New 6mm Advanced Rifle Cartridge

[Gtscotty]

If you can wait a few months just get a custom. X-Caliber's sale this weekend should put you in that same price range.
Not sure what WC is thinking with their unusual sales strategy.

I might should just do that, I had heard/read some pretty mixed reviews on X-Calibur a few years ago and kind of counted them out. Have you had good experiences with them? Thanks for the heads up on the 20% sale.

Maybe. But Bill Wilson has a ranch where he shoot’s pigs all year round, and he hunted with both barrels, and found the 18” mid gas better than the 18” rifle gas, and he hunts with a can.

So, there must be something behind it.

I wonder what those pigs taught him that Hornady/Proof/secret squirrel customer couldn't have learned during development? Apparently something no other 6ARC barrel manufacturers know as well.

When I finally got ahold of the customer service, the, the guy I talked to knew what I was calling about about 3 words in. Pretty sure I wasn't the only person they hosed that called to ask WTF. At any rate, from the conversation, it sounded like they sold many, many more of the Recons than they had... Maybe they'll take the hint and make what the customers want even if it isn't what "Bill prefers" (customer service's words).

 

[TonyTheTiger]

I might should just do that, I had heard/read some pretty mixed reviews on X-Calibur a few years ago and kind of counted them out. Have you had good experiences with them? Thanks for the heads up on the 20% sale.

I've got a 5.56 and a 6mm Grendel from them and they shoot great, but with the caveat that I'm in the minority of shooters here in that I do a real quick and dirty load development till a barrel shoots sub 3/4" then I never shoot it on paper again with the exception of an occasional zero check. Last two times I checked the 6mmG zero:

I bet with the WC thing they just flipped a coin on gas system length and then decided afterward they preferred the weight/profile of the Tactical Hunter better and chose that one with no regard to gas port location.

 

[CaptArab]

IME with multiple WC 223/308 barrels, they ensure the weakest ammo on the market will cycle in suboptimal conditions with a standard weight buffer- I typically find them over-gassed for my preferences.

 

[Ledzep]

One thing I've noticed is that people will habitually throw adjustable gas blocks on everything, and the 18" 6mm ARCs set up with Rifle +1 basically require the gas to be full open to run. A Rifle or Mid-length system may actually benefit from adjustable gas blocks, where as the rifle +1, you might as well just throw a $20 low-profile block on and roll with it.

 

[lennyo3034]

IME with multiple WC 223/308 barrels, they ensure the weakest ammo on the market will cycle in suboptimal conditions with a standard weight buffer- I typically find them over-gassed for my preferences.

My experience is the opposite. Had a 16” mid that was undergassed with anything. Opened up the gas port with reamer and worked great afterwards. Was not a big deal to do and honestly prefer it this way over too big a gas port.

 

[TonyTheTiger]

One thing I've noticed is that people will habitually throw adjustable gas blocks on everything, and the 18" 6mm ARCs set up with Rifle +1 basically require the gas to be full open to run. A Rifle or Mid-length system may actually benefit from adjustable gas blocks, where as the rifle +1, you might as well just throw a $20 low-profile block on and roll with it.

Yes and no, gas blocks adjust gas volume but not port pressure and you can absolutely run into timing issues because of excessive pressure. You may still get it to run but you may not be able to tune out high pressure side effects, like brass mangling or less than optimal suppressor use. That and a tuned longer system will always be softer than a tuned up short gas system.

 

[newageroman]

I got most of my issues resolved. It was a clogged gas tube mostly, gun cycles brass into a 3'oclock pile once again.
I tested some more ASC mags today, I got a couple more 10 rounders and a 25 rounder. I didn't get to test the 25 at full cap, maybe next time. I had about 10 or 15 when it got emptied on the 380 yd target.

Then I pulled out the 1903USMC rebuild and knocked all the steel off the hangers. Fuddrunner!!!

 

[357Max]

Loaded x 10 A-tips with 29.5 Lever = 2650/SD10.5 @100y .9" group / @300y 2.9" group. These were at 2.295/1.673 (max for the Brenton mags).
Not a mark on the head stamp.

