A question about AA1680

[sarky]

Accurate 1680 is the go to powder for the 7.62x39, so why isn't it a powder for the 6.5 Grendel? The case capacities are almost identical between the 2 rounds.

[rabiddawg]

[LtDan]

Low Pressure round vs a Higher Pressure round.

[LR1955]

Accurate 1680 is the go to powder for the 7.62x39, so why isn't it a powder for the 6.5 Grendel? The case capacities are almost identical between the 2 rounds.

Sarky:

The case capacity is not the same. 7.62 X 39 has significantly less case capacity, the shapes are different and 7.62 X 39 brass is much thicker. You can run a search on the forum for case capacity comparisons as others have measured it but I think it is around ten percent.

If there is load data for the Grendel using 1680, then go for it. If there is no load data then I would not advise going for it. I believe 1680 is way too fast for any Grendel load.

LR55

[bj139]

Bore diameter is the key. The rapidly increasing high pressure gas has more room to expand into a 30 cal bore once the bullet starts moving than in a 6.5mm bore.
AA1680 might be good for reduced velocity rounds in the Grendel but I don't know what loads to try.

[sarky]

I am aware that the shapes are different for the 2 cases, I was a benchrest (22PPC) shooter for a long time. but the capacity difference (in grams of water) is .6

[41bear]

Sarky, I would think that 1680 would work if your application is for lighter bullets in a shorter barrel. That said it's really dirty and there are better fast powders that will give you the same effect. Rel7, 2015, or 10x come to mind.

[LR1955]

Guys:

Look here on page 38. http://www.accuratepowder.com/wp-con....0-Web-REV.pdf

There are not many cartridges using AA 1680. And it is used in cartridges with neck diameters very close to the diameter of the cartridge body.

I would have thought it would be useful in .357 and .44 magnum but apparently not. Got to be a reason for that, too.

After looking at the AA data on 1680, I believe it would be downright dangerous to use in any Grendel load.

I have a pound of it from my experiments with 7.62 X 39 and can't find any other use for it aside from duplex loads for black powder cartridges.

LR55

[Jeepster18_88]

Sarky, I asked the same question about Reloder 7. It was pretty condemned as an option. AA1680, 4198, and Reloder 7 were pretty much the go to powders when I started loading for the 7.62x39. I had trouble getting decent groups with 4198 and I couldn't find AA1680 anywhere but I found Reloder 7 and every single load from start to max with every .308-.310 bullet was accurate. Velocity was right there with best factory ammo and what was indicated in the load data. There was someone using 4198 in a 12" Grendel recently with good accuracy and reduced muzzle blast, which is what I was after, but he didn't Chrono it. It did the job on the animal he took so it obviously wasn't too slow for his distance. I'm not one to go into foreign territory so I'm not trying Reloder 7 anytime soon but I still haven't seen evidence that it simply won't work, although it isn't going to give the highest velocity which most are chasing. One thing to consider, it's been said that the Grendel cartridge doesn't show pressure signs until after you're already over the pressure for the AR platform which makes uncharted territory more risky. Good luck, be careful, and let us know what you find in testing with any powder. I like to know my options.

[sarky]

I have a ton of 1680 that I use for my 7.62x39 guns and get .8" groups at 100 meters out of my bolt action.

[revbc]

1680 is a go to powder for max loads in the 357 MAX.