Short barrel velocities

[AKJ]

There is a lot of data on 308 and even 6.5 creedmoor velocities out of shorter barrels, but what are you all getting with other cartridges, namely .270 win, .30-06, .280ai, or similar?
I’m looking to get a rifle and cut it down to 16-18” and run a suppressor for hunting.

 

[Antares]

Subtract 25-30 fps per inch of barrel length lost. Most factory ammo velocities are based on a 24” barrel.

 

[z987k]

Subtract 30fps/in to be on the safe side, you might get a bit less loss than that, but that's what you should count on.
Sometimes it gets bigger as you get really short, like under 16in sbr stuff.

 

[JP100]

Really depends on each case and the load you use, powder selection can help.

Currently I have an 18" .308 shooting 165s at just over 2700fps, which is the same as book load data for 24"
I had a 20" 300wsm shooting 180s at 2950fps

'bigger' bores will loose less velocity per inch, ie .30cal vs 7mm etc. a .308 is better than a 7mm08 if all else is equal when it comes to shorter barrels, .338 federal would be better again......and so on

Short fat cases should burn the powder better aswell, ie a WSM vs a normal 'magnum'

.308 and WSM, SAUM family of cartridge's are really popular here for shorter barrel suppressed rifles(everyone has one).

Also with load work, step to a slightly faster powder(ie faster burn rate)

You dont loose as much as you think, and in the field on game, the difference is not noticeable.

 

[loadsandlattes]

For what it's worth, I cut a 24" 7mm Rem Mag down to 20". Before I cut, I chrono'd HSM Berger 168gr VLDH handloads at 2940. After cutting it down to 20, I think it was right at 2750. This was with a suppressor.

 

[thinhorn_AK]

My 30-06 lost around 80fps with 4": removed from the barrel.

 

[762 ULTRAMAGA]

There is a lot of data on 308 and even 6.5 creedmoor velocities out of shorter barrels, but what are you all getting with other cartridges, namely .270 win, .30-06, .280ai, or similar?
I’m looking to get a rifle and cut it down to 16-18” and run a suppressor for hunting.

I'm getting 2800 fps from an 18" barrel with 180 vlds from a 7-300wsm improved, basically a 7 wsm.