6mm ARC and 108 eldm with 6 5 Stabal

[Ray123]

Had the components and decided to put them together as some hsve wondered about the 6mm ARC and 6.5 Stabal. So here is what I found with the equipment I have...for intertainment purposes only, it could be harmful to you.
AR 15 18" Proof Research barrel
Starline 6.5 Grendel brass sized and trimed to 6 mm ARC... CCI BR-4 primer, Hornady 6mm 108 ELD-M bullets 2.290 COAL fit mag.
Base line personal load fired today before the test with 108's was 2667 ave fps 2.0 S/D.
On to the test:
108 eldm with 6.5 Staball powder 6mm ARC 18" AR.
30.5 gr =2405 fps
30.8 gr = 2427 fps
31.2 gr =2437 fps
31.5 gr=2511 fps
31.8 gr =2527 fps
32.1 gr= 2607 fps
32.4 gr = 2597 fps
32.7 gr = 2650 fps
33.0 gr =2631 fps
33.2 gr = 2650 fps
Some fluctuations in velocity as powder charge increased and compresses and seating stem may be an issue also. The 32.1 gr area looks like a good max for my rifle and testing.
No pressure testing equipment available and this could be extra dangerous in an AR with it's thin bolt...but mine survived and no damage appears on the brass.
The real surprise was the AR 10 in 308 Win but NOT with 6.5 Stabal. 18" AR Proof 5 groove was running 2 loads with 200 gr Sierra MK CN .715 BC first was 2606 fps 10.2 S/ D and the 2nd was 2621 fps and S/D of 12. Top velocity was 2636 fps, single load with Bob Sled mag, but very fast for a 18" 200 gr bullet out of an AR 10. Top velocity was the most accurate about 1" but it's a 10 twist barrel and the bullet manufacturer calls for a 9 twist. These are really accurate in my 9 and 8 twist bolt guns. Need an 8 twist for my AR 10...probably have to get a barrel blank and barrel extension for that experiment, and make my own.
Or not...it was a fun day shooting. Can't ask for more.

 

[darkangel_r2]

Had the components and decided to put them together as some hsve wondered about the 6mm ARC and 6.5 Stabal. So here is what I found with the equipment I have...for intertainment purposes only, it could be harmful to you.
AR 15 18" Proof Research barrel
Starline 6.5 Grendel brass sized and trimed to 6 mm ARC... CCI BR-4 primer, Hornady 6mm 108 ELD-M bullets 2.290 COAL fit mag.
Base line personal load fired today before the test with 108's was 2667 ave fps 2.0 S/D.
On to the test:
108 eldm with 6.5 Staball powder 6mm ARC 18" AR.
30.5 gr =2405 fps
30.8 gr = 2427 fps
31.2 gr =2437 fps
31.5 gr=2511 fps
31.8 gr =2527 fps
32.1 gr= 2607 fps
32.4 gr = 2597 fps
32.7 gr = 2650 fps
33.0 gr =2631 fps
33.2 gr = 2650 fps
Some fluctuations in velocity as powder charge increased and compresses and seating stem may be an issue also. The 32.1 gr area looks like a good max for my rifle and testing.
No pressure testing equipment available and this could be extra dangerous in an AR with it's thin bolt...but mine survived and no damage appears on the brass.

What charge did it start to compress? How many shots at each charge did you do?

The real surprise was the AR 10 in 308 Win but NOT with 6.5 Stabal. 18" AR Proof 5 groove was running 2 loads with 200 gr Sierra MK CN .715 BC first was 2606 fps 10.2 S/ D and the 2nd was 2621 fps and S/D of 12. Top velocity was 2636 fps, single load with Bob Sled mag, but very fast for a 18" 200 gr bullet out of an AR 10. Top velocity was the most accurate about 1" but it's a 10 twist barrel and the bullet manufacturer calls for a 9 twist. These are really accurate in my 9 and 8 twist bolt guns. Need an 8 twist for my AR 10...probably have to get a barrel blank and barrel extension for that experiment, and make my own.
Or not...it was a fun day shooting. Can't ask for more.

Thats insane from an 18".

