Roger,

Apologies for jumping in on my first post to stir the pot.....

Although I would not be in favor of using that Remington for any rifle caliber of power, make no mistake about it.....the gun has Triple Bites. Not sure where Bob's take on the lockup is coming from, but you can see all three bites in the photo you posted of the receiver.

1) Barrel Extension
2) at the base of the Face
3) The Split bite that frames the second 2 in 2280

The split bite could be made to be solid as well with a barrel alteration.

Also, it matches exactly, the 12ga Remington sitting here in my lap (triple bites). It was actually one of the better built American doubles, although HEAVY. Many brands were, as mentioned, only locked by the rib extension which is dubious at best.

Not suggesting you proceed with a rifle, although is would make an interesting rim-fire, albeit an Eight or Nine pound rim-fire.

Droplock.