I am getting a new 7 Rem Mag barrel. I am thinking of tracking down some of the new IMR 7977. Supposed to reduce/eliminate copper fouling. Anyone here tried the new IMR powders yet, especially 7977? any observations on effectiveness on copper fouling?

Yeah, I've tried all three of the Enduron powders. They all contain enough decoppering agent (as I recall tin oxide) to noticeably reduce copper fouling.

For me, the 7977 proved to be good in my new 7 Mag barrel. I haven't shot it enough to comment on effectiveness of the de-coppering agent long term yet. But, It provided some very accurate performance. Stuck with what the Hodgdon reloading guide suggested. When I got near the top, it started getting cloverleafs. One other observation is that the powder seems to be very dirty. Leaves a lot of black smut in the barrel. Cleans easily however.

Good report, what bullets did you end up trying? I recently got a take off 7mm RM barrel put on my old Sako and also picked up some IMR 7977 and 4451 to try. Have some 150 gr Ballistic Tips and Partitions along with some 154 Hornady Spire Points to try.

Gerrygoat, Used sierra 140 SPBT, seated about .040 off the rifling. This new barrel is a Apache Gunworks Chrome Moly alloy. the chambers and throat are very snug when he sets them up.

Strut64,

My guess is the “black smut” in the bore is the decoppering agent mized with copper. That’s how they work: The heat of the shot amalgamizes the agent and the copper, and while most gets blown out by the next shot, some can sit in the bore between shots. I’m guessing this because the barrel cleans so easily.

Glad it's working out so well for you. Hodgdon shows some pretty good loads for IMR 7977. Surprisingly IMR 4451 looks pretty good as well, hope to get out this week for some testing of both.

I purchased six pounds it is proving to be very consistent in my 6.5x284.
Barrel is a benchmark ss, load I have been using to get groups under a 1/2 " is cci mag primers 123 Laupa, Laupa brass, and 57.5 gr of IMR 7977. Copper fouling is nonexistent.

My 280 AI did not like it with 160 gr Accubonds.
Next will be trying it in my 300 win m

I had a chance to go out and shoot some 154 gr Hornady Spire Points with both IMR 7977 and 4451. Worked up to 71 gr with the 7977 and 60.7 gr with the 4451, those are Hodgdon's max loads with both powders and the 150 gr Partition. Didn't chronograph today but I would expect both to be +/- 3040 fps like the data. The 4451 was just over 1 " and the 7977 was just under 1" so it looks like there is something to work with there. Going to try the 150 gr Partition's next.......