New (to me) Diana 48 and Beeman R9

[HectorMedina]

Incredible shooting with an incredible tune. Can short stroking and this type tuning help marksmanship and proficiency in magnum energy guns?

Ron;

It ALL depends on WHAT you define as "Magnum" energy. LOL!

What happens with waisted/skirted pellets is that because of their shape, they exhibit a stability limit at around 875 fps. And this is ONE, possibly the ONLY, tenet that holds across all the airgunning world. SOME pellets may tolerate a bit more, some a bit less, at some altitudes this number may change slightly (it's a function of the Reynold's number that depends on the density of air), but IN GENERAL, this number is one (possibly the ONLY one, I repeat) of the "HARD" numbers in airgunning.

So, for an 8.44 grs. pellet, the MAX stability velocity under normal atmospheric conditions is a "paltry" 14½ ft-lbs, or thereabouts.
Surprised?  most veteran airgunners are, also. And some don't even believe it, but to each his own.

When you go to 0.22", again talking about STEEL SPRING guns, there seems to be a practical limit at the 16-18 grs. pellet. Some actions are even limited to the 14 grainers. It all depends on the swept volume, length of barrel, and "rail speed" of the piston/guide assembly. So, that with the 0.22" cal. guns you CANNOT exceed the stability limit of the pellets because you would have to find an ACCURATE barrel in a gun that can yield 27 ft-lbs. Those guns that can reach these energy levels, are usually gas springed and take 45-55# of peak cocking force, so they are not truly shootable enough to acquire the necessary skill/muscle memory level.

This is where the 0.20" cal is interesting. at 13.X grains (either the Baracuda or the JSB), the 0.20" cal. CAN be shot at around 23 ft-lbs for 875 fps., maximizing the ballistic potential on all fronts. The guns themselves are the limit here. Apart from the D54 family I know of no other gun capable of achieving this level in a consistent, reliable, and stable manner. Sadly, 0.20" cal D54's are VERY scarce (and expensive), but that is the reason for existence of the few that are around.

What is MORE available is the D48 and the D460 in 0.22". And that is something we can work on together, if you want.
It CANNOT yield top ballistic performance in a short-stroke/easy-cocking version, and the best long range pellets in existence today for the limits of the spring-piston powerplant are probably the 16 and 18 grainers from JSB so if you really want "Magnum" performance from a fixed barrel gun, you should be looking at the D48 or the 460.

IMHO, the 48 is more a "shooter", the 460 is more a "hunter".
At these power levels, you will NEED  to lift the gun from the bench to shoot the next shot, re-positioning the gun into the rests is easier with the 48 than with the long and slender 460. The 460 carries better into the field and comes into action in a more, better, and "quick" ready.

The T06 Trigger CAN be set to around 15 oz safely, though I would advise against a very short first stage pull. The slant of the pistol grip in a sporter stock is better taken advantage of by using a LONG first stage and a "swept back" position for the trigger break; because then you can "squeeze" the trigger between ball at the base of the thumb and index, without putting any pressure/force into the rest of the stock with the trigger hand. It is something that you will probably need to become accustomed to, but a worthwhile skill when shooting springers of any appreciable power level.

Coming back to Greg's gun: it could have rather easily developed the 14.3 ft-lbs with a little more cocking effort, BUT, humans are peculiar creatures, we can think nothing of lifting our 160 # step by step in a staircase, but if you ask us to do a dozen chin-ups, few of us would manage even a few repetitions, let alone the dozen.
Cocking an airgun requires some muscles that we do not generally use, and some shooters substitute muscles they shouldn't, and then get "tennis elbow" or other pains in the joints, especially the shoulder joints.
After some years of seeing some friends leave the spring-piston rifle for the PCP world due to hurt shoulders and/or diminished strength, the short-stroking solution came into being. Since then it has helped quite a lot of Juniors, Ladies, Senior Gentlemen, and friends with torn rotator cuffs/repaired elbows.

Hope this clarifies the intent, the limits and the facilities allowed by the DIANA 48->56 platform.

Keep well and shoot straight!





