7mm AM, 1/9 load developement

[Ridge Runner]

finaly got a cool day, kinda put the AM up last spring due to the temp. sensativity of 872 powder. so this morn it was 75 F, loaded up 4 different charges, 107 gr, 109 gr, 110 gr, and 112 gr. with fed 215 match primers and 160 nosler accubonds.
107 3402 fps
109 3455 fps
110 3502 fps
112 3627 fps (sticky extraction and a pierced primer)
so twice that I've acheived 3600+ fps with the 1/9 twist I've also had extraction problems so I guess that around 3500 fps is the max velocity for a lilja barreled 1-9 twist in this chambering.
Our deer season can run anywhere from 20 degrees F, to mid 70's so I won't load it any higher, but 3500 fps will get done what I need.
JS

 

[davewilson]

have you tried any 869 powder? or 180 gr bergers? also have a hunch you might have tried some 200's in that 9 twist of yours.did they stabilize? my pick would be the bergers but i'm guessing you like that speed.how far are you intending to shoot that cannon?

 

[Buffalobob]

James
It was nice to have that heat wave pushed out of here wasn't it.

You are a lot more patient than me. But in the end you still have plenty of time before deer season. I agree with you on the load, I am not a big fan of pierced primers.

 

[Ridge Runner]

Dave, haven't tried the 869 yet, I have 15 lbs of 872 and I wanna use that up, from what I gather its about as easy on barrels as any, dan's to proud of his long tubes for me to burn this one up in a year so I'm pacing myself. my next bullet to try is the a-max, after that I'll try a few more, yes I've tried the 200 gr. wildcats and yes they will stabilize, but its right on the borderline, they shoot tighter groups at 300 yds than they do at 100, this tells me its absolutely the heaviest I can go with the 4 groove 1/9
JS

 

[Ridge Runner]

bob, yep I've never seen it this hot here
yeah but can't understand why the primer ruptured, it was slightly sticky and just a hint of ejector pin mark, and the one other round I tried that hit 3600+ fps, which was just as heavy on the bolt lift and sticky on extraction (106 gr. of 872 and 90 degrees F) didn't rupture so I'm stumped there.
JS

 

[davewilson]

good move going with the 4 groove.

don't have much experience yet but what i gather the 872 does seem more in it's "comfort" zone with big cases and cold weather.

might try some CCI primers.had better results in my 7rum with them.not quite as hot and the metal is a bit tougher.possibly easier to read pressure signals.

 

[keithcandler]

James, what gives you slight extraction problems now in the Summer, my be just fine in actual hunting season.