Combination gun won’t open

[AlanBigStick]

I took my son out shooting while he was on leave (Navy). I let him shoot an old Merkel 16g over 6.5x58R. I have an 10” 45acp rifles insert in the shotgun barrel. He came back a few minutes later and said the gun wouldn’t open. He’s right. Any idea how to deal with this problem?

 

[Russ16]

Does the top lever move?

Did you try taking the fore end off?

 

[AlanBigStick]

the lever will not budge. The forend come off and on cleanly. The hammers are not cocked. The safety moves cleanly between F and S without affecting the opening lever.

 

[Mark A Ouellette]

A firing pin may be hung up in the .45 ACP primer.
Use a rubber mallet to tap the butt and maybe the firing pin may break loose and rebound.
If that doesn't work, try tapping the muzzles with the rubber mallet.

 

[AlanBigStick]

I only have a 4oz mallet available. In addition to buttstock and muzzle whacks I put used a fiberglass driveway stake to pound the primer area directly. Still no release.

 

[Hunter-Habib]

At the beginning of this 2024-2024 waterfowl season, I recently saw an old Isaac Hollis & Sons hammer side by side in 12 gauge (2.5”) which also wouldn’t open after certain shells (containing more than 30 grams of shot) were fired through it. We concluded that it was a pressure issue.

 

[AlanBigStick]

Are you familiar with how they eventually opened the action? The stuck firing pin seems as likely reason as any, but for all my mallet banging I’m in the same predicament.

For clarity, it’s a hidden hammer (or striker) O/U. Not that I think that has much barring on the solution.

 

[buckstix]

Try inserting long brass rod that goes into the fired empty 45 acp case, and try rapping on the rod with an ordinary hammer as you apply pressure on the lever.

 

[AlanBigStick]

Try inserting long brass rod that goes into the fired empty 45 acp case, and try rapping on the rod with an ordinary hammer as you apply pressure o the lever.

That’ll require a trip to the hardware store, but I’ll absolutely try it if you think that will make a big difference over the fiberglass driveway rod I used.

 

[93marlin]

I have had the same problem with a combination gun. It was a case of the primer had flowed back around firing pin in the frame.
It was a pressure issue with the rifle cartridge

 

[buckstix]

The 45acp cartridge generates 21,000 to 23,000 pounds of pressure - I suspect the case and the insert have expanded and are gripping the 16gs chamber walls. If that doesn't work, You may have to use a rod large enough to push against the front of the insert, and rap as you apply pressure to the lever.

 

[Russ16]

I’m obviously not familiar with this particular gun. But on most break actions I’ve used the top lever retracts the locking lugs and breaking the action cocks the hammers. Primer flow wouldn’t necessarily lock up the top lever. It would certainly prevent the gun opening once the lever had moved though. Although you say the hammers are cocked. I’m not sure how they got cocked if the lever won’t move and the gun won’t open. At least one of those should be necessary to cock the action.

I there was any debris in the locking surface that could be combined with the high pressure to have caused the locking mechanism to bind which would lock up the top lever.

If that’s the case if it was a box lock I’d start by removing the foreend and trying to get some lateral movement in the barrels to free them. Then I’d take the stock off and see if I could see any debris that needed to be removed.

On a sidelock I’d just pull the side plates to get a look.

All this after making sure all barrels had been fired of course. If one is still loaded and won’t or can’t fire for some reason this whole thing would be very complicated.

 

[AlanBigStick]

I’m obviously not familiar with this particular gun. But on most break actions I’ve used the top lever retracts the locking lugs and breaking the action cocks the hammers. Primer flow wouldn’t necessarily lock up the top lever. It would certainly prevent the gun opening once the lever had moved though. Although you say the hammers are cocked. I’m not sure how they got cocked if the lever won’t move and the gun won’t open. At least one of those should be necessary to cock the action.

I there was any debris in the locking surface that could be combined with the high pressure to have caused the locking mechanism to bind which would lock up the top lever.

If that’s the case if it was a box lock I’d start by removing the foreend and trying to get some lateral movement in the barrels to free them. Then I’d take the stock off and see if I could see any debris that needed to be removed.

On a sidelock I’d just pull the side plates to get a look.

All this after making sure all barrels had been fired of course. If one is still loaded and won’t or can’t fire for some reason this whole thing would be very complicated.

Neither hammer is not cocked. Both triggers were pulled trying to troubleshoot before asking for help. The top chamber’s hammer fell when shooting the 45acp round. The second after my son returned the gun to me.

I can’t imagine debris working into the action, but my son was shooting. He’s no brain surgeon, but surely he has more sense than shooting with chit in the action. Gawd I hope so.

It’s a boxlock. I’m going to keep trying to loosening it up. Flowed primer grabbing the firing pin seems a reasonable conclusion.