The reference I made to the 700gr load for a 2 Bore was said tongue in cheek, I am currently building a Cartridge 2 Bore in a Jones Underlever for a customer. The company that makes the brass for it(S&H Precision) has there cases set up to take a 700gr FFg max load under a 3500gr brass solid. A true 2 Bore is 1.326" diameter. I do have a little experience shooting them, not because I particularly enjoy it, but because it is how I make my living and the 2 Bores seem to be popular right now. The experience I have with 2 Bores has taught me that in a 24 pound shoulder mounted rifle that is well balanced and fits well 500gr FFg is the max load that I can handle for felt recoil. And I'm no small boy either, I'm 6'-5" and about 250-260. Wyosmith(Steve) and I have had this discussion several times, that you can't scale up proportionally in big bore rifles because the recoil rapidly becomes more than a normal person can handle. For instance, the "average" charge for most 8 Bore's is around 300 grains with a 835gr ball, so scaling that up you would have 600gr with a 1750gr ball for a 4 Bore, but in reality most people draw the line at 450 for a 4 bore because while the charge and ball weight can be doubled, the weight of the rifle only increases 5 or 6 pounds(usually), so the amount of recoil generated is substantially more even with a smaller than double ratio. Now applying this same scaling approach to 2 Bore the charge would be 900 grains(if you went off of the 4 bore normal charge) and the ball would weigh 3500gr but the rifle would weigh around 24pounds, as compared to a 18-20 pound 4 bore, so while you have doubled the charge and ball weight you only added 4-6 pounds to the weight of the rifle and I can tell you from experience that 900grs would be injurious at the least and possibly fatal. 2 or 3 shots at 500grs and I can feel the stress's taking place in my lower back and waist area from the rifle trying to twist me around and fold me over all at the same time.
If things where truly scaled up with full magnum charges based on the original writings of some of the African hunters of the 1870-1890 the magnum charge for a 2 Bore would be approx. 1600grs, and I can assure you that the recoil produced in a 24 pound rifle would cavitate your chest cavity and kill you. Think of it like putting your shoulder at the back of a field cannon and taking all the recoil into your body without the benefit of the weight of the carriage the cannon it sitting on.
I don't know if this really answers your question for the forest service, but that has been my experience with 2 Bores and many hours of discussion with Steve on this subject. If you want historical references, look for writings by Sir Samuel Baker about is experience with "Baby" and for the references by Selous on his 4 Bores(google books online previews), they are about the most descriptive as far as loading data.
If you want to see video of me shooting the last muzzleloading 2 Bore I built, there is a thread on this forum that has pictures of the rifle and links to videos, there is a youtube video of a 450 grain shot that is in slow motion that really shows how much the recoil pushes me around. The current 2 Bore is a cartridge gun, so not appropriate for this forum, you'll have to go to my website if you want to see the build documentation for it.
Colin
Topic: Questions about big bores 2 and 4 bores (Read 639 times)