 

[Ray123]

What charge did it start to compress? How many shots at each charge did you do?

Thats insane from an 18".

These 200 SMK have a .715 BC and require a 1-9 twist they are. 054" longer than the 225 ELD-M.
I ran 3 rds each at the top end, with a 3 tenths grain increase than the top charge, and fired 3 more rds. These have only have a modest
compression even at the top charge. The top charge was a 1" group at one hundred yds., but you really need a 9 twist to take full advantage of this bullet. With a 9 twist you have a super sonic load past 1500 yds, almost 3100 ft/lbs of muzzle energy and almost 1100 ft/lbs at 1000 yards, with 30 moa drop and 59 to 60 of drift in a 10 mph cross wind at that distance. Not bad for an 18" 308,...but all ya need is a 1-9 twist. Just did it to see what can be done in an 18" AR. I shoot the same load in a hunting 22" 9 twist rifle and a 30" 8 twist PRS type long action 308. The 22" runs 2740 fps and the 30" runs 2856 fps. Had the 30" to 2880 fps but accuracy was 2856 fps, from a 308 case a 200 gr bullet with a 715 BC shooting in the .3" 5 shots. Even the 22" 9 twist hunting rifle shot 9 rds into .782" at 2740 fps ave. These are very accurate bullets with 8 and 9 twists, I bought many thousands of them. I'd like to have an 8 twist AR 10, cause heavy bullets is where it's at. I have utilized up to 230 ATIPS ...but the 225 says 10 twist and they show accuracy in a ladder test, a bunch went into .5" as the velocities increased.
I shoot 150 at 2850 fps, and 2723 fps 168 Bergers, as normal 18" AR 10 loads. Always experimenting with different powders and bullets...in every caliber I own. It's enjoyable and keeps me busy.
Does your 9 mm AR pistol shoot 1900 fps with 76 gr copper HP, or 1720 fps with 115 gr or 1600 fps with 124 gr. 1300 with 147 gr.? How about 158 gr, or 185 gr. 9 mm? Lot's of things are possible if ya have the time, components, and machine tools to experiment.

 

[Ray123]

What charge did it start to compress? How many shots at each charge did you do?

Thats insane from an 18".

The powder charge starts to compress in the 6mm ARC where I'd probably consider it too much compression when the velocities became erratic at 32.1 grains, eventhough the homemade seating stem left no marks. Staball is on the slow side for this cartridge velocities around 2525 to 2550 in a 18" AR barrel is probably best for accuracy...but I can beat that with Leverevolution in the 108 eldm in velocity and accuracy is good. You may be looking for better temperature stability, but I don't know if 6.5 Staball is any better then Leverevolution. Someone else will have to do that, as I'm not concerned about it.

 

[darkangel_r2]

The powder charge starts to compress in the 6mm ARC where I'd probably consider it too much compression when the velocities became erratic at 32.1 grains, eventhough the homemade seating stem left no marks. Staball is on the slow side for this cartridge velocities around 2525 to 2550 in a 18" AR barrel is probably best for accuracy...but I can beat that with Leverevolution in the 108 eldm in velocity and accuracy is good. You may be looking for better temperature stability, but I don't know if 6.5 Staball is any better then Leverevolution. Someone else will have to do that, as I'm not concerned about it.

I have used staball 6.5 in my 6.5creed ar10. Shooting in 80 degrees to 30 degrees it lost about 15 fps. Thats only my results but thats miles better than other ball powders I've tried.

I really just want to match 308 ballistics with the 6 arc. If I can do that and throw a temp stable ball powder instead of measuring each that makes it a remarkable dmr system. Slap a primary arms 308 acss scope and tune the load to match its drop window and you've got a light weight dmr that can engage targets quickly and accurately out to 1000 yards being able to throw a ball powder in there is just gravy for faster reloading.

