Inconsistent neck tension

[WestMOhunter]

Have a new pressure issue. When doing load dev on new Peterson brass I chamfered and loaded. Good results. Calibrating charge & neck tension for fire-formed w/ following approach: Hand anneal (torch/drill), Hornady One Shot, FL size with bushing die and expander ball, wet tumble, chamfer/debur, load. I will get a HARD seat on occasion which are giving me velocity spikes. I thought the issue may be annealing, but I’m careful to be consistent with flame placement and timing (1,2,3,4,dump) - same annealing coloration and location as Peterson. Still, could be that. I have read that wet tumbling can create a dry, “sticky” neck, but you’d think that would be consistent and new brass is “clean.” I’m seeing this more with 162 ELDX, not with 168 ABLR. So bullet dia., copper hardness and/or bearing surface is making whatever is going on worse. I’ve dropped back over a grain.

Charge weight variation is a possibility (Chargemaster) but 0.1-0.2 gr variation isn’t going from good to bad. I’ve shot 100 yd pressure test groups w/ 2 grain swings and had better results. A little perplexed. Next step is expander mandrel, but I’ve never had to do that and many outside BR shooting say unnecessary. Last thought is media tumbling to eliminate the dry/sticky neck. Thoughts?

 

[KyleR1985]

I don’t tumble, I just wipe brass with a paper towel and rubbing alcohol to clean it. And brush inside of neck wjth nylon brush prior to sizing.

It gets wiped again after loading to remove any lube.

I’m an idiot when it comes to reloading. But it seems like doing whatever you’re going to do to clean your brass, should be done before you size it. Otherwise whatever neck imperfections, debris, etc. is gumming up your expander ball bushing and the neck of the brass.


Seems like tumbling after sizing is a good opportunity for necks to get dinged and imperfect. Then chamfering will cut into parts of the neck more than others. That could be the culprit.

If the goal is to minimize variables/maximize consistency - expander ball out and powder bullet in - with nothing in between, seems best.


Again - reloading idiot.

 

[WestMOhunter]

Good point. And it’s a variable I hadn’t previously introduced. It’s not my typical process, but got some smaller stainless pins and thought I’d see if it cleaned up the primer pockets. Got in the habit of wet tumbling because I run cans on everything and filthy brass and lube can gum up the die.

 

[KyleR1985]

Good point. And it’s a variable I hadn’t previously introduced. It’s not my typical process, but got some smaller stainless pins and thought I’d see if it cleaned up the primer pockets. Got in the habit of wet tumbling because I run cans on everything and filthy brass and lube can gum up the die.

Didn’t you say you’re sizing before tumbling though?

That’s my point - you’re still gumming up the die if so.

And then chamfer a potentially dinged or misshaped neck before sizing is adding to that.

 

[WestMOhunter]

Yeah, sorry that probably didn’t make sense. Meant I’ve gotten in the habit of wet tumbling FIRST because of nasty brass. Suppressed ARs. Since this is a bolt gun, brass wasn’t that dirty so I decided to tumble after to get case line off. I won’t do that going forward.

 

[Vern400]

I also anneal by hand, and match the coloration of my new Lapua brass. When I get a bullet that seats with more Force than others, I find that sometimes it's a poor inside chamfer on the neck. If you're going for this level of accuracy, it might make sense to use a dry lube inside the neck when you're loading. On my Precision stuff I'm testing mandrel expanding to see if I get more consistent bullet insertion forces.