HM

[Jshooter71]

Excellent information, Sir Hector! Is there a list of Maximum Stability Velocities and Factors for known pellets for us to look for guidance? And about that Reynolds factor, I’m at 1400 ft... I’d imagine barometric pressure as well plays a part. Not the first time I’ve heard about elevation affecting velocity, but never really been explained other than slower at altitude. Is there a way for us to do some calculations to determine if we’re playing within a certain set of rules for success vs. beating ourselves trying to make something happen that never will? Like you alluded to, I would imagine from one platform to another things would be different. Some things are still trial & error since most advertised FPS per manufacturer is inflated.

[Yogi]

" Maximum Stability Velocities" this would be very individual barrel  and pellet specific.  Some barrels are better than others on the same model gun.
Every pellet is different.  That is why top level shooters weight and size their pellets.  However, general rule of thumb that I have heard is 925 fps is about as fast as you want to go.  Most guns shoot well in the 800-875 fps range.  PCP's may be different?

-Y

[HectorMedina]

Yogi brings out an interesting point. SOME barrels may be so badly made that they will not stabilize pellets at speeds even approaching the Max Stability Limit mentioned here.
And this is the difference: For ME a limit is a limit. It is a place beyond which, no matter what you do, you cannot go.
And so, as my experience is concerned, no skirted/waisted pellet can fly well at MV's much higher than 875 fps. EVEN IN THE BEST OF BARRELS, pushing the MV much above that is jut a delusion.

Let me tell you a story from the world of the PCP's:

There was this shooter that claimed that "X" pellets out of his PCP were flying very accurately at around 1,000 fps. He presented a number of different test targets to prove it. All target shot at his normal range (apparently he had a large backyard). We had some discussions and we never agreed, so unilaterally, I agreed to disagree because I really have little time to discuss with people who do not want to understand.
Over time, he reduced the MV's of his guns and when he was queried about it, he said that the shot count had become important.
Then he said that he had detected some "wobbling" of the pellets, but that he thought those were from a "bad batch"
Then he claimed that the wind was playing tricks on him.
Finally, he commented that he had been shooting from a SECLUDED section of his property (indoors), and that the first 15 yards were "protected". It was when he moved from that location that he realized that his pellets had been at the EDGE of stability, and that once they were not afforded the protection of seclusion, pellets started flying "funny".
;-)

It did help that a video appeared a few months later showing that REDUCING some pellets' MV's also reduces the "corkscrewing/wobbling" in the trajectory.

LOL! In any event, he settled into the 950 fps region and, as a hunter, he is happy. So am I!

If that tickles his fancy, so be it.

For design and implementation purposes, I will stick to the 875 fps as a good, solid number at which we can be CONFIDENT that we can do as much as we can and STILL see results of smart improvements.

Now, as to the altitude effect:
Springers are MUCH MORE affected by LACK of air in the powerplant, than the pellets are affected by the change in air density/Reynolds number.

The effect on the stability limit is about 1.7% for every 5,000 ft of elevation. While the loss of power/energy due to altitude changes (on average) at a ratio roughly equivalent to 2.5% loss per 1,000 ft above the first 1,000 ft in a compounded manner.
So the loss of ME is vastly superior to the slowing down of the MV Stability limit.

HTH, keep well and shoot straight!





HM

[chemclay]

Hector

Can the D48 be tuned to be a smooth and accurate shooter at factory energy and cocking effort so as to be enjoyed by a much less knowledgeable air gunner?

[Oldgringo]

Hector

Can the D48 be tuned to be a smooth and accurate shooter at factory energy and cocking effort so as to be enjoyed by a much less knowledgeable air gunner?

Hector did it to mine.  Viva Hector!

[chemclay]

Hector

Can the D48 be tuned to be a smooth and accurate shooter at factory energy and cocking effort so as to be enjoyed by a much less knowledgeable air gunner?

Hector did it to mine.  Viva Hector!

Then I really need to get together with Hector!

[Oldgringo]

Hector

Can the D48 be tuned to be a smooth and accurate shooter at factory energy and cocking effort so as to be enjoyed by a much less knowledgeable air gunner?

Hector did it to mine.  Viva Hector!

Then I really need to get together with Hector!

YES!  Hector is a Gentleman and a scholar.

[HectorMedina]

Thanks Greg for your kind words. Greatly Appreciated.

