What's going on here?

[Varminterror]

Thank you...I knew there was a reason I tagged you.

Since there can be a lot of variation (I assume) in the thickness of the neck wall brass, do you do this for every round, or a small sample, or what?

There typically isn’t a terrible amount of variability in neck thickness within a Lot of brass. Certainly more variability and non-uniformity in some brands of brass than others, but not usually so much that a guy has to measure and adjust for every piece. Measure 5-10, see how much variation you have, and pick an appropriate dimension out of the lot.

If you’re using standard dies, you won’t have control over neck tension. You CAN send your die to the manufacturer (or local machinist) to have it honed for the right neck diameter and you can either turn expander balls to the right diameter or buy mandrels of the right size, or you can adopt using neck bushing dies… but neck tension is a very important influence on good burn.

But I didn’t ask yet - are you using magnum primers?

 

[LocoGringo]

#1 save that H414 for when your son graduates to the 140s. My wife’s 7-08 loves it with all the 140s I’ve tried in hers; beat out RL17, RL19, IMR 4350 every time I’ve switched bullets.

#2 let your barrel cool til it’s like warm to the touch, not “not too hot to touch.” I don’t know if this will fix your SD, but it should improve accuracy. They sell battery powered fans to blow air through your barrel that significantly reduces the time it takes to cool.

That was my plan for H414. I have 500 139gr Hornady Interlock BTSP that came with my kit when I originally bought it. I also bought 100 162 grain SST to tinker with. I noticed that H414 seemed to do well with heavier bullets in 7mm-08 even if it's temp sensitive.

Have you tried StaBall 6.5? I've heard good things about that powder for 7mm-08, but I don't want to commit a sizeable sum of money before reading/hearing more.

My barrel never got "too hot to touch". It's a HEAVY contour that is fluted.

 

[LocoGringo]

But I didn’t ask yet - are you using magnum primers?

Federal 210M

 

[Varminterror]

Federal 210M

I’d give it a run with 215M’s to see if hotter primers clean up your ignition.

 

[Random 8]

Short reply before as I was in a hurry. I've worked a lot with Bl c2, mostly in. 308. It does not like soft loads. It can be superb at or near compressed with high pressure. If you are going after 7x57 speed loads, I'd look to one of the IMRs or H4895, possibly AA2495.

 

[kalielkslayer]

That was my plan for H414. I have 500 139gr Hornady Interlock BTSP that came with my kit when I originally bought it. I also bought 100 162 grain SST to tinker with. I noticed that H414 seemed to do well with heavier bullets in 7mm-08 even if it's temp sensitive.

Have you tried StaBall 6.5? I've heard good things about that powder for 7mm-08, but I don't want to commit a sizeable sum of money before reading/hearing more.

My barrel never got "too hot to touch". It's a HEAVY contour that is fluted.

No, I didn’t try Stabil 6.5. I don’t think it was available when I did her load developments.

I started with Hornady 139 SSTs. They were the most accurate of any bullet I tried. But after a few antelope/deer kills, I realized she needed a heavier constructed bullet for elk. I started with the 140 grain Barnes TSX, and never looked back. Again H414 was the winner, if only by a little over RL19. She’s killed 2 elk with that bullet, both between 180-200 yards. One died in it’s tracks. The other staggered 8’, and died. That said, bullet placement was optimal in both cases.

Good luck with your work up.

PS: I kind of did the same thing as you are doing with my daughter. I worked up a 120 grain Ballistic Tip for my .280, downloaded. I let her shoot it quite a bit when she was 12-13 yo. But she hunted with full load 150 grain bullets. I let her build confidence with the light load, but didn’t compromise when it came to hunting. I don’t think she knew the difference shooting at game.

 

[LocoGringo]

I’d give it a run with 215M’s to see if hotter primers clean up your ignition.

The challenge will be finding some now.