I have a 30-06 Winchester M70 with a 23.5" barrel and my freind has a 30-06 Savage 110 with a 22" barrel. My M70 was correctly settled in and cleans up very quickley compared to the Savage that was never settled in and gets only fair cleanings as my freind doesn't know how to properly clean the bore (I'm trying to teach him). The M70 seams to only get 2850fps from 165gr Nosler Ballistic Tips in front of 58gr H4350 and the same 2850fps even with 165gr Light Magnums. The Savage pushes the same Noslers at almost 2900fps and the same Light Magnums to just under 3000fps. Same cartridges, shorter barrel, more fps. All I can figure is that the M70 barrel is so smooth that the bullet leaves the barrel too quickley to allow the full pressure to build for maximum fps. Does this sound anywhere near correct or could there be something else going on?

Thanks for any info

Do the guns have the same twist rate? Sometimes twist rate can make a difference.

There can be a number of reasons your friends barrel is "faster". Your smooth clean barrel might be able to use a couple of grains more powder to build to the same pressure level as your friends, internal barrel dimensions can also influence the velocity. You can take two barrels made by the same maker, chamber with the same reamer, load, same length, test with the same case, bullet, and powder charge, and sometimes the difference will amaze you.

Both rifles have the standard 1 in 10 twist. I never thought about internal bore dimensions. That makes sense as the barrels are from different manufacturers. You have to admit though that 100-150fps more speed out of a 1.5" shorter barrel seems a little much. The M70 groups .5 - .75 with the Noslers so I guess I really shouldn't complain.

hudsonm,

Welcome to the forum.

This sort of thing happens quite a lot with different barrels.

We've had 5 identical factory rifles shoot the same factory ammo with 150 fps difference between the fastes and slowest.

I have heard all sorts of different reasons given for this, but I am afraid non of them sound convincing to me.

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saeed@ emirates.net.ae

www.accuratereloading.com

That not at all uncommon, velocity can vary 100 FPS in barrels of the same make, twist and lenth...

There are fast barrels and slow barrels, depending on snugness, depth of rifling and various other factors...

It just happens....

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Ray Atkinson

ray@atkinsonhunting.com
atkinsonhunting.com

Chamber dimensions and freebore can also have and effect on velocity.

Thanks for all the input. At least it appears that nothing is wrong.

Thanks again,
Mark