Testing the 155.5G Bergers

Great explanations Dan.

I've been using a Lee Collet for quite some time, and have been quite happy with the results. I feel that if there is an inconsitancy in the neck, the collet will force it to the outside, rather than a bushing puching it to the inside. I dunno, but it helps me sleep better.
 
mpwolf said:
I've been using a Lee Collet for quite some time, and have been quite happy with the results. I feel that if there is an inconsitancy in the neck, the collet will force it to the outside, rather than a bushing puching it to the inside. I dunno, but it helps me sleep better.
Click to expand...

I have the same concerns but address it in a different way. I use a Forster Bushing/Bump die and select a bushing that gives me a neck tension that is about 1/3 of a thou too tight, and then open it up that last 1/3 of a thou with an oversized expander ball. Forster sell these oversized balls in 1/2 thou increments.

Oversized Expander Balls

While significantly more costly to get into than a Lee Collet, I think it gives you a bit better control of neck tension without inducing runout.
 
Ron AKA said:
I have the same concerns but address it in a different way. I use a Forster Bushing/Bump die and select a bushing that gives me a neck tension that is about 1/3 of a thou too tight, and then open it up that last 1/3 of a thou with an oversized expander ball. Forster sell these oversized balls in 1/2 thou increments.

Oversized Expander Balls

While significantly more costly to get into than a Lee Collet, I think it gives you a bit better control of neck tension without inducing runout.
Click to expand...

I've been using the same Forster bushing bump, w/ a .335 bushing, and then running the case into the lee Collet, that just happens to produce .336 necks. Loaded rounds end up being .337. Going to have to try the Forster oversized balls. It would be nice to eliminate the extra sizing stem.
 
Don't you find the expander ball works your neck outlandishly.
Measure the case lenght before and after the ball has been removed, and you should see a difference.
 
RIFLEF said:
Don't you find the expander ball works your neck outlandishly.
Measure the case lenght before and after the ball has been removed, and you should see a difference.
Click to expand...

That can be true in a standard neck or FL die. That is because the neck is sized down 3-4 thou too small, and then opened back up again by that amount. It not only can stretch the case, but also can cause runout especially if the ball is located low in the die. The bushing approach reduces the ball sizing to just a light kiss to uniform and round out the ID.
 
I personally ditch the expander ball on almost all dies. (I use the stem from a 223 die) I use neck-turned and annealed brass. I re-size with a bushing and I use and expander mandrel. This means I am only using the elastic recoil of the neck for neck tension, and it means that imperfections are pushed to the outsude (Far more precisely than dragging a plug through the neck) , including any doughnuts, but these are trimmed as required. VLD bullets seem to love this combination. The 1 thou or so neck tension that results, is actually stout enough that I can jam to 15 thou and not push the bullet back in the case. At least with a number of 6mm ans 6.5mm cartridges.

I have a cool gizmo I found that is like a portable fish weighing scale and it is used to measure setaing pressure on the press (in grams). It results in very consistent results
 
Ishodu said:
I was playing around again and found that the OAL from tip of bullet to the base is 2.956 to the lands with these 155.5g bullets.
Click to expand...

I checked mine and found they were 2.925.

I did a test yesterday starting at 44.3gr Varget, all the way to 47.0gr, in .3gr increments. I loaded 4 rounds at each of those 10 increments, plus 2 foulers.
I shot at 300yds, very little breeze at all, running up to the target after each shot to mark it, so it was about 4 minutes between shots. The 28" barrel was cool, but not cold for each shot. Sorry, no chrony.

Here's what I noticed, and these were consistent across all 4 targets:
- load testing the Amax 155 using those same 10 steps took between 12 to 15 inches in height on the target paper, but with the Bergers, the highest vertical spread was 5.75 inches, and the smallest was 4.0 inches.
- there were 2 nodes: 45.2 to 45.5, then a small jump up on the target at 45.8 to 46.1. I'll be testing that last one.
- for some reason, my barrel hates 46.4gr with this bullet: rather than continue the climb as the load increases, every time this shot was significantly lower than you'd expect.

I'll update when I get the final test done.

Updated 05/16/11: 46.1gr has the least vertical dispersion.
 
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