FPS question

[bugsNbows]

If an ammo manufacturer states an expected FPS for the bullet to travel (3000 FPS for example), how does this change with different barrel lengths? I assume they use 24" barrels as standard, how would it translate to a 22" barrel? Would I be correct in assuming a typical decrease of at least 50 FPS in that shorter barrel (from 3000 to 2950)?

ORIGINAL: bugsNbows

If an ammo manufacturer states an expected FPS for the bullet to travel (3000 FPS for example), how does this change with different barrel lengths? I assume they use 24" barrels as standard, how would it translate to a 22" barrel? Would I be correct in assuming a typical decrease of at least 50 FPS in that shorter barrel (from 3000 to 2950)?

What I have noticed is from barrels 20-28, you can count on around 20-30fps/inch. Below that, things change drastically. So many factors play like powder used. Its definately not a linear change. If your bullets say 3000fps, then you should expect anywhere between 2850-3100fps.

[stubblejumper]

Firstly,the velocity can easily vary 100fps or more between rifles with the same barrel length.Secondly ,the amount of velocity loss varies with the particular cartridge.Smaller capacity cartridges like the 30-30 aren't affected nearly as much by barrel length as large capacity magnums.While the 30-30 may only vary 10fps per inch of barrel,the 30-378 could vary by up to 50fps per inch of barrel.

[stalkingbear]

The posted velocity is always with test barrels that are usually longer and possibly tighter in dimensions and will be higher than you get in your rifle in almost all cases.

[Northern Hunter]

The old rule of thumb was 50 fps per inch with center fire rifles. However that doesn't always hold true. The answer may be, you never know. IMO there won't be enough difference in 2-3 inches of barrel to effect performance to a measurable degree.

[eldeguello]

ORIGINAL: bugsNbows

If an ammo manufacturer states an expected FPS for the bullet to travel (3000 FPS for example), how does this change with different barrel lengths? I assume they use 24" barrels as standard, how would it translate to a 22" barrel? Would I be correct in assuming a typical decrease of at least 50 FPS in that shorter barrel (from 3000 to 2950)?

As a shaky rule, one can expect to lose around 25 FPS for every inch that is cut off a standard 24" barrel using a non-magnum cartridge. However, experiments in cutting off barrels and chronographing the load at different barrel lengths has given some pretty unexpected results on occasion. Some of these strange results were barrels in which NO velocity was lost, or where velocity was actually greater from a shorter barrel.

Now, please be advised that because an ammo manufacturer "expects" a certain load to develop3000 FPD DOES NOT MEAN that it will do so in your gun! You could get more, (unlikely but it has happened), or it could be less-sometimes significantly less. The ONLY WAY to know, is to use a chronograph with that ammo and YOUR rifle. If you do this, then your problem is solved, and very positively!