I would like to try IMR 7977 in my 6.5x68mm using the 127 gr Barnes LRX bullet.

I have max load data from QuickLoad for Retumbo, IMR 7828 and H1000.

Are there any % conversions for any similar slow burning powders based on max load? I've sent an data request to Hodgdon a couple weeks ago and haven't received an answer from them. I sent another request this evening.

I'd appreciate any help on this little project.

Graybird I have a 6.5x68 and use only RWS brass. While there is very little load data for this cartridge using North American components I get by quite nicely. Case capacity of the 6.5x68 is a couple grs larger than the 264 Win. I would suggest using 264 data and working up watching closely for signs of excessive pressure. I have found 7828 to be the best powder in my rifle. Best accuracy and near top vel with all bullets I've used. Hope that helps

I've used lots of IMR 7977 in a 280 AI. 7mm Rem Mag and a 300 RUM. My buddy has used some in a 6.5 x 280 AI (I've only used RL-26 in mine).
7977 has given good results and I like the temp stable characteristics.
sorry, not too much help but I think you're barking up the right tree with that powder.

Zeke