Muzzle Velocity of .308 with 30" barrel

Quinny · Post by **Quinny** » Tue Aug 30, 2011 9:13 am

Has anyone chronographed the speed of a 155gn bullet through a 30" barrel?

I am using 45.8gr of 2208 with a Dyers HBC projectile, and would be interested to know roughly what the muzzle velocity would be (I don't have access to a chronograph and don't really want to buy one). For any calculations for elevation adjustment etc I am working on 2950fps, but no idea how close this is.

saum2 · Post by **saum2** » Tue Aug 30, 2011 9:32 am

Hi,
Yep did exactly that testing a couple of weeks ago with the same load, powder & barrel.
I used my cheap Chrony & got speeds of 2917, then used a top of the market chrony (3 sensors) with same loads etc & got 2935 average. The second test was on a different day and temperature etc. The batch of 2208 I have now is a lot slower than my previous batch by a long way. I'm looking at at least .5 gns more new powder to achieve the speed of my old 2208.
hope this helps.
Cheers

Quinny · Post by **Quinny** » Tue Aug 30, 2011 10:04 am

Thanks, that is interesting to know. I guess anything over 2900fps is pretty good, and should be enough to get out to 1000yds.

I didn't realise that 2 batches of the same powder varied that much - something else that is interesting to know.