Single Barrel Conversion....

[RPRNY]

It sounds like any receiver made for a centrefire bulleted round should be good for a rifle, but although I am quoting from distant memory now, that may not be entirely the case. I believe the .44 Magnum rifles and maybe some others, or some of them, were built on shotgun receivers and yet marked SB2 on the barrel, which was to that specification. I would think that those receivers are quite a bit better than some earlier cast iron ones used to be. If they investment cast one in alloy steel, why not investment cast the other - and good mild or lower-spec alloy steel is then just as easy to use as cast iron. But I would want to find out more before using one.

Unfortunately, earlier Toppers by H&R and NEF were made using cast iron receivers that were fitted with barrels chambered in centerfire pistol calibers and low pressure rifle cartridges like 30-30, so the ONLY way to determine which receiver is suitable for higher pressure rounds is to determine whether SB1 (low pressure) or SB2 (high pressure). I looked and unfortunately the picture on the H&R 1871 site used to show the difference is no longer available. The only way to tell is to look at the receiver at the butt stock. SB21 is solid at the stock - bolt enters a solid piece, whereas SB2 is skeletonized at the stock bolt entry point.

Anyone in doubt should post a pic of their receiver and get multiple confirmations.

[fixit]

Most shotgun actions are perfectly capable of handling low-pressure rifle or handgun rounds, so long as the pressure is kept below 40 or 45,000 psi. The biggest problem with a lot of shotguns, is the oversize firing pin. The two shotgun to rifle conversions that I did ran afoul of that fact, resulting in cratering of primers when fired. The 357 rifle that I did craters so severely that sometimes the primer would blank out, leaving a hole where the primer pushed back into the firing pin so severely that it essentially Acted like a punch break, leaving a small Brass disc That dropped into the action when you opened it. I had to fashion a sleeve for that Breech face With a properly sized firing pin to solve that problem.

[Texas by God]

The firing pin size issue is a concern. Luckily the H&R Toppers I've used have small diameter firing pins. An oldaluminum framed hammerless Savage I used with a 9mm liner would pierce 1 of 3 primers so I unconverted it.

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