 

[darkangel_r2]

These 200 SMK have a .715 BC and require a 1-9 twist they are. 054" longer than the 225 ELD-M.
I ran 3 rds each at the top end, with a 3 tenths grain increase than the top charge, and fired 3 more rds. These have only have a modest
compression even at the top charge. The top charge was a 1" group at one hundred yds., but you really need a 9 twist to take full advantage of this bullet. With a 9 twist you have a super sonic load past 1500 yds, almost 3100 ft/lbs of muzzle energy and almost 1100 ft/lbs at 1000 yards, with 30 moa drop and 59 to 60 of drift in a 10 mph cross wind at that distance. Not bad for an 18" 308,...but all ya need is a 1-9 twist. Just did it to see what can be done in an 18" AR. I shoot the same load in a hunting 22" 9 twist rifle and a 30" 8 twist PRS type long action 308. The 22" runs 2740 fps and the 30" runs 2856 fps. Had the 30" to 2880 fps but accuracy was 2856 fps, from a 308 case a 200 gr bullet with a 715 BC shooting in the .3" 5 shots. Even the 22" 9 twist hunting rifle shot 9 rds into .782" at 2740 fps ave. These are very accurate bullets with 8 and 9 twists, I bought many thousands of them. I'd like to have an 8 twist AR 10, cause heavy bullets is where it's at. I have utilized up to 230 ATIPS ...but the 225 says 10 twist and they show accuracy in a ladder test, a bunch went into .5" as the velocities increased.
I shoot 150 at 2850 fps, and 2723 fps 168 Bergers, as normal 18" AR 10 loads. Always experimenting with different powders and bullets...in every caliber I own. It's enjoyable and keeps me busy.
Does your 9 mm AR pistol shoot 1900 fps with 76 gr copper HP, or 1720 fps with 115 gr or 1600 fps with 124 gr. 1300 with 147 gr.? How about 158 gr, or 185 gr. 9 mm? Lot's of things are possible if ya have the time, components, and machine tools to experiment.

Mid 2800s with a 7bc is very impressive. Sierras 308 data for the 200 tops out at 2550 even at saami+ with 4350 class powders out of a 24 so that staball puts it about 150 fps faster for the same barrel length. Thats pretty dang good.

 

[Ray123]

I have used staball 6.5 in my 6.5creed ar10. Shooting in 80 degrees to 30 degrees it lost about 15 fps. Thats only my results but thats miles better than other ball powders I've tried.

I really just want to match 308 ballistics with the 6 arc. If I can do that and throw a temp stable ball powder instead of measuring each that makes it a remarkable dmr system. Slap a primary arms 308 acss scope and tune the load to match its drop window and you've got a light weight dmr that can engage targets quickly and accurately out to 1000 yards being able to throw a ball powder in there is just gravy for faster reloading.

I'd load the 6mm ARC in the Dillon progressive, for my AR 15. I do it with Leverevolution and 108 ELDM, or Berger 108 gr. generally the most accurate but Sierra 110 are good too... Dillion loaded ammo with sometimes hit 5 shots near a quarter inch, but most are .3" to .6" with progressive loading and single digit S/D most of the time. A big fan of the 6 mm ARC, after I got away from the factory assembled upper and installed a Proof Research S.S. barrel. Went from 2.5" groups to 1/2" groups. So I ordered the last 6mm ARC Proof barrel in stock and it was slightly more accurate than the first. But the 308 is no slouch, it depends on what ya shoot it in, or your willing to single load. I just shot a 225 ELD-M .777 BC at 2461 ave fps in an 18" into .6" group, but the .715 BC Sierra MK is smokin fast over 2600 fps in a 18" barrel.
The Bob Sled mag makes single shot fast. But even mag length 208s are promising, as its the heavy bullets that lose less velocity as barrels become shorter. Loading a bunch of 308 today, 110 gr to 230 gr.
Just got back from Sportsman's they had a few pounds of 6.5 Staball in stock, but no primers.

 

[Lkwebb]

Leverevolution and varget i found to be better powder when I had my 6mm arc

 

[Ray123]

Mid 2800s with a 7bc is very impressive. Sierras 308 data for the 200 tops out at 2550 even at saami+ with 4350 class powders out of a 24 so that staball puts it about 150 fps faster for the same barrel length. Thats pretty dang good.

