My buddy and I spent about half of last season shooting an interesting old rifle. It was a 300H&H in a Winchester Model 70 (pre-'64, of course) that showed up on the second-hand rack at a nearby gun shop. The thing was being sold by the son of the original owner because it had BIG problems: spit back gas and flames every time he fired a .300 WinMag out of it. Thing was marked clearly 300WM.
Problem was that the rifle was rechambered when new.... and it was old enough that the 300 WinMag still wasn't a gleam in its creator's eye. The thing was a 300 WEATHERBY. We got it at a VERY good price.
So my friend, who was 75, now had a 300 Weatherby and he didn't think that his heart (he has had 4 heart attacks) would handle the recoil.
So we spent all last year shooting a 300 Weatherby at LESS THAN .30-30 power levels and it shot beautifully. Powder used was SR-4759, which is wonderful for this type of shooting because it has a lot of energy, a little goes a long way AND it is very bulky and very quick, takes light very easily. You have zero unburnt powder, even shooting 123-grain x39 slugs out of a 300 Weatherby.
Lotsa funs!