I use the 50 BMG in the following: 338 Lapua with heavy bullets, 30-378 180- 190 gr bullets, 338-378 with anything over 225 gr., and lately it has given great results in a 28 Nosler I picked up a year or so ago. In .300 Weatherby, I tend to go with something like 4831, 7828, 7977, RL22, Vihtavouri N165, etc. Even H1000 and Retumbo are too slow for the .300 Weatherby unless you go with bullets over 200 gr., but here you can be "stability" limited by the 1:10" twist of the .300 Weatherby. Hodgdon doesn't list H50 loads for the .300 Weatherby. Yes, you could make some squib loads, but what's the point? You're using primers (which are like hens' teeth lately), putting some wear on your expensive brass, getting low velocity and burning up a Weatherby barrel with that slow burning powder. For what purpose? If you want .30 cal squib loads, you can go with 30-06 or .308 110 gr carbine or 125 gr pointed bullets, and light loads with Unique or 2400 for 2000 fps, or H4895 for fast loads, and have a much better optimized system. Just my 2 cents.