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  #1  
Old 05-02-2021, 01:24 PM
layer3guru
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SK HIGH VELOCITY MATCH: BARREL LENGTH AND VELOCITY DOWN RANGE



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WHY
I was able to get my hands on the brand new SK High Velocity match ammunition. In all my my years of shooting 22LR high velocity and match was not something you used in the same sentence. Though with SK and the quality of their 22LR lineup I was willing to give it a try. This ammunition was made in Germany and developed for PRS and NRL22 courses of fire.

DATA GATHERING
Not only did I want to see what accuracy I would achieve with this ammunition. I wanted to make sure I had captured sound results, by trying this ammunition in 3 different rifles all with different barrel lengths. Christensen Arms Ranger 22 16in barrel, Lithgow LA101 20in barrel and a CZ455 Trainer with a 24in barrel.

This time I wanted to place the chronograph down range to see if these rounds would make the transition from Supersonic to subsonic before reaching the target. This was an important piece of data for me as this transition can often cause instability in the projectile.

I have also read from many experts that the ideal length for a 22lr barrel is 18inches. After that it is believed that the extra length in barrel starts to slow velocity.

TESTING SPECIFICATIONS
All Groups Shot At 50 Yards
Wind Gust 10-15Mph West South West
63 Degrees
Chronograph placed in front of the target at 50 yards
SK High Velocity Match 1263fps as printed in SK literature
RESULTS
Pictures are worth a thousand words right so video has to be even better






By the numbers and the graphs above it would seem this ammunition is continuing to pick up velocity even in the 24in barrel of the CZ455. Though I was shocked that the ammo had made the transonic transition by the time it reached the target at 50 yards. Though could this potentially have been caused by the wind? Interesting sure enough.

ACCURACY
Not sure if I could have expected better on such a windy day, though the SK High Velocity proved to be a bit better than the Federal Gold Medal High Velocity Match I previously tested. Both are in the same price range.



Lithgow101 turned in the smallest group of the day at 0.718in
CZ455 Trainer had the second best group at 0.827in
Ranger 22 had the third best group at 0.875in

The Average MOA for all rifles was 1.64MOA

https://dayattherange.com/?p=8682
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  #2  
Old 05-02-2021, 01:57 PM
jaia
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I'm unwilling to accept the transition as cause for trajectory spread with hi-v 22lr.
Up to 1250 fps mv, the 40 grain 22lr is subsonic before 40 yards. What I do see
is problems with manufacture and assembly of components creating physical defects
with the bullets, primer and brass that produce mv spread and trajectory dispersion.

Last edited by jaia; 05-02-2021 at 02:02 PM.
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Old 05-02-2021, 02:07 PM
layer3guru
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Great points Jaia that most likely will greater impact. If we could really get it all consistent do you believe there would be NO impact?
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  #4  
Old 05-02-2021, 02:16 PM
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Thanks for posting the results.

The extreme spreads seem high for short shot strings. That suggests quite a lot of variation in a box -- at least with this lot.

While the accuracy results are inconclusive given the wind, the velocity comparison with the different length barrels is interesting. There seems little difference between the 16" and 24" barrels. Of course, the data is too limited to draw any firm conclusions and these barrels may not allow an apples to apples comparison of barrel length and MV.

With regard to the placement of the chronograph, if you place it close to the muzzle you will know the MV and ballistics calculators can give a reasonable idea of the velocity at 50 yards. This suggests an MV of about 1200 fps for this ammo in the rifles tested.
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Old 05-02-2021, 02:48 PM
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Interesting post, but really not conclusive evidence with the velocities comparisons with barrel lengths since they are all different barrels.

Velocity drops are about what I would expect given the muzzle velocity stated. Not sure I agree with jaia's conclusions that all the trajectory spread is due to manufacturing causes and not Sonic barrier disturbance. At what point do you accept that manufacturing can only be made to be accurate to a certain degree and the fact that the guys in benchrest who shoot tiny little groups no matter the conditions all use SV/Subsonic ammo? The degree the sonic barrier causes accuracy issues is debatable, but I have a hard time simply discounting that part of ammo accuracy issues offhand...
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Old 05-02-2021, 03:26 PM
jaia
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Why do benchrest competitors use only match grade subsonic 22lr?

That's easy to answer. Nobody manufactures high quality hi-v 22lr. Nobody.

The one time that it did happen was for the Aberdeen Ballistics Laboratory.

Special order of RWS and Tenex for use in verifying accuracy with both hi-v and subsonic 22lr.

Note.... cartridges made on the same machines from the same components with the same standards of quality.

Results produced a conclusion in the published study....No significant difference in accuracy.

The reason hi-v 22lr reeks is because it's low quality bulk ammo.
Not because it's running the transition. When y'er ammo looks beat to snot fresh out of the box,
there is no way it's going to be capable of matching the accuracy of competition grade 22lr.

