Question about pierced primers , any ideas

[onelight]

I have 2 Ruger 327s a single seven and a 4.2 SP101 both will pierce primers about 10% of the time .
The primers I use are WW small pistol . They pierce in 32 s&wl , 32 h&r and 327 the loads are light to moderate here is a pic. of the primers in 32 h&r that were loaded with a 115 rnfp on 3.4 grains of Unique out of 100 rounds 11 pierced . From the Single seven when I look at the firing pin tip it is rounded with light machine marks.
I use these same primers in 20 or 30 hand guns none pierce but my 2 327s . Any ideas on what might cause this ?

[metricmonkeywrench]

I have a second Gen Colt in 357 that does the same thing for all Mfgr's primers both standard and Magnum. Same conclusion, for mine the hammer mounted firing pin (original) basically hits big and hard and deep (almost think its trying to turn the primers inside out), looked at the firing pin over and over, nice smooth and well rounded. I haven't see a firing pin protrusion measurement for it but it looks to be no more than my S&W Model 10.

I just accept it and move on until it becomes an issue and I start seeing signs of flame cutting on the firing pin or frame.

http://castboolits.gunloads.com/show...ighlight=range

[rancher1913]

might try a harder primer and see if that helps.

[onelight]

Some of the 327 factory loads I have heard are loaded with small rifle primers also some load data for 327 call for small rifle I don't know if Ruger would use a longer firing pin in a gun set up for small rifle primers.
I have a SP101 357 I will compare the pin protrusion with the 327 and see if they are the same.
If I can figure out a way to measure it.

[Thumbcocker]

I have an SP101 in .327. It pierced primers even with .32 long loads. Called Ruger got a call tag. It was returned with cylinder honed and hammer, trigger, and other internals replaced. They also removed my reduced power trigger return spring. The nice lady at Ruger seemed to have no problem helping me so my feeling is that this is not unheard of on these models.

[metricmonkeywrench]

Heres a "tool" for the task. I have a drawing somewhere abouts for a go/No-go for a S&W Model 10. Having the tool is one thing, finding the correct dimensions is another

http://pacifictoolandgauge.com/misc-...ion-gauge.html

[onelight]

Thanks , I have several other Ruger revolvers that do not have a problem with a way to measure I can at least compare to the ones that work.

[Valley-Shooter]

It was my understanding that the 327 uses small rifle primers.
Have you used small rifle primers?
I would try that.

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[rintinglen]

Both of my single sevens will do the same thing with either Remington or Winchester small pistol primers. CCI 500 primers seem not to be prone to this problem, nor do WW SP Mag primers. 42,000 PSI loadings put some strain on the primer cup when the hammer fall stretches and thins the metal under the firing pin, though why your mild loadings should exhibit this problem, I do not know. Examine the firing pin tips with a magnifying glass, see if they are more sharply pointed than on your other revolvers. If so, you may be able to lightly sand the tips to round and smooth it. Use a fine sand paper, 600 grit or finer.

[onelight]

I looked them over under magnification hoping to find a burr or something that would be easy to fix but they looked good.
I may just load some of the light loads with small rifle like Valley-shooter suggested and see if it stops the problem that would be an easy fix 😃 am I wrong in thinking the rifle primers have a thicker cup?

[EMC45]

I had the same problem in my S&W Model 30 in .32 Long. I looked closely at my firing pin and there was a little "beak" on it. I stoned it a little and fixed the problem.

[megasupermagnum]

You don't need small rifle primers. Federal and Winchester primers are generally the softest, however, I have not had any piercing problems with either. The problem is almost certainly the guns. It could have started with a bad load that left a mark on your firing pins, or maybe they came that way from the factory. The fix is easy if the guns are relatively new. The firing pins are held in with a screw in bushing on the back of the frame. I made the bit to fit it with a flat screwdriver, and used a Dremel to form it into two points that correspond with the holes in the bushing. All you have to do is unscrew the bushing, inspect and polish your firing pin tips, and reinstall. You will need to remove your grip and hammer too, to gain access. To polish you are going to want something fine like 1000 grit sandpaper, scotch brite, polishing compound, etc. You want to knock off the sharp spot, not remove a lot of metal.

[dimaprok]

At some point I was trying to limit my primers to 1 type so I used S&B rifle primers in my Ruger GP100 for 38 SPL loads because they didn't have any pistol primers in stock and they worked ok, primers were $20/brick at local Cabela's while CCI primers were $30-32 a brick. Sometimes the primers didn't go off, but same thing was happening in Ruger American bolt action 300 BLK, I blamed the primers which disappeared off the shelves in a year or so. I sent Ruger my Ruger American rifle and they determined the gun was at fault and offered me replacement. I don't think Mossberg 223 ever had issue with those primers. Later I learned that semi-auto pistols like Glock does not like rifle primers so I started buying pistol primers again.

[onelight]

You don't need small rifle primers. Federal and Winchester primers are generally the softest, however, I have not had any piercing problems with either. The problem is almost certainly the guns. It could have started with a bad load that left a mark on your firing pins, or maybe they came that way from the factory. The fix is easy if the guns are relatively new. The firing pins are held in with a screw in bushing on the back of the frame. I made the bit to fit it with a flat screwdriver, and used a Dremel to form it into two points that correspond with the holes in the bushing. All you have to do is unscrew the bushing, inspect and polish your firing pin tips, and reinstall. You will need to remove your grip and hammer too, to gain access. To polish you are going to want something fine like 1000 grit sandpaper, scotch brite, polishing compound, etc. You want to knock off the sharp spot, not remove a lot of metal.

The firing pins look good both are nice and round with only normal tiny machine marks checked them both under magnification. But I have not measured them for how far they protrude compared to my other Ruger revolvers.
I know the protrusion is important but I have seen rugers with almost no end shake to excessive end shake that did not have this problem . I am stumped .
I think I will take a box of factory 100 grain load next range trip and see if they pierce the primers.

[samari46]

My Beretta 92FS has a conical style firing pin and useing the ReM-umc el cheapo ammo in 9mm the firing pin pierced the primers. And cost me for a new firing pin and spring. The firing pin tip almost resembles a center punch. Other makes of 9mm showed no problems. When the smith did the replacement pin and spring I asked if he would sell me a spare firing pin which he did. Always good to have a plan B. Frank

[Greg S]

Your firing pin may be scorched from a jet of hot gas eroding the pin causing a dimple. When the pin hits the primer, the dimple grass the primer metal and it tears and cass the problem. The other issue would be to light of a mainspring causing blanking.

[Ed_Shot]

Had a New Model Blackhawk 357/9MM bought 4 years ago that consistantly pierced 1 or 2 primers out of every 6. Small Rifle primers stopped the piercing but I didn't want to pass-it-on with the problem. Sent it back to Ruger and within a week they called to say the firing pin channel was drilled too deep into the frame and they sent me a new Blackhawk. Well.....the replacement pistol they sent pierced 3 out of every 6 primers and it was promptly returned. They replaced the hammer on the second pistol and it hasn't pierced another primer.

[onelight]

Your firing pin may be scorched from a jet of hot gas eroding the pin causing a dimple. When the pin hits the primer, the dimple grass the primer metal and it tears and cass the problem. The other issue would be to light of a mainspring causing blanking.

Could you explain , I do have lighter springs in both. What is blanking ?

[Larry Gibson]

Could you explain , I do have lighter springs in both. What is blanking ?

Did the revolvers pierce primers with the original springs [particularly the hammer springs] in them?

[ioon44]

The only pierce primers I have is out of my 38 S&W which is a H&R model of 1887, the firing pin is really sharp and I have been using Fed 100 primers.