6mm Ackley Improved build

[Barry]

Im going to be doing a projed rifle with a Vanguard 2 action and puting a Shilen SS match 6mm barrel 1 in 8 twist for a 6mm Ackley Improved chamber. Finish at 26". I cant find any load data for this caliber ie: start/stop data. Im going to be using 107gr bullets and would like to go with 4831sc. Anyone have this data?

 

[Brians356]

Sierra publishes 6mm AI data (and 6 other AIs):

Savage 12VSS, 26" 1-8 barrel, Win case, 9-1/2 primer:

For 107-gr HPBT and H4831 SC:

42.0 grs 2800 fps
44.0 2900
45.9 3000

Sierra's "accuracy load" is RE-22 @3100 fps (and top velocity 3200):

43.2 grs 2900 fps
45.1 3000
47.0 3100 *
48.9 3200

Also top velocity 3200 from IMR-4350, RE-19, IMR-4831.

 

[gotcha]

+1 for brians356. My 6mm AI is a 10 twist. RE-19 is the ONLY powder that produced great groups, as well as, outstanding velocity with 100/107 gr. bullets. If 4831sc produces less than outstanding results, give it a try. It worked well for me with bullets from 75 to 100 gr. I found the RE-19 to be temp. sensitive and developed loads for hot and cold weather.

 

[Barry]

Thankyou Brains. I would love to try Re powders but up in this neck of the woods theyre hard to come by. Also with the temp extremes we deal with Hodgden is about the only powder feasable to use. IMR works fairly good. I may try some IMR4350 as well. Was there a listing for H4350?

 

[Brians356]

Thankyou Brains. I would love to try Re powders but up in this neck of the woods theyre hard to come by. Also with the temp extremes we deal with Hodgden is about the only powder feasable to use. IMR works fairly good. I may try some IMR4350 as well. Was there a listing for H4350?

IMR-4350:

41.8 grs 2900 fps
43.4 3000
45.0 3100
46.6 3200

 

[Gary in MD]

I only shoot varmint bullets in my 6mmai, up to 80 grains. The powder that shoots the best has been VV160. Great velocity, excellent accuracy and really clean burning. It would be worth a try if you can get it.
Good luck,
Gary

 

[Barry]

Sierras data must be INCREDIBLY consertive or Ive been misinformed on load development for Ackley cases. They list max load as 45.9 yet max load listed for 6mm rem on Hodgdens website is 48C of H4831, same burn rate. Ive been told for Ackley cases start at parent case max and work up? Does anyone have a qauickload program that could give me some tentative psi's for 48gr H4831sc and up with 107 bullets? Ive seen loads up to 48gr. on reloaders nest.

 

['Freak]

What’s your rifle, via pressure sign, been sayin’ whilst incrementing up to what Sierra found that for their specific combination(s), and by their lawyers’ reasoning, 45.9 grains should be its maximum charge weight?

 

[Brians356]

I have not known Sierra data to be overly conservative, but YMMV as always. I would start somewhere in the middle of the Sierra data, and just load past their max load, using a reasonable increment, and watch for pressure signs. The usual drill. "As always, should you or any of your I.M. force be caught or killed, the Secretary will disavow any knowledge of your actions. This tape will self-destruct in five seconds. Good luck, Jim."

 

[Chuckhunter]

Barry I shoot 47.5Gr's of H-4831SC out of my 9 twist .243AI with 107 Danzac coated SMK's. If you are going to shoot naked 107's I would reduce that load to 45.5 gr's and work back up in .3Gr increments, keeping an eye out for pressure signs. According to QL 46.8 would be about your MAX with naked bullets. I shoot Lapua Brass. Are you going to fire form with the same powder and bullets? If so I would load up approx. 41Gr's, seat them hard into the rifeling and you should be good to go. Good Luck and as always be careful, let us know how you make out..............Chuckhunter

 

[Barry]

Appreciate the info Chuck. I will be shooting 107gr Matrix bullets naked, (the bullet of course). All reports are 3100 to 3200 to be the accduracy for this bullet weight. Will be fireforming with creme of wheat.