Ron.- What is hard to convey through a keyboard is how difficult it is to shoot a powerful springer with REAL consistency. So let me give you two bits of data, that apply to TARGET SHOOTING ONLY:

1.- EVEN where the rules allow up to 20 ft-lbs of energy, the truly good "open piston" class shooters choose to operate at between 12 and 14 ft-lbs using an 0.177" cal gun for shots out to 55 yards.
2.- In MOST shoots, the top 5 WFTF class Piston shooters, usually OUTSHOOT the middle of the pack PCP shooters. And all WFTF shooters shoot at UNDER 12 ft-lbs 0.177 cal rifles.

With a 23# peak coking force, it is much more probable to reach a high level of proficiency, than with a 37-45# PCF level. You will shoot a lot more and, therefore, get better in the long run.

I have prepared a LOT of hunting airguns, and those are different because, at most, you take 30 shots in a session (10 to warm up and re-zero, and 20 to get rid of pests). Then you have lunch and have another go in the afternoon. (we're talking pigeons, starlings. grackles, and other flocking birds under ranch/stable/farm conditions). Squirrels? You take at most 10 "for score" shots. Woodchucks? Maybe three "for score" shots, and so on. So, that is a COMPLETELY different setting and, curiously enough, it has been my experience that stability of the FIRST/COLD bore shot is more important than anything else.

For target shooting, it is much more "human" to stay where the body and mind can stay focused.

So, if you are mostly interested in target shooting out to 55 yards, then I would suggest following Greg's route: A short stroked 48, FITTED to your size, because 48's are a bit "short" for some adults.

If you REALLY have to push the limits out to 100 yards, then you will need to go to a 0.22" Full power, no "easy cocking" (37-45#), smooth yes, but not "easy". You will have to commit to a certain degree of physical fitness, maybe even exercise a little.
Maybe using a heavier than normal piston and a heavier than normal spring, to achieve stability with 18 grs. pellets.
A good Mount, a good scope (36X) because 100 yards is a really long shot for a 0.22 " cal. projectile (even when fired from a RF).

Paraphrasing the Olympic Motto (Citius, Altius, Fortius) into: Forcius Altae Stadia; It takes strength to reach higher and farther.

;-)

Is there a way to reach out to a 100 yards with a short-stroked version?  Not with any reasonable surety.
As you can read here:

https://www.ctcustomairguns.com/hectors-airgun-blog/the-wide-and-wonderful-range-of-a-short-stroked-d-54

The performance limit of the short stroked platform (24# of PCF) is about 15 ft-lbs. In a 54, that is still manageable, in a 48, it borders on "bucking bronco" territory. AND, not all barrels will be accurate at this limit (900 fps with an 8.44 pellet).
It COULD be that, with a 0.22" cal. gun, we could reach the 17-18 ft-lbs, just because of the expansion ratio of the barrel.
That would mean a MV of about 720 fps for a 16 grain pellet/750 fps with a 14.3 grainer, and that would entail VERY SHARP wind-reading skills to be precise on target under open field conditions.

So, your choice/your decision. Technologically, it is possible and I am willing to do the experiment for you in any of these two ways.

Drop me a PM through my contact page in the website

https://www.ctcustomairguns.com/contact-us.html

to get the project launched.

Keep well and shoot straight!





HM

[Yogi]

Hector what would be the pellet drop at 100 yards with .22 pellets with your maxed out D48?

FWIW-For me anything that requires more than 3 1/2 hash marks holdover, I consider a lucky shot...

-Y

[chemclay]

Hector

PM sent.

Ron

[Jshooter71]

Fantastic stuff, Hector!

[HectorMedina]

Hector what would be the pellet drop at 100 yards with .22 pellets with your maxed out D48?

FWIW-For me anything that requires more than 3 1/2 hash marks holdover, I consider a lucky shot...

-Y

It all depends on how you are accustomed to shooting, Yogi.

If you think of the old time "Big Fifty" Sharps shooters that used to shoot Bison commercially at between 500 to 1000 yards, the challenge is comparable.
People still use old time Black Powder Cartridges (like the 0.45"-70-405, more commonly known as "45-70 Government") to shoot at 1,000 yards. And some of them do not even use a scope.
Slow projectiles, as long as you shoot them in the velocity ranges where their drag coefficient does not change much can be surprisingly accurate and precise.

