Pimply Primer mystery

[125JHP]

Help me figure out what is going on with these primers....

All of them are the same load... 124gr Berrys HBFP 4.8 WST @ 1.113"oal. running about 1030 fps
The primers are in pics A,B,C,&D are Magtech and the ones in pics 1a thru 4c are Remington 1 1/2, but I have seen similar results with other brands.

I know this is a fairly warm load. The only manual I could find with any data was Hornady #4 which showed a JHP WST load of 4.8 min - 5.4 max @1100 fps

Searching WST posts from various forums turned up suggested 124gr loads from 3.8 to 5.2 with most in the 4.6 to 4.8 range @ 1.125" and velocities around 1040 so that part checks out with my results.

All of the below analysis is my observation & opinion and not based on any scientific fact... if you know better or have additional insight, I would appreciate your input so I can learn a little something. different guns are represented, but are not specified in the photos.

In photos A1, B1 & C1 the primers look fairly normal with rounded shoulders and very little primer hole fill-in. The brass has been loaded several times but there are some shiny spots that are likely from this firing but no major metal flow.

Photo C2 we see signs of pressure. The primer fills the pocket and the shoulder is squared off. Some cratering of the firing pin hole is present and breech face machine marks are starting to show on the brass.

This is obviously some military brass (off hand I think its Norinco IIRC) so it's likely this may have caused the higher pressure (other reasons such as charge or OAL are not ruled out but this seems the most likely).

D1 looks a lot like A1 B1 &C1... nothing too unusual.

Now we get to some interesting primers...all from the same gun

Although the primer shoulder and brass of D2 look fine, we now see a 'pimple" around the primer indent. Also the primer indent is shallow and it looks like the end of the pimple is either flattened or sheared.

D3, D4 & D5 show more of this pimple effect.

1a thru 4c is another batch of this same load with some angles and side shots where you can see just how flat these primers are.

Note that I have even seen this pimpled effect with some factory ammo, which I assume is within pressure norms so I have some skepticism that it is entirely from load overpressure.

Although the load is at the bottom end for jacketed bullets, I still have a nagging feeling these are telling me there is something not quite right and I fear I may be pushing the pressure limit. I have read that WST has a somewhat fine line between well-behaved and wildly-explosive. OTOH the rounded shoulders and lack of other metal flow sort of puzzles me. In addition there are all the other normal looking primers from the same load.

What do you guys think?
Could it just be something with the breech face & primer hole?
Could it be case volume since some of these are military cases?
Is it excessive pressure?

 

[BlueOvalBandit]

Well I know in rifles a sloppy firing pin hole and firing pin fit will show cratering even with safe loads and the primer edges are still round.

I doubt mixed brass volume differences have anything to do with this, you'll probably have more volume differences just in 0.001" oal seating variances.

Are these federal primers? They are pretty soft to begin with.

 

[Frank46]

Your primers are also showing some what look like firing pin drag marks. Sort of when all the pressure has not gone down and the slide has started to move. Could be that you need to replace either the firing pin spring or recoil spring or both. I used to shoot the 9mm Rem-Umc as put out by Remington in my 92fs. This is their yellow box stuff. Cost me the price of a firing pin and spring. The firing pin punctured a primer unknown to me at the time and left a little crater on the tip of the pin. Only noticed it when I went to pickup the empty brass. Switched to Winchester after I had both the pin and spring replaced. No problems after that. I use wst in my 45acp and have never seen what you are showing. From looking at the info that various dealers print about wst it is used for shotgun and 45 auto, no other mention of any other calibers. But have not checked as to reloading data using wst for any other calibers. your pics show rounded shoulders on just about all the primers, but the one with the machining marks on the slide kind of makes me wonder if your load in mixed commercial and military brass just might be your problem. The military brass is supposed to be heavier and thicker meaning there is less volume for your powder. But then again as the previous poster has said federal primers are softer. Try using winchester small pistol primers using the same powder, bullet, seating depth and see if that still gives you the same looking primers. When handloading change only one variable at a time primer, bullet, powder etc. Hope this helps. Frank

 

[125JHP]

Good observations, Some of the ones with drag marks are striker fired and IIRC don't have a return spring in the firing pin but rather use the recoil to reset the pin behind the breech face. That little smear is normal. Both C & D are new guns with 200-300 rounds thru them.

Pics that start with a number (1a, 4c etc) were not marked as to which gun they were from but I have my suspicions.

