How is this problem fixed?Just want to know in general.

add metal to the end of the reciever and machine it back into specs.

Paul, It needs metal added to the breech end of the barrels. Reciever is fine.

I hesitate to say this, but the only person who can truly evaluate this gun and determine what it really "needs" is a professional. That is, if the gun merits a proper fix.

Dave, that is what i was trying to say.
Kensal. you are correct, I was just trying to inform the owner that there is hope for his gun.

the barrel lug on the barrel especially a large heavy barrel can cause the gun to be off face...the mills 8 ga parker he got at silent auction was off face a 1/4 inch and im not eagirating a bit...the barrel lug was loose on this gun it would slide a little more than a 1/4 inch it had been fixed at a bunch of times with siver soilder and one time with brass rods..ive got it back on face really good on the right side but its still off a little on the rite barrel it shoots fine but the lug i believe has been waroped over the years ive redone the barrel lug 3 times and believe me that think as to be down to hundreds of thousand before it will shut properly...this was the big 8 problem the barrel lug...and ive got another lifter 8 ga parker thats off face a hair and ill bet a nickel against a doughnut hole that its got the same problem...i doubt if this ever happens to a small bore gun because they are not barrel end heavy...but its my opinion that this is why a lot of heavy long barrel gun get off face like heavy barrel 12 ga and 10 ga and espically the 8 ga...the old gun im shooting now the mills guns fireing pins could not reach the shell it was so bad and it would not even britch it was so off face...i hope some body else like brian or one of the other boys that truly no how to put a parker back on face will comment on the heavy barrel theory i have causing the big gun to get off face..i know for sure that the barrel lug has broken loose it will get off face in a hurry i have a gun to prove it... hope i did not try to steal the thread.... charlie

Charlie;
My belief is that the barrel lug wears due to lack of proper lubrication and not recoil. I always clean, then relube with a good grease, the radius of the lug, the sides of the lug, the radius of the frame where they meet the forend and the forend lug, fore and aft. Most of the wear on the forend lug occurs on the aft side of the lug (the side towards the receiver). If you take notice this has a slight angle to it and without proper lubrication will wear and cause the forend to become loose. Shoot 'em often, keep them clean and lube them for another 100yrs. of use.

While Lab's recco on proper lubrication should be taken to heart by all double gun enthusiasts, I believe there is another culprit at work here: Inertia.

Large bore guns generally fire large charges of shot and powder in heavy massive barrels. When things go boom, the laws of physics take over. And the whole mass, barrels included, want to go forward. In an 8 or 10 bore gun this is a relatively LOT of metal... all held back by a narrow little hook and some relatively soft metal.

The workmanship and solidity of the lump attachment is yet another strength issue.

Fire enough Jupiter-size shot and powder charges through a double gun like this, and things will naturally want to come apart.

On the other hand, I believe the sheer weight of the barrels and their "hanging weight" on the hinge pin has little to do with it.

just my opinion...

Two questions to get to the root: Is your gun a doll's head action? If it is not a doll's head action, can it be forced back to the breech with the forend removed?