So, how much effect does it have on long-range trajectory? I got the tools I need to measure bearing surface and sorted out 120 Sierra 6.5mm 142gr MKs. I got a spread of .009" Is this anything to worry about? Am I too anal?

Thanks, Lee

The only way to know is to shoot them and see. It would probably take a rifle capable of 1/4 MOA to be able to tell subtle differences in bullet construction downrange.

My guess is that if what you're looking at is actually an accuracy concern, Sierra would have stricter tolerances.

I plan on trying that same bullet in my Swedish Mausers in the near future, in hopes of duplicating the Swedish military 143 grain long range round.

Dan

Lee

I have gauges that I have made to measure the distance from the (rifling)contact point on the ogive to the end of the bullet, bearing length, heal length (if boat tail design), etc, ad nausim. Even with my rifles in a rail gun type of rest (return to battery system, I can tell very little difference, until I start shooting at 400 yds+.

I have just finished loading 200 rounds of 300 Win Mag (on steroids), 79.0 grains of H4831, Fed 215 primer, 190 BTSP (Hornady), @ 3150fps. DON'T EVEN THINK OF USING THIS LOAD IN YOUR RIFLE! ! ! I used two boxes of bullets, both from the same lot, but with bullets that varied by .045" in length, with a bearing surface length difference of .035". Guarnteed, these 200 rounds (which I will use for 200-300 yd gong work) will shoot so close to the same point of impact that I could never tell the difference.
I have found that bullet construction, ie. jacket & core hardness seem to have more effect on pressure than a few thousands difference in bearing length.
Any insite that you have, when you shoot your rounds would be appreciated, as we all learn from someone elses experiences.

Good hunting,
Dale (M70)