At 1:86 twist with shallow (.004) rifling, the Pedersoli 72 caliber rifle is approaching a "Forsyth"-rifled barrel as Steve Z has said above. But with a short slug for 12 ga. barrels I think you will be surprised and it will shoot with that 1:86 twist. However, I also agree that the usage of a HARDENED round ball for dangerous game is well proven from the past, and it is the momentum of the big ball coupled with lack of deformation that lets you possibly get after buffalo with such a gun. Think about it, you certainly don't need to expand a projectile that is already nearly .72 D to create a good wound channel! Anything over about .45 is going to do that without expanding, with the desired penetration then depending on velocity, mass, and maintenance of projectile shape.

While an awful lot of game, some quite large, has been taken in N. Am. with MLs of 50 and 54 bore, we are wise to consider that English and European folks with WAY more experience shooting game than we will ever have considered these DEER calibers. Pumping today's American MLs up to high velocity to get more oomph creates brutal recoil using these light guns. And remember how much trouble the Lewis and Clarke party had on perhaps 6-800 pound grizzlies using similar calibers? I don't mean to offend, and use them too, but a .50 or .54 RB with typical American charges gets marginal just for elk and large deer out past 75 yds., tho the .54 is certainly superior. If all game allowed us standing broadside shots it would be different! See the Lyman Black Powder handbook for a myriad of tested loads and some eye-opening data.

The English did not take 12-bore (.729) MLs to Africa and India for no reason, and for dangerous game the 8-bore, or larger, was favored. Yes, the "smaller" 14 and 16 bores were great in India BUT this was with shallow, slow-twist "Forsyth" rifling as above, and heavy charges of powder. Forsyth rifling is about 1:95 to 1:120 twist. Smaller hardened ball but HIGH velocity got the job done and with superior trajectory. See Lt. Forsyth's wonderful small book from 1862, "The Sporting Rifle and its Projectiles".

Nonetheless, a water buffalo is very big animal. American ML shooters in particular have been bred on the "low charge - save powder" principle, and many think 100 gr. is a heavy load. Obsession with light weight guns and inexperience with heavy recoil makes this tendency even worse. Please heed Steve's words above about a HEAVY charge if using a 12-bore, and keep your range short for both aiming and penetration reasons (60 yds. or less IMHO). If recoil is brutal, you can make hollows in the rear of the buttstock and insert bags of lead shot or a lead plug. And you can increase the size of the buttplate if necessary, or add gun or shoulder pad. Yep, have that guide with a .470 nitro backing you up!

Aloha, Ka'imiloa