So I whipped up a quick "gauge" so if the data seems off, thats why, should be consistent though. The datum diameter ended up at .401". I measured 30 processed unfired cases, 23 measured 1.640" +/-.002 and seven cases were 1.625"+/- .002. The fired cases measure 1.640" +/- regardless of the primer condition. BTW I will be getting a real headspace gauge.

more amps

Hi all... just got back on island.   Perhaps some processing info from our end might help out.

The 762 primer pockets are actually more on the tighter side (esp when compared to 556).  On a side note, fast and friendly brass makes fantastic swap-in parts for the Dillons.  We switched to the FFB swage rods a year or so ago, and they are a much better quality. 

Bushido, you are spot on that the brass companies (us included) do bump the shoulder back so that the case will fit the majority of guns.  Because of spring tension, to get the 762 back to size it takes three full length sizes and two neck sizes.  The military brass is considerably thicker than commercial and is just tougher to size.  Early on, we learned that the Dillon trim die shrinks the neck so a second neck sizer is on the last station.  Also, taking your comments on the 556 neck size into consideration, we will likely modify the 556 final station to mirror the 762 set up.  In terms of case length, our 556 and 762 are trimmed to the longer side, and 300blk is cut to a more mid-length spec.  The reasoning behind this is that material can be trimmed but its pretty impossible to add back on.  As with any operation there will variance (we post +/- .005 but the variance is typically closer to +/- .003).  We also second using the LE Wilson gauge to check case sizing.  Also, the majority of our brass is processed in large batches to minimize variances between setups.  When we cleared inventory in Q1 of this year, tighter batch organization was implemented. 

In general, we've found that there are two groups of reloaders: the reload because it is cheaper (no shame! us too...) and the precision reloaders.  For the former group, the variance of bulk is an acceptable cost/benefit, but for the latter group, we started offering a more customized line of brass ('artisan').  If you wanted specific case dimensions (trim length & shoulder bump etc) this could be a worthwhile option to consider.  Its a couple cents more per piece, but we still aim to keep it in the affordable range.

So I whipped up a quick "gauge" so if the data seems off, thats why, should be consistent though. The datum diameter ended up at .401". I measured 30 processed unfired cases, 23 measured 1.640" +/-.002 and seven cases were 1.625"+/- .002. The fired cases measure 1.640" +/- regardless of the primer condition. BTW I will be getting a real headspace gauge.

That's an awesome tool! 

1.640 looks to be max chamber size.  1.625 looks like it would get .015 of play from the back of the brass to the bolt face.

I think you've found the problem. 

 


Brass maybe a little out of spec and maybe fine for one cycle of firing for a case, such as in military application, where brass is considered a consumable in most instances, but for reloading it may not work out so well.


I'd recommend using the brass closest to your 1.640 chamber size.

What I think is happening.

Firing pin strikes primer, pushing the cartridge all the way forward in the chamber.

Primer ignites powder, 60,000+ psi expands case, expanding the brass, brass sticks to chamber walls.

Primer is pushed out of case .015" pressure flattens it against the bolt face.

Case stretches back .015" slamming against bolt face and re seats primer flattened into the primer pocket.

Since the front of the case is still sealed against the chamber, the case head is pulled apart from the main case body. (Undesirable)

Of course, all this is no knock on Kaleo, I too use their pre processed brass in 5.56, and have had great results with it. 

What I think is happening.
Firing pin strikes primer, pushing the cartridge all the way forward in the chamber.
Primer ignites powder, 60,000+ psi expands case, expanding the brass, brass sticks to chamber walls.
Primer is pushed out of case .015" pressure flattens it against the bolt face.
Case stretches back .015" slamming against bolt face and re seats primer flattened into the primer pocket.
Since the front of the case is still sealed against the chamber, the case head is pulled apart from the main case body. (Undesirable)

Sorry, so why is this happening in 1 in 5 rounds?

