My H&R Topper 158 .30-30 was made in 1968. I've tried a couple newer Handi barrels on it to no avail. I suspect the newer barrels don't work because they're engineered not to so a high intensity barrel can't be used on this low intensity receiver. From what I've been able to learn the only other calibers available for that receiver at the time were .22 Hornet, 12, 20, and .410 ga. I'd sure like to have .22 Hornet and at least a 20 ga modified barrels to go with it.
I bought a Weaver base and had a scope on the rifle, until I shot it. The comb slapped my cheek so hard it bled, so I took the scope off. I've had good results with the factory open sight using cast bullet loads. The secret, which once was open knowlege, to consistent good results with a cheap tip-up single shot is simple. Take it out and shoot it. I found a cheap, consistent load that works very well. 1CC of Unique under a Lyman 311291 cast bullet. I use wheelweight metal and shoot them "as cast," no gas check and tumble lubed with Lee Liquid Alox, AKA "Mule Snot". As hard as this load hits rocks and tree stumps, I have no compunctions about trying it for deer.
Gerry N.