Exploring the limits of the DIANA 54 action in 0.20" cal.

[HectorMedina]

At the request of John (FWBSport) in the "New to me DIANA 48" thread, I will post here what a 0.20" cal spring piston in the 22-24 ft-lbs region can do.
It is NOT a "How To" thread because, for all intents and purposes, the basic rifle we will be talking about here is made of "unobtainium". There are 30 rifles like this in the world, and given the current state of affairs, it is not foreseeable that there will be more.

So, let's start with the basic history/description of the gun itself for those that are not too familiar with these "unicorns" of the airgun world.

A bit over 10 years ago, I convinced my friends at the "Alte DIANA" to make a prototype gun for research: It was a 54 action with a specially made L-W barrel made to my specs. The specs for the barrel had been used very successfully in over a 100 barrels made for PCP's. The rifling geometry was specifically designed to maximize the performance of the  0.20" cal. JSB 13.7 grs. pellet (and that is another story all in itself, LOL)!

The prototype was under testing for two whole years, after which the possibility was opened to make a special run of the 430 Stutzen (30 of those were made in 0.20" cal, 5 in 0.177" cal). Those guns were very accurate, and so, the decision was taken to make a special run of the 34, but with a Premium stock and shorter barrel, it became the 34k Premium (k for "kurtz", 30 guns were made under that configuration) and they also proved to be very accurate.
Lastly, a run of 30 D54's was launched, but there were some problems at the factory, and even some sabotage attempts by some of the old line workers. SO, the whole project started souring and people that had committed to purchases backed out.
After the usual problems derived from conflict, I decided to simply shut the project down, take delivery of the guns on my own funds and see who really wanted their guns. Some people offered to "take them off my back" for pennies on the dollar, probably thinking that I would go under if I didn't accept. I didn't, and the rest is history.

A FEW guns remained, and for some discriminating shooters, I have offered those guns. They are not inexpensive, but they are few and far between. They are not collection nor museum pieces. They are shooters. Designed built and customized to each shooter according to THEIR wishes. From a smooth shooting 16 ft-lbs to a brick-breaking 24 ft-lbs. From peep sights, to long range scopes, passing through amazingly SIMPLE scopes that do the job to almost perfection.

I've learned a LOT along the trip with my customers. It hasn't always been an easy ride. Some have been bumpy.

In a way it was almost expected. It would be like offering a race-car performance sedan to the general public, and then expecting every average driver to drive it carefully and proficiently. Light pistons (which are essential for smooth cycles) got crunched; seals that would perform remarkably well on a diet of 50 shots a day, went under when the shot count raised above 100; the extremely short cycle with the attending high temperatures and pressures needed to achieve the high performance had already required the re-design of the breech seal with the issue of the 430 Stutzen. The piston face was re-designed three times until I realized that we ARE dealing with a small, and very quick, "deflagration"; therefore the principles of "shaped charges" apply.  SO . .  it has been a long  learning curve.

Few shooters can take 100 shots a day for a month from a Hatsan 135, the recoil is simply too much at that rate and your head will start telling you it is no fun, and in that sense the user "self-regulates". But the 54 is different in that sense. It allows you to do that and more, if you want. Except that even with the best materials available, every engine has its limits.

And so, we now know that 22-23 ft-lbs is the limit of the platform. 24ft-lbs start pushing it and things start bending/breaking, holes get enlarged pins get peened, etc.

What we will need to do is to re-build John's rifle with this limit in mind. We will test different springs and different pistons to make sure he gets what he wants: a smooth shooting gun capable of the delivering the 15.9 grs. 0.20" cal JSB with accuracy and precision.

At present, we already have the gun back in working order. It needs some shooting to "run-in" the piston seal, once that is done, we will proceed with the search for the ideal spring for this "heavy-for-caliber" pellet, and when we find it, we will test if it is a stable platform.
Launching a 16 grainer at 780 +/- 4 fps for a 20 shot string is not a bad start.

