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Discussion Starter · #1 · (Edited)
Got a chance to hit the range this morning. Beautiful, sunny day. About 35 degrees.
16" ARP barrel. 4-16 scope. YHM ULT can.
SSA brass, Accurate 2200, Federal SPP, and the Midway blem bullets I was asking about in this thread: Help identify these bullets?
Hopefully you can see the pics ok. For some reason they got flipped.
ProChrono DLX at 10 feet.
Brass pic shows lowest charge on the right working left.
I'd appreciate any input on the data I gathered. Thanks!


 

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You sent a lot of components down range. I typically found the lower half of the published powder range has limited usefulness. The first 5 loads have low velocity for the potential of the round you are shooting. And, charges closer to 100% case capacity typically have the better accuracy potential for me.

I use 0.5 grain steps for larger cartridges like 30.06 and 0.3 for 6.8mm. 0.2 grain steps are too close to being the same. Primers and no significant swipes indicate you could explore slightly higher charge rates if you are comfortable reading pressure signs - WAIT - I take that back. You said it was 35F and AA2200 is temperature sensitive so don't go any hotter.

What was your COAL? Adjusting COAL is a powerful lever for improving accuracy. I use 0.015" increments to see if I can tighten up a group. Do you measure your distance to the lands? You may be able to try a longer COAL depending on your magazine and what these loads were seated at.
 

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Discussion Starter · #6 ·
You sent a lot of components down range. I typically found the lower half of the published powder range has limited usefulness. The first 5 loads have low velocity for the potential of the round you are shooting. And, charges closer to 100% case capacity typically have the better accuracy potential for me.

I use 0.5 grain steps for larger cartridges like 30.06 and 0.3 for 6.8mm. 0.2 grain steps are too close to being the same. Primers and no significant swipes indicate you could explore slightly higher charge rates if you are comfortable reading pressure signs - WAIT - I take that back. You said it was 35F and AA2200 is temperature sensitive so don't go any hotter.

What was your COAL? Adjusting COAL is a powerful lever for improving accuracy. I use 0.015" increments to see if I can tighten up a group. Do you measure your distance to the lands? You may be able to try a longer COAL depending on your magazine and what these loads were seated at.
Yeah, "warm" Wyoming winter day, 4000 feet elevation.
I'd like something that will also work in the summer (rarely above 95 degrees), so I didn't bother going above published max in the Western manual.
Using PRI mags, I was just able to fit them in the mag at 2.26". Ballistic tips.
I have never bothered measuring distance to lands on an AR. Seems mag length limits that, and I only shoot from the mag, I don't single load.
 

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2.260" COALs in the 6.8mm will likely not be an issue either. Loading beyond 2.260 would be good to check. You could try 2.245" COAL and see if it tightens up your group. Otherwise, enjoy your trigger time.
 

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You're doing better than I am, that's for sure. I got 700 of those midway blems in 30 caliber that seem to be 165 gr Hornady SST's. Yesterday I tried load ladders with 3 different powders. 5 shot groups, and none of them were less than 3" at 100 yds, many of them quite a bit bigger. I shot a few 1" groups with a factory loading, so I can't blame the rifle. Not really digging these "blems."
 

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You're doing better than I am, that's for sure. I got 700 of those midway blems in 30 caliber that seem to be 165 gr Hornady SST's. Yesterday I tried load ladders with 3 different powders. 5 shot groups, and none of them were less than 3" at 100 yds, many of them quite a bit bigger. I shot a few 1" groups with a factory loading, so I can't blame the rifle. Not really digging these "blems."
I’ve found on several occasions that “blem” bullets did not perform as well as regular retail versions of the same. I don’t think it is always just a cosmetic reason that a bullet is a blem.

In cases blem bullets have shot the same.

it can be a crap shoot.
 

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My understanding is that the category of "blems" includes bullets that fail lot accuracy tests or have other known issues. They are still safe to shoot, though ( well, as long as nobody is at the wrong end of the barrel). I suspect that a lot of blems are undersized enough to fail accuracy testing but still within SAAMI spec. SAAMI spec for 270 bullets for 6.8 SPC and 270 Win is 0.278" - 0.275". We know that most rifles seem to like the 0.277", so most factories hold tighter internal tolerances. In other words, it is possible to have a lot of bullets that are technically "in spec" according to industry standard but produce poor accuracy.

Blems will also include bullets that have problems with jacket thickness uniformity and core distribution. Lead is so much heavier than the jacket material that just a little variation of jacket thickness or core distribution makes the bullet slightly off balance. The bullets are spinning so fast when leaving the barrel that the forces from an unbalanced bullet literally cause it to jump to the side slightly as soon as it leaves the barrel.
 

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If having problems it may help to weigh each bullet and separate them into weight groups of your choosing. I bought 500 blems and weighed them. IIRC they were 100 gr bullets that ranged from somewhere around 96 gr to 104 gr. Pretty sure that mixed they would really throw some wild groups. Have not loaded or tested any of them yet.
 
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