QC on multi-fired brass

[Nature Boy]

So I'm loading for .308 in a semi-auto.

I'm about to get to my 4th reloading on a bunch of lake city brass. What I've read on this subject is somewhat contradictory. Some say 3 firings and toss while others will say keep checking for case head separation and toss at first sign.

I've also read the technique for using a bent paper clip and feeling for a "drag" on the inside of the case near the head.

Can you guys help me better understand what I'm feeling for and how I might detect it. Feel is somewhat abstract. In a perfect world I would be sitting at a bench with a veteran reloader who had one that was bad, could hand it to me and say, "here, feel that? You guys will have to be the mentors on this one.

 

[LiveLife]

This thread with pictures should help with inspecting for incipient case head separation - http://www.thehighroad.org/showthread.php?t=734058

 

[Dave P]

Instead of a paperclip, after you clean them, look inside with a flashlight. You can often see a groove developing.

Paperclip is better, tho.

 

[mdi]

Excellent reply, bds, and an excellent post by Walkalong. Personally I won't toss any brass as long as it's still in good shape, and safe to shoot (four and toss is silly/wasteful to me). I shoot reloads in my Garand (30-06) and so far have gotten 6 reloadings out of most of my brass with some going 7 (I have a lot of HXP, LC, and Hornady brass). I closely inspect each and every case each time it is reloaded paying close attention to the area where separation normally occurs. I have a piece of hard stainless rod, sharpened and bent, that I use to feel for thin spots...

 

[Nature Boy]

That helps a lot guys (especially the link to walkalong's tutorial)

Will be checking brass when I get home

Thanks!

 

[medalguy]

Just FYI, I have several .308 battle rifles including an M14 that I shoot fairly often. I reload for all and toss brass after 4 reloads, 5 firings total. I FL size for each reload. I have not yet had a case separation in any of my rifles.

Yes, it might be possible to get another load out of the brass, but I don't want to risk any damage to the chamber by having brass split or have gas leakage. Brass isn't all that expensive. An ounce of prevention.....

 

[gamestalker]

I often cringe at the thought that so many good pieces of brass get tossed in the trash simply because they had been loaded X number of times.

It's good, refreshing even to see a post in which a reloader is interested in assessing their brass, rather than just letting it go to waste without cause.

GS

 

[jeeptim]

I prefer a dental pick with about a 70 ° bend at the end.

 

[Bart B.]

It's my opinion (based on all sorts of facts) that the single most cause of short bottleneck case life is resizing fired cases such that their shoulders are set back way too far. That happens mostly with people following instructions saying (in so many words) "set the die in the press so the ram cams over as the shell holder presses hard against the die's bottom.

That typically ends up with the case head space (head to shoulder reference dimension) at or near SAAMI specs. If the rifle's chamber head space to its shoulder is a bit on the long size, that makes more room for the case to stretch back until the case head stops against the bolt face at peak pressure. And that causes thinning of the case wall at the case pressure ring area about 1/10th inch forward of the extractor groove. Incipient head separation starts with a single crack that often ends up letting most (if not all) of the case head blowing off the case body when fired.

That pressure ring around the case head is normal as that part of the case body expands more than the case head does. If it's uneven, then so is the case wall thickness. Here's a picture of one .308 Win. case showing the pressure ring clearly visible on one side of the case but none at the point opposite of it. A sure sign of uneven case wall thickness.



That case has about a .002" spread in neck wall thickness; it's thinnest part is in line with the pressure ring's highest point away from the case diameter at the extractor groove. That indicates where the thinnest part of the case is all the way from head to mouth. But those cases still shot sub MOA at long range in spite of their necks not being turned.

Get some tool that measures case head space. Measure that of a fired case, then set and lock your full length sizing die in the press so it only bumps that fired case shoulder back about .002". People have done that for decades getting several dozen reloads per .308 Win. case using bolt guns. Best accuracy, too.

Semiautos are different; they need a bit more head clearance (space between bolt face and case head; often incorrectly called some sort of head space) on chambered rounds to ensure reliable functioning. And that leads to shorter case life. 5 to 6 reloads per case used in semiautos is about the limit for most people;. It can be as little as 2 or 3 if they're setting the fired case shoulder back too far when resizing it.

 

[Walkalong]

It's my opinion (based on all sorts of facts) that the single most cause of short bottleneck case life is resizing fired cases such that their shoulders are set back way too far.

I definitely agree.

Here is another pic of the "pressure ring" mentioned. Fat chambers will make them look worse.

 

[Bart B.]

Many folks think that bulged part of the pressure ring is caused at the top of the case as the case rests on the chamber bottom. There's space there they think the case can expand up against. And there's no room at the chamber bottom for it to expand. All rounds rest at the chamber bottom when fired.

Such people don't realize the case head is pressed up or sideways against the chamber wall by the extractor pushing it there when the bolt's closed on it. There's space between the case and chamber bottom. If you orient fired cases' primer imprint indexed to the same place, that bulge happens in all directions.

 

[rogn]

With luck and concentric ammo the case will be in the center of the chamber and the expansion bulge will occur at the weakest point in the case wall. This is sort of like blowing up a balloon when it deforms in the least resistant direction. And its my 0.02$ that the expander ball has a role in shortening case life. SA or bolt.