30-06 velocity and barrel length

[JeeperCreeper]

I know this has been beat down before, but looking for fresh data.

I scored a CZ600 in 30-06 for $350 (after rebate) and waiting for it to come in. If it shoots like my Creedmoor, it should be an easily consistent sub MOA rifle.

But the velocity out of the 20" barrel concerns me. I might want to use it for hunting. I'm in Alaska. And I want to use copper bullets (need for speed for maximum performance).

How much velocity should I expect to lose on a 20" barrel as opposed to a 24" with factory ammo?

I'm worried that I'll be limited to 250 yd with 180gr Hornady CX with velocity.

Thanks in advance for your thoughts!

 

[Russ57]

Probably about 100-150 fps.

If I was going all copper I'd trade bullet weight for velocity to ensure expansion. I wouldn't be afraid to try a Barnes 130-150 grain if I needed to reach out there. Inside of 300 yards 165-168 grain should do fine.

Of course bullet choice depends on what you want to hunt.

 

[Gtscotty]

https://www.snipershide.com/shooting/threads/16-18-inch-shorty-rifles.68099/post-9940168

There's a post I made collecting up some of my shorter barrelled rifle velocities. My 165gr .30-06 load lost ~120 fps when I had the barrel chopped from 22" to 18.5". I'd expect less loss per inch going from 24" to 20", as you get shorter the velocity tends to drop off quicker.

 

[jmr40]

If you start with a 24" barrel with a known velocity and cut it down to 20" expect to lose 15-25 fps per inch. Or around 60-100 fps. There have been dozens of guys who have done this and posted the results online. It depends on the cartridge, but I've never seen anyone lose more than 35 fps/inch and that is with magnum rounds. Many non-magnum cartridges are closer to 10 fps/inch, but 30-06 class cartridges are usually in the 15-25 fps range.

Where you start and end matters too. There is a reason most rifles have 20", 22" or 24" barrels. Anything longer than that just doesn't net you very much velocity gain. You'd have to go to a 26 or 28" barrel to see any real gains over a 22" barrel. But once you get below 20" you see velocity drop in bigger chunks as you go shorter.

The problem is that no 2 barrels, even of the same length will shoot to the same speeds. I have 2 rifles in 30-06, both with 22" barrels. The Winchester is consistently 90 fps faster than the Remington and is 130 fps faster than a friends 22" barreled 30-06. That is a little on the high side, but 25-50 fps velocity difference between equal length barrels is the norm.

I have 4 rifles in 308 with barrels ranging from 18" to 22". The 2 with 22" barrels are 25-30 fps different, but the one with the 20" barrel is faster than either. The 18" rifle is almost 100 fps slower than the 20" rifle.

In short there is simply no way to know until you shoot it. I'd shoot it over a chronograph at 24" to see what speeds it is getting. Once you know that you can have a pretty good idea where it will be after you cut it.

But a 30-06 @ 20" is still going to beat a 308 shooting the same bullet from a 24" barrel. It's going to be less of a handicap than you may think. The biggest disadvantage is that a 20" 30-06 is going to be obnoxiously loud.