Last edited by jaia; 05-02-2021 at 03:29 PM.
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Old 05-02-2021, 03:40 PM
BobSc
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Kind of assumed you would respond in this manner. I've read all your posts, tests, and other conclusions and I'm not trying to start a pissing match with anyone but I simply don't agree with all of your conclusions in this field. I do agree with some of your ideas, but not all.... but hey, I'm sure there is a lot of useful information in your testing methods...
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Old 05-02-2021, 03:47 PM
jaia
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Bob, serious question...give it some thought.

How would you test for supersonic transition with 22lr?

Would you compare Midas+ to CCI Mini-Mags?

Do you think the results would indicate transition caused pitch or yaw?

Do you think the results would indicate the quality and mv consistency of the cartridges used?

How would you determine the cause of trajectory spread? Is it due to transition or cartridge quality?

Last edited by jaia; 05-02-2021 at 04:06 PM.
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  #9  
Old 05-02-2021, 04:53 PM
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Quote:
Originally Posted by jaia View Post
Nobody manufactures high quality hi-v 22lr. Nobody.

The one time that it did happen was for the Aberdeen Ballistics Laboratory.

Special order of RWS and Tenex for use in verifying accuracy with both hi-v and subsonic 22lr.

Note.... cartridges made on the same machines from the same components with the same standards of quality.

Results produced a conclusion in the published study....No significant difference in accuracy.

The reason hi-v 22lr reeks is because it's low quality bulk ammo.
Not because it's running the transition. When y'er ammo looks beat to snot fresh out of the box,
there is no way it's going to be capable of matching the accuracy of competition grade 22lr.
The reference to the Aberdeen Ballistics Laboratory must be related to the 1990 study by Robert McCoy "AERODYANMIC CHARACTERISTICS OF CALIBER .22 LONG RIFLE MATCH AMMUNITION" https://apps.dtic.mil/dtic/tr/fulltext/u2/a229713.pdf

It's worth noting that the "high velocity" ammo used in this study was not Eley or RWS ammo. The only Eley and RWS ammo were commercially produced Tenex and R50, respectively. The other ammo was "custom-loaded rounds, whose bullets were similar in shape to the Eley and RWS bullets, but loaded to above and below standard velocities."

According to McCoy, this ammo was provided by Steve Chernicky, then head of the US Shooting Team Ultra Match (high accuracy .22 rimfire ammunition) project. The "nominal muzzle velocities" of these two ammos were 1200 fps and 950 fps.

McCoy says "The purpose of the firings at non-standard velocities was to determine a possible optimum muzzle velocity for minimizing the sensitivity of the
bullet to crosswind." He says nothing about shooting it for accuracy.

Among his conclusions on p.11 is this one, which refers to transonic speeds (890 to 1340 fps)

"5. The nonlinear Magnus moment acting on caliber .22 match bullets at transonic and
subsonic speeds causes a slow-arm limit cycle yaw of approximately 1.8 degrees. The
slow arm grows to the limit cycle value at about 50 metres range, and the limit cycle
persists out to 100 metres range. The limit cycle yaw adds approximately 2 percent
to the zero-yaw drag, but has an insignificant effect on accuracy, retained velocity and
wind sensitivity."


Does McCoy actually say that the accuracy of .22LR ammo that is supersonic is not affected by transonic turbulence as it slows down?

Is there anything in the McCoy study to suggest that he tested the custom 1200 fps ammo for accuracy?
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  #10  
Old 05-02-2021, 05:25 PM
BobSc
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Quote:
Originally Posted by jaia View Post
Bob, serious question...give it some thought.

How would you test for supersonic transition with 22lr?

Would you compare Midas+ to CCI Mini-Mags?

Do you think the results would indicate transition caused pitch or yaw?

Do you think the results would indicate the quality and mv consistency of the cartridges used?

How would you determine the cause of trajectory spread? Is it due to transition or cartridge quality?
Okay, for the sake of discussion, how would you test for the causes of inaccuracies in lower level ammo? How do you determine if the inaccuracy is caused by damaged bullets in manufacturing, or powder loads not measured as accurately as higher end ammo? Or incorrectly placed primer compound? Or all three..... ? Or none of the above?

Without the proper equipment, test facilities, test protocols, and controls this is all just fun discussion and conjecture. Some of it makes a lot of sense and some of it doesn't, but that doesn't make the discussion any less interesting and anything that adds to understanding this fascinating hobby is great discussion IMO....

I do respect all you have done to reach an understanding of what is/is not good ammo in your opinion and the causes as you understand them. Great information and the effort is appreciated.... but it doesn't mean I agree wholeheartedly with all of your conclusions. Call it the scientist in me (I'm actually an electrician )

Bob
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Old 05-02-2021, 05:55 PM
jaia
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Thanks for the replies PG and Bob.