Tried 109's @2.287/1.675, 2.290/1.678, & 2.293/1.681. Five rounds each @100 shot .830", .550", & .625". These were all loaded in Hornady brass & Lapua is a little more accurate due to the +.002 necks. Figures this gun would like the unobtanium 109's. Only have 500 & the 6GT loves them too.

I'm now going the other way with the 100gr TGK's (more jump). Loaded 2.265/1.690, 30.1 Lever = 2820 & put 4 rounds in .42", but of coarse I yanked the 5th making it .9".

Gave up on the 100gr PVA's

 

[RMB]

Has anyone tried the 95 gr SMK? Before I start working with these any input would be appreciated. My initial results look pretty good.

 

[TonyTheTiger]

Has anyone tried the 95 gr SMK? Before I start working with these any input would be appreciated. My initial results look pretty good.

Yes, in my 6mm Grendel (functionally identical to 6ARC) and they shot great with no load development. I think I was using a mild charge of 8208 and getting 2775-2800 fps with a 22" barrel.

 

[lennyo3034]

I happen to have a spare KAC SR-15e3 bolt and barrel extension (currently mounted on a KAC barrel). Wondering if it’s worthwhile to open up the bolt to grendel bolt face and have new barrel turned for KAC extension. If nothing else, the KAC bolt should be less likely to break under pressure.

 

[r.tenorio671]

i just finished up my 6 arc build for hunting coyote. worked up a nice load using 70 gr nosler varmageddons.
32.6 gr cfe223.
average velocity - 3020 FPS
ES-11 SD-5
20" cmmg 1:7.5 barrel
vg6 brake
shooting sub MOA @100 yards. i'll upload pics tomorrow of my rifle setup and grouping.

all in all im happy with the round. only using CFE223 cause thats what i happened to have on hand and Lever powder was no where to be found.

...just a FYI, using 30.0gn XBR8208 I was able to attain 3067 avg FPS with the Nosler 70gn VG FB, 18" 1/7 barrel, RLGS. Per my chamber, went with CBTO of 1.641", COAL of 2.121", no pressure signs on converted virgin Starline 6.5 Grendel brass. Was pressure testing, still avg'ed ~1MOA @100 yds.

...8208 is reported to be more temp stable than CFE, not a concern for me, year round temps in my locale avg 80F

 

[troupe]

Finally got to shoot my new build with the Douglas/Compass Lake 20" 6mm ARC. Only fired 12 rounds so far, did not get a velocity reading from the factory Hornady 103's. It did shoot 5/8 @100 so far.

 

[loclass]

I'll add another data point for the group. I put the first rounds downrange last night with a new rifle. Barrel is a Compass Lake Engineering 22" 7.5 twist from a Criterion blank, +1 rifle length gas. 24 rounds total. A quick 3 shot group of Hornady Black 105 bthp factory ammo yielded a .42" group at 100 yards. The next groups were 5 shot groups with Hornady 108 ELDM factory ammo.... First was .86" and the next was .66". Velocity of the 108s averaged 2702 and the 105s were just under 2700 fps. Chrono is a Labradar and all groups were shot suppressed. So far it looks very promising for accuracy.

 

[Gtscotty]

If you can wait a few months just get a custom. X-Caliber's sale this weekend should put you in that same price range.
Not sure what WC is thinking with their unusual sales strategy.

Finally wound up taking this advice and ordering an 18", RLGS lightweight profile barrel from X-Caliber during their Memorial day sale. Hopefully it comes in time to get a couple loads worked up for deer season.

 

[JKGTR]

Have just under 100 rounds through my custom X caliber. 22” rifle length 7.7 twist 3R groove with head spaced JP bolt. First, I will say that this is one of the nicest barrels I’ve seen.
Still working with some harmonic issues. Out of curiosity I started swapping BCGs and learned that BOTH of the JP bolts I have are somehow causing poor accuracy. This was discovered when I randomly decided to take the BCG out of by friends 223 gun swap the bolt faces and threw it in mine. Was not seeing even close to sub MOA accuracy with either of the JP bolts, but when I threw in the other cheapo BCG it shot factory hornaday Black ammo at about .5” multiple times. Very strange.

