Barrel Length vs Velocity. Some practical examples.

I recently had the barrels of two hunting rifles shortened which gave me the opportunity to actually measure the difference in velocity between barrel lengths in the same rifle with the same load.


7x57
130gr Peregrine VRG4
48.5gr IMR4350
Velocity 22" barrel: 2757fps.
Velocity 20" Barrel: 2714fps
Difference in velocity: 43fps
Average velocity loss per inch: 21.5fps


6.5 Creedmoor
143gr ELD-x
39.5gr S365
Velocity 24" barrel: 2590fps
Velocity 18" barrel: 2450fps
Difference in velocity: 140fps
Average velocity loss per inch: 23.3fps

Thats good confirmation of the 25fps/inch rule of thumb...

If you want more examples, google "Ballistics by the inch".

They have cut down a fair variety of calibers incrementally and recorded the results.

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Originally Posted by Heath Robinson

If you want more examples, google "Ballistics by the inch".

They have cut down a fair variety of calibers incrementally and recorded the results.

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Thanks, I have seen that, rifleshooter.com also have some interesting examples of cutting back the barrels on rifles in a few popular calibers.

Thanks TStone. Why did you cut them down as a matter of interest?

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I recently had the barrels of two hunting rifles shortened which gave me the opportunity to actually measure the difference in velocity between barrel lengths in the same rifle with the same load.

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Were the barrels shortened by cutting off sections at the muzzle end only? Or also re-chambered (shortened from the breech end)?

[QUOTE=Desperatezulu;1516136]

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Originally Posted by TStone

I recently had the barrels of two hunting rifles shortened which gave me the opportunity to actually measure the difference in velocity between barrel lengths in the same rifle with the same load.
Were the barrels shortened by cutting off sections at the muzzle end only? Or also re-chambered (shortened from the breech end)?

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Only shortened from the muzzle end.

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Originally Posted by DaavG

Thanks TStone. Why did you cut them down as a matter of interest?

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I wanted to put suppressors on the rifles without affecting the handling or adding too much weight.

Quote:

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Originally Posted by TStone

I wanted to put suppressors on the rifles without affecting the handling or adding too much weight.

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Ahh okay.

Decided to send a PM instead.