Base to Ogive on Berger Bullet

[Kmccord]

I was reloading for.my 6.5 Creed using Berger 140 EOL, and would measure CBTO on each one and noticed sometimes it would seat .0035 deeper. I re-adjust my seating die, pull bullet and reseat to correct CBTO, then I get one about .0035 to .0045 longer, then have to re-adjust again and then end up seating deeper than previous again. I checked my die, nothing moved, then got to thinking about the bullet, and just measured base of bullet to Ogive and noticed some measured .709, .711, .7125, .713 and the worse was .7145. Do you guys verify your CBTO and notice changes in your seating depths ever so often? I am working on load development and about to pull my hair out with the seating depth changing as much as it was. I had even changed dies at one point in another session thinking the die was an issue..

 

[Huntnful]

Hahaha, yeah they'll vary a little bit. It doesn't seem to affect my groups much at all though. I would let the gun tell you if that .003 difference is worth stressing over. You could always sort them beforehand if it really bothered you though. But then you'd have to determine if that extra length is coming from the base of the boat tail, or from the o-give. I'd just load em and shoot em and see if it even has any affect.

 

[Dmagna]

.003 is my limit, I haven't seen it make a difference in accuracy. Especially with a Berger hybrid

 

[BrienM]

That's the reason short action customs among others are doing the "jump" test to find the window where your gun runs the most consistent over a few different lengths.

 

[Shane Lindsey]

I have found if neck tension/thickness causes a harder seating pressure, it tends to be a little longer and have had to adjust the die.

If I overseat/too deep and I pull it, forget about it. Unless I size it again. I just re-seat and mark that as a fowler.

 

[can1010]

as mentioned earlier neck tension will cause a problem. but I would put my money on the nose length not CBTO on a hybrid being a problem bottoming out in the seating stem. the hybrid nose are known to be inconsistent. try bedding your seating stem using the bullet with the longest nose

 

[Kmccord]

Neck tension is set with a Century 21 mandrel at .2625, it was driving me crazy measuring and seeing the three round group fluctuate in seating depths.

 

[MagnumManiac]

I had the same issue, so I started trimming meplats, but didn't point the tips after.
Still had a variance, so I started pointing, and the variance went away and the BC ended up quite higher.
Now I have all this gear and no bullets to trim or point!
Had to move to a solid CNC turned 338 323g bullet, no trimming or pointing required.
It is the ogive that is varying, not your die or seating stem, it can be a head scratcher.

Cheers.

 

[Kmccord]

Yes sir it can be a head scratcher, I have an issue when the three round group has one that is off by .003 and when I have a flyer in that group then it has me wondering was it me or something else. I think I am going to try me some Hammer Hunters in 123gr and see if those have the same issue.

 

[ShtrRdy]

Be aware that the seating stem in the seater die contacts the bullet at a different place on the ogive than bullet Comparitor tool.

 

[Jud96]

I'm surprised Bergers were that inconsistent. I generally see less than .002 difference from Berger bullets. My CBTO are all +-.001 using Berger's. Maybe you just got a bad lot?

 

[Kmccord]

I have another lot to try, I plan to open those and test them.

 

[Jud96]

I have another lot to try, I plan to open those and test them.

If that lot is equally as bad, you may want to contact Berger and let them know. That's pretty bad by their standards.

 

[MagnumManiac]

Have seen variance in just about every manufacturer except Sierra, although their meplats vary quite considerably.
Have also had to turn up seater stems to suit some new bullet profiles like ABLR and EOL.

Cheers.