Stalled on 308 load development

BLACKBRIAR

BLACKBRIAR

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New barrel load development and I'm stumped on best way to proceed, trying to be efficient with components. Seating depth is my next step, then tuner to clean up as needed.
IBI barrel 24" 1:10, EC Tunerbrake @ 0 (14 rounds through it before LD started)
168 ELD-M
Lapua 2x fired (annealed, trim, 2 thou tension mandrel, 2 thou shoulder bump)
CCI BR-2

All 5 shot groups with VARGET

43.0 gn - 2684 fps, ES 24, SD 9.3 group size .523 (small "r" looking)
43.5 gn - 2709 fps, ES 25, SD 10, group size .374 (cluster)
44.0 gn - 2750 fps, ES 28, SD 12, group size .581 (Meh group - ugliest looking)
44.5 gn - 2776 fps, ES 23, SD 10, group size .512 (T looking group)
45.0 gn - 2796 fps, ES 27, SD 11, group size .427 (4 rounds in .240)

I was hoping for a stand out low ES, but they are all close. Do I just pick one (43.5 or 45) based on group size and carry on. Any input is appreciated.
 
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Are you FL sizing or just kissing the sholder?
I found that made a difference in my 375ruger.

Playing with seating depth will change load density.
Which will change Es and Sd from what I read.
But I don’t have a crony yet. It’s in the mail now. Lol.
 
What distance are they for?

If anything beyond 100, the SD does not matter much.

Shoot at 300 or 600 and find the least tall group.

Virgin factory-primed Winchester brass, Sierra 155 525 yards. 20 shots. About 1 3/4" tall

vM2tcbE.jpg
 
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43.5 looks good I would play with primers personally. I know your using BR primers but I have several target loads where normal primers shoot as well or better then the Br ones do.
 
^^^^ Not sure what the issue is in the above post, but I see how he drives up his post count. ^^^^

Ganderite: out to 1,000 yards ( I added the SD because someone would have asked)
sonichanxiao: Autotrickler v4. I will develop my load for now and verify the load with a higher round count later. I do expect the barrel to settle.
6.5 shooter: I do have some Fed 210M, CCI 200 and 250. If I can get some more powder down the road I will try a different primer

extra info Whidden FL bushing die, .306 mandel, Forster micro seating die. Bullet run out 1-2 thou
 
BLACKBRIAR said:
New barrel load development and I'm stumped on best way to proceed, trying to be efficient with components. Seating depth is my next step, then tuner to clean up as needed.
IBI barrel 24" 1:10, EC Tunerbrake @ 0 (14 rounds through it before LD started)
168 ELD-M
Lapua 2x fired (annealed, trim, 2 thou tension mandrel, 2 thou shoulder bump)
CCI BR-2

All 5 shot groups with VARGET

43.0 gn - 2684 fps, ES 24, SD 9.3 group size .523 (small "r" looking)
43.5 gn - 2709 fps, ES 25, SD 10, group size .374 (cluster)
44.0 gn - 2750 fps, ES 28, SD 12, group size .581 (Meh group - ugliest looking)
44.5 gn - 2776 fps, ES 23, SD 10, group size .512 (T looking group)
45.0 gn - 2796 fps, ES 27, SD 11, group size .427 (4 rounds in .240)

I was hoping for a stand out low ES, but they are all close. Do I just pick one (43.5 or 45) based on group size and carry on. Any input is appreciated.
Click to expand...

Depending on what chrono you're using, the differences in SD/ES between all those loads could be well within the error range of the chrono itself. Most chronographs don't have the mechanical capability to genuinely reflect a 1-2 FPS spread.

Personally I'd do 44.5 or 45.5 and rock that load till you're broken in, then reevaluate.
 
BLACKBRIAR said:
^^^^ Not sure what the issue is in the above post, but I see how he drives up his post count. ^^^^

Ganderite: out to 1,000 yards ( I added the SD because someone would have asked)
sonichanxiao: Autotrickler v4. I will develop my load for now and verify the load with a higher round count later. I do expect the barrel to settle.
6.5 shooter: I do have some Fed 210M, CCI 200 and 250. If I can get some more powder down the road I will try a different primer

extra info Whidden FL bushing die, .306 mandel, Forster micro seating die. Bullet run out 1-2 thou
Click to expand...

From the data you captured, it seems you probably want to focus the powder charge around 43-43.5gr. I just checked mine, it's within that range too. My SD is single digit and ES is around 10.
I reckon your ES and SD would settle down a bit more after few hundred rounds. Maybe try to use some cheaper components during this period of time.
 
BLACKBRIAR said:
^^^^ Not sure what the issue is in the above post, but I see how he drives up his post count. ^^^^

Ganderite: out to 1,000 yards ( I added the SD because someone would have asked)
sonichanxiao: Autotrickler v4. I will develop my load for now and verify the load with a higher round count later. I do expect the barrel to settle.
6.5 shooter: I do have some Fed 210M, CCI 200 and 250. If I can get some more powder down the road I will try a different primer

extra info Whidden FL bushing die, .306 mandel, Forster micro seating die. Bullet run out 1-2 thou
Click to expand...

OK. You may be doing the development backwards,

I would test at 900 yards, in 0.2 gr increments, and find the load that shot the shortest group. Lets say it was 45.2 gr of powder and 2825 fps. The key number is 2825. This is the velocity that had the right barrel harmonics.

Once you have that velocity established, THEN you see if you can reduce the SD, without changing he velocity.
 
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