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An absolute dream of mine is to convert my grandfather's Stevens 5100 SXS to a double rifle. All it is, is a safe queen sitting around collecting dust anyway. I never use it & it's in great condition. The lockup on the doll's head is still very strong & crisp. The only problem I have been able to discern in it's design is that there is no double underlug. There is only one lug & the doll's head. It seems very strong though, maybe 550 grain 45-70 strong? The single underlug worries me. It feels very strong, but doesn't look like there's much material to the single underlug.

I've got a mockup for ya!...It starts with a Stevens 5100 & two unturned 28" barrel blanks @ $225 a piece from preferred barrel blanks. Take the already bored blanks (to your preferred caliber) to your local machinist (everyone knows one). There's a circular 90 degree shelf at the end of the 2&3/4 inch chamber that the machinist can turn the blanks down to via lathe; using the chamber-to-barrel union as a horizontal circular shelf & ensuring the bullet doesn't try to twist the sleeve out of the barrel. The measurements have to be precise by calipers so the inserts will fit snugly. As a caveat, I am not a fan of the monobloc design, even though my design is heavy but minimalistic, without embellishment & heavy new sight wedges. Maybe just buy chrome-moly barrels instead of stainless? I think if you're going to chop up a gun, you just lost the dual functionality of it. This wouldn't be a tack welded insert, just so snug that one would have to tap the inserts out with a mallet from the muzzle to remove them. After the chamber side & meat of the barrels are turned down that part is done.

Next is bushing the firing pins so you don't crater primers, by just drilling the firing pin holes out until you're about 1/8 inch away from the overall diameter you've decided on for the bushings. Then, tap the bushing holes with a tap & dye. Afterward comes the hard part...finding commercially available firing pin bushings & not having to go all the way to Westley Richards to find them in the proper size. My thought on a field expedient bushing would be a cut down grade 8 threaded bolt, with something like a .065 hole drilled through the middle. Screw in the completed bushings, & don't forget to drill spanner wrench divots in the outer edge of the top of the bolt shank, so you can get the bushings back out!

One of the other minor last steps would be to construct a new ejector that takes advantage of the vertical strength of the breech face, i.e. the ejector extends all the way up to the 2nd lockup on the top. The barrels breech side & the ejector would have to be milled on a vertical milling machine, so the ejector indexes with the breech/barrel face & the barrels line up circularly with the ejector. Also, there would need to be set screws on the breech/barrel face that keep the barrels in their proper orientation. Possibly that position could be under the new ejector, seated flush with that face.

Finally, thread the outer inch of an exposed 28 inch barrel, after cutting off one inch for muzzle rings/retainer nut use. The 5100 has a 26 inch barrel, so one extra inch out the front of the muzzle for male threads & one inch left over to make female threads from the remaining stock. Now, the rib on the 5100 is kinda' small so the exterior of the nut has to be tight tolerances. Also, the retainer nut has to be over bored so the bullet doesn't try to re-engage rifling.

Also, the inserts would have to be bored out for cartridge length and headspace...I don't think they do that from the factory. But, I would like a double rifle that I could re-convert to "Papa's ole' shotgun" & still have functionality, albeit changing out ejectors. Which leads me to another question: The shotgun should still fire shotgun shells with smaller firing pins, right? Without having to change out bushings?

If the inserts are quality made to tight tolerances, it should pattern just like a ole' scattergun...i.e. just point and shoot out to 50-75 yards. Almost everyone in America has an old shotgun of this sort. If there were kits to do this commercially available for some models, money could be made...

I have read that bushing the firing pins are a must for the higher pressure loads, i.e. 40-44,000 psi and above. I'm sure it would help in a shotgun to bush em' at 20-30,000 psi...Do you guys think that with the bushed firing pins, this thing would hold up to those higher pressures with only one underlug?

If I go ahead with the project I will be buying, "Building Double Rifles On Shotgun Actions by W. Ellis Brown", heck I might just buy it anyways.

What'd ya say...order some .375 H&H blanks...She might be able to handle it with the bushed firing pins!