Correction: I looked at the load labels again and the primers for the last group (numerical 1a,4c) are Remington 1 1/2 from the 1991 era. The primers are in pics A,B,C,&D are Magtech.
Some of my recent recent tests have been with Magtech and Wolf primers so off hand I thought these were all from those batches.

 

[lebomm]

Is there possibly a firing pin bushing in the breechface that is below flush ?

 

[125JHP]

I don't think it is from any of the guns. All of them will produce normal looking primers and also obviously flat primers from high pressure (like C2)
On occasion, I have seen this pimple come from different guns at one time or another... sometimes with factory ammo as shown below.

 

[gwpercle]

You take excellent photos. I can't figure out how to get my photo,s to a large size. How do you take such up close and in focus pictures ?
I can't seem to figure these new digital camera's out, I try all different settings and still get out of focus dark pic's. What kind of camera and lens are you using ?
Back in the day I had a Minolta 35 mm SLR and a caseful of lenses and was considered a pretty good photographer.....
not anymore. And as for your primers I think Frank46 might be onto the problem. The 9mm is a pretty high pressure round and I find it sometimes troublesome, unlike the 45acp which is about the easiest to load.

gary

 

[125JHP]

one year my wife got me a microscope for my birthday, presumably so we could look at insects and butterfly's but I found a better use for it!! ...heh heh I got one of those eyepiece cameras that hook the microscope into my computer and use the screen to view the image and save the files as JPG pics. The only problem is it is a little too powerful and gets a little too close. I reduce the file sizes which helps on my system but the online software seems to blow them up to full size again, which ai find a little overpowering in the thread. I need to buy another lens set to back off the power a little and then I can do coins also. I started taking pics of all my loads partly as comparison records and partly as a learning curve. I also scan in my targets and then make a composite PDF for each load including the primer pics and recovered bullets if I have them. It all gets filed for future reference and comparison.

I had another thought on the primer pimple... could it be the starting phase of pressure buildup, before there is enough to flatten the shoulder but enough to start deforming the pin indent? Sort of an early warning stage?

 

[jepp2]

You really do take excellent macro pics. A couple of thoughts:

- primers aren't always be a good indicator of pressure. Have you thought about other signs of pressure? A good resource (although much better for rifles than handguns) is pressure signs

- some things are better viewed at normal size rather than extreme magnification. I think your pictures could fall into this category. To me, none of the primers seemed seriously flattened that would make me start to worry about high pressure. But as I mentioned primers aren't my main indicators of pressure

- for my 9mm's, I find to get reliable ejection, I need to load to a minimum of around 24K psi peak pressure. Since I tend to load longer than most manuals list, I use Quickload to check my powder adjustment. So I am always checking the calculated pressure for all my loads, and comparing that with all pressure signs of the fired case and the firing action.

- my main signs of pressure increases in 9mm: is a significant change in ejection and how the exterior of the brass case is marked from the irregularities of the chamber.

You probably already know this, but Remington states on the side of their 1 1/2 primer cartons not to use them in some high pressure loads and while the 9mm isn't listed, I consider it on the edge and maybe a different primer is a better choice. I switched to WSP or CCI 500 primers for use in my 9mm loads and am very happy with them.

 

[125JHP]

Thanks for all those tips Jepp, especially the warning on the side of the box.
I agree on the excess magnification. I normally use WSP but lately have been using up some misc primers on hand, bought during the 'primers of any kind' shortage a couple years back, and looking to see if there is any practical difference between them.

I generally also make a note of how far the cases are thrown from each gun. In most cases standard pressure stuff lands about 4 to 5' @ 4pm when I see the cases 16' away I take notice.

 

[papajohn428]

I use a lot of Federal primers, which are among the softest available, and the first to show early pressure indications. Reading primers is a lot like reading tea leaves, and subject to a lot of interpretation, but sometimes you can safely say that the loads are hotter than they oughta be. I found these 9mm cases at the range last week, and brought them home to photograph and contemplate. I've loaded some pretty warm loads over the years, but NONE of them ever looked like this!

