bullet weights.

[tracker12ga]

Me and my friend are getting into the long range game and we are in the process of getting loads worked up for our weapons. My friend is using Hornady 7mm 139gr SSTs in his 7mag and they are shooting pretty good at 100yds. one thing we have noticed though is that when we weighed the bullets out of curiousity, we discovered that they are all not exactly 139gr. they vary from 138.9gr to 139.7gr. We did the same thing to a box of Sierra 7mm 150gr MKs and discovered that they ranged in weights from 149.9gr to 150.1gr. Much more close than the Hornadys.

I understand that at a couple of hundered yards, the various bullet weights in the SSTs propbably are not going to make make a difference. But what will happen at several hundered yards with the SSTs? Will these different weights make a difference in POI?

 

[kiwi3006]

There will usually be a bit of variation in bullet weight, it will make a bit of a difference, but probably not as much as other things,ie neck tension and velocity difference between shots.
The 7mm mag is a great long range rifle, but to get the most from it you might like to try the higher BC bullets, like the 162 a-max and the 168 berger VLD both have a G1 BC greater then 0.6.
You won't shoot these as fast and you might get more drop (but that is easy to calculate and allow for) but you WILL get less drift, and that can be hard to judge at times.
For example at 600 yds with a 10mph crosswind my friends 7mm mag with 150 Sierra gamekings drifts 3.7 MOA, my 7 mm mag with 168 bergers drifts 2.7 MOA, that is 1 MOA or 6 inches difference, thats enough to blow you off the shoulder into the guts if your estimation of the wind is wrong.

Stu.