 

[troupe]

I think that it has something to do with the bolt lock up. Just a theory that I can't prove, but when I fired the first 3 shots through my barrel, it was about a 1 3/4. Cleaned and the next 3 were in 1". Cleaned and the next 3 went into 5/8. Lock up seemed smoother. I think bolts have to settle in just like a barrel. Maybe not, but just my guess.

 

[evilsvt]

22” Proof pushing 55hr Hammer Hunters at 3625 with 32.8 GR AA2230

 

[Gtscotty]

View attachment 7885567

22” Proof pushing 55hr Hammer Hunters at 3625 with 32.8 GR AA2230

Well that's pretty cool, I'm surprised that the little ARC will push them so fast. How's feeding in the Origin? Do you use MDT BR mags?

 

[Dino11]

I use these MDT mags in my 6mm ARC in an Oryx chassis.

 

[JKGTR]

I think that it has something to do with the bolt lock up. Just a theory that I can't prove, but when I fired the first 3 shots through my barrel, it was about a 1 3/4. Cleaned and the next 3 were in 1". Cleaned and the next 3 went into 5/8. Lock up seemed smoother. I think bolts have to settle in just like a barrel. Maybe not, but just my guess.

The issue is that only the carriers were swapped. I was using the same bolt head that was headspaced to the barrel. So it doesn't make any sense to me.

 

[Yondering]

I wonder if the JP carriers are fit a little tighter to the bolt, so that there’s less gas leakage past the rings and bolt tail. This would make them a bit (more?) overgassed, which definitely can degrade accuracy. Something to consider.

 

[steve101610]

The issue is that only the carriers were swapped. I was using the same bolt head that was headspaced to the barrel. So it doesn't make any sense to me.

First thing I would do is get rid of the jp one piece gas ring. I had undergassed issues every time I have tried them. It was so loose on a 6mm creedmoor that it wouldn’t cycle the bolt. Swapped in regular gas rings and it cycles perfectly now.

 

[357Max]

+1 on that. I only have 2 JP bolts & threw there 1 pc rings in the trash before firing a shot.

Also check to see how well the gas tube aligns with the carrier key. I flip mine upside down so carrier is at top of receiver to simulate rounds in the mag. Some of the taller gas blocks like Oden .875 adj. really need a straight tube for best alignment.

 

[JKGTR]

First thing I would do is get rid of the jp one piece gas ring. I had undergassed issues every time I have tried them. It was so loose on a 6mm creedmoor that it wouldn’t cycle the bolt. Swapped in regular gas rings and it cycles perfectly now.

That’s interesting I’ve never heard of that but might as well try. But still doesn’t explain the issue since the rings are on the bolt head. I will say though I was having issues with bolt lock on empty mag with both the JP bolts. It seems to be a little better with any other BCG so far.

 

[evilsvt]

Well that's pretty cool, I'm surprised that the little ARC will push them so fast. How's feeding in the Origin? Do you use MDT BR mags?

It’s close to max. It feeds fine out of the BR mags, I have a couple of the .224 poly mags to try out.

 

[lennyo3034]

The issue is that only the carriers were swapped. I was using the same bolt head that was headspaced to the barrel. So it doesn't make any sense to me.

I've had this happen. Have a carrier that causes any rifle its in to shoot like shit. No idea as to why.

I'm not talking making a gun slightly worse either. I'm talking turning a .5 MOA Bartlien barrel rifle to 4 MOA.

 

[Tx_Aggie]

The issue is that only the carriers were swapped. I was using the same bolt head that was headspaced to the barrel. So it doesn't make any sense to me.

I'll second the suggestion by @357Max to double check gas tube alignment with the gas key. If the JP carriers have a tighter internal diameter on the gas key (and they likely do because they're intended to run with reduced gas drive), and your gas tube is slightly out of alignment, the interference may be inducing some stress on the barrel. That can really mess with barrel harmonics because not only is the barrel no longer free-floated, it's probably stressed a little differently every time the rifle cycles.

Or you could have an out of spec carrier that won't play well with any upper.

Service rifle gunsmiths routinely spend some time bending gas tubes to ensure perfect alignment when assembling an upper.

Over time interference between a gas key and gas tube will cause the tube to wear on the edge doing most of the rubbing.

A cheapo BCG/Carrier might have a key machined loosely enough that you'd never notice a slightly misaligned gas tube.

