Here’s links to part 1 and part 2.

Just returned from the gun range having shot all the rounds I loaded in part 2. I have results, and they were not what I expected.

What did I expect? I expected to see primers backing out.

What did I see? No primers backed out.

Not a one.

You can see in part 2 how many different loads I made.  I expected somewhere in there to see some difference in primer behavior, but I didn’t see anything. I also shot some Georgia Arms Canned Heat as a “control” and they had no issues either (tho their cases were filthy).

Of course, I’m pleased to see this, but now I have to wonder why the first loads had primers backing out.

I can only think of 2 variables:

1. I cleaned the rifle before going to the range.

Previously I hadn’t cleaned the rifle but didn’t expect it to be that dirty. I have mostly been shooting Georgia Arms Canned Heat and did notice every piece of ejected brass was filthy. Not sure why that is as I don’t have that problem using the Canned Heat in other AR’s… maybe the shorter carbine-length gas system on this Bushmaster isn’t letting things burn well enough, I don’t know. But what I can say is when I cleaned the Bushy a couple days ago, the first turn of the chamber brush dislodged a lot of crud — I had flecks of black stuff landing on me. Could it be the chamber was so dirty? something with the locking lugs? maybe there was just a hair bit of an opening with the bolt? I don’t know.

2. Using different bullets. Here I was using Winchester 55 grain FMJ BT, and the first loads were using Barnes TSX 62 grain. Could that be causing enough difference?

So what now?

Brass doesn’t seem to be an issue. The Remington brass seems to shoot just fine.

Brass prep (e.g. primer pocket uniforming, flash hole deburring) didn’t seem to be a factor here. Note tho all I was doing was shooting and looking for primers. No chronographing, no checking for accuracy.

Primer itself doesn’t seem to be an issue.

So….

I have some 53 grain (or maybe it’s 55 grain, can’t remember,) Barnes TSX. I also have the 62 grain. I’m going to load a few simple loads. Once again I will use new Remington brass, prepped as much as I can prep it. I will use TAC powder. I will use a midline charge weight for the TAC, which will be 25.0 grains for the 55 grain bullet and 23.5 grains for the 62 grain bullet. I will load some “control” with the Winchester 55 grain FMJ bullet. I will load some with the Barnes TSX 55 grain bullet. I will load some with the Barnes TSX 62 grain bullet. And we’ll try again.

If all goes well, I guess I can say “good enough” and move forward in finding the accurate load with the 62 grain TSX (tho I’ll always keep my eyes open for the primers). If it doesn’t go well, well… I’m not sure. Cross that bridge when and if I get to it.

Updated: link to part 4.