follow through and barrel time

[B_Koes]

I've got this nagging question that has been keeping me up at nights and I'm hoping some of you can help me out.  I've read that some (or many) of the rifles used by the top shooters in the country have long barrels (like 25"+), but this seems counterintuitive to me as I would think it is important to get the bullet out of the barrel as soon as possible...thus the reason follow-through is so vitally important.

I read Tony Tello's post that the national champion uses a bloop tube on the standard rifle and a 20" barrel on the hunter rifle.  Is this a common setup for the "top" shooters?  Enquiring technical minds want to know what is generally considered a good trade-off of barrel weight and length.

[ajj]

Just guessing here but it seems logical that the last few inches of barrel aren't that important. For follow through we first consider lock time between trigger breaking and the start of ignition. Then, barrel time should be affected more by the fact that the bullet must be accelerated from rest...that is, it's moving so much faster near the muzzle that a little extra length shouldn't matter. Should it? I'm trying to say it spends most of its time in the first half of the barrel. Sometimes I miss things (other than targets.) I remember reading somewhere that barrel time for the projectile is approximately 16 milliseconds for a match (500-600 fps mv) airgun, 8 ms for standard vel .22 rimfire and 4 for the average highpower. I don't know whether that's right either.

[shootingpaul]

I think Anschutz was the first one making rifling for only 17 inches and then it was only a tube (for peeep sights), so they figure out that after 17 inches (in 22) there is no gain for the bullet, I agree that the shorter barrel the smaller time for the bullet to leave it, but for our game if you have a good follow through then - it does not matter if it is 17 or 24 inches, by the way I did not see many guns above 24 inches - lets specify 24 inches of rifling, usually custom 22s are around 19 or 20 inches rifling and then it is only a tube.
for HP is a different story - because you can gain higher vel fom a longer barrel - so for sure in HP I would like to shoot more than 24 inches
I hope it hlep you, if not then you just got confuseed as i am right now -so it is time to end...............
have a good one!!!

[dave imas]

everything said is true...  but don't forget balance.  probably the most important reason folks will have a barrel longer than 17"  good balance allows a slower barrel, more time in the target, and better executed follow-thru.
dave

[genphideaux]

Well said dave  imas and to add to your answer the optimum barrel lenght for a .22 is about one full rotation of the bullet in the barrel anschutz twist is 16.5 so a 17in barrel is pretty close, as they say all the rest is just personnal.

Dawg

[B_Koes]

Thanks for the responses.  I find it very interesting.  This question really started in the pistol realm where I started (and continue) to shoot silhouettes offhand.  There is a general consensus that a 10" pistol barrel is better than a 14", but there is precious little (if any) data to support that.  I am hoping to do an experiment with some various length barrels like 14", 10", & 6" in the .22LR chambering to see if I can get a distinguishable difference of offhand groups.  There has to be similarities between the pistol and rifle game so this is why I was asking.  Of course there are differences as pistol shooters do not have benefit of the gun being in contact with the shoulder nor are they allowed to brace either arm against the body which makes for a much more unsteady hold.  This is why I think it is probably even more beneficial for the pistol shooter to get the bullet out of the barrel quicker.  Afterall, subsonic ammo attains over 90% of its terminal velocity in the first few inches of the barrel.