Flat primers in BHA Match Brass.

[amlevin]

I've found a fantastic load for CFE223 using 170gr Lapua Lock Base bullets. Load is 47.3 gr of CFE223 in the BHA Match cases. This is below the published max for a 175 gr bullet but no data available directly for the 170 gr.

Here's what I'm seeing. The primers are FLAT, like in REALLY FLAT, from starting load all the way to the 47.5 grain max load given by Hodgdon for the 175 gr SMK. Even though the primers are flat there is NO cratering at the firing pin and bolt lift is as smooth as butter.

The starting loads gave me soot all the way down the neck to the shoulder junction but as the test loads increased, the soot line moved up the neck. Max load had just a very slight soot ring about 1/8" down the neck.

The velocity for the load that I settled on is 2784 avg with an SD of 8. Vertical dispersion at 300 yards is well under .200" and any horizontal dispersion is up to "me and nature".

Other than the flat primers (and I mean really flat) I see no ejector marks or "bolt wipes" on the case head. I've used Fed GMM210M primers as well as the Wolf Large Rifle primers (which give me lower SD than the Fed's) and get the same flattening. I've measured the primer pockets after 4 firings and the Ballistic Tools "NO-GO" end of their tool won't even start to enter the primer pockets. It takes a really strong "squeeze" to seat the primers, so the primer pockets aren't showing signs of overpressure.

Any ideas? This load almost exactly duplicates the Lapua HPS load for .308 and since I still have hundreds of the 170's left I want to continue with this load.

Could it be a function of primer flash hole size. That's about the only thing I haven't measured on the BHA Match cases. The cases appear to be very similar to Winchester in weight and case volume.

 

[CatShooter]

Flat primers under the circumstances that you describe, are typically from excess headspace (or face clearance as the politically correct police prefer).

The primer forces the case forward into the space, the powder lights, the pressure forces the case back, and smushes the protruding primer.

If the chamber walls are dry, the case stretches in front of the head, and you are on the way to a head separation - if the chamber is wet with oil or bore cleaner, the case will slide back, fill the chamber and be great when you reload it.

 

[amlevin]

Flat primers under the circumstances that you describe, are typically from excess headspace (or face clearance as the politically correct police prefer).

The primer forces the case forward into the space, the powder lights, the pressure forces the case back, and smushes the protruding primer.

If the chamber walls are dry, the case stretches in front of the head, and you are on the way to a head separation - if the chamber is wet with oil or bore cleaner, the case will slide back, fill the chamber and be great when you reload it.

In my case neither are a factor. The bolt closes on a "snug" cartridge. I've set my sizing dies to a .001"-.0015" shoulder bump. Before every range session I clean the chamber with a clean, dry, oversized, bore mop but with the snug cases I am measuring no change in chamber wall thickness in the "separation zone".

I thought of those factors earlier and ruled them out

BTW, the rifle is chambered with a "Match Reamer" and the cases are sized with a Forster BR F/L die. From fired to sized, I'm barely moving any metal Almost like a "Custom Die" with this combination.

 

[CatShooter]

Got any pictures??

 

[amlevin]

Got any pictures??

You need a picture of FLAT?

 

[CatShooter]

Got any pictures??

You need a picture of FLAT?

Yeah... I collect them for my picture album

Seriously... I use them to teach in my classes.

 

[bigedp51]

I was at the range one day and picked up a .223/5.56 case and the primer looked like someone had installed a large rifle primer and I was perplexed. I took three of these cases home and removed the primer and saw the problem. Whoever removed the primer crimp used a case mouth deburring tool and over reamed the primer pocket. The primers from these three cases looked like mushrooms because the primer had flowed sideways into the over beveled primer pocket.

Question, what do your removed primers look like and could your primer pocket have a lot of bevel at the mouth of the primer pocket.

I'm asking because my Remington .223 cases have a larger curved bevel at the primer pocket mouth than the military case with the crimp removed. And the Remington cases have flatter primers than the military cases with much less bevel at the mouth of the primer pocket with the same load.

The over reamed primer pockets look like the case below and when fired looked like a large rifle primer.

Below my Remington cases have "rolled primer pocket" and always flatten more than the military type crimped primer pockets. The "roll or beveled" primer pockets will allow the primer to flow outward and mushroom more than other type primer pockets.

Soft primers and the type of primer pocket mouth opening are the only thing that comes to mind about your problem. (My WAG)

If the chamber walls are dry, the case stretches in front of the head, and you are on the way to a head separation - if the chamber is wet with oil or bore cleaner, the case will slide back, fill the chamber and be great when you reload it.

P.S. I'm worried about CatShooter, he seems to be greasing "EVERYTHING", do you know if CatShooter wears glasses and has Playboy Magazine pinups at his work and home?

The old fart keeps posting the picture of his imaginary girlfriend below and may have slipped over the edge. :

 

[Old Navy]

Flat primers under the circumstances that you describe, are typically from excess headspace (or face clearance as the politically correct police prefer).

The primer forces the case forward into the space, the powder lights, the pressure forces the case back, and smushes the protruding primer.

If the chamber walls are dry, the case stretches in front of the head, and you are on the way to a head separation - if the chamber is wet with oil or bore cleaner, the case will slide back, fill the chamber and be great when you reload it.

+1 Fix it before reloading the cases again. You may save them from an early death. Later! Frank

 

[amlevin]

The over reamed primer pockets look like the case below and when fired looked like a large rifle primer.