Besides, the drop from "Zero" depends on where the "Zero" is ¿no?  ;-)

So, more than enter into a debate of where the zero should be, what is "reasonable" or not, or how each of us shoots, let's look at cold numbers (somewhat hypothetical, but based in reality):

System   Diana 48 SS / Sightron SII Target 36X42                   Projectile   JSB Exact   0.22   Inch   15.9   Grain       BC   0.031   Profile   GA             MV   700   (Ft/s)   ZR   75   (Yard)       SH   1.75   (Inch)                AmbT   15   (deg C)   AmbP   29.92   ("Hg)       Wind   7.5   M/h   Full value                                   Range   POI   POI   Drift   Cd   Time   Vel.   Energy (Yard)(mrad)(clk)(mrad)   (prj)   (sec)   (Ft/s) (FtLbf)                       40   4.1   -57   1.3   0.288   0.19   599   12.67 45   3.6   -50   1.5   0.287   0.21   588   12.19 50   3.1   -43   1.7   0.286   0.24   577   11.73 55   2.5   -35   1.9   0.285   0.26   566   11.30 60   2.0   -27   2.1   0.285   0.29   555   10.88                       65   1.3   -18   2.3   0.286   0.32   545   10.47 70   0.7   -9   2.5   0.286   0.35   534   10.08 75   0.0   0   2.7   0.287   0.37   524   9.70 80   -0.7   10   2.9   0.288   0.40   514   9.34 85   -1.4   20   3.1   0.288   0.43   505   8.99                       90   -2.2   30   3.4   0.289   0.46   495   8.65 95   -3.0   41   3.6   0.289   0.49   486   8.32 100   -3.8   52   3.8   0.290   0.52   476   8.01 Sorry for the misalignment of some numbers, but inserting a graphic table takes too much time. So, for this hypothetical system, sighted in at 75 yards, you come DOWN 50 something clicks to shoot at 40, and you come UP about the same number of clicks to shoot at 100. The lowest Cd (Drag coefficient) is 0.285, the highest is 0.290, so we're keeping the Cd and therefore the BC to a reasonably constant value. Wind drift has been calculated for a 7.5 Mph wind at full value (3 or 9 O'Clock) Compensating wind with clicks is an interesting skill. At 100 yards, as long as there is enough DIFFERENCE in ground and air temperature you can read the drift by using the rolling waves  of the mirage with a scope backed out about 1/3 of the distance to the target. Now, if I wanted to do this, I WOULD  choose the SIGHTRON SII Target scope, which would mean that I would need to DOUBLE the clicks on the table (table is calculated at 1/4 MOA, scope has 1/8 MOA). So at 100 clicks EITHER way,  scope is at about 1/2 of its full excursion from one end to the other (60 MOA's) Of course, MOST probable scenario is that a special scope base would need to be contrived/made, but, again, that is doable and it depends on the real values of the system in question. Which we will not know until we decide to test the concept. As to how to make the trajectory to 100 yards keep within the first two or three hash marks, the solution is simple: Use an 8X Crossbow scope with a 50 yard Zero! LOL! ¿Chicken-Egg; Anyone? Keep well and shoot straight! HM

[Yogi]

Well at least you did not say, "the solution is simple use a Duplex reticled scope," LOL.

I should have said,  a maxed out D48 zeroed at 30 yards.  I believe that +/- 3-5 yards, this is where most springer airgun scopes should be zeroed.  A 75 yard zero might be realistic with a powerful PCP, but not any springers...

-Y

[HectorMedina]

Well at least you did not say, "the solution is simple use a Duplex reticled scope," LOL.

I should have said,  a maxed out D48 zeroed at 30 yards.  I believe that +/- 3-5 yards, this is where most springer airgun scopes should be zeroed.  A 75 yard zero might be realistic with a powerful PCP, but not any springers...

-Y

Yogi;

Again, you are talking about custom and habit.
Some FT shooters use 45 yards "zero" 's, even though they "click" for every shot, so they are ALWAYS on "Zero". Under this set of circumstances, the 45 yards is just where the barrel has been regulated to be at the optical center of the scope.

Those of us that shoot without clicking, normally use the "Apex" of the trajectory, or very nearly so, to set the zero because that offers the most control about mil-dot windage in those reticles that have the Christmas tree style of reticles.
Back when I was shooting my full power 0.20" cal D54, I used to use a 40 meters (about 44½ yards)  zero because at the apex (27 meters), the shots were ½ mrad high, and out to 70 meters (about 77 yards), I was still within the 2 ½ mrad, or 5 divisions in my SIGHTRON SIII MOA-H. But that gun shoots the 14.7 grs at 850 fps.
Again, this is where the 0.20" cal maximizes the possibilities of a piston airgun.
I've shot a few 100 yards groups, normally in the 2½" region, but at times, you CAN get groups in the 1¾" region, which is very enticing.