 

[Chuckhunter]

COW method is good, saves some barrel life. My load chronos at 3232 M.V, could go higher but it shoots tight right on out to, and beyond 1000yds. Hope you enjoy your AI as much as I do mine.

 

[Brians356]

COW method is good, saves some barrel life. My load chronos at 3232 M.V, could go higher but it shoots tight right on out to, and beyond 1000yds. Hope you enjoy your AI as much as I do mine.

I used corn grits, but all same same. Next time I form bulletless, I'm going fillerless / wadless as well. Increase powder charge ~30%, point rifle towards where our Dear Leader ain't goin', and pop cap.

 

[nastynatesfish]

I wouldn't be afraid to try some slow powder. H1000 or retumbo. My 22/6mm shoots real well with retumbo at 51.5gr.

 

[40X Guy]

Barry, with H4831SC and an 8 twist barrel in 6MM AI, you will find a node around 3150 to 3200 fps. My 6AI loved 48.0 grains of 4831SC and MV was right at 3178 in a 28 inch barrel. I used 7X57 Mauser brass made by Norma necked down in my rifle. I had started with RL-22 but found H4831SC to be cleaner burning. Beware of carbon in the throat with a 6AI. High intensity cartridge but if properly tuned will get the job done.

Frank

 

[Barry]

Thanks for the advise onthe H1000. I have a good supply of that but I do see some nice groups out there with the 4831sc and thats what I have for my 6.5-284. Going with a 26" Shilen on this one. Looking forward to any and all advise I can get.

 

[Elwood]

Barry this may be of some help to you. The Crusader is essentially the 6mmAI but with a different shoulder angle

http://ukvarminting.com/forums/topic/10600-6mm-crusader/

N560 worked very well, as did RL25 using the 115 Dtacs. I did test H1000 and H4831 sc but if I found accuracy I didn't get the speed I wanted, or if I got the speed I didn't get the accuracy. I do know of several other 6mm AI shooters that did find both with H4831 sc.

 

[Barry]

I do believe H4831sc is going to be my go to powder for this rifle. It sounds llike 47.5 to 48gr is where the accuracy is going to be it will be interesting to see what the velocity from a 26" barrel with naked 107gr bullets will turn out to be.

 

[Barry]

Barry, with H4831SC and an 8 twist barrel in 6MM AI, you will find a node around 3150 to 3200 fps. My 6AI loved 48.0 grains of 4831SC and MV was right at 3178 in a 28 inch barrel. I used 7X57 Mauser brass made by Norma necked down in my rifle. I had started with RL-22 but found H4831SC to be cleaner burning. Beware of carbon in the throat with a 6AI. High intensity cartridge but if properly tuned will get the job done.

Frank

Project complete. Did a 15 shot break in with carbon and copper clean as we go. Load was 41gr of a 40 year old can of win 760 and some jammed speer 87gr bullets I was givin eons ago. All 15 shots into 1 hole at 100yds, (truthfully about 70 cal. when done but 1 hole all the same). Not bad for a junker load. Today out with a ladder test with Matrix 105gr and Fed match primers with H4831sc from 45.9gr. to 48.9gr. The whole ladder was in a 2 1/2" square at 216yds, (200m). Shots 48.3, .6 and .9 came in at .229moa with velocity average of 3193fps. Any 3 in the bunch was almost as good. No pressure signs, nada, nil. Primers from start to finish look near the same. Smooth bolt lift throughout. Now will test 3 shot groups of 48.6gr. with 20, 30 and 40 thou jumps. As usual safe load in my rifle might blow you and yours to hell so start low and work up.

 

[BCBRAD]

Barry, I have Quickload, if you supply some details I can model some powders for you.

Spotted at the range today for you.