speed difference

[acssa]

I have 2 of the same VLP Savage 243 Win rifles.... the one shoot 100+fps faster than the other.

Free bore difference 0.083" ... I can use factory ammo or hand loads... one always shoot 100+fps faster. (same brass, same powder, bullets.... same factory ammo from same packet.)

according to Quickload the pressure is over max on one rifle and OK in the other.( i dont load touching the lands using 0.02-0.03" jump)

any comments please?

 

[Marksman63]

It should be faster the one with less fb, isn't it?

 

[acssa]

The one with less FB is faster, but does it make a difference if the COAL is the same... and not one is on the lands.

It should be faster the one with less fb, isn't it?

 

[Brians356]

If the bullet jump is only 0.020" and the bullets are seated deep enough, and are long enough, then the base of the bullets should both be still well within the confines of the cases when the bullets enter the rifling. And the one will be 0.083" deeper in the case than the other. I could easily see how max pressure would be different, and also the pressure profile.

But the condition of the bores could be a lot different - one could be tighter, or rougher, or both. 100 fps is not a whole lot to account for. Also, we assume both chronographed under the same ambient conditions (i.e. temperature) and you have alternated between the two guns enough times to reveal a definite repeatable pattern. And the guns have both been in the same state of cleanliness WRT fouling (powder and copper.)

 

[Ggmac]

Back to , each gun is a rule unto itself . Bore size , condition ,chamber reamer ,first chamber cut or last . Same for deep hole drilling and ream and buttons . Hammer forged I don't know much about but would guess it's the same . They all have min and max allowable tolerances ( new vs used about to be replaced .

 

[vlcakc]

Not too unusual. Two friends ordered identical Remington 700's in 7mm Rem Mag at the same time. One consistently shot several factory loads 90-100 fps faster than the other. Both brand new guns just a few serial numbers apart. Just normal manufacturing tolerance differences. Vic