The UK's Finest Independent Forum for Shooters and Gun Owners. Est 2010.

Was doing some OGIVE measurements on straight-pull AR-10 308 (POF-308)
Bullet head is Sierra 175grn matchking. The OGIVE with hornady guage was consistently giving 2.3"
However, I tried reloading according to this OGIVE measurement in new Hornady case, the the O/L was exceeding the SAAMI spec of 2.810"

Should I reload to the max O/L of 2.810" to get the bullet as close to the lands as possible?
or just replicate GGG match ammo with the 175grn heads which is a bit shorter O/L?

How does the GGG 175gn shoot? If it shoots well then why change. I find OAL tuning is the last thing to worry about after having found the best powder/bullet/charge. Closer to the lands is not necessarily better, your bullet may like a considerable jump. If you are feeding from a magazine, then mag length might be your deciding factor.

Bullet heads ?
Heads ?
There is no such thing as a bullet head.

Do both and see which works best?

If you are using the Hornady LnL OAL gauge with a modified case and pushing the bullet into the barrel then you're measuring the distance to where the bullet hits the lands.

That will give you a maximum COAL, that's why it will be longer than usual.

I have a Steyr 308 which, with Lapua 155's, gives a maximum COAL of 2.93", I simply load them to 2.8".

Don't beat yourself up....try measuring the overall length and length to ogive of a couple of dozen bullets and look at the production tolerances.

Pete

Build to factory, 2.800" it is an AR10

As long as it fits in the magazine...

Thank-you for all the feedback and advice, much appreciated!