6mm ARC - Practical Reloading

[ClintR]

@ClintR: Welcome to the forum. Looks like we are practically neighbors! What kind of accuracy do you need to be successful in Across the Course? Can you shoot from a magazine in XTC or is it single load?

You have a great selection of the right components. CFE 223 is definitely a good 6mm ARC powder and I have shot a lot of it. Would be worth picking up some LEVERevolution to test with as well. It gives more MV than CFE at the same or similar pressure and has produces great single digit SDs consistently. I have tested it in temperatures from 35 to 65 with no change in MV. This summer will be interesting for sure...

Good luck with your rifle. Sounds like a great build.

Henryrifle

I went to the range yesterday and collected some data to share. I'll enclose my research, a ladder using CFE, 108 ELD-M and cci 400 primers. I also collected data on the factory load (108gr ELD-M) enclosed.

 

[ClintR]

@ClintR: Welcome to the forum. Looks like we are practically neighbors! What kind of accuracy do you need to be successful in Across the Course? Can you shoot from a magazine in XTC or is it single load?

You have a great selection of the right components. CFE 223 is definitely a good 6mm ARC powder and I have shot a lot of it. Would be worth picking up some LEVERevolution to test with as well. It gives more MV than CFE at the same or similar pressure and has produces great single digit SDs consistently. I have tested it in temperatures from 35 to 65 with no change in MV. This summer will be interesting for sure...

Good luck with your rifle. Sounds like a great build.

Henryrifle

Sorry, I just noticed your questions regarding XTC discipline. Accuracy needed is less than 1 moa is best of course, but that is only a part of what is needed. XTC is a sling shooting discipline. Starting at the 200-yard line standing slow fire from the offhand position, then down in the sitting position in rapid-fire using sling and magazines with a magazine change in the string. Then moving back to the 300-yard line in the prone position rapid-fire using a sling and w/Magazines and a mag change in the string. Moving then to the 600-yard line from the prone position shooting with a sling and slow fire. More than 50% of success is in the position. Without mastery of your shooting positions with the sling, even a 1/4 moa weapon will not be of benefit. Shooter and Weapon as one.

 

[ClintR]

Due to component shortages, I want to reserve my remaining CCI 450s and BR4s for competition. I tested those two plus regular CCI 400s and actually saw slightly higher MV with the 400s. With LEVERevolution the SDs are still in the low single digits. All of this was in approximately 60 degree temperatures and on the same day. Accuracy was unchanged.

Normally, I want to shoot small groups but have learned a lot from this rifle and project. The rifle shoots at approximately 1 MOA. This was disappointing at first and, to some degree, still is. I can shoot groups in the .65 MOA range but that seems to require me (as a shooter) to use a rear bag rather than a squeeze bag. I have been working on my AR shooting technique but obviously have a ways to go yet.

What I've learned is that the rifle works great for small to medium sized deer here in Georgia within 300 yards (haven't tried it at longer ranges), is super fun to shoot at distances out to 1000 yards on 2 MOA steel and can do all of that out of an AR platform. I have even shot it out to 1300 yards with a 27% hit ratio on 1.5 MOA steel. Nothing to brag about but impressive, in my opinion, for an AR.

Can't wait to see/read about some results.

Henryrifle

Is this who I think it may be? Were you at RBGC yesterday afternoon?

 

[Henryrifle]

Yes and yes.

 

[Raptor]

I made it to the 100yd range yesterday and got some encouraging results. Keep in mind my COALs are an approximate measurement for reference. I use a comparator to measure to the ogive of the bullet for my actual seating depth measurements.

Ok so I had 44 - three round groups with COALs starting from 2.136" and going up to 2.265" in .003" increments. I had 22 sub moa groups. Six of those groups had large groups on each side of them so they got tossed out. In my rifle the factory match 108gr ELDs seem to like to be seated a fair amount deeper than the factory seating depth. With COALs from 2.157" to 2.184" I had 8 out of ten groups sub moa with 5 of the 8 groups under .523". The smallest group of the day came in at .342". With powder tuning it may be possible to get sub .250", at least with three round groups. Now that I've found my seating depth node I want to stretch it out to 500yds and see how it does. If I like it I might just call it good.