Taking John's scope (because he likes it a lot and is remarkably simple and clear) reviewed here:

https://www.ctcustomairguns.com/hectors-airgun-blog/the-traditions-hunter-series-scopes

AND, under the ballistic parameters outlined above, if he sets the scope at 9.5X, and a 35 yards "Zero" to the TOP hashmark, then the main crosshairs meet at 45, the first hashmark under meets the trajectory at around 50 yards, the second at 57 yards, and the third at 62 yards.

That is quite a breath of "certainty" for an airgun.

Can it improve with  a bit more energy? for sure it can, it's a question of finding the right combination of piston weight, seal, spring and guide to accomplish the right "rail speed" that will result in  accuracy at optimum power.

This will be an ongoing thread so, please bear in mind that every minute I spend answering questions are minutes I cannot be tinkering or testing.

I will post here as I have further news of the process.

Keep well and shoot straight!





HM

[Jshooter71]

Interested; following!

[dtdtdtdt]

Chiming in! 

I have one of the 30 rifles in 20 caliber that Hector is talking about.  I have put lots of stuff on GTA site about it.  Most recently, I "tuned" the harmonic tuner for best accuracy (for me at least!). See below.
 
https://www.gatewaytoairguns.org/GTA/index.php?topic=178561.0

I am the hammer-hands who destroyed one of Hector's beautiful pistons.  The rifle slipped off my knee as I was cocking it and bounced off the bench and that was the end of that piston.  He detuned it a bit as I don't really need the ultimate in power and it has been just fine since.

My second 54 is more-or-less OEM in .177 caliber and has served admirably for about 10years in my hands to the chagrin of about 400 chipmunks.

I'm hoping for one of the .22 D54Pro rifles that Hector is bringing over.  Whenever they get here.

A typical shooting day for me is about 100 shots. 

[fwbsport]

Well today the "stand in" .20 HW98 took the prize in the varminter realm for 3 more! 

This is the best .20 I've ever had with the HW80 .20 a close second.  I do notice the .20 hits harder and kills faster (immobilizes) those pesky varmints! 

I could admit a few misses were done with the PCP Daystate Huntsman--but I blame myself for not yet "mastering" the touch of shooting a light PCP like the short Huntsman!

However, I also notice my mind is more at ease using a springer instead of a PCP to kill instead of to shoot paper or reactive targets.  Yet, even though the D54 recoilless .20 feels like shooting a PCP the spring instead of the compressed air seems to make it "smoother" and "easier" for me to rely on.  Even if it is just "mental" the memory of the springer in me is decades older than the PCP memories!

I am MISSING the D54 .20 rather intensely, but I am surprised at how far Hector has already come with the rifle once in his hands. 

This rifle is number 27 LW .20 out of 30.  I didn't pick the number it just came to me as #27.  I can already say 27 has a rich history already!  I remember ALL of it and it makes the rifle more special to me!  When it is in operation it breaks bricks at 25 yards and makes one holers exactly where the cross hairs are on the 3.5-10X Traditions Black Powder Scope with the French Resistance or OAS type double hash crosses above and below the actual crosshair.

Vision in this $70 scope is the same as I see in my Swarovski Z3--Bright and Clear!

 

[fwbsport]

I got news from Hector!

"Hello John!

I am close to finishing the powerplant. Discovered a few things that needed correcting.

It's doing 21.7 ft-lbs with the heavy pellets of your choice.

I still need to do some accuracy testing and some shooting, but I hope to be able to close the whole project next week.

I tried three different springs and two styles of tune, so out of 6 possible combinations, this is the best I found.

Cycle is steady and uniform. Std Dev of MV is 4 fps. Average is 783 fps

So, that gives us 21.7 ft-lbs energy.

Will keep you posted!





HM"

So........BUMP for Hector so he won't have to go to the second page to post his report!

I was MISSING the .20 D54 believe it or not and it was HARD to keep from bugging him about it!  I hope I passed the patience test (Hector!)!

