Primer Bulging Toward Receiver After Shot

[merhunts]

My Dad has an old HR Topper 16 GA. About 25 years ago he bought a 22 Hornet barrel for it. Back then I don't think you had to send the receiver in to be fitted. For some odd reason he never really started shooting it until recently. The primers are bulging back towards the frame when he shoots it, and when he breaks it down to load another cartridge in, he has to hit it on his knee at the hinge, because the bulging primer.The barrel is very loose when it is broken down. Does anyone have an idea what is causing this. I know its not the ammo because I have a TC Contender in 22 hornet and the ammo shoots fine in is with no problem at all.

[Ireload2]

You can get the gun open easier by cocking it and pulling the trigger on the fired round. The firing pin should knock the primer out of the way.
If the primer is extruding into the firing pin hole it will cause it to lock up. If the primer is backing out without the primer extruding into  the firing pin hole the gun has a bit of head space. Whether it is excessive can only be told with measuring instruments or go-no-go gauges.

[quickdtoo]

Read the barrel fitting info in the FAQs, that will give you an idea of what to expect and how to check the barrel to frame gap. Sounds like the the barrel to frame gap is excessive resulting in too much head space. It also explains how to fix it.

Tim

[LaOtto222]

I agree with Ireload2 basically. Excessive head space can certainly make the primer back out of the pocket, in fact it is almost a certainly, I would think. The firing pin pushes the case all the way into the chamber. At firing the case grabs the chamber walls locking the case in. The pressure of the shot then backs the primer out. Really look at the primer, is it getting "smeared" where the firing pin makes it's crater after it is opened? Is there a crater or is it blown out too? If it is getting blown back into the firing pin hole, that will lock it up. I guess that if the primer came back hard enough to the beach face it could lock it up too, but that by itself would be a lot of force. As the barrel is opened it would start to pull away from the breach face. Chances are the primer is extruding into the firing pin hole. Some thing else to consider is the primer maybe extruding around the firing pin. This can happen if the firing pin hole is large in comparison to the firing pin itself. I am theorizing here, but it sounds like you have two problems. 1. Too much head space. 2. The primer is extruding into the firing pin hole. Really look at the primer and see if the crater (caused by the firing pin which is normal) is there and if the primer is smeared (obliterated). Excessive pressure can cause primers to back out too. Just because the load shoots fine in one gun, does not make it good for another. I had a 221 FB round that was not hot, but the neck was a little too thick to release the bullet like it should. I had a very high pressure problem on this one. The primer fell out of the pocket. Had to throw that case away. The rest of the cases were OK. That one just did not have the neck turned far enough for some reason. I had turned them twice because the first time was not enough. I must have missed that one on the second time around. You said that the barrel is loose when broken down, does it lock up tight, will it lock up on a .002 thick shim? If your answer to either one of these is no, chances are there is too much head space. You can find answers to this problem in the FAQ sticky. If there is a head space problem, get it fixed and then see if the primers are still backing out. I hope I did not confuse you here. I will try to make it a little more simple. I think you have a head space problem. This may be causing the primers to extrude into the firing pin hole making it difficult to open. It could be caused by other problems, but I would have to see the primers still in the case after being opened to make a better assessment. it is my 2 cents worth.

[LaOtto222]

Tim, While I was typing that long winded answer , you replied and said the same thing, so much quicker and to the point

[skifastchad]

The primer is extruding into the firing pin hole. Really look at the primer and see if the crater (caused by the firing pin which is normal) is there and if the primer is smeared (obliterated). Excessive pressure can cause primers to back out too. Just because the load shoots fine in one gun, does not make it good for another.

The H&R/NEF shotgun frames have a firing pin and hole about 3 times the size of the firing pin on the rifles.  Maybe the extruding you speak of is the problem here if the rifle barrel does close up properly before firing.

[merhunts]

As far as head space, when the barrel is closed it is very tight with no movement. It has no space between the frame and barrel back. And I forgot to mention that he is shooting factory loads. The primers themselves are not backing out it is just the area where the firing pin is hitting, is bulging backwards. He has replaced the firing pin twice since starting to shoot it.

[quickdtoo]

Take a look at the frame pics in the FAQs, there's a comparison of shotgun frames and rifle frames, as has been mentioned, the larger firing pin hole causes problems. The SAAMI MAP for the Hornet is 43kcup, so it's not as low pressure as you might think.

Tim

[merhunts]

Thanks for the info. I'll have him check to see how big the firing pin hole. If it is too big than he probably will need to stop shooting it. He bought it as a shotgun. So my guess would be that it is a shotgun frame and he shouldn't shoot the 22 hornet barrel with it. If I am wrong please let me know.  The part of the primer that is bulged out  is sheared off when we finally get it open. So most likely the firing pin hole is too big for center fire ammo.

[trotterlg]

If I recall right early on H&R would fit Hornet and 30-30 barrels to shotgun frames, in the 80's?  Am I just imagining this?  Larry