Semisane

I think I pretty much understand the twist/bullet lenght/stabilization thing. But I'm still interested in resolving the different view points expressed by UncleNorby and Articap.

If a bullet is shot from a barrel that has a 1:48 twist, is it possible for it to increase its rate of rotation after it leaves the barrel? That just doesn't seem possible. It seems it would rotate once for every 48 inches of travel. The issue is number of rotations per unit of distance vs. number of rotation per unit of time. Actually, rotation must slow down over both time and distance due to air friction.

Clearly, a faster bullet will have a higher RPM (time). But how can shooting a bullet faster cause the rotation to exceed the twist of the rifling (i.e. one rotation in 48 inches)?

(EDIT: Bronko got his answer in before this hit the screen. I agree.)

sabotloader

bronko22000

OK - I am having trouble with this one.... Would not the Revolutions Per Minute be consistent for only a short distance out of the barrel and then start to decay with distance. As it decays it reduces RPM. The trick is to get it to the distance you want it get to before velocity and RPM's have decayed to the point that accuracy is lost...

Granted as Bronko says with greater velocity it will cover the distance quicker before decay become as factor.

But I am still thinking velocity and RPM's will reduce over a given range????

Thinking that is where I always get in trouble..

Semisane

Yep. But velocity decays faster than RPMs.

Big Z

SL, velocity degrades much faster than RPMs.

lemoyne

all that is correct but a lot of it does not apply. Most muzzle loaders do not push the bullet 2000 fps a few heavy loaders and smokeless shooters that use a muzzleloader will push up to 2400 fps at these velocities a 1- 28 or a 1-24 depending on the length of bullet will do the job what amazes me is that people using 70 or 80 gr and shooting 1350 to 1450 fps get such good accuracy, one thing in there favor is that there is very little stress or barrel whip with the very light loads.

sabotloader

Yes, i agree with both of you but the fact is RPM's will decay. So in my thinking the greater the velocity the longer the projectile will retain the RPM's to remain stable from a given twist??????

sabotloader

lemoyne

But, Lee I think that goes right back to your shooting background... when you were shooting bench competition were you shooting for velocity or accuracy? I believe greater accuracy (consistently) can be had with a reduced load from what you might use hunting...

Semisane

I'll buy that (and I want a side order of fries), though I suspect it's not an issue except with bullets that are "longish" for their caliber.

Big Z

From a given twist, the higher velocity will give greater RPMs and therefore deterioration would obviously take longer..

Semisane

Unlike some of our threads.