AR15 6MM ARC update.

[David Milisock]

Ok, my goal with my new rifle was to obtain function in close ranges comparable or improved to the M2 Carbine in M1A1 configuration and the M4 in 5.56 NATO. However I wanted more energy in close and out to 600 yards with the improved in close handling. Improvement in down range wind drift was also a main goal as the rifle. The rifle was created for protection and medium game.

My Aero Precision M4E with a Ballistic Advantage barrel shooting Hornady Black 105 factory ammo, A2 front sight, standard military rear folding aperture sight, 2 stage National Match trigger. Chronographed at 2,500 FPS (real average was 2501, from 5 shots) from a 16" barrel from a bench front and rear bags. 300 yard center of 6" group measured 10 1/4 " high from point of aim, Hornady ballistic program points to a 400 yard zero.

At 100 yards I got exceptional accuracy, sub minute of angle, regularly 1/2" groups using a custom target. Plotting group centers from 100 to 300, 8 1/2" high, 12 1/4" and 10 1/4" high at respective ranges. This is close to what the Hornady Ballistic program plots, not perfect but close.

ENERGY, DROP and DRIFT 10 MPH wind at 90 degrees 6,000 feet ASL.

30 Carbine 18" barrel, 110 grain 2000 FPS 977 FTLB at the muzzle, 264 FTLB at 400 yards. At 400 yards, drop 72" with a 200 yard zero, 10 mph wind drift 47".

M4 16" barrel, 68 grain 2700 FPS 1101 FTLB at the muzzle, 482 FTLB at 400 yards. At 600 yards, drop 57.6", wind drift 45.3", energy 306 FTLB.

AR15 A2 20" barrel, 68 grain 2900 FPS 1158 FTLB at the muzzle, 619 FTLB at 400 yards. At 600 yards, drop 41.4", wind drift 30.4", energy 437 FTLB.

A5 15 M4E 6MM ARC 16" barrel, 105 grain 2500 FPS 1457 FTLB at the muzzle, 941 FTLB at 400 yards. At 600 yards, drop 47.4", wind drift 22.6", energy 744 FTLB.

As you can see I've achieved my goal, the 6MM ARC compared to the 30 Carbine and M4 5.56 68 grain with 18" and 16" barrels respectively, significant gains in trajectory, wind drift and energy both in close at out to 600 yards.

Compared to the AR 15A2 20" barrel the A2 had a 6" better drop but the A2 had about an 8" greater drift and about 320 FTLB less energy.

Shooting the Aero Precision, at 8LBS is significantly less bouncy in rapid fire in close than the other 3 compared rifles. Out to 300 yards the A2 with the 20" barrel and the ARC are close to the same in accuracy with iron sights but the 6MM ARC has over 320 more FTLB energy. However the ARC is smoother and has less felt recoil than any of the rifles.

Next I'm moving the iron sight plots out to 600 yards and then I'll install a 1x8 tactical scope.

 

[pazdad]

Ok, my goal with my new rifle was to obtain function in close ranges comparable or improved to the M2 Carbine in M1A1 configuration and the M4 in 5.56 NATO. However I wanted more energy in close and out to 600 yards with the improved in close handling. Improvement in down range wind drift was also a main goal as the rifle. The rifle was created for protection and medium game.

My Aero Precision M4E with a Ballistic Advantage barrel shooting Hornady Black 105 factory ammo, A2 front sight, standard military rear folding aperture sight, 2 stage National Match trigger. Chronographed at 2,500 FPS (real average was 2501, from 5 shots) from a 16" barrel from a bench front and rear bags. 300 yard center of 6" group measured 10 1/4 " high from point of aim, Hornady ballistic program points to a 400 yard zero.

At 100 yards I got exceptional accuracy, sub minute of angle, regularly 1/2" groups using a custom target. Plotting group centers from 100 to 300, 8 1/2" high, 12 1/4" and 10 1/4" high at respective ranges. This is close to what the Hornady Ballistic program plots, not perfect but close.

ENERGY, DROP and DRIFT 10 MPH wind at 90 degrees 6,000 feet ASL.

30 Carbine 18" barrel, 110 grain 2000 FPS 977 FTLB at the muzzle, 264 FTLB at 400 yards. At 400 yards, drop 72" with a 200 yard zero, 10 mph wind drift 47".

