I have and still do play the speed and bc game a bit, especially for 200-300 yard/meter matches. Those things may well be worth a very small amount but they just won't carry you very far, and that's assuming equal accuracy in good conditions. I've been shooting a 6 Grendel for a few years now with 80 grain bullets. I've had more than my share of good luck with that combo and I feel it shoots just as well with 80's as with 68's..maybe a small tad bit better at 200-300 but none of that makes up for pulling the trigger at the wrong time. That said, I think that combo is worthwhile, as I can't tell a bit of difference at 100 and I think it helps some at further distances, but we're splitting a pretty fine hair here. I can shoot the 80's at 3400fps if I step on the gas hard but I have no problem shooting them at about 3250-3275 and have a lot better brass life there.
Ultimately, I go with what shoots best in my guns, be that 68 or 80's..or fb or bt bullets. I believe it was Ferris Pindell that did some early testing of 81gr bullets in a ppc, that said it was like cheating compared to the lighter bullets he and most used at the time. I wouldn't go that far but I do think there is a tiny edge to be found there. Of course to shoot the 80's, it takes a little faster twist and to be throated to accommodate them. In the 6 Grendel, I use .070 freebore and 1-12 twist bbls but I may try a 12.75 twist soon. I don't think much is to be gained or lost between a 12 and 13.5-14 twist bbl with lighter bullets. I won a UBR nats in 2019 shooting 68's in a 12 twist. The kicker is that I did not feel like it was my best rifle...just the way the cards fell that match. I felt like my unlimited rifle with 80's was a little better gun and the results agreed with that in prior matches leading up to that nationals.
Bottom line I guess is shoot what shoots best for you, in your barrel and don't pull the trigger at the wrong time.
Ultimately, I go with what shoots best in my guns, be that 68 or 80's..or fb or bt bullets. I believe it was Ferris Pindell that did some early testing of 81gr bullets in a ppc, that said it was like cheating compared to the lighter bullets he and most used at the time. I wouldn't go that far but I do think there is a tiny edge to be found there. Of course to shoot the 80's, it takes a little faster twist and to be throated to accommodate them. In the 6 Grendel, I use .070 freebore and 1-12 twist bbls but I may try a 12.75 twist soon. I don't think much is to be gained or lost between a 12 and 13.5-14 twist bbl with lighter bullets. I won a UBR nats in 2019 shooting 68's in a 12 twist. The kicker is that I did not feel like it was my best rifle...just the way the cards fell that match. I felt like my unlimited rifle with 80's was a little better gun and the results agreed with that in prior matches leading up to that nationals.
Bottom line I guess is shoot what shoots best for you, in your barrel and don't pull the trigger at the wrong time.