 

[Frank46]

PJ428, In your pics the primer shoulders are still round. However in the same pics the center of the primer has bulged out. I would not be suprised if the firearm was not locked breech type. Instead I would opt for a blowback action. Usually when a shell is fired rearward expansion of the primer is stopped when it contacts the slide. In a purely blowback action depending on how it is built the breech face will only be there long enough to allow the cartridge to be ejected. And certain blowbacks use the residual pressures to aid in the ejection of the spent cartridge. Scary primers those. Frank

 

[125JHP]

Wow! those primers are almost erotic

So Frank,
Assuming that most 9mm are locked breech designs. If the gun is unlocking early would it do it all of the time once it got past a certain threshold pressure level or, could there be one pulse level that would cause that failure (thus producing the pimpled primers) but while higher levels of pressure would cause enough case wall friction to return to normal operation. (just guessing here).

or... Could it be that the gun producing the 'pimples' is designed to unlock a bit earlier than traditional designs to take advantage of the recoil pulse, thus allowing the primer indent to deform back as the recoil drives the slide to rearward to it's stop. It seems I read on the internet that newer designs use this recoil to reset the striker and perhaps in other ways.

So, the direction I am postulating is that this early unlocking process, to use the recoil energy, has a byproduct of primer deformations that produce these pimples in some guns with some ammo at certain pressure levels. Does this make sense? Wouldn't this then be common from open bolt SMG's

 

[VAdoublegunner]

I have seen that before and two things come to mind.

One is a slight headspace condition where the cartridge is slightly driven forward before it fires and slams back into the pin. Is your brass well used? Cartridges that headspace as yours do will often grow shorter with repeated loadings, resulting in that sort of phenomenon where the extractor holds the case head enough for it to fire, but it really isn't quite headspaced correctly.

The other is a weak firing pin spring, or even more likely it is gunked up with lube of something that is restricting motion. I had an issue like that that occurred in a 4006, plus the FP swipe which that particular model was known to have issues with. Some thorough cleaning with brake cleaner, relubing, and a little FP polishing cured the double dimple, not so much the fishtail. Upping the slide spring a couple of pounds helped that.

 

[shovelwrench]

While I won't venture a guess on what your cause are . I will say that It wouldn't bother me much to shoot any of those loads, none of those are what I'd call flattened, or really showing "pressure" signs. The sheared ones would concern me slightly(more in getting a stuck firing pin), but in the realm of 9mm I've seen some god awful looking primers in the range brass lying around. And none of yours look even close to some I've seen. I could show you some .38 Super that cuts the whole firing pin dimple right off and is a book load...... Looks like you have standard issue sloppy firing pin fit/bore to me. (and new firing pin springs never hurt)

Really, for experiments sake, you should be loading in at least matching head stamps, and repeating your test.

 

[buck460XVR]

1a thru 4c is another batch of this same load with some angles and side shots where you can see just how flat these primers are.

.....for the life of me, I cannot see any primer flattening at all in any of those pics.

Note that I have even seen this pimpled effect with some factory ammo, which I assume is within pressure norms so I have some skepticism that it is entirely from load overpressure.

......there you go.

 

[papajohn428]

.....for the life of me, I cannot see any primer flattening at all in any of those pictures.

Agreed. Those aren't flat. Check out the S&B brass in the middle. THAT'S flat!

 

[125JHP]

Even with slightly visible shoulders, I would consider all of those as flat enough for concern, no doubt that S&B is. Am I over-estimating the pressure shown by that degree of flatness?


anyone else have a favorite "almost-disaster" pic to show???

 

[Frank46]

I too have seen the fishtale firing pin marks on 9mm brass and I have seen 9mm fired in glocks where the striker mark on the primer has almost been sheared off. That S&B 45 case is downright scary to say the least. The 9mm's that I have are the 92fs and sig P6. Fired many rounds through each and all I ever saw was normal primers. No experience with open bolt guns. But did have a treat when a good friend let me shoot his MP5 with a silencer on it. All I can say it was about the most fun I ever had. I'm thinking that blow back pistols that depend on the recoil force to eject the cartridge, cock and lock back into the firing position with a round in the chamber have to basically function with just about any (in this case) 9mm ammunition. Ammunition companies have to adhere to SAMMI specs but use different powders with different burning rates to do so. Some powders reach their peak faster than others. That's why they use non-canister grades of powder. Add in to the fact that these powders have to work with just about any small pistol primer out on the market. I'd think they do a good job. One other thing to consider, the non-cannister grade powders the ammo mfgr's use is probably made up in lots of thousands of pounds to get the best performance with the least cost. Even if they save 1 grain on each round and they load millions of cartridges the savings will mean real $$ for the mfgr's. Frank