;-)  You do have to be "top of your game" for that, and, MOSTLY, you need to know the range very well to "feel"/read the wind.

Keep well and shoot straight!





HM

[Yogi]

Hector,

I solidly agree,  Never heard of a 45 zero for hunter class though......
At anything over 40 yards, any anglular wind over 10 mph needs to be taken into account.  I'm sure at 100 yds, times 10.
At 15 to 20 yard hunting scenarios, much less so.

What I get is a 18 grain .22 pellet with a BC of .04 (maybe 2 high) leaving the muzzle at 900 fps, zeroed at 30 yds drops 2 inches to the zero and another 2 FEET to 100 yards, with 0mph wind.
2 feet, 24 inches, 60 cm., more hash marks than I can count.

May 2021 be MUCH better than 2020, can't get any worse.....

-Yogi

Ps any chance that you can convince Sightron to make a dicated 16 X fixed power scope just for FT hunter Class?  If they could make a superior scope in the $300-500 range, every FT hunter class shooter I know would buy one.

[fwbsport]

Well Hector this is something I heard from you before leading me to get your D54 .20, which I said was "breaking bricks" at 25 yards behind my reactive targets.

The .177 Daystate Huntsman Regal has the working pressure at 210 BAR for average mv of 898 fps which hits on target closer than all other rifles (I leaned into a rested upright position to make one hole groups at the beginning of 225 BAR and 180 BAR) and still have those groups on paper to see!

The HW95 .177 uses JSB Exact to have an average of the SAME: 898 fps mv and THAT springer is as I have posted AMAZING!  Even nced agrees!

While the Daystate uses 10.33 gr Rangemaster Sovereigns (they are heavier but the PCP is able to deal with it) to get one hole groups the HW95 can use Lite JSB exacts as well with a vertical change in impact not measuring too much.

Shooting your rifle in .20 (mine now!) reminds me of the Daystate PCP in firing character.  The only thing "different" is the sidelever vs the PCP reservoir!

Now, I think by NOW you have my rifle in your hands to re-adjust and I WOULD like you to explicate what you found out with it and what you are intending to do right here on this forum!  May I ask this in view of your fine work here on this with the D48?

Our minds are mesmerized by your revelations!

 

[HectorMedina]

John;

I think we have hijacked enough Greg's thread.

So, I'll start another one.

Here:  https://www.gatewaytoairguns.org/GTA/index.php?topic=180541.msg156050341#msg156050341

Keep well and shoot straight!




HM

[HectorMedina]

Hector,

Ps any chance that you can convince Sightron to make a dicated 16 X fixed power scope just for FT hunter Class?  If they could make a superior scope in the $300-500 range, every FT hunter class shooter I know would buy one.

Just to answer your question:
We HAVE been working on a completely new scope with SIGHTRON.
And I say "we" because Scott Hull is also part of the effort. For those that do not know him Scott has been National Champion in Hunter Piston class, he always places top five in any competition he goes to, he is a remarkable marksman, and an all-around nice guy.

The specs of the scope is a 9-45X56 FFP mrad based scope with a really useful reticle. ED glass in the objective, aspherical lenses in the erector assembly. It WOULD have a 16X mark in the mag ring, to be legal for AAFTA Hunter FT.

Why variable? because as SWFA showed, the fixed mag scopes do not have enough market to ensure their commercial survival.
This scope will be a cross-over scope between FT, Hunter FT, Police Marksman and F Class shooters, so we HOPE that that will mean enough users to make it a reality.

The scope specs had been settled and we were in the process of the reticle design when CoViD struck, so the project is somewhat at a standstill, but the interest is there on both sides and I do think that it will become a reality sometime in the future.

The first iteration out of Japan was a disaster BTW, ROFL! At almost 40 oz, it was completely unmanageable.

So, back to the drawing board for the optical engineers, ;-)

HTH, keep well and shoot straight!






HM

[Yogi]

Well what do you expect with a  9-45X56 FFP scope?  What was the target weight, 39 oz?
Anything over 20 oz on a 12fpe springer would be a deal killer for me......
One size DOES NOT fit all.

-Y