 7.25 inches, more or less (the actual barrel length of a model 6 pistol is nominally 7 inches).

Diana 72 target rifle muzzle

The “muzzle” is just the end of a hollow barrel shroud that covers the 7-inch pistol barrel. It gives the sights more separation.

Giss contra-recoil system
I’ve written about this before. In the Giss system, there are 2 pistons. When the gun fires, the forward one compresses the air that powers the pellet. The rear piston is simply a dead weight that balances the impulse of the forward piston, canceling the recoil. This is a pistol action, so the recoil is slight to begin with; but when this rifle fires, all you feel is a faint impulse in your hand that lets you know something happened.

Diana model 72 target rifle Giss system

The momentum of the forward piston is canceled by the rear piston in the Giss system.

Diana 72 Giss trunions
The round cap at the upper right covers the trunion, or anchor point of the 2 pistons. It’s actually where the upper and lower gears engage and that controls the piston rods.

General description
The rifle is 31-3/4 inches long — depending on which spot on the curved rubber buttpad you anchor the tape measure. It weighs 4 lbs, 8.5 oz. without any buttplate spacers installed. The metal is blued steel, and the stock is beech wood finished to an even medium brown.

Diana 72 Benjamin 392

By itself, the 72 appears normal-sized. When placed next to a Benjamin 392, you can see how small it is.

The trigger is two stages and adjustable. I’ll tell you more about that in the next report.

The sights are a globe in front with replaceable inserts and a small target peep at the rear. As I said, this rifle had no extra inserts when I got it, but Mac had installed an aperture element in the front, which is what I would have wanted. I’ll say more about the sights during the accuracy test.

Diana model 72 target air rifle

Diana used a rear sight that they put on many of their less formal target rifles. It suits the model 72 well — both in size and precision.

Very much in demand
As you might guess, a little gem like this is always in demand. While the rifles were still selling new, airgunners criticized the additional cost of the recoilless model; but the instant they went off the market in the middle 1990s, the price doubled. It has come back down somewhat since then, but a Diana 72 is a gun you lay on your table just once and take the first offer of the full cash price. It isn’t that the rifle appreciates in value so much as it can always be sold in a very short time.

There are many model 72s in this country, but they don’t change hands that often. This is the sort of airgun that you hold onto. This one will probably stay with me a long time.