M4 16" barrel, 68 grain 2700 FPS 1101 FTLB at the muzzle, 482 FTLB at 400 yards. At 600 yards, drop 57.6", wind drift 45.3", energy 306 FTLB.

AR15 A2 20" barrel, 68 grain 2900 FPS 1158 FTLB at the muzzle, 619 FTLB at 400 yards. At 600 yards, drop 41.4", wind drift 30.4", energy 437 FTLB.

A5 15 M4E 6MM ARC 16" barrel, 105 grain 2500 FPS 1457 FTLB at the muzzle, 941 FTLB at 400 yards. At 600 yards, drop 47.4", wind drift 22.6", energy 744 FTLB.

As you can see I've achieved my goal, the 6MM ARC compared to the 30 Carbine and M4 5.56 68 grain with 18" and 16" barrels respectively, significant gains in trajectory, wind drift and energy both in close at out to 600 yards.

Compared to the AR 15A2 20" barrel the A2 had a 6" better drop but the A2 had about an 8" greater drift and about 320 FTLB less energy.

Shooting the Aero Precision, at 8LBS is significantly less bouncy in rapid fire in close than the other 3 compared rifles. Out to 300 yards the A2 with the 20" barrel and the ARC are close to the same in accuracy with iron sights but the 6MM ARC has over 320 more FTLB energy. However the ARC is smoother and has less felt recoil than any of the rifles.

Next I'm moving the iron sight plots out to 600 yards and then I'll install a 1x8 tactical scope.

Dave, have you reloaded any of the Hornady Black brass? If so can you provide insight as to load work up?
I have the 20" Aero complete upper (Brownells) on an Aero lower (like you) with a Larue MBT2 trigger. I am using 6.5 Grendel Starline brass resized on Hornady dies. I've had success with CFE223 and Leverevolution powder(s). My gun shoots 1/2 - 3/4" groups for about 40-60 shots then I start getting random fliers. I discovered it develops a carbon ring in the throat just off the trim edge of the brass. I discovered this using a bore scope. I clean the carbon ring by soaking with wet patch for a couple of hours and then rotate a bore brush in the throat. This process removes most of the build up. Accuracy returns, then the entire process repeats. Further, when installing a new Aero adjustable gas block I removed the muzzle device and found significant carbon build up on the crown. I am interested if you have seen similar issues with carbon? Thanks, Mike

 

[troupe]

I am following this post, I am wanting to build a 20". I have read so much about good barrels and bad barrels. I want to be in the 1/2 to 3/4 range at 100. I will hand load down the road. Would like to be in the 2800 FPS range with a Sierra 90gr Game Changer bullets. Hope that I will not be off base by much. just got to find the right barrel . I can't do the $700 Carbon barrel, although I would like the lighter weight.

 

[David Milisock]

Dave, have you reloaded any of the Hornady Black brass? If so can you provide insight as to load work up?
I have the 20" Aero complete upper (Brownells) on an Aero lower (like you) with a Larue MBT2 trigger. I am using 6.5 Grendel Starline brass resized on Hornady dies. I've had success with CFE223 and Leverevolution powder(s). My gun shoots 1/2 - 3/4" groups for about 40-60 shots then I start getting random fliers. I discovered it develops a carbon ring in the throat just off the trim edge of the brass. I discovered this using a bore scope. I clean the carbon ring by soaking with wet patch for a couple of hours and then rotate a bore brush in the throat. This process removes most of the build up. Accuracy returns, then the entire process repeats. Further, when installing a new Aero adjustable gas block I removed the muzzle device and found significant carbon build up on the crown. I am interested if you have seen similar issues with carbon? Thanks, Mike

Getting to the end of my chemotherapy this month will be reloading after that. I bought leverevolution powder.

 

[pazdad]

David, sorry to hear this, wishing you a successful treatment and full recovery into the new year. I look forward to future exchanges when you are well. Take care, my thoughts and prayers are with you and your family.
Mike

 

[pazdad]

I am following this post, I am wanting to build a 20". I have read so much about good barrels and bad barrels. I want to be in the 1/2 to 3/4 range at 100. I will hand load down the road. Would like to be in the 2800 FPS range with a Sierra 90gr Game Changer bullets. Hope that I will not be off base by much. just got to find the right barrel . I can't do the $700 Carbon barrel, although I would like the lighter weight.

