Tweaking OAL

[bsekf]

I use the Hornady tool on my caliper to measure OAL and Forster BR seating dies.

After I settle on a powder weight, I tweak the OAL by turning the seating stem in about 1/2 turn from Jam. That gives me nearly .01, is that too much? I do not measure and sort bullets and I find them to be +- several thousands, so an increase of .003 seems moot.

I never cease to be amazed seeing the groups move around on the target as I adjust seating depth.

Bill

 

[Texan]

Which bullets are you loading?

I'm not sure there is a too much.

I'd load to a length where I got the most accuracy, whether that's jammed or jumped.

Just remember to reduce charges if you decide to load into the rifling.

Any other variables that may be affecting your group sizes?

 

[T-shooter]

I use the Hornady tool on my caliper to measure OAL and Forster BR seating dies.

After I settle on a powder weight, I tweak the OAL by turning the seating stem in about 1/2 turn from Jam. That gives me nearly .01, is that too much? I do not measure and sort bullets and I find them to be +- several thousands, so an increase of .003 seems moot.

I never cease to be amazed seeing the groups move around on the target as I adjust seating depth.

Bill

I use the tool when seating and ignore the overall length of the bullet. I have 2 different caliber inserts and both measure .010" under the bullet diameter. The same bullet can be quite a bit different depending on the lot#. As far as the jump, you should test it to see which shoots the best, maybe in .005" increments, while watching for overpressure signs. In my .308, the 168g Sierra and Hornady and the .208 A-Max shoot the best with a .025" jump. I've been experimenting with the Berger 200.20x's and my best so far is with a .005" jump. A few years ago, I did this test at 100 yards shooting once on each target 1-6, and starting over again. I confirmed the .025" group later with a 10 shot group.