I've been using GOEX FFg in my T/C White Mountain Carbine. If I go with FFFg will I need to reduce the load generally?

"Technically" yes you will need to reduce the load 15%. Although I was shooting a Renegade with 90 grains of 2f and when I tried 3f in it, it shot best with 90 grains... so all you can do is rework the load with the 3f powder.

Reduce what it normally shoots with 2f .. 15% and see what happens. You might still climb that powder measure a little. With the faster powder you will get a little more velocity and faster burning time. But you might not notice the difference and it is slight.

With 777 FFF there is a pressure spike in my guns at 110 gr, I would not load more than 110 gr in my guns.

I have the same gun and it thrives on 3F Goex. With the short barrel of the WMC a faster burn is a good thing. Around 70 gr for PRB / 90 for conicals. Mine doesn't like sabots in the factory barrel (48"twist) I have a green mountain LRH barrel for it that is the same length as the white mtn. That likes 110 gr of 3F under a green crush rib sabot and 300 gr Hornady XTP in .44 cal. What projectiles are you using? Round ball?

Thanks for the information gentlemen. I'm looking forward to using the 3F more now.

Gearheart, I have been using T/C maxihunters with 90 grains of 2F. I'll probably start with the same load using 3F and see how that goes.

lemoyne,
I noticed that you said you wouldn't use more than 110 gr of FFFg in your guns. Why is this? I'm newer to the powder so there's a few things that I still might not know about it thus far. I've tried 110 grains in my triumph. Should I try a little less? Would a little less generally give better accuracy? Any help is appreciated. Thanks in advance.

Oh, one other thing. I shoot the black sabots with the 250 grain SW bullet and noticed the black sabot was missing a petal or two upon recovery. Is it bad when a sabot breaks as described above?

Try a little less and work it up untill your groups start to come apart. Then go back to your best most accurate amount. The bottom line is shot placement. A less than max load will kill a deer just as dead and your shoulder will thank you. That White Mtn will beat you up with heavier loads.

All the hype about "magnum" loads up to 150 gr. of various propellants has many of us using loads heavier than necessary. 50 caliber loads as low as 70 - 80 gr. are quite adequate for deer. Those lower loads are also often more accurate. The heavier loads may be desirable for long range shots and large game such as elk, but are totally unnecessary for deer at normal ranges.