308 Winchester verifying the cartridge OAL

**kemmercur** · 02-01-2011, 02:46 PM

308 Winchester Verifying the cartridge OAL. I have a new Shaw barrel on my model 16 which I have headspaced and checked it twice. I loaded three dummy rounds with Sierra 165 Grain Spitzer Boat Tails with a OAL of 2.850". They feed through the magazine (all three), they are touching the lands. I will back off on the OAL starting 0.35" off the lands and move them closer in towards the lands shooting for groups.
My question is--- the reloading manual states the maximum OAL should be 2.750" with these bullets, is the OAL Maximum I come up with close to real day length's? I'm measuring with a Dial caliper base to tip.
Thanks for any input.

Aircraftmech76 · 02-01-2011, 06:41 PM

Start .020" off the lands and move forward in .005" increments. Be aware that when you get to the lands, the pressure will spike on you if you stay with the same powder charge.

Kevin

NeverNoLuck · 02-01-2011, 07:37 PM

the manuals are a good start on length for any given gun but not every gun

once had a 22-250 barrel that to touch lands bullet was all the way out to 2.49?" when the books said 2.350"

helotaxi · 02-01-2011, 10:27 PM

Originally Posted by kemmercur

My question is--- the reloading manual states the maximum OAL should be 2.750" with these bullets, is the OAL Maximum I come up with close to real day length's? I'm measuring with a Dial caliper base to tip.

The actual max OAL is set by SAAMI and is 2.800" for the .308 Win. The 2.75" listed in the Sierra manual is their tested COAL. Pressures and velocities are based off that length for their load development. If your rifle will allow you to seat them farther out and they shoot better with a longer COAL, go for it. If you need/want to go shorter, you'll need to back the powder charge off and watch for pressure signs.

**GaCop** · 02-02-2011, 08:25 AM

Do yoy use the Hornady OAL Gauge? if not, you'd be better off getting one to find out what your length to ogive is and work from there. Done with the Hornady tool, manual OALs are meaningless. After determining your OAL to the lands, adjust the length to be compatible with the length of your mag box.