doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com light primer strikes

My early 1950's 12g Boswell box lock double gun has a light primer strike in both barrels, but only on about every 3 or 4 cartridges in each packet. I've experienced the same issue with a couple of brands of factory ammo where the primers appear to be flush with the base of the cartridge ie. not sunken in.

I've has both V springs replaced recently and the gun is not off face. The gunsmith would have cleaned the action when he replaced the springs.

The firing pins protrude enough to strike the primers when extended.

I'm confused as to why the pins strike the primers with enough energy to fire and also show a decent indent on the spent cartridge, and with the same ammunition only just strike the primer with hardly any indent at all?

If the pins or springs work most of the time, what can cause the odd misfire using the same ammunition?

Any advice would be appreciated.

Not always the easiest problem to over come as there can be a number of factors to consider , had the gun come to me these would be my first thoughts and what I would check :
1,Are the rim depths to deep ?
2, Have the trigger pulls been altered at some point , thus the sears may have been shortened to much so there is not sufficient throw/drop on the hammers .
3, Does it have loose strikers or are they integral to the hammer , which is most common . If loose are the floating freely with enough free play ?
4, There could be an outside chance of something along the cocking train that is preventing the hammers from falling fully . This can only really be investigated by stripping down a checking .

Having dealt with this issue I narrowed my problem down to the ammo, one particular brand, B & P Comp One. I first suspected the gun, then found it would happen in every gun I owned with the exception of two external hammer guns, one double and one single barrel. It boiled down to gunman's no. 1 point, about the rim depth being too deep, but in my case only too deep for the particular shell brand in question. However, and again, not the gun's fault due to chamber rim depth being cut too deep, but the shape of the rim on the shell head itself.

I had bought two or three flats of those shells to use in my vintage doubles due to their light recoil and low chamber pressures, and had reached the point that I figured to just use them up in the external hammer guns, until a member here private messaged me a solution that would allow me to be able to use them in my other vintage 12 ga. doubles ............. I went to the dollar store and bought a package of tiny rubber bands that women use for their hair, as I recall. They are about 1/2", or less, in diameter. They stretch over the head of the case and you slide it up against the rim. When seated in the chamber the tiny rubber band holds the case head snug against the standing breech and ignition is 100%. You get a blue million of the little thingies for about a dollar.

Have you attempted to isolate the issue to either the ammo your are using, or to the gun itself ?

I had light strikes on a primer and compared the shell head to others. The rim of the head was noticeably thicker causing the light strike. Shell is near the coin. Both too little and too much headspace can cause issues. Gil

I like shooting hammer guns and back then no one wanted them mainly because of having Damascus barrels. Some had light pitting/fouling but in the 12 gauge I was using light 3/4 oz. loads. Some were loaded with Remington primers (when they were still priced like the others), some with Winchester 209 and Cheddite primers. On this one particular hammer gun that I had I was shooting 100 rounds of sporting clays. Went through the one box using Remington primers and everything went fine. Opened another box with Winchester primers and on the first set of doubles the second barrel would not fire. Tried again and nothing. So for the rest of that box I was shooting singles. The next box was not Winchester primers and I tired shooting doubles and worked fine.
At home took the locks off and looked at everything, the firing pins were protruding the same, took the right side off and used the mainspring for the left side, same problem, made the firing pin .030 longer, no luck and last resort measured the ejector depth on both sides and they were the same. completely baffled now and elected not to shoot Winchester primers out of that gun. Just sold it an told the new owner the problem and said he would not shoot Winchester primers. Gun is an L.C. Smith.

Reidy reported that some primers were flush with the case head while others were below flush. As some of us, handloaders, have sadly found out; primers that are not fully seated sometimes fail to fire. We believe this is caused by the firing pin expended seating the primer rather than crushing the priming pellet. I suggest he try firing the misfired cartridge a second time. If it (they)had the primer seated by the first strike, the second strike may fire it. I'm not suggesting this for regular usage but for diagnosis.
Mike

An acquaintance loaded RMC brass hulls for his .410. All cases caused light hammer strikes. Shotgun shells headspace on the rim of the shell. The heads' rims were too thick. He belt sanded them down to match plastic hull rims which solved the dilemma. Gil

Thank you to all for your helpful advice and suggestions. I am revisiting my gunsmith soon to see if he can rectify the issue. I will make notes of the various points that have been included this forum and discuss these with him.

I really like using the Boswell on clays at my local clay target club and hope it can be repaired soon. Using an unreliable gun on the range is certainly a sure way to break your concentration and confidence that the next shot fired will actually go bang.

Cheers to all.

Couple of points I missed and probobly not relevant here , is that on occasion you get batch of cartridges that have harder than normal primers .
Production being such that when this occurs you may have a whole load of them , but if you have tried different brands then this probobly not the case .
I have also come across and accepted the strange fact that some guns do not like some cartridges .

Amen to that. It doesn't just mean problems occur when ammo is being fired. There are also the nightmares of problems during ejection attempts, also.