Well, I also own the Remington 700 Muzzleloader.

I am also a victim of the double bang when using the Triple 7 pellets, but I do not have any problem when using the granulated Triple 7.

Therefore, in my opinion, the problem is with the pellet version of Triple 7.

eb, I would like to hear from you if you find that Remington makes a different nipple for the Model 700 muzzleloader.

Also Please Note!

The pellets had a different point of impact than the granulated. And I'm not talking a small difference either...it was about 3 inches! In other words, I'd have to sight the gun in twice...once if I want to shoot pellets and and 2nd time if I want to shoot granulated.

Bottom line:

Triple 7 sucks in my opinion. I will not be buying any more of it.