 

[HectorMedina]

Thanks to John for being so patient. Yes, I know it's hard, specially at this time of the year.

Anyway, after some further testing, and some minor tweaks, I have come to the conclusion that 22 ft-lbs is about the max the platform can REALLY stand in an intensive use mode.

In the end, I added a heavy TopHat  (the  weight of 24 pellets) and the cycle settled down, everything now sounds right when the shot goes off and cocking effort is not unduly high. It's about 5% higher than it was.

Anyway, test targets are interesting, at 25 yards the gun is capable of putting 10 shots in a single ragged hole. At 45 yards and fighting against vanishing light and increasing wind as preparation to tomorrow's snowstorm, I still managed a reasonable  group.

The test target may not look too impressive:



Until you add a US "dime" for scale:


As you can see the small darker circles are about ˝ the size of the dime; the larger light grey circles are less than 2" across. The whole 25 yards group easily falls under the dime, and of the 45 yards group, 6/10 shots are completely inside the dime.

Shooting from an FT position with diminishing light and picking up wind.

It has been an interesting development, I have found a few additional items we need to take care of when we come up with what eventually will be the "EMS" version of the side-cockers.

In particular the 54 has a bright future ahead.

Now, it will be up to John if he wants to take delivery of the gun as is, or if he wants me to do some further "refining" of the gun.

Keep well and shoot straight!





HM

[Jshooter71]

Nice work, Hector! Add a 20+ FPE .20 to my wishlist? Someday~

[fwbsport]

No! Send it home!
And the bill!
Very thankfully yours (I know what to do with what you have already and you refining things can go on longer than my Christmas spirit can!)! 

[HectorMedina]

No! Send it home!
And the bill!
Very thankfully yours (I know what to do with what you have already and you refining things can go on longer than my Christmas spirit can!)!

It's a snow day here, so I will pack it and send it your way.

Thanks for your patience!






HM

[fwbsport]

No! Send it home!
And the bill!
Very thankfully yours (I know what to do with what you have already and you refining things can go on longer than my Christmas spirit can!)!

It's a snow day here, so I will pack it and send it your way.

Thanks for your patience!






HM

No I thought you were mad at me for electing you as the Man of the Year after I found out Gals like Lizzie and Joannie (NCG) weren't even on the list.

Anyway, be sure all locking nuts and washers and china caps and anything holding the pins to lever against a system resisting as pressure mounts are LOCKED with permanent studs or welds so I don't lose a tiny scrap piece in the middle of winter to find it in the Spring (I.e. the little washers there under the cocking lever need to be really PUT in place and NOT allowed to be RUBBED off by my finger that got bloodied on them!)

Anyway, I see the crosswind in your 45 targets.  What will happen is it will be shooting about 8 clicks to the right (for you) and I will adjust 8 clicks to the left!.  It ALWAYS happens!  I shoot offhand!  Can you use Physics to explain why this ALWAYS happens when I get my D54 from you!

 

[HectorMedina]

No! Send it home!
And the bill!
Very thankfully yours (I know what to do with what you have already and you refining things can go on longer than my Christmas spirit can!)!

It's a snow day here, so I will pack it and send it your way.

Thanks for your patience!






HM

No I thought you were mad at me for electing you as the Man of the Year after I found out Gals like Lizzie and Joannie (NCG) weren't even on the list.

Anyway, be sure all locking nuts and washers and china caps and anything holding the pins to lever against a system resisting as pressure mounts are LOCKED with permanent studs or welds so I don't lose a tiny scrap piece in the middle of winter to find it in the Spring (I.e. the little washers there under the cocking lever need to be really PUT in place and NOT allowed to be RUBBED off by my finger that got bloodied on them!)

Anyway, I see the crosswind in your 45 targets.  What will happen is it will be shooting about 8 clicks to the right (for you) and I will adjust 8 clicks to the left!.  It ALWAYS happens!  I shoot offhand!  Can you use Physics to explain why this ALWAYS happens when I get my D54 from you!

 

Actually John,

NOTHING fell from the lever.

