Need some help!!!!!! (Mearsuring Bearing Surface of Bullet)

[wildcat]

Hey everybody, I started mearsuring my 142 grn MK'S today with my new Bearing Surface Comparator. This is what I found so far. I conducted a test on 200 bullets. I found my zero point (.000)and started the test. Most of these bullets (160) measured between .002 from each other. There were some(40) that measured .004 and .005 from the group that fell into the zero to .002 range. I think I am doing this right. WHAT IS AN ACCEPTABLE DIFFERENCE, IN MEASUREMENT, BETWEEN EACH BULLET. I know I am supposed to be looking for the bullets that have the same bearing surface, or close to the same. I need help with this process, I am new at doing this and want to make sure I am doing it right. Thanks guys, Wildcat.

 

[goodgrouper]

The numbers you came up with indicate to me that you are doing fine and the lot of bullets you have is very consistent and it is average for Sierra 142's.

To measure 200 bullets and only have .002" variation in most of them is going to be fine. The few that are out .004" from the average will still shoot fine, you just need to load them up together and label them somehow so when you are out shooting you can shoot all the same for group size.

I usually take a sharpie and make different symbols or colors on the case heads. Then I know to shoot all the same symbols before I move on to the next. /ubbthreads/images/graemlins/wink.gif

 

[wildcat]

Goodgrouper, thank you very much!!!!! I thought I was doing it right, but I just wanted to make sure. I knew I could depend on someone, on this board, to give me advice. Thanks a bunch!! Wildcat