LeFever shotgun problem

[Silver_Rings]

I purchased a LeFever side by side shotgun a while ago.  It shot fine for about 25 rds.  I shortened the barrels to 18 1/4" and did dry fire practise using snap caps.  I started having problems with it not cocking the strikers.  I put a shim made from a 45 colt case brass between the cocking lever and the cocking rod for each barrel. This appears to fix the cocking problem and works fine with snap caps.  When I fire live rounds, I have to smack the barrels while holding the opening lever to the side to get the barrels to open.  Any ideas as to what is wrong?

Silver Rings 

[Blackfoot]

Normally hard opening of a sxs can be caused by the firing pins (one or both) not retracting after firing.  Don't know about the LeFever,  anyway a good cleaning and checking firing pin condition may be in order.

Blackfoot

[Silver_Rings]

The gun is clean.  I think you may be right about the firing pins.  It opens fine with snap caps, but if I put in fired cases and fire it, I have to rap it with my hand to get it open.  The fired cases drop right in and drop right out, so it's not the case hanging up.  I'll take a look at the firing pins and see if I can find anything.

SR