Of course if you were going to that trouble, it would be good to improve the extractor, improve the trigger, and cant the breechblock slightly so that it cams closed. I'd love to have one that was a safe shooter for modern cartridges.
#WALNUT STOCK FOR HOPKINS AND ALLEN SHOTGUNS CRACK#
I've been tempted more than a few times to mill one out of good modern steel with a threaded in barrel and a slightly redesigned profile to eliminate the tendency to crack at the back of the block mortise corners. I see hundreds of the large frame 12 ga that are just beat to death from use. For a poor and weak action, these things were well loved and extremely well used. The design made for a weak stock, and I rarely see one that isn't cracked, broken, or repaired, or some combination thereof. The weak point of all of the H&A is the stock at the wrist. The deluxe rifles such as the ladies model and some of the better sets are quite nice and well put together rifles. Although it is stronger, it is not a particularly strong action either. The rifles were offered on the medium frame, which, paradoxically, is stronger than the large frame. I love these old shotguns, but they're really not strong enough for even medium strength cartridges, or sustained use. It's hard enough to keep them from wearing out, the takedown system isn't too rigorous. The reason for the barrel clearance is that these actions don't cam into the chamber, and need some clearance to keep from pushing on the barrel and wearing on the takedown screw as the action is worked. I would cut the chamber so that there is a rim recess that the cartridge fits into, till the cartridge is about flush to. You will want to face off the breech as needed, and then cut a new extractor slot to fit your cartridge and the H&A ejector.
![walnut stock for hopkins and allen shotguns walnut stock for hopkins and allen shotguns](https://assets.catawiki.nl/assets/2020/5/28/1/a/6/1a6c30d5-6435-4a63-9fc7-6c1fef5cd326.jpg)
Because they're a slip fit takedown action, they can't take the thrust of much of a cartridge. They are not suitable for 12 ga, many of them have incipient cracks at the top of the breechblock mortise corners.
![walnut stock for hopkins and allen shotguns walnut stock for hopkins and allen shotguns](https://www.collectorebooks.com/gregg01/shotgun3/DSC00406.jpg)
Congratulations, you are the first fellow that I have heard ask about converting these to a rifle that has picked a cartridge that they are safe with! Although massive, they are a weak action, and suitable only for relatively weak cartridges.