Author Topic: Blackened primers after fitting (Read 768 times)

JerryKo · « **on:** December 10, 2007, 04:00:32 AM »

Good thing I waited to shoot to post that I attempted my first barrel fitting. I had a factory fitted 357mag barrel that only worked on one frame. All my other recs are pretty close and can swap barrels, so in my attempt to make my world right I thought I would try. My factory fitted barrels do not conform to the FAQs here. They all lock up tight and cannot remove a .0015 feeler gauge from the receivers, so I stuck to that as my guidelines. Took me 2hrs for 2days each to finally get the lug down to match my guidelines. I used all hand power with a screw driver wrapped in emery cloth and rotated back and forth.. Every thing seemed perfect after I honed the rear of the lug for latch engagement.

My bubble burst when at the range shooting 110 JHP factory Win loads I started noticing periodic blackened primers. Gases are leaking out of the center of primer. This leads me to believe that I need to take at least another .001 or so to correct this. But before I tried I wanted to get some opinions other than mine. I did try some plinking loads of mine and they had the same results, so it is definitely caused by my fitting. I'm just afraid of making the barrel too loose, as it has a good lock up now.

JerryKo

Slufoot · « **Reply #1 on:** December 10, 2007, 08:41:24 AM »

Hello Jerry, It sounds to me like your firing pin is piercing the primers. You have probably got this barrel set up with zero headspace and the primer can't handle the full protrusion of the firing pin. The SAAMI allows a tolerance of .006" for headspace.
I would measure the firing pin protrusion and if it's more than it should be I would make it the correct length. Some of the more knowledgeable Handi owners on this sight will probably know the maximum firing pin protrusion measurement. The worst thing that could happen would be that your other barrel might not work with the shortened firing pin and you would have to make or order a new one.
This is just my thoughts from reading your post.

GOOD SHOOTING!
Slufoot

JerryKo · « **Reply #2 on:** December 10, 2007, 08:45:45 AM »

Thanks Slufoot for the reply. I did consider shortening the firing pin, but realized as you said the the other barrels may not work. I'm wanting to alter the barrel some more, but just want some more input on it first.

JerryKo

Slufoot · « **Reply #3 on:** December 10, 2007, 08:46:30 AM »

Jerry, I thought of this while I was posting my first response.
Look at the firing pin diameter from the receiver that you took the 357 barrel from and see if it's a smaller diameter than the frame you have it on now.
I know that some revolvers use a smaller diameter firing pin for cartridges that use small primers.

GOOD SHOOTING!
Slufoot

JerryKo · « **Reply #4 on:** December 10, 2007, 08:51:05 AM »

Good thought. I will look, but the frame from the 357 barrel started life as a 270 , and the new frame is from a 7mm-08. But it is possible. I'll check.

Thanks,

JerryKo

Slufoot · « **Reply #5 on:** December 10, 2007, 09:12:00 AM »

Hey Jerry, Something else to check.
Take the 357 barrel off the frame. You may have to pull the extractor/ejector and then drop a cartridge into the chamber and see if the cartridge sticks up a little over the breech of the barrel.
If it does, measure it and then you will have to allow for this much more for fitting. If you can't pull a .0015" feeler gauge from between the breech of the barrel and the receiver and if the cartridge is sticking up from the breech of the barrel a couple thousandths or so, then this could be the reason the primers are getting pierced.
Just another thought!

GOOD SHOOTING!
Slufoot

quickdtoo · « **Reply #6 on:** December 10, 2007, 09:12:44 AM »

Is there an actual hole in the center of the primer, or it the primer just blacked from around the primer pocket? Pierced, or perforated primers as they're called, have been reported by those using rifle barrels on shotgun frames.

You can have zero gap between the frame and barrel face, but still have excess headspace due to the chamber or rim cut being cut too deep, one of the first steps in barrel fitting is to make sure a sized case is flush with the chamber face when chambered, if it's recessed very much, the barrel face should be flat filed to reduce the headspace. Headspace on a break barrel is that recess amount plus the barrel to frame gap, the total amount has to be .006" or less according to SAAMI as Slufoot mentioned, .001"-.0015" is much better.

