My first load was created back in Dec/Jan for a 7mm-08 with a Barnes TTSX, and Varget. I followed the directions on Barnes’ literature, and things went swimmingly well. I’m very happy with that load.
Now I’m trying for 280AI with a Barnes LRX. Brass is new in box Nosler and powder is H4831SC. I’m not doing a ladder test like I did with the 08 (thanks to reading Jim’s posts and watching Hornady’s podcasts), but I did want to load up a few rounds at differing powder loads (much larger changes in charges 1grain vs 0.5 prior) just to check for pressure.
Using a Forster micrometer seating die, Forster Co-ax press.
So loaded up the first two charges and all went well. Then on #3 when I checked the base to ogive it was 0.005 longer than #1 and 2. #4 was even longer by another 0.005. Not feeling any crunching or hearing any. I’m about 1 grain away from the max listed on Barnes’ literature which is listed as compressed.
I pulled all of those bullets and dumped the powder and tried again on fresh cases. Exact same findings, #1&2 ok, #3 longer and #4 longer again. Tried a 3rd time and yet again, exactly the same.
I’m guessing that the powder is keeping the bullet from seating fully, but if anyone has other explanations I’m all ears.
Going forward, should I:
crank down further on the die and see if that will get the bullet to the appropriate depth?
Just stay with a load which doesn’t lead to the bullet not seating fully? That will put me at the very bottom of the H4831SC range.
Switch to different powder, assuming I can find any?
Accept the difference in seating depths and see how it shoots?
If you’re a full grain away from a compressed load, I can’t understand how the seating depth would be changing.
My best guess is the die is just slipping a tiny bit as you load more. You could test that theory by loading them in reverse and seeing if the last cartridges have a longer seating depth when going down in powder charge instead of up.
5 thou of variation in seating depth is not huge but still probably something you’d want to chase down to see why it’s changing.
Congrats on diving into reloading. Intimidating at first but addictive in the end. I always feel like a mad scientist after I reload.
I will have a difference like that some times. I check my length on every bullet and some are londer. I save those for the end and turn my die down a little bit till the long bullets seat all the way. I assume not all bullets are shaped exactly the same. Maybe the o-give is different every once in a while.
First, I don’t have a lot of faith in the Hornady seating depth tool. The measurements for “jam” are very inconsistent, by 10’s of thousandths of an inch. I’ve measured some factory ammo that should be jammed up based on my measurements with the tool, and they function just fine w/o sticking the bullet.
Done some more work with 4831SC with some minor changes to charge and seating. I will say this, it’s a very consistent load. I’m getting 0.6 to 0.8 inch groups at 100yrds, and with varying the depth or charge, there’s no statistically significant change in group size at all.
However I am concerned about what my Labradar is telling me. I’ve got SD’s in the mid-teens and ES of up to 40 fps. Thinking that if i stretch this gun out to longer distances, those big spreads will bite me.
So today i found some Hybrid 100V, which is on Barnes’ list. It’s max capacity is quite lower than 4831SC, so no issues with compression at all. Shooting a 20 round test my MV’s were darn close to 4831SC, but my SD was 7 and ES 20 (roughly 1/2 of what i get with 4831).
However now my groups have opened up to just over an inch.
So, should I:
Stick with 4831SC and just live with the ES/SD issues because it’s shooting smallest groups, (and is temp stable, etc)
Work some more with hybrid 100V? Make some large seating changes and see if I can tighten it up?