There is a small E Clip that affixes the cocking linkage to the lever, and that was in place.

You ADDED an outside retaining ring (ORR), when I sent you the rings, thinking they had fallen from the trigger pins, but, again, the trigger pins had all the 6 ORR's.

So, it's a MYSTERY.

The UNDERSIDE of the cocking lever linkage should look like this:





Everything was as it should have been. . . . Ti-riri-ri, ti-riri-ri (Twilight Zone music)

Now, about the scope's POA:

I disassembled the gun, repaired it, tested 6 different setups and recorded a BUNCH of shots.

When doing the final assembly, I mounted the scope, walked out to the 25 yards range, aimed dead center, and that is the bullseye that is labelled "Warming up and sighting in" As you see, it is shooting a little to the right and low for ME.
I did NOT move the turrets. Just used the scope's reticle aimpoints to shoot the other two groups.
The fact that it is shooting to the SAME POA at 25 and at 45 yards was a huge surprise for me. I would have expected a little more drop from the trajectory. But somehow, this rifle wants to shoot as a faster rifle, even with the heavy pellets.

So, I HOPE you will not need to adjust the turrets, as I did not move them at all. It was a pleasant surprise that after all that massaging, it was still "Spot On".

Rifle was picked up this morning, so hopefully, it will register soon in UPS tracking system. Key is going separate way.

Keep me posted!





HM

[fwbsport]

I see something is coming in the delivery on Tuesday I guess it's the machine!

I had ordered 5 tins (500 each) of the 15.89 gr .20s some time ago and the only other rifle around here I'd use them in NOW is the HW80 and the D54.  I've saved the 13 grainers (and some odd decimal that I can't remember half the time!) for the HW98 exclusively.

I am looking forward to doing the "unnatural act" of cocking a side-lever!  I've MISSED the thing Hector!

Fondly,
John

[fwbsport]

No! Send it home!
And the bill!
Very thankfully yours (I know what to do with what you have already and you refining things can go on longer than my Christmas spirit can!)!

It's a snow day here, so I will pack it and send it your way.

Thanks for your patience!






HM

No I thought you were mad at me for electing you as the Man of the Year after I found out Gals like Lizzie and Joannie (NCG) weren't even on the list.

Anyway, be sure all locking nuts and washers and china caps and anything holding the pins to lever against a system resisting as pressure mounts are LOCKED with permanent studs or welds so I don't lose a tiny scrap piece in the middle of winter to find it in the Spring (I.e. the little washers there under the cocking lever need to be really PUT in place and NOT allowed to be RUBBED off by my finger that got bloodied on them!)

Anyway, I see the crosswind in your 45 targets.  What will happen is it will be shooting about 8 clicks to the right (for you) and I will adjust 8 clicks to the left!.  It ALWAYS happens!  I shoot offhand!  Can you use Physics to explain why this ALWAYS happens when I get my D54 from you!

 

Actually John,

NOTHING fell from the lever.

There is a small E Clip that affixes the cocking linkage to the lever, and that was in place.

You ADDED an outside retaining ring (ORR), when I sent you the rings, thinking they had fallen from the trigger pins, but, again, the trigger pins had all the 6 ORR's.

So, it's a MYSTERY.

The UNDERSIDE of the cocking lever linkage should look like this:





Everything was as it should have been. . . . Ti-riri-ri, ti-riri-ri (Twilight Zone music)

Now, about the scope's POA:

I disassembled the gun, repaired it, tested 6 different setups and recorded a BUNCH of shots.

When doing the final assembly, I mounted the scope, walked out to the 25 yards range, aimed dead center, and that is the bullseye that is labelled "Warming up and sighting in" As you see, it is shooting a little to the right and low for ME.
I did NOT move the turrets. Just used the scope's reticle aimpoints to shoot the other two groups.
The fact that it is shooting to the SAME POA at 25 and at 45 yards was a huge surprise for me. I would have expected a little more drop from the trajectory. But somehow, this rifle wants to shoot as a faster rifle, even with the heavy pellets.

