I bought one of the 50 cal. double rifles. Been wanting one for a long time, and, finally made the jump! It has arrived and I am soooo pleased with its appearance. The question I have now, since I've had a chance to actually think about shooting it, is..what bullets do y'all (you all)think I can use without the second barrel load jarring loose when the first barrel is fired? I've been thinking about projectiles and figure I need one that will seat tight enough that its not going to vibrate away from the charge at the first shot. Any suggestions?

What's the twist rate?

Well, dang! You've asked me something I'm not sure of! That would help wouldn't it? Guess I'll check into it.

If that's the traditions that I was posted about earlier today, it's got a 1:28". I would load to 100gr max with the first shot (probably both), and go ahead and use whatever sabot shot most accurately. Most sabots fit tightly enough that you shouldn't have any issues with movement from the first shot. I don't know that I'd try powerbelts, as they seem to load more easily and 'might' move on the first shot (though I still doubt it). I would suspect that if there were any issues with loads moving that the owner's manual should have some warning. Please be sure that it doesn't have any caveats about what you can and can't use. Congrats on the gun! While not what I'd think of in any traditional sense for hunting, it is a very attractive gun.

I think your concern about movement of the second barrel's bullet is valid.

I'd load both barrels, but only cap one. Then shoot the capped barrel and check the second load with the ramrod to see if there was any movement. If you do that the first two or three times you shoot a particular load and get no movement, you can be pretty confident of that load.

I'd do this any time I changed to a newbullet, sabot,or powder charge.

This gun has a 1:24" twist. It's not the Traditions O/U double, it's the Kodiak SxS. You can see one in the Cabela's online.
RiverOtter, you're probably right about the Powerbelts. Actually, the Powerbelts is what got me thinking about loose projectiles because they are so easy to ram in.
I like Semisane's idea. Think that's what I'll try with a couple different bullets.
Thanks guys!!