Tim

JerryKo · « **Reply #7 on:** December 10, 2007, 03:07:21 PM »

The inserted cartridge is completely flush. The blackening appears to be from the center of primer. I cannot see an actual hole though. The blackened primers are still rounded, so they are not reaching good pressure I assume due to the leak. Also the firing pins are same size both dia and protrusion.

I think at this point I should just take another thous. or .0015 and refire. At the worst I 'll have to shim or find another frame for it.

I'll keep ya posted, but if any other ideas come along let me know. Sure wish I had a round file.

JerryKo

iceking02 · « **Reply #8 on:** December 11, 2007, 03:52:10 AM »

Take a picture of the cartridge base (after firing) and post it to the forum. Don't file off a good fitting barrel until you get a little more info out there. It could be a $100 oops. Get a side profile, and rear view of the cartridge.

If you have leakage ONLY on the primer, not on the edges of the cartridge, and yet there is no perforation of the primer it would sound more likely to be an ill-fitting primer to the cartridge's primer pocket. Are these reloads or factory loads?

IceKing02

JerryKo · « **Reply #9 on:** December 11, 2007, 03:58:53 AM »

Have a quick trip to the range planned at lunch today to refire. I took 120 more twists of my emery wrapped screwdriver and now the .0015 feeler can be pulled out with effort. It will close tight on a .002 and lockup but it doesn't sound like a total lock up.

I was also wondering if just firing primers would still test this, or do I need a pressure load to push everything back to the breech face. Never mind, as I typed that it answered my question.

JerryKo

Iceking02 I quess you posted as I was typing. Thanks, but too late as you can see. I think it is ever so lightly pierced. I cannot see light through it, but it looks like a slit rather than a hole with magnifying glass. These are both factory and handloads and too different frames. I'll get it right. Its only a plinker anyway. And so far it has been fun tinkering.

OR-E-Gun Bill · « **Reply #10 on:** December 11, 2007, 04:30:53 AM »

JerryKo, you mentioned that your factory loads were Winchester. Are your reloading with Winchester primers as well?

Bill

JerryKo · « **Reply #11 on:** December 11, 2007, 08:46:51 AM »

Bill,

Nope,...CCI on the reloads. The problem seems resolved though. I shot 75 through 2 different frames and all looks good. It was fun shooting them gongs. It's been a while since I did that. Way too much paper shooting lately.

Anyway thanks to all for the help and suggestions.

JerryKo

Slufoot · « **Reply #12 on:** December 11, 2007, 09:12:44 AM »

Glad to hear that you got it straightened out.

GOOD SHOOTING!
Slufoot

JerryKo · « **Reply #13 on:** December 11, 2007, 09:55:17 AM »

Tim,

I've been looking for a round file without a taper but this one looks like the taper starts closer to the end. Any thoughts. I can only get them in a pack of five and the cost is 22.78 each. So if it would work, and I could get some others interested the cost could be split. I 've never had to buy a specific file before but it seems steep to me.http://www.pferdusa.com/products/201/20112/2011204P.html#b11072H.

Thanks again,

JerryKo

quickdtoo · « **Reply #14 on:** December 11, 2007, 10:09:06 AM »

If it's got a straight section that is 3/8", it would work great! If you decide to get em, count me in for one plus shipping.

I think the second would be my choice, unless you can get them to mix em.

Tim

Steve P · « **Reply #15 on:** December 14, 2007, 09:54:57 AM »

357 mag factory ammo have small pistol primers. They are very soft. It is relatively easy for a rifle firing pin to pierce them. Lots of shooters using rifles, contenders, etc, have gone to small rifle primers instead. They work better.

Just another possible fix.

Steve

wtroger · « **Reply #16 on:** December 14, 2007, 10:13:56 AM »

The small pistol primers can be the problem your frame is for a rifle cartridge and the firing pin is set up to ignite the harder rifle primers. I have seen this on other pistol cartridges that are fired in rifle frames.
I have a Win model 94 trapper in 45 LC that will not fire 45 LC that are loaded with rifle primers it has never failed with pistol primers. So some manufactures do set up there firing pins for specific cartridges maybe H&R does maybe they don't.