So, I HOPE you will not need to adjust the turrets, as I did not move them at all. It was a pleasant surprise that after all that massaging, it was still "Spot On".

Rifle was picked up this morning, so hopefully, it will register soon in UPS tracking system. Key is going separate way.

Keep me posted!





HM

That washer lock I reinserted from the ground of rocks 35 yards away standing.  It had cut my right forefinger during shooting earlier and had come off.

That little washer should have a more permanent device to lock the pin and make sure the pin is not lost that takes all the bearing transfer leverage.

That is what I meant.

I shall look at that washer on the arrival of the .20 and I will probably try to figure out a solution beyond Diana's capabilities because this rifle is NOT a regular punched metal thing with your handiwork.

I would not buy a D54 unless you modified it from the factory.

[fwbsport]

This arrived today instead of tomorrow!
I was absolutely taken off guard!
I was shooting the HW98 .20 and the Daystate Huntsman .177 and the rifle from Hector arrived!  I was really surprised because all my practicing in .20 today and yesterday was mostly with the HW98 in its Diana Zero Recoil mounts.  The .20 is listed in my signature below as the HW98 .20.  Well, by today for some reason I was used to HW98s and their whole style of shooting any caliber available in them and why they beat out the R9 or even the R1.

In my mind they beat the R1 for easy target shooting offhand so that is my way.

Hector's .20 D54 arrived today and I really was shooting the HW98 .20 when packages came to our address and I saw the case realizing it is THE GUN.

So I took out a tin of Heavy .20s JSB and opened them up before carrying the rifle into the house to shoot out the back door!

My steel targets were all there set-up for the last shot I took with the HW98 .20 and then I loaded a heavy .20 after cocking the sidelever which Hector says would be a bit stronger than before but to me there was no difference and cocking the D54 each time to me was a reminder of what I enjoyed about the recoilless action, no matter how much power is cocked the rifle shoots like a PCP with a fine trigger and hammer to release air.

Each shot felt like releasing air on a PCP using a trigger different and a system of air different and recoilless.  I could see the brick (red) underneath the steel flapper and shoot a bit low (offhand) and the red brick JUST underneath the steel started to crumble away with pock marks like the old D54 did to these red bricks.

The rifle BREAKS apart in a couple of shots red bricks used for fireplaces!


It was already dead center on target at the steel I was shooting 25 yards away.  With JSB .20 16gr.

So Hector thank you and for some reason the cocking effort is NATURAL to me!  It is the best spring piston air rifle I have ever owned.

The 98s keep me busy and in place for shooting offhand but your rifle offhand is as easy as an HW98 in any caliber.   It is perfectly balanced. 

Thank you Hector!

John

[HectorMedina]

This arrived today instead of tomorrow!
I was absolutely taken off guard!
I was shooting the HW98 .20 and the Daystate Huntsman .177 and the rifle from Hector arrived!  I was really surprised because all my practicing in .20 today and yesterday was mostly with the HW98 in its Diana Zero Recoil mounts.  The .20 is listed in my signature below as the HW98 .20.  Well, by today for some reason I was used to HW98s and their whole style of shooting any caliber available in them and why they beat out the R9 or even the R1.

In my mind they beat the R1 for easy target shooting offhand so that is my way.

Hector's .20 D54 arrived today and I really was shooting the HW98 .20 when packages came to our address and I saw the case realizing it is THE GUN.

So I took out a tin of Heavy .20s JSB and opened them up before carrying the rifle into the house to shoot out the back door!

My steel targets were all there set-up for the last shot I took with the HW98 .20 and then I loaded a heavy .20 after cocking the sidelever which Hector says would be a bit stronger than before but to me there was no difference and cocking the D54 each time to me was a reminder of what I enjoyed about the recoilless action, no matter how much power is cocked the rifle shoots like a PCP with a fine trigger and hammer to release air.

