As I have stated before, I am relativly new to pistol reloading. I loaded up some 357 mag. cases with 7.6 gr. of Unique and set them off with CCI 500 Sm.Mag. Pistol primers.
I noticed that some of the primers were dis-colored. After looking at them with a magnifying glass, I saw that about 6 of 15 fired in a Ruger SP 101 were pierced. I have never had that happen with that pistol before... that I am aware of. Really wouldn't have noticed except for the dis-coloration of the primers.

Any comments on what is going on are welcome.

How heavy a bullet??
7.6gr of Unique is listed as a max load with a 158gr bullet in Hodgdon #26. If you are shooting anything heavier then a 158gr, you are over max and in dangerous territory. In any event, pierced primers are not a good thing. Unless you have a really shot barrel, Unique is faster then what I like for the .357 Mag. I would suggest trying something slower, 2400, H110, W296, and AA9 are all proven performes in the .357 Mag.

I loaded 158 gr. bullets. My Alliant catalogue shows 7.8 gr. to be max. with Unique.

The piercing was at the very bottom of the firing pin indentation and was very small. It almost appeared that the firing pin strike was over-extended and the cup of the primer was simply thinned out to the fullest. Not sure though.


I measured with a Hornady electronic scale that has a +/- of 1/10 gr., I believe. Yet the charges seem to vary some. I need to do more chrony work on that load.

I will try some 2400 or H-110. I have both and should be using the Unique in my 45ACP.

should be using large pistol mag primers! the small mag primers are probably too soft!

Try the CCI 350 primers. Good Luck!

quote:

should be using large pistol mag primers! the small mag primers are probably too soft!

Large pistol and small pistol primers are a differnet size. they are not interchangeable.

If you are piercing CCI pistol primers, you need to back the charge off, IMHO. They are the thickest cups of all the pistol primers I tried.

And as Sniper said, you can NOT substitute large primers for small primers, but I'm sure you know that.

Are the fired primers flattening against the revolver? Do the cases take more effort to extract than usual? No split necks or visible bulges in the fired cases?

quote:

Originally posted by NightDriver:
Are the fired primers flattening against the revolver? Do the cases take more effort to extract than usual? No split necks or visible bulges in the fired cases?

Nightdriver,
None of the above. Like I stated earlier, I would not have even noticed anything except for when I took the empties and put them back in the ammo box. I noticed the primers were a little dark and dull looking compared to the shiney ones next to it. I took a magnifying glass to have a looksy and saw the very small pierced hole in the bottom of the f-pin indentation.

The primers are of an older vintage, but I don't see what that would matter.

I am going to check the firing pin on the SP 101 a little closer. This has got me baffled.

Ant....sniper, I saw a thread just up/down from this one on 357 loads and several said that Unique was "their" go to powder for the 357. I don't think that is the problem. I have always been told by some old pistol shooters that Unique works good in everything pistol-wise.

There can be great differences in pressure and velocity between guns. My old Speer book took a bunch of 4" revolvers and with the same lot of 125 gr factory ammo got velocities from 1200-1600 fps IIRC !!
Always load for that gun with those specific components !

Mete, I totally understand what you are saying about the difference between guns as it is the same for rifle chambers, etc. But as I stated (just above), the cases were not hard to extract, no buldges, etc. In other words, no pressure indications. I have shot factory loads with a lot more recoil than what I was getting from these loads also.

Something doesn't add up, unless it is a bad lot of primers.

quote:

Originally posted by Curly-Bud:
should be using large pistol mag primers! the small mag primers are probably too soft!

Curly-Bud: You should use the little icons available a the top of the reply box like this



when you are trying to be facetious, else you might be thought an idiot for suggesting to utilize primers which are approximately .210" diameter in a primer pocket which is approximately .177" diameter.

Rae, I see what you are saying on the other thread. Where you have no other pressure signs, and the issue seen to be isolated to the primers, I'd try a different batch of primers. As mentioned earler, CCI primers have the hardest cups. Winchester primers have the softest cups, and pierce the easiest, so I will use them for my "Canarie Loads" when I"m double checking for pressure issues. Either way that give you a couple options, maybe some Winchester primers, or some a different lot number of CCI primers.

You might want to check the end of your firing pin for a burr.
If it is smooth just back off a little or change powders or primers.

I wasn't thinking about the physical size of the primer sure missed that one! Sorry!

Curly-Bud, no problem. We all do it. My first thought until I re-read the CCI was that they might have been Wolf primers and then the difference between standard and magnum primers IS the primer cup thickness (but not diameter). Something gets lost in the Russian translation of "magnum".

quote:

Mete, I totally understand what you are saying about the difference between guns as it is the same for rifle chambers, etc. But as I stated (just above), the cases were not hard to extract, no buldges, etc. In other words, no pressure indications. I have shot factory loads with a lot more recoil than what I was getting from these loads also.

Cut your loads. Primer piercing is a positive indication of too high of pressures, regardless of whatever conflicting data you may have observed.

Our ability to read pressure signs is somewhat better than reading tea leaves, but not much. But I can tell you, leaking or pierced primers, you can bet it all on excessive pressure and you will end up winning every time.

quote:

Originally posted by SlamFire:
Cut your loads. Primer piercing is a positive indication of too high of pressures, regardless of whatever conflicting data you may have observed.

Our ability to read pressure signs is somewhat better than reading tea leaves, but not much. But I can tell you, leaking or pierced primers, you can bet it all on excessive pressure and you will end up winning every time.

Exactly.
Primer piercing is something to pay attention to; your loads are too hot.

Don

Well I took the wooden end of a swab and poked around on the firing pin of my SP-101. I didn't really feel any burs but there was a bit of trash (powder, etc.) around it. The SP-101 won't let you extend the firing pin with the cylinger out, and I wasn't about to take it apart. Anyway I cleaned as best I could with a tooth brush.
Loaded up the exact same loads (7.6 gr. Unique) and fired them. Absolutely no problems. So I hope some grit just got in the wrong place at the wrong time.

DMB, I have to dis-agree with you on the pressure thing. There is .010" of daylight between the cylinder and barrel. The brass almost fell out of the cylinder, actually grit was holding them in. The recoil was not anything like many of the factory rounds I've fired in the very same pistol. I am a firm believer that brass swelling/flowing in conjunction with other things tells one if there is a pressure problem. I even loaded up to 7.8 gr. of Unique and had no problems in that pistol. I loaded up to 8.0 gr. of Unique for another 357 Mag. and again had no problems in that pistol either.

Anyway, who knows, the next time I take it out and shoot that load, I might get the piercing again. We'll see.