I've been reading about the theory behind trajectory and drift and "experimenting" by playing with one of the commercial calculators, QuickTARGET. 

I'm observing that subsonic loads suffer least from wind drift. Is this true in practice? 

With subsonic muzzle speeds, do typical velocity spreads more greatly affect vertical stringing?

What sort of speeds do off-hand shooters gravitate towards and why?

I'm a bit out of the ASSRA loop, but I'll be living in Illinois again later this year, and I might try to make some of the matches one day. Are jacketed bullets permitted in the matches?

Thanks,
Karl

I'll have to disagree with that.  22 target shooting is done almost exclusively with subsonic ammuntion.  Vertical group size is no greater than the horizontal and, in fact, accuracy with the subsonic .22s is very close to the supersonic centerfires with their much much heavier bullets.  I don't think you give up any accuracy just because you are subsonic.  You might even gain a small advantage.   

Brent

boats, have you ever seen anyone try subsonic centerfire?  Could be that you ain't seen it because it's not been seriously tried and it ain't been seriously tried because no one has seen it.  I am aware of no laws of nature that suggest it cannot work.   

I'm willing to bet that a .32-20 can be shot subsonic more accurately than any .22 and may be any centerfire.   

Brent

My concern with subsonic would be in the vertical. Even if the velocity variation were the same percentage (which would require a smaller absolute span), it seems the arcing trajectory may amplify the errors downrange. Unfortunately, the trajectory calculators can't handle what happens when a given rifle fires a load which is 2% slower than another. They can't compute recoil on your shoulder and how that affects the initial launch angle. Only experience will determine if it is successful.

The low predicted wind drift for high BC bullets launched subsonic is tempting. There's some very high BC 22s and 24s these days, nearly equaling many 30s (jacketed, that is). I wonder how these flying pencils would do in practice.

Pity you can't use jacketed at the matches. The .32-20 Brent mentioned is one of the chamberings I was considering, using spitzer FMJ-BTs made for the .303 Brit. (Ok, I'm too lazy to cast and paper patch similar bullets.)

Brent tell you the truth I don't try much new. After all these rifles and methods are 100 years old.  I have to assume the kinks have been worked out of most loads normaly used in Schuetzen matches.  If matches are and have been won with 32/40's at 1450 fps that's all I need to know.

Not to be against anybody's theories or sport.  If someone wins or places well in a match with sub sonic 32 cal center fires I may give it a try.  May even consider if I saw a test that was valid showing potential. Otherwise better places to spend my time.  Conditons, postion, and trigger pull.

Why not give the 32/20 sub sonic a run showing the results.

Boats

You are right.  100 is not 200, and thus the bulls are different.  It is true with respect to wind as well as gravity.  And I don't see any vertical stringing - unless you use junk ammo (big surprise)....

Brent

Jim_Borton wrote on Jan 21^st, 2008 at 7:04pm:



Really?

What Jim Borton said!  He lives the theory and proves it each and every time he shoots another 250 or tiny group at Etna Green.  There anr not many out there who have made more of a study of trajectory, velocity, and wind effect. and...

Like I said..."what Jim Borton said"

Believe it!