Each shot felt like releasing air on a PCP using a trigger different and a system of air different and recoilless.  I could see the brick (red) underneath the steel flapper and shoot a bit low (offhand) and the red brick JUST underneath the steel started to crumble away with pock marks like the old D54 did to these red bricks.

The rifle BREAKS apart in a couple of shots red bricks used for fireplaces!


It was already dead center on target at the steel I was shooting 25 yards away.  With JSB .20 16gr.

So Hector thank you and for some reason the cocking effort is NATURAL to me!  It is the best spring piston air rifle I have ever owned.

The 98s keep me busy and in place for shooting offhand but your rifle offhand is as easy as an HW98 in any caliber.   It is perfectly balanced. 

Thank you Hector!

John

I am glad you are happy!

And thanks for allowing us to derive much needed information about the real limits of this design.

I will be taking off on holidays, so I will be somewhat "away from the PC" for a while.

Keep well, and the best of all Holiday Seasons to all!





HM

[fwbsport]

More input as I didn't shoot anything else but the .20 D54 yesterday.

The cocking system feels "bolstered" and "tighter" than it was before.  That forward snap of the opening lever (when closing it) is tighter.  It is shooting slightly right but I am going to make some groups before touching the windage dial.

I may be shooting low since those bricks are getting hit below the flappers but it's all offhand and I have to go ahead and get into a modified rest with it.

I kinda wish I knew what "some problems found" were by Hector--I assume the heavier pellets were getting blasted out of the rifle too fast to cause the "send it back" problems, but so far every shot is at least coming OUT the barrel to the targets!  (and not hitting the lawn before it).

[HectorMedina]

John;

When you stress a system to its limits is when you find the weak links.

Some of the issues have already been addressed, others we will address them when we go to the EMS version.

We do, really, greatly, appreciate the opportunity you gave us.

Have the best of holidays!




HM

[fwbsport]

I noticed the rifle felt different cocking it and the lock point is not quite at the same place it was, so there is now a little give after the 7th ratchet (Full Cock) to settle the sidelever into full cock.

The first 25 or so shots were loud and I know it because it's silenter than it was out of the case.

I have not readjusted the zero Hector sent it back to me in.

I think it took me awhile to shoot it again offhand to really get used to the touch to the cheek on the leather buttstock pad he had installed the first time.

I had been shooting the HW98s a lot before his rifle came back tuned to 15. something close to 16 grains of lead in .20 using JSB Exact.

I thought the rifle was shooting right an inch or two at 25 yards offhand thinking this is what always happens Hector's line of sight and interpretation through the scope shifts the image in his own eyes and I have only to adjust 2" to Left to get "his" scope sighted into my scope.

But I didn't shift anything sticking to the rule to shoot the gun and see where it is going and then keep shooting and make sure you see where it is shooting and then make sure you shoot again and again and again to reassure your self in the offhand position that all the "offhand" data while shooting is imprisoned tattooed burned into your consciousness and clarity in shooting and criticism for myself increases.

To realize I don't have to move a thing on Hector's own adjustments to the scope.  I am beginning to shoot the pellets exactly where the "Day of the Jackal" (w/Edward Fox) crosshairs of the Traditions 3-10X scope are sighted.

Nothing in the image changed, it was when I started getting finicky with myself about how far to adjust left and the question itself made me want to recheck my own optic sight hold.  Mysteriously I don't have to change a thing on the rifle as it was delivered in the way of the Scope sighted in for 25 yards.

Yet I know I was moving my own hold on the rifle to ease up and relax and pay attention to the trigger with the crosshairs and stand upright comfortably while the shot is made.

So if Hector says the scope is centered and zeroed without moving the turret adjustments further than their own zeros I am inclined to leave all alone!

The other thing.  He wasn't satisfied until I said I was satisfied (the rifle is truly an experiment in the limits of using .20 Heavy pellets) and there is NO TRACE of lead anywhere the rifle has impacted.

Whether it hits steel or brick or flagstone at 25 yards the lead absolutely disintegrate on impact.