BTHP trouble reloading

[GunTroll]

Any one ever had problems with COAL using BTHP? I can't get two cartriges to measure the same in my .308 win using either seirra or hornady bthp. I've got a rcbs 308 die that works well with every other bullet but bthp's. Allways +/- .010 of my desired COAL. Is it the hollow point affecting it? I'm new to loading any bthp and just don't get it.

[10x]

RCBS are good dies as you said and you sound well experienced.
Theonly thing that I can think of is too much neck tension that is causing some crushing some of the bullets when seating.

The BTHPs are not tough bullets.

[GunTroll]

I found out what was up. The tip isn't uniform from one to the other. After doing some research out there on the net I found a device that measures seating depth as a good way to tell COAL. I'm gonna post a link to what I found. I made on of these and the other contraption he has made out of a piece of brass. It's amazing what one could find on the net. I have found all of my "problem" loads to be +/-.001 after using this. Its neat to know your chamber length as well. You just got to find a sweet spot for your mag to function with the loaded ammo. I got somewhere around .120 of jump to the lands after measuring my chamber. Accuracy was still good with this jump but I'm gonna extend them a bit and see what happens. If anyone makes the brass thing be sure to remove the burrs from the neck before use. It took me 20min to make the caliper gauge thing. Real easy to do.
http://www.larrywillis.com/calipers.html

[10x]

Well, I am surprised about the bullet tips. I would have expected the BTHPs to be more uniform. Glad that you found a solution.