I have A recent H&r single shot 20ga and have always wondered if the rifle barrels could be added to that gun? Thanks
It's odd that you can use any barrel with the SB2 but lower pressure chamberings for the solid SB1.Yes, it can be done. Sometimes rifle barrels drop right in and sometimes they require fitting. H&R shotguns used an SB1 receiver, so that is almost certainly what you have.
There is an easy way to tell for sure. Take the buttstock off and look at the back of your receiver. The SB1 is solid; SB2s are skeletonized (see the attachment).
View attachment 252927
If you have an SB2 receiver, you can use any barrel. However, the SB1 frames are safe only with low pressure cartridges like the 22 Hornet, 30-30, pistol cartridges (44 mag, 357 mag, 45 Colt) and maybe the 45-70 with nothing hotter than trapdoor loads. BTW, like apparently everything else, H&R barrels have become hard to find and pricey. Good luck and stay safe. Just because a high pressure rifle barrel fits an SB1 frame doesn't mean it's OK. My two cents.