As to barrels for your older H&R, you would need to watch the auction sites for both barrels and complete guns - H&R will fit new barrels to guns that they built, but unfortunately, the current H&R did not build yours, so they won't fit anything to yours. You can find out the details on their website under the Accessory Barrel Program under Support. The new barrels may fit your receiver - I say may because that is the case for all used barrels with any receiver, You may get lucky and it may fit perfectly or you may have to fit the barrel by removing some metal or adding shims - see the stickys for fitting info. One final option would be to take a welded lug shotgun barrel and have someone use it to make you a new barrel (search for barrel stubbing for more info on this). Most early shotgun barrels are brazed and may not be strong enough for rifle calibers. Same comments on fitting that barrel would still apply. My suggestion would be to buy a new .357 gun and send it in to have a 44 barrel fitted by the factory. If you buy a new riffle caliber like 223, you would have more options, since the .357 and 44 are built using shotgun frames and can only be factory fit with a shotgun barrel or the .357 or 44 barrels. There are a lot more options for the Centerfire Rifle (SB2) receivers