When you're looking at my photo the shortest COAL was group 1 and the longest was 44. Groups 38 & 39 are closest to factory loads out of the box which explains a lot. Group 44 had a cartridge jam and dented the shoulder before I fired it giving me the only 3"+ group of the day. With group five I was super loose on the grip and accidentally 'bump fired' one of the rounds off the top of the board as I was shooting at the top row so there's that. Neither of those groups had anything exciting going on around them so I didn't worry to much about those mistakes.

Now were these all factory loads with only seating depth changes??? Thanks!!

 

[Kurbe105]

Now were these all factory loads with only seating depth changes??? Thanks!!

Yes. These were factory match 108 eld loads right out of the box with only the seating depths adjusted on this test.

 

[Raptor]

Was out to my son in laws place and we got a chance to do some more load testing. He built his for calling coyotes so went with a 16" barrel on his. (Ballistic Advantage) We found a couple of loads that were consistently under an inch. I believe he is going to stay with the 80gr Berger with 30.4 of CFE. We cronographed it at 2730 FPS so was happy with that for a 16" barrel. We didn't get a chance to "Walk it out" like we wanted. The damn weather turned nasty on us. 30+mph winds this morning......

 

[Kurbe105]

Was out to my son in laws place and we got a chance to do some more load testing. He built his for calling coyotes so went with a 16" barrel on his. (Ballistic Advantage) We found a couple of loads that were consistently under an inch. I believe he is going to stay with the 80gr Berger with 30.4 of CFE. We cronographed it at 2730 FPS so was happy with that for a 16" barrel. We didn't get a chance to "Walk it out" like we wanted. The damn weather turned nasty on us. 30+mph winds this morning......

I like ballistic advantage for the simple fact they put a 1:7 twist in their barrels. I have another build with an 18" BA bbl. I read somewhere the 1:7 twist is better for stabilizing the longer bullets like bergers. I plan on working up loads for this build as well but don't want to confuse myself testing more than one rifle at a time. I wish Proof and BSF would at least offer 1:7 twist as a custom option.

 

[Raptor]

Son in Law called and said he reshot the 80 Bergers and they grouped between .6 and 1" at 100yds but when he shot them at 300 they really opened up!! They shot about 6"!!!! He said he can't figure out what the hell the problem is so he set it aside and will look at it later when he gets a warmer day.....

 

[Kurbe105]

Son in Law called and said he reshot the 80 Bergers and they grouped between .6 and 1" at 100yds but when he shot them at 300 they really opened up!! They shot about 6"!!!! He said he can't figure out what the hell the problem is so he set it aside and will look at it later when he gets a warmer day.....

 

[Kurbe105]

Erik talks about groups opening up down range. I'm not trying to start a debate about his methods or ideas just saying this video really helped me. Also Berger has a page that talks about testing bullet jump up to .150" which is just about minimum COAL with the 6ARC. https://bergerbullets.com/getting-the-best-precision-and-accuracy-from-vld-bullets-in-your-rifle/
I'm going to try and get to the range today and stretch it out to 300yds with some of my tuned factory 108ELDs to confirm the seating depth node I found at 100yds.

 

[ClintR]

I'm going to give this theory a try. I had a recipe for my 223 service rifle with an 80gr VLD that shot low ES and great groups at 100y but opened up downrange. It's worth a second look it appears.

 

[Shifty6br]

Had a chance to test some loads over the v3. Cold, cold, cold so everything was done at indoor range. LvrRev with 75 vmax at the moment, plan on trying some heavier pills near future but no real intention of going past 105gr at the moment.

20" Proof, formed 6.5g brass and cci 450.