In terms of case length, our 556 and 762 are trimmed to the longer side, and 300blk is cut to a more mid-length spec.

I started noticing this with the 300BLK Hornady brass and the brass I bought from you at the gun show so I started to convert my own.

I do like you stuff. Do you have a store front or just internet sales? I couldn't see it on your website. 

Sorry, so why is this happening in 1 in 5 rounds?

I measured 30 processed unfired cases, 23 measured 1.640" +/-.002 and seven cases were 1.625"+/- .002. The fired cases measure 1.640" +/- regardless of the primer condition.

^ This

Seven out of 30 cases were short . . . not one out of five but close enough. So theoretically, I believe, if I load and fire these 30 cases, seven would have flattened primers and stretched cases.

I think you've found the problem.

Noooo . . . You guys found the problem
You guys are awesome.
I think it's great how when a problem is posted, those that can help do!
I learned a lot here.
Mahalo 

I will load the 1.64" cases and confirm the diaognosis 

So have we concluded that the rounds are not over pressured, just some are too short?

So have we concluded that the rounds are not over pressured, just some are too short?

Yes we determined that there was no over pressure situation. The cartridge overall length was assumed to be correct. And the case length was assumed to be correct. It was the location of the shoulder that caused this. How do you define "too short"?

This is an example of why I always stress that reading primers can be very misleading.

How do you define "too short"?

Quote from: dogman on August 08, 2017, 09:36:51 PM
I measured 30 processed unfired cases, 23 measured 1.640" +/-.002 and seven cases were 1.625"+/- .002. The fired cases measure 1.640" +/- regardless of the primer condition.
^ This

Do you have a store front or just internet sales?

This summer we began renovating a site that will a storefront, new manufacturing facility, and warehouse, but it is not in Hawaii.  The facility in North Dakota is a decommissioned ICBM launch support building, but it sat vacant since 1996 so it needs a lot of work.  For now, it will probably remain internet sales in Hawaii, but we're pretty available to come chat at the Hawaii Kai range or do local drop off/pick up.  We will still live in Honolulu (winter is way too cold in North Dakota...) so Kaleo will still be in Hawaii just with an mainland extension.  Steep storefront rent is the main prohibitive factor on a local storefront tbh. 

For now, it will probably remain internet sales in Hawaii, but we're pretty available to come chat at the Hawaii Kai range or do local drop off/pick up. 

just meet at kahala mcdonald's
 

Are you measuring the FPS or just looking at primers. What is the ideal shoulder length you are looking for? I can tell you from experience military cases respond differently than commercial brass.

Are you measuring the FPS or just looking at primers. What is the ideal shoulder length you are looking for? I can tell you from experience military cases respond differently than commercial brass.

Minimum headspace is 1.630" so a case that is sized 1.625" shot in a chamber that is 1.640" is a little too short.  I have known many experienced reloaders that don't use chronographs to come up with loads for rifles and pistol.  I don't consider that mandatory equipment to reload.  Dogman's loads are within published load data and considered safe.  It is true that military brass, being thicker, will need a lighter load, as pressures will increase quicker than in thinner commercial brass.

The original question was that of looking at the primer, and what a primer should look like during load development.  As pointed out there was an obvious anomaly, and we all are working through it.   With the conditions as they are in this instance, a chronograph wouldn't have shown anything excessive, as the lightest to the heaviest load had the primer flattening issue. 

Not sure what you are being critical about?

So have we concluded that the rounds are not over pressured, just some are too short?

Some rounds had excessive headspace, which caused flattened primers, and incipient case head separation. 

The scratches are from the paper clip

The scratches are from the paper clip

Very telling. 

The scratches are from the paper clip

nice "or similar"

So along the same lines as the finding of this thread. Has anyone had success "fire forming" cases that have excessive headspace? I have quite a bit of cases that are over full length sized. I've tried without success to blow the shoulder forward but without stretching the body.