PG, y'er right, I was commenting from memory, and unsurprisingly, got the details wrong...again.

No excuses.

Bob, you point out the same problem I have with attempting to figure out why rimfire
slings those odd strays and fliers. My quandary, is when my results don't fit the accepted claim
that supersonic transition caused accuracy problems with hi-v 22lr.
I've shot CCI Blazer that grouped better than CCI SV.
Eley Contact and Eley Force, where the hi-v produced results that matched the subsonic.
If the transition is such a problem, then why do my results not support that theory?
Noremf also questioned the transition problem and pointed it out in a couple of discussions.

Side note, I prefer folks to disagree with my thoughts.
I'm no professional shooter, just an interested amateur.
I try things to find out which ideas work, which don't.
When results don't fit accepted theory, the theory needs revision.


PG, conclusion 5 of the McCoy report...less than 2% increase in pitch/yaw...
that is the effect of the transition on a 22lr, correct? The disturbance to the bullet stability
that causes the bullet to shift it's trajectory? It has no significant effect on accuracy....am I interpreting that incorrectly?

Last edited by jaia; 05-02-2021 at 06:24 PM.
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Old 05-02-2021, 10:32 PM
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Jaia, I wish there was more clarity in conclusion five. It's possible that 1200 fps ammo is not troubled by transonic turbulence. But does McCoy explicitly determine that?

The wording in conclusion refers to "transonic and subsonic speeds" which covers the velocities of all the ammo he tested. In fact it covers all .22LR ammo with MV's no greater than 1340 fps. Match ammo with an MV of 1050 - 1100 fps is always transonic to at least 100 yards.

I'm not sure we know that conclusion 5 was meant to be so broad as to be a general statement that was meant to confirm that supersonic .22LR ammo doesn't experience transonic turbulence. It's unlikely to mean that the custom loaded 1200 fps ammo was just as accurate as the Eley or the RWS factory ammo.

Significantly, since both the 1200 fps and 950 fps ammo was custom loaded ammo, not factory ammo, McCoy couldn't reasonably compare their accuracy with that of the factory ammo. Indeed, there wasn't anything McCoy could compare it with other than itself. Such a comparison couldn't conclude it was more or less accurate than any results it gave. Therefore it couldn't be determined if it lost any accuracy in the short subsonic zone from about 35 - 50 yards.

McCoy said the purpose of the faster 1200fps ammo, like the 950 fps ammo, was to determine a possible optimum muzzle velocity for minimizing the sensitivity of the bullet to crosswind. The optimum muzzle velocity, he appears to say in conclusion 7, is 950 fps.

In the end, the explicit overall purpose of the McCoy study is to examine the characteristics of .22LR match ammo, which the the custom loaded ammo is not.
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Old 05-02-2021, 11:05 PM
jaia
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From the conclusion...

....acting on 22 match bullets at transonic and subsonic speeds...
defines both the object of study and the velocities we are most interested in.
Very specific verbage to which the rest of the statement applies.
A fairly precise description of the effect of the transition
and the distances from the muzzle for which the effects were observed, follows,
...leading to a final statement: the transition induced yaw has insignificant effect
on accuracy, retained velocity and wind drift.

That conclusion statement is quite precise in it's measurements,
the description of the object that was observed and the effects
on the object and it's trajectories.

Match quality 22lr does not suffer any significant effects from supersonic transition.

Does that apply to lesser quality rimfire ammunition?
How can that be determined, when the cartridges themselves
are prone to mv spread and defect caused strays?

Still thinking about it.
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Old 05-03-2021, 06:06 AM
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Reading through the information above plus the Aberdeen files and a 1940 video on transonic is a .22 LR projectile between 890 f/s to let’s say 1200 f/s affected by a transition to subsonic?

Or is it always in transonic?

If always ‘transonic’ is it always ‘unstable’?

Or stable in ‘transonic’?

Just asking?

E.

Last edited by ECC; 05-03-2021 at 06:14 AM.
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  #15  
Old 05-03-2021, 06:46 AM
David Valdina
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Just thinking here on yaw and accuracy...

I am just thinking here on yaw and accuracy. I believe I have read that many centerfire cartridges start out with some yaw before they go to sleep, and that may be at 100 yards or more. The accuracy is there. Now, if this is correct, then the occurrence of yaw in a .22 rimfire bullet does not necessarily result in a degradation of accuracy. And I have read that a bullet passing from supersonic to subsonic does not necessarily make it inaccurate, in spite of many years of "wisdom" to the contrary. So perhaps it is better to concentrate on what results we are getting without too much speculation as to why. Quality control seems to have the greatest effect in our cartridges. Not owning the ammo companies, we can only select what is the best. Beyond that, it is up to the rifle and the shooter. One last caution, without wind flags or shooting at an indoor range, we have the influence of wind on results and that is huge and makes almost impossible other diagnosis as to what is going on as there are just too many variables.
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