 

[rpoL98]

I've had this happen. Have a carrier that causes any rifle its in to shoot like shit. No idea as to why.

I'm not talking making a gun slightly worse either. I'm talking turning a .5 MOA Bartlien barrel rifle to 4 MOA.

maybe the carrier has sloppier tolerances? more clearance between the carrier rails and the receiver bore? or the carrier bore is out of whack? not concentric, colinear with barrel bore axis? or the hole at the back of the carrier that the bolt tail rides in is wallered out, or otherwise out of spec? something is out of whack, and is causing inconsistent lockup. there's a lot of dimensions that need to be aligned correctly for good results. just my guess.

 

[JKGTR]

I've had this happen. Have a carrier that causes any rifle its in to shoot like shit. No idea as to why.

I'm not talking making a gun slightly worse either. I'm talking turning a .5 MOA Bartlien barrel rifle to 4 MOA.

This is kind of what I was experiencing. I went through three different barrels, currently on my 3rd which is the x caliber. Was seeing awful groups. Makes me think there was never anything wrong with the barrels to begin with and most likely the BCGs. I find it strange that there’s not much data out there as to what causes this.

 

[JKGTR]

I'll second the suggestion by @357Max to double check gas tube alignment with the gas key. If the JP carriers have a tighter internal diameter on the gas key (and they likely do because they're intended to run with reduced gas drive), and your gas tube is slightly out of alignment, the interference may be inducing some stress on the barrel. That can really mess with barrel harmonics because not only is the barrel no longer free-floated, it's probably stressed a little differently every time the rifle cycles.

Or you could have an out of spec carrier that won't play well with any upper.

Service rifle gunsmiths routinely spend some time bending gas tubes to ensure perfect alignment when assembling an upper.

Over time interference between a gas key and gas tube will cause the tube to wear on the edge doing most of the rubbing.

A cheapo BCG/Carrier might have a key machined loosely enough that you'd never notice a slightly misaligned gas tube.

Interesting thoughts, and I will look further into this. However it was happening with two different JP bolts so I don’t think it was out of spec tolerance related.

 

[2aBaC̶a̶]

soo many moving parts in a gas gun. guess before you condemn a rifle as a bad shooter one needs to try a different bolts and or carriers. this is why bolt actions rule the accuracy game. less moving parts = more consistency.

so what BCG combo worked the best for the X barrel?

 

[Tx_Aggie]

Interesting thoughts, and I will look further into this. However it was happening with two different JP bolts so I don’t think it was out of spec tolerance related.

A shorter way of saying what I meant - if the gas tube is off center when it enters the upper, it will bind in the gas key, inducing stress in the barrel, making the rifle shoot fliers and larger groups. If a specific brand of carrier were to use a gas key with a smaller (tighter) bore, it would make this worse.

Also, for reference:

This is a bolt:

This is a Carrier:

A bolt + carrier, firing pin, cam pin, etc. makes a BCG.

 

[JKGTR]

soo many moving parts in a gas gun. guess before you condemn a rifle as a bad shooter one needs to try a different bolts and or carriers. this is why bolt actions rule the accuracy game. less moving parts = more consistency.

so what BCG combo worked the best for the X barrel?

So far my friends ZeroFail BCG has had the best results. I currently have a Lantac in there.

 

[rpoL98]

so, just to get this straight, JP bolt, and LANTAC carrier. and when you swap the carrier with your friends' ZeroFail carrier, keeping the JP bolt, you get better results?

 

[JKGTR]

so, just to get this straight, JP bolt, and LANTAC carrier. and when you swap the carrier with your friends' ZeroFail carrier, keeping the JP bolt, you get better results?

Originally was JP bolt and carrier... But yes, that is accurate.

 

[JKGTR]

Found a bit of literature on the whole gas tube alignment issue.

Gas tube alignment: Proper gas tube alignment in the AR-15 leads to improved accuracy with fewer fliers. Here's how to improve it. - Free Online Library

Free Online Library: Gas tube alignment: Proper gas tube alignment in the AR-15 leads to improved accuracy with fewer fliers. Here's how to improve it.(BENCHWORK) by "American Gunsmith"; Sports, sporting goods and toys industry Sport, sporting goods and toys industry

www.thefreelibrary.com

Though not sure how I feel about smacking my gas tube with a hammer/screwdriver.