I haven't loaded anything below 103 grain. I can get 107 grain Sierra BTHP MK's to 2,700 (w/o pressure signs) with my Aero/Ballistic Advantage 20" barrel and 29 grains of LeverEvolution (in warm temps/summertime). CFE 223 runs approx 25 fps slower. The Hornady 105 grain BTHP Match does nearly same speed but not as accurate. My gun shoots consistent 1/2 - 3/4 groups with these heavier bullets in the 2600 - 2650 fps range. Groups tend to open up as I approach 2700. I run a longer OAL to get the bullet 0.020 off the lands which is considerably longer than the boxed Hornady 105's that are seated really short (my loads still fit the mag) . If I was looking for working room in the 2800 fps range with the 90's I'd look to at least consider a longer barrel, 22 or 24" especially if you are just punching paper. That way you can play with multiple powders and projectiles. I can share specifics of what works for me when you're ready to start reloading. Be aware reloading components, powder, projectiles, brass and primers are currently scarce/ hard to find and expensive.

 

[troupe]

Thanks for the feedback. I appreciate it. I have yet to pick up a barrel. I want a good barrel that I know will shoot in that ball park. Hope not to go with a custom barrel. I have everything else. I will want to go with a 20" because it will be a hunting rifle mostly.

 

[David Milisock]

David, sorry to hear this, wishing you a successful treatment and full recovery into the new year. I look forward to future exchanges when you are well. Take care, my thoughts and prayers are with you and your family.
Mike

Thanks man, I'm doing well and too busy to be sick.

 

[The boogalorian]

Thanks for the feedback. I appreciate it. I have yet to pick up a barrel. I want a good barrel that I know will shoot in that ball park. Hope not to go with a custom barrel. I have everything else. I will want to go with a 20" because it will be a hunting rifle mostly.

Check out Craddock Precision.

6mm ARC Bartlein Barrel

craddockprecision.com

I have a 22”. Working with varget, vv 140, vv 150, blc2. Getting es of 20 and sd’s around 8-9 fps on 20-30 shot strings.
Didn’t like Berger 105’s and 109’s, still working a load for the 108 bt’s. It does like the 90gn Berger’s, but I am going to limit it to 2700 fos cause I am wanting to be cautious.
I am building this rifle for prs.

 

[troupe]

I would not mind Craddock, but not willing to wait. Same as waiting for Compass Lake.

 

[The boogalorian]

I got some Hornady black ammo for the brass. It shot 3/4"-1" (5) shot groups at 100yds. Shot at 2640 fps out of my 22" barrel.
Recently got some Hornady match ammo, it is a little better than the black. Only 2570 fps out of my barrel.
I am a little disappointed at the speed, but it is what it is. 90gn pills at 2700 fps is going to make shooting 700-1000 yards very difficult. Just getting a load right now, haven't shot out to distance yet.
Might look at building a 224 valkarie upper if this doesn't work past 900 yards.

 

[Hoffman01]

Anybody seen rings on there brass like this this is the third time I’ve polished the chamber and they got some better but can’t get them gone. I’m afraid the the case will separate when I reload this brass. Any ideas?

 

[moorepower]

Anybody seen rings on there brass like this this is the third time I’ve polished the chamber and they got some better but can’t get them gone. I’m afraid the the case will separate when I reload this brass. Any ideas?

Yikes, and nothing like that!

 

[David Milisock]

Anybody seen rings on there brass like this this is the third time I’ve polished the chamber and they got some better but can’t get them gone. I’m afraid the the case will separate when I reload this brass. Any ideas?

I don't think that will polish out, I'd get the barrel maker involved.

 

[CAPTHOOK58]

Anybody seen rings on there brass like this this is the third time I’ve polished the chamber and they got some better but can’t get them gone. I’m afraid the the case will separate when I reload this brass. Any ideas?

I'd check it out with a borescope first. Had rings similar to that on some LAPUA brass before they came apart. Strange thing is that it appeared after first shooting of virgin brass but was "not" hot loaded. Used Nosler with same load and no problem.