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BigDanS
Posts: 6,992 Senior Member
.22 supersonic to sub, another crack at it., ( pardon the pun ) or what I learned...
BigDanS
Posts: 6,992 Senior Member
I was on Rimfirecentral discussing the Aguila Interceptor, a .22 LR 40 gr bullet that chrony's about 1450 FPS from a 20 inch barrel, and we were discussing the SoS transition. What I didn't understand before today is that it starts to occur at about 1300 FPS. I had been calculating destabilization occuring at the actual sound barrier but it appears to happen before. Therefore, if you look at trajectories, it would seem any super sonic .22 is only stable down to about 1250 FPS. It explains a lot, like why stingers are not accurate past 75 yards. They reach 1250 FPS at 75 yards or so, and according to the disturbance occuring before the break of the SoS this would be their accuracy point.
Another example is that the Aguila Interceptor is traveling at 1250 FPS at 50 yards and therefore that would be its accuracy limit. The Aguila SuperMax travels at 1710 FPS, but reaches the break point at 85 yards.
So in conclusion supersonics are accurate till the breach about 1300 fps, and the longest, accuracy you can expect from hyper velocity .22's are:
CCI Stinger 32 gr hp 75 yards
Aguila Interceptor 40 gr 50 yards
Aguila Supermax 30 gr 85 yards
And again hypersonic .22 LR past 100 yards that are accurate don't exist... unless you go to the .22 WMR.
What's your experience?
IMHO
D
Another example is that the Aguila Interceptor is traveling at 1250 FPS at 50 yards and therefore that would be its accuracy limit. The Aguila SuperMax travels at 1710 FPS, but reaches the break point at 85 yards.
So in conclusion supersonics are accurate till the breach about 1300 fps, and the longest, accuracy you can expect from hyper velocity .22's are:
CCI Stinger 32 gr hp 75 yards
Aguila Interceptor 40 gr 50 yards
Aguila Supermax 30 gr 85 yards
And again hypersonic .22 LR past 100 yards that are accurate don't exist... unless you go to the .22 WMR.
What's your experience?
IMHO
D
"A patriot is mocked, scorned and hated; yet when his cause succeeds, all men will join him, for then it costs nothing to be a patriot." Mark Twain
Alcohol, Tobacco, Firearms and Explosives.... now who's bringing the hot wings? :jester:
Alcohol, Tobacco, Firearms and Explosives.... now who's bringing the hot wings? :jester:
Replies
Can hit a 12" plate at 230 yards with a stinger just as easily as with bulk ammo.
The question is can you hit a 75 yard target with bulk ammo in .75 inch circle... and can it be done with supersonics?
D
Alcohol, Tobacco, Firearms and Explosives.... now who's bringing the hot wings? :jester:
What you need to keep track of is not the velocity in FPS, but rather in terms of Mach number, understanding that the only thing that affects the speed of sound is temperature. So, on warm days, the speed of sound is higher, but the bullets travel faster because the air is less dense. If it's humid, the bullets go even faster. On cold days the speed of sound is lower, but the bullet travel less quickly because the air is more dense, and dryer which further slows the bullets down. Also, the powder in the bullet may be affected by the lower temperature.
JBM is an excellent site for trajectory calculations and I have been using it for years; they just get better all the time. JBM will show you the speed of sound for given temperatures and you can see the Mach number as one of the columns with respect to the velocity of the bulelts. So for the very best results with JBM, you must provide the proper environmental conditions, else it's garbage in, garbage out.
It has been know for a very long time that .22LR live in the range of Mach .95 to 1.25 and that is why .22LR match ammo is all subsonic. The bullets will not destabilize during the transonic regime, but they will be less accurate. I don't remember ever seeing my .22LR bullets keyhole on the paper targets, they were all stable even after going subsonic. Just not very accurate.