Just letting people who are interested in seeing what is possible with common cartridges and new components. I am a retired machinist with a machine shop with quality machine tools and inspection tools in my garage, and shooting is a hobby. So I build and chamber my own rifles. Order the barrel, chasis, trigger, & parts needed.
So instead of waiting months for a custom gunsmith. I have a completely finished competition 6 mm dasher... my last rifle in a day or two (if I'm lazy or a late start) trued Remington 700 reciever, chambered & threaded barrel, muzzle break, bolt knob etc. Scope installed and Ready to shoot the next day. By the way the 6 dasher is very accurate. So I have my own reamers to chamber my favorite calibers. Do crazy things, with wild ideas, and experimenting to see if works . I alter actions, machine recievers ...how about a 3+" COAL for AR10, cut out mags and reciever and barrel machining required. I realize the average guy probably won't have skill, the tools, or even want, to do those things, but it's nice to know it's possible, and see the results.

 

[Ray123]

Leverevolution and varget i found to be better powder when I had my 6mm arc

I like Leverevolution too, it's what I use... it's accurate, consistent, fast, shoots small groups, meters accurately... so I purchased 16 lbs...Varget was never considered...it's too slow . Used lots of Varget over the years, but today it's on the back burner. Sometimes it's not accurate, and common positive quotes about it don't hold true, depending on the cartridge it's used in.
What do you mean, "When I had my ARC?" It's a great AR 15 cartridge and accurate with both of my Proof S.S. barrels, it wasn't with the assembled upper I bought, that was a 2.5" barrel with match ammo, change to Proof went to 1/2" same ammo same day. Unless you traded your ARC for a 6mm dasher I don't understand... The 6 mm dasher is my favorite, but that's a bolt gun platform...
Have a good day.

 

[usmc 0311 rvn 67-68]

So, what powder are you using in the .308 loads?

 

[Ray123]

I use a variety of powder for 308, depending on what I'm experimenting with, what type of action, or barrel length I'm working with. I have 6 308s to choose from, with twist rates of 12, 10, 9, and 8.
I have even used Varget with Berger 200.2 like everyone else, and it gives accurate results .3 "5 shot groups in 8 twist 30". But for me it's a 2nd fiddle powder, as I get faster speeds and accuracy out of other powders. I shoot out of the box loads 200 SMK .715 BC has a much higher BC than the Berger and more accurate in a 8 twist, or even the required 9 twist which I built rifles around. 200 gr SMK .715 BC is my best all around LR bullet, but I've been getting good results with 225 eldms shot back to back groups, with low .3" Lapua brass and .4 with Lake City brass as an experiment. The 230 Atip needs more extensive experimentation. With a .823 BC at over 2600 fps is alot more interesting than a 200.2 Berger with .640 BC at 2650 fps.
I have tried RL 26, 6.5 Staball, Superformance, 2000MR, RL15, Varget, Big Game. Tac, w748, w760, RL17, cfe223, h380, 2520, 4064, 4895, 4350, h322, hybrid 100v, a223, and trail boss makes very accurate subsonic loads in all twist rates from 12 to 8 with 175 SMK, and barrels from 18 to 30 inches. These are the powders I have recently tried that I remembered. The heavy bullets is where its at if ya want to go long in my opinion.
That said I hit a 1000 yrd milk jug with 130 gr Speer varmint at a muzzle velocity of 2650 fps, with a .244 BC as an experiment on tumbling inaccuracies...it didn't happen.. at around 60 moa drop, way below subsonic, they arrived on target. Not a particularly good 1000 yd bullet but informal fun is there. I'm working with the 18" AR 10 now and gonna try some nosler 110 and imr 4198 to see what velocities can be obtained. Already done a work up on 230 Atip, 225 eldm, and 200 gr Sierra and Berger, and posted it, with barrels from 18 to 30 inches. The best appears to be 200 SMK at over 2600 fps in an 18" AR but requires a 9 twist or 225 eldm at 2470 fps... Or the 208 eldm at 2500 fps, but eldms have a long bearing surface. The 230 Atip is a better design. Right now I'm picking the 225 eldm to play with, it will work with a 10 twist...

 

[SD guy]

Has anyone here worked much with Alliant Power pro 2000 in the 6mm Arc? AR or bolt action??