 

[TheOE800]

Though not sure how I feel about smacking my gas tube with a hammer/screwdriver.

Michiguns Ltd. - AR-15 Tools and Accessories

 

[Yondering]

So far my friends ZeroFail BCG has had the best results. I currently have a Lantac in there.

There's another way besides gas tube misalignment that a carrier can stress a barrel and cause accuracy issues - gas keys tend to build up hard fouling inside, which mostly stops right at the end of the gas tube. But gas tubes don't always end at the same spot in every rifle, so if your rifle has a slightly longer gas tube, and you use a carrier from a shorter one, it can jam into the tube on closing and cause some stress in the barrel, as well as inconsistent lockup.

I had this happen with one rifle, and it took me quite a while to figure it out. Reaming the carbon out of the gas key solved it though.

 

[JKGTR]

There's another way besides gas tube misalignment that a carrier can stress a barrel and cause accuracy issues - gas keys tend to build up hard fouling inside, which mostly stops right at the end of the gas tube. But gas tubes don't always end at the same spot in every rifle, so if your rifle has a slightly longer gas tube, and you use a carrier from a shorter one, it can jam into the tube on closing and cause some stress in the barrel, as well as inconsistent lockup.

I had this happen with one rifle, and it took me quite a while to figure it out. Reaming the carbon out of the gas key solved it though.

Good info. But in my case these were all fairly new parts, and I have less than 100 rounds through the gun in total.

 

[Elite_KG]

I have all the parts in had for a custom build. Got a CLE Bartlein SDM fluted in 18” rifle. V-seven hand-matched upper and lower (tightest Ive ever handled). Toolcraft bolt carrier and Jp bolt. Fortis butt-stock on V- seven buffer tube. Gonaa either get a TT diamond or stone-out and reprofile a mil-spec trigger to hit 3-3.5 lbs (made several this way). Not sure about Optic. Start with my old trust SWFA HD 5-20x50 and maybe run my thermal for a bit.

Waiting on time and stencil to lay a custom Cerakote paint scheme. Hopefully this ine shoots as I sold one of my match grade barreled 6.8 SPC to fun the build. Still got my old trust 18” 6.8 hanging around.

 

[Tx_Aggie]

Michiguns Ltd. - AR-15 Tools and Accessories

That's the tool I've used in the past. Works great!

 

[ormandj]

What magazines have people settled on as being best? I’m still using my CPD Duramags (working fine thus far) but am about to buy a few more so was curious if people had better options now.

 

[Elite_KG]

I would also like to know about mags. Buikding a precision AR in 6 ARC. Coming from 6.8 SPC and 224 Valkyrie. Has no issues with my 6.8 mags. Thought I read somewhere the 6.8 mags were working for 6.5 Grendel and 6 ARC in some cases. I haven't bought mags yet, but i have all the rifle parts.

 

[Bantam1]

I have been running both the ASC and Duramags with zero issues.

 

[iOdysseus]

I’m curious about mags as well, looking to grab some before the “high cap” mag ban in WA. Mainly looking for 17-20 rd mags.

 

[Tx_Aggie]

What magazines have people settled on as being best? I’m still using my CPD Duramags (working fine thus far) but am about to buy a few more so was curious if people had better options now.

My ASC 6ARC mags have run 100% perfectly.

 

[mrtoyz]

My ASC 6ARC mags have run 100% perfectly.

Does anyone make a reliable mag with larger capacity? 20+

 

[sam4886]

I’m curious about mags as well, looking to grab some before the “high cap” mag ban in WA. Mainly looking for 17-20 rd mags.

I'm also in wa. I was only using the PRI mags because they give you a tad more OAL potential, but ordered a few duramags because of the ban. I've tired them and the elanders a bit and they both seem to work fine. Had terrible luck with ASC so didn't try any of the higher capacity ones.

Favorites in order go PRI, duramag, elander

 

[iOdysseus]

I was curious about the PRI mags. Saw them mentioned in a couple of threads about seeing if they ran, but there was never any follow up. Thanks