31.7 3110
31.9 3140
32.1 3144
32.3 3150
32.5 3170
32.7 3205
32.9 3211
33.1 3228
33.3 3234

Hoping to brave the weather and shoot for groups today.

 

[anti-pattern]

I have been hitting some nice, sub-moa groups using Lever Evolution 30.3gr with 90gr ELD-X bullets seated at 2.25" COAL. I'm running a Uintah Precision upper so it's a bolt gun vs gas gun. I'm good up to 62,000 psi for the most part. I also have 90gr Berger Target and 105gr Berger Elite and some 95gr SST bullets I plan to try out. so far, the CFE 223 and the Lever Evolution seem to be working best. Running standard CCI 400 primers without any issues.

 

[Raptor]

I tired the CFE and Leverloution but with a can it is so DIRTY!!! I can not believe how fast my gun gets carboned up!!! As luck would have it I found a good load with Varget that was in the same speed range. My rifle is a HAMMER!!! It shoots as well as a bolt gun!! I shot it out to 800yds today and all of my 3 shot groups but one were at .5 MOA or under!! I love this damn thing!!!

 

[Raptor]

Hey guys I am looking for the H20 case cap. of the 6.5 Grendel case compared to the 6.5 Grendel StarLine cases. Then the same on the Hornady 6ARC case. I know I read it on one of these forms somewhere but don't want to go back and read through 30+ pages on some of them...Thanks guys!!!

 

[457ciSBC]

6ARC is in here. If you don’t get the others soon.I could get the SL and AA brass 65 grendel measurements for you.

6mm cheat sheet info

i am just gathering info, please let me know what the correct numbers are, just gathering info for fun H2O nk length shlder ang 6x47 Rem 31.1 289 23 6x50 Mo Better 33.1 266 23 6x47 33 6PPC 33.74 280 30 6mm ARC 33.96 224 30 240 Tomahawk 36.2 170 40 6mm...

forum.accurateshooter.com

 

[Hoot]

Hey guys I am looking for the H20 case cap. of the 6.5 Grendel case compared to the 6.5 Grendel StarLine cases. Then the same on the Hornady 6ARC case. I know I read it on one of these forms somewhere but don't want to go back and read through 30+ pages on some of them...Thanks guys!!!

My FL sized 6.5 Grendel Lapua cases hold 36.2 gr H20.

Hoot

 

[Raptor]

Thank you!! I found where some are saying 35 For Lapua so I am guessing a 6 ArC will be about 34 grs...

 

[Snodgrass]

I am shooting a .243 LBC (6mmAR) in a CZ527 bolt gun, 20.5" 1:10 twist 3 groove Pac-Nor stainless barrel.
The powders I have tried: Alliant Power Pro Varmint, ADI BM8208, Alliant AR Comp.
I am using Lapua 6.5 Grendel Brass, necked down to 6mm, then neck-turned, trimmed and annealed.
I am using CCI 450 primers exclusively.
Power Pro Varmint gave good velocity with low pressure, but was too sensitive to differences in ambient temperature.
BM8208 (Hogdon XBR in the USA) gave good velocity & accuracy without excessive pressure, BUT started to fire-crack the edges of the lands in the throat after just 40 rounds! This stuff eats barrels at an even greater rate than AR2208 (Varget).
Enter AR Comp: The best velocity & accuracy yet. NO copper fouling after 50 rounds with Hornady 87g V-Max bullets and acceptable pressure.
Bulk density of this powder is lower than BM8208, I have to really work at getting 29.5g in the case with that V-Max bullet jammed .015" into the lands. Average velocity is 3060fps. Best 100 yd 3 shot group so far was .307", ES of 15fps, SD:7.
A lot of people complain that Alliant powders are dirty: what is left in the barrel is soft sooty stuff (the anti-coppering additive) that is easily removed with nothing more than Hoppes #9.
Single based ADI powders by comparison, appear to burn very clean, but they fire-crack barrels quickly and the little carbon they do leave behind is the hard, caked-on kind.
I carefully clean my barrel and then bore scope after every shooting session.