Overpressure signs here?

[Nordeste]

Gents, please do have a look at let me know if any overpressure signs are spotted. I'm not good at recognizing the symptoms. To me they looked OK except for the small ring around the firing pin hole in some of the cases, which made me send the photos to a more experience buddy who stated his opinion and I'd like to have yours.

The cases correspond to two different loads shot from two different pistols. The one with the whole of the case head marked in blue was shot from my Star 30M. It contained 5 grains of Optima A, which is a medium burn rate, simple base powder that comes in flakes. There's not much to choose from over here when it comes to powder choices and this one is the best bang-for-the-buck all around performer. Bullet was a 125 HN (German) HS RN, copper plated at 1'15". I had found this load gave better groups in my pistol, but my buddy's opinion is that I might be pushing the OAL and pressure a bit too far. He says the "ring" or bulge near the case head shows overpressure. It chronoed at 1070 fps.

Lying at its left, and shot from my 30M also, the same bullet under a 4'7 grain load of the same powder, at 1'13". This one looks OK to me and to him.

What concerned me were the first one on the left, and the one marked in blue that is standing, second from the right. Those are the 1'13" and 4'7 grain load, fired from a CZ SP01 Shadow of another buddy. They have a small "ring" around the firing pin hole. I heard something about the CZs having tight chambers and I don't know if this can have to do with it.

The first one from the right is an old Santa Bárbara NATO spec 115 FMJ. Those are military ammo and known for being quite hot. It chronoed at over 1200 fps and it shows an even bigger "ring". I've told my buddy to stop using this ammo. It's asking for trouble, sooner or later, IMHO.

To be continued in the second post...

 

[Nordeste]

Third photo. This case is a Remington UMC shot from another CZ SP01 Shadow. It's factory ammo. There is another visible ring around the firing pin hole. This ammunition isn't hot by any means. Bullet weight is 124 grains, flat nose, chronoed in this Shadow at some 1040 fps.

I don't know if there is actual overpressure signs, or, if there are, if they aren't too serious to be concerned about them.

Your inputs appreciated .

 

[mugsie]

From what I can see in the photos, they look fine to me.

 

[rcmodel]

No, none of them show any sign of high pressure.

High pressure results in very flattened primers with the rounded edges ironed out clear to the edge of the primer pocket.

Yours show absolutely NO signs of high pressure.
Just the reverse in fact.

rc

 

[Nordeste]

No, none of them show any sign of high pressure.

High pressure results in very flattened primers with the rounded edges ironed out clear to the edge of the primer pocket.

Yours show absolutely NO signs of high pressure.
Just the reverse in fact.

rc

It's relieving to know. You say just the reverse, RC?. That means low pressure. How do you come to that conclusion?.

 

[Walkalong]

The edges of the primers are still rounded as much as before they were fired, or at least almost as much. That says your just fine.

Like these:

 

[rcmodel]

How do you come to that conclusion?.

Because the rounded edge looks like it did before they were fired.

Near as I can see in the cell phone photos anyway?

Medium or high pressure loads will flatten the primers to one extent, or another.

The higher the pressure, the more the 'or another'.

Rc

 

[gamestalker]

For an untrained eye, AL pistol brass can be difficult to read at best. Often times, by the time you notice excessive primer flow, you'll experience some form of case failure, vertical splits down the side is fairly common with excessive pressures. But yes, from what I can see in your photo's, those appear to be operating within a normal pressure range, if not a tad light.

GS

 

[Nordeste]

Well, yeah... sorry for the mobile phone photos but it was all that was handy. My digital camera is in another location and wasn't accessible at that moment.

Thanks all for your inputs. I feel more confident now. Perhaps this friend of mine has been too analytical on this. This is one of the reasons that makes THR worth spending time on. People willing to help and lots of knowledge available .

I won't ditch my hotter load, then. I waiting to do some more testing with it. I'm waiting for a friend to get home some parts he's ordered from there (from the US) for his Ramson rest. One is for my Star. Guess that will be the proper way of finding out which load suits her better.

 

[Arkansas Paul]

Just FYI, it isn't as easy to notice pressure signs in straight walled pistol brass as it is in bottleneck rifle stuff.

Often in handgun stuff, pressures are at dangerous levels well before the cases/primers begin to show signs of it.

At least that's what I read on the interweb.

 

[627PCFan]

These are flattened primers

 

[spitballer]

Excellent photo by 627pcfan! Primers seem to be the weakest link and the first area where pressure shows up. I've had them puff out in three directions like pop-n-fresh biscuits. But I'm not sure that flat primers by themselves are reason to stop and unload your cases.

Of more concern are cases that are hard to pull from the chamber. The only time I ever really had concerns was once when I had cases that were hard to remove, and it turns out that the flash holes were oversize. They may have been federal cases, I don't remember. Beware of large flash holes!