This is the reason I invested in a Dillon Super Swage. I REFUSE to ream a primer pocket to remove a primer crimp.

P.S. I'm worried about CatShooter, he seems to be greasing "EVERYTHING", do you know if CatShooter wears glasses and has Playboy Magazine pinups at his work and home?

The old fart keeps posting the picture of his imaginary girlfriend below and may have slipped over the edge. :

All I can say is "that is definitely not flat 8)

 

[amlevin]

Flat primers under the circumstances that you describe, are typically from excess headspace (or face clearance as the politically correct police prefer).

The primer forces the case forward into the space, the powder lights, the pressure forces the case back, and smushes the protruding primer.

If the chamber walls are dry, the case stretches in front of the head, and you are on the way to a head separation - if the chamber is wet with oil or bore cleaner, the case will slide back, fill the chamber and be great when you reload it.

+1 Fix it before reloading the cases again. You may save them from an early death. Later! Frank

I'm not sure what needs fixing. No headspace problem (measured a set of fired cases then measured again after sizing using both a case gauge and a Hornady "headspace" tool. About .001" of bump.

I've already fired these cases 5 times and the primer pockets take a real firm "squeeze" to seat the primer so they aren't loosing up at all. No excess "radius" or "bevel", look just like my Lapua and Winchester cases. Only thing I haven't done yet due to some household repair priorities is to measure the flash hole sizes on the different cases. Wondering if the BHA's have a larger hole and allowing a higher pressure peak in the primer pocket.

For this powder (CFE223, I may just go to .308 Lapua Palma brass and see how much more speed I can get. Still have room in the case for more powder and other than the flat primers I see no other pressure signs. It seems like the more powder I add with the CFE223, the better it performs in SD/ES, and 300 yard groups. Current load gives me 2750 fps with a 175 gr Nosler Custom Comp BTHP. Would love to see what another 50fps would do. "On paper" it lools like 1.5 MOA of elevation at 1,000 yards. Looking forward to see if that's right

 

[searcher]

Perhaps try loading up a few virgin cases - or cases you know have not been subjected to high pressures - and take base measurements before and after shooting. base expansion is much more reliable than looking for ejector marks or primer craters - especially in a well made rifle. Also, you mention closing the bolt on a "snug" case. Obviously, you are a seasoned reloader - but sometimes things do get overloooked. Is there any possibliity the snugness is not due to the shoulder contact - but rather a neck O.D. that had grown thicker and is contacting your chamber? If a new gun or newly chambered barrel, how about a chamber that does not allow for a maximum brass length as is normal for the caliber (I encountered that in one of my barrels). These are two items that could make you think your shoulder is making light contact when it really could be off quite a bit.

 

[amlevin]

Perhaps try loading up a few virgin cases - or cases you know have not been subjected to high pressures - and take base measurements before and after shooting. base expansion is much more reliable than looking for ejector marks or primer craters - especially in a well made rifle. Also, you mention closing the bolt on a "snug" case. Obviously, you are a seasoned reloader - but sometimes things do get overloooked. Is there any possibliity the snugness is not due to the shoulder contact - but rather a neck O.D. that had grown thicker and is contacting your chamber? If a new gun or newly chambered barrel, how about a chamber that does not allow for a maximum brass length as is normal for the caliber (I encountered that in one of my barrels). These are two items that could make you think your shoulder is making light contact when it really could be off quite a bit.

No base expansion at all. No "muffin top" either where the case expands at the end of the web and where the case "cavity" begins. Necks have been turned for uniformity and there's no interference with the chamber. The chamber length is .010" longer than my brass and I trim after each firing so I have a nice square case mouth.

I'm using Wolf primers and my other brass they are the last to flatten like this. Still a mystery to me. All I can say is the result "on paper" are great. I'm heading out this morning to shoot this brass for the 5th time and when I seated primers for this outing they went in as snug as if the brass was brand new.

We'll see, I suppose. Maybe I'll get around to measuring the flash hole dimensions and compare with my Lapua and Winchester. Still wondering if a larger flash hole could cause this flattening with the primers. Remember, the flattening started with the published Starting Load and it was so weak I had soot on the necks.

 

[CatShooter]

Have you considered exorcism???

 

[jhord]

It's probably the powder. I have experimented with CFE in my M1A NM a fair bit. Since they do not have published gas gun loads in .308 I started off by taking their lightest bolt load and reducing it even further. With 168SMK's I got 2510 fps and flat primers. (but it shot great) I kept reducing charges until the primers stopped flattening, and ended up at 2400 fps. The lower I went the more soot I got and SD/ES opened up, and so did groups. I don't intend to shoot CFE in my M1A all the time but I wanted a backup plan in case I run out of I4895. I do shoot CFE all the time in my AR-15 NM, with N77's, and guess what, even at reasonable velocities I get flat primers... I just don't let it bother me anymore because the powder has many other redeeming qualities.

 

[amlevin]

Have you considered exorcism???

No, but Voodoo, yes


After yesterday at the range and putting all 10 shots in the "10 Ring" at 300 yards I decided that I'm going to just ignore the primers. Load shoots too good and the cases aren't showing ANY signs of pressure so I'm not going to torture my brain anymore. Got lots of CFE223 left and I now have a pretty "universal" powder for my family of .223's and .308's.