Load Data for AA1680

[ppd3180]

I need some help with load data for 1680. I have a ton of 170 gr round nose and I am looking for a good subsonic load using 1680 and a 10.5 tp555 barrel with the port in the pistol position. I am also interested in any other data for 150'S,168's,180's, 200's and 220's using 1680. I have settled on my light load of 130 grain speer HP's using 19 grs of 1680. Functioning has been perfect, accuracy has been just under an inch, but I have not had a chance to Chrony them yet. Any help would be greatly appreicated. Thanks Rob

[pomofo]

If you give me the bullet length and cartridge OAL for that 170 I can try to run some stuff through Quickload for you. I've worked up to 17.3 with the 175 grain Berger VLDs (OAL 2.245) and 18.1 with the 168 grain Prvi BTHPs (OAL 2.260) with no pressure signs. Worked up to 13.8 with the 190 Prvi BTHPS (OAL 2.050) and 12.8 with the 220 Hornady RNs (2.000 OAL), also with no pressure signs.

ETA: My port is in the carbine position with a 16" barrel, so YMMV.

[ppd3180]

I was able to measure everything today. The bullet length is .997 for a 170 grain round nose 30/30 bullett. When seated to the cantalure(sp) the COAL is 1.850. I am at about 5100 feet elevation if that will help. Thanks Rob

[Colohunter]

I load 10.5 gr of AA1680 behind a Hornady 150gr FMJ. It gives me about 1095fps out of a 16" barrel. I have a carbine length gas system and it will eject and feed all rounds, but doesn't have quite enough gas to lock the bolt back at the last round.

[nwcid]

I run 11.3gr under a Hornday 220. This keeps them SS out of a 16" suppressed AR with carbine position gas block.

I was shooting some the other day at about 30* and seemed like some of them were cracking. I did not get my Chrony out to find out yet, it is on my list of projects.

[pomofo]

According to Quickload, that 170-grain bullet with 11.0 grains of AA1680 should be doing 1100fps with 20000psi chamber pressure at ignition, and 7000psi chamber pressure when the bullet reaches the pistol port. If I were you I might start off with loads that should be supersonic (like 13.0 grains) and work your way down carefully to make sure that you don't stick a bullet in the barrel. The lowest loads I've used were 20000psi initial chamber pressure, and I'm not sure I'd want to go any lower.