Hi.  New to the forum and new to the AR-15, though not new to the M-16.  I've been shooting as long as I can remember, reloading for a long time, but not as seriously as I ought.  Now that I'm retired, I have time to do all those things more seriously.  I've been sitting on a stripped lower for quite a while and thinking about what to do with it.  I got excited about the Valkyrie but waited long enough to see that it wasn't the end of all things.  Then the 6mm ARC came along and I jumped.  I've built a 6mm on a conventional lower with an Aero Precision upper and BA barrel.  Happy to be here to follow the progress of others experience with this new cartridge and learn from all the wisdom you have to share.

I've been a tad nervous about barrel life since Whitley came on here and said that his customers would generally send uppers in for rebarreling around 3k.

Anyways, I'm trying to figure out some issues where my 95 grain TMKs magically disappear at around 600 yards if the wind is blowing with the theory that they may be destabilizing at that threshold and tumbling or helicoptering into oblivion. Kind of sucks when your spot on to the low 500s and then neither you or the spotter can see any sort of impact on or off the target at 625 on the 5th target of a hit to move on stage. Called Sierra this morning and that of course isn't possible with one of their bullets. The tech theorized that maybe my barrel was shot out and the throat was shredding the jacket and that 600 yards is where the issue is manifesting itself. I'm not anal about keeping round counts and my guess is that it's in the low 2ks. 

So I went to the local reloading supply shop and purveyor of $100 bricks of primers (they had Federal Small Pistol Match today!) to buy some JB Bore Paste. Never used it before because it scares the crap out of me and told the son my problem. He said Dad can borescope it for $5 if he's around. Dad was around so I ran home to get my upper. He said it looked pretty good - a little bit of firecracking in the throat but that it wasn't bad and that there was certainly nothing that could damage a jacket and it had plenty of life left. I asked "at least 1k rounds?" and he said most certainly - at a very bare minimum. This shop services a bench rest crowd who are ready to convert their Bartleins to tomato stakes faster than anyone, so that left me feeling pretty good. Maybe the 5k some theorize is correct - I'm certainly feeling like 4k is achievable. And it sees it's share of rapid fire with 15 -20 going down the tube at Hornady max charge in 90 seconds.

The bad news is that the 16" Six Sigma Lilja 6ARC barrel that will be the 243 LBC's replacement is going to have to wait patiently in the back corner of the closet a little longer than I thought. I'm glad I had it cerakoted Patriot Brown to go with GiGi's FDE scheme. Otherwise i'd be tempted to cobble together another AR that I don't need......

The tan one has a 16" Proof CF wrapped barrel and the black one has a 20" Faxon heavy fluted barrel. I have had the tan one together and shooting since NOV. I got the black one together several weeks ago but haven't had a chance to shoot it because of work and weather. That will change this afternoon.

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UPS guy dropped my upper off today, Uintah told me it would be 5 to 6 weeks so they could build it and get it shipped out. It only took them 17 days to have it at my door. That's pretty good turn around in my book during these times of civil unrest.

The first thing I did to it was stripped it down and removed the barrel so I could remove the Durakote from the barrel. I am going to have the bolt and barrel Nitrided after it is broke in so the Durakote had to go. I used a wire wheel on a cordless drill and followed up with 1000 and 1500 grit wet sanding and it came out with a polished look.

Barrel fit to the upper was an interference fit and was quite snug, had to heat the upper to remove and reinstall tapping it lightly with a non marring hammer.

Then I bore scoped the barrel and gave it a good cleaning, they fired a few rounds through it as it was pretty dirty with carbon fouling and a little bit of copper. Next I will blueprint it with all the chamber measurements so I can load up some precision rounds. Also got myself a new induction annealer so I can get proper neck tension.

I have not received my lower from them yet but I used another that I have. It has an MBT2 trigger in it and it seems to work just fine, but they sent a Velocity 3 lb single stage with the upper.

If the weather cooperates I might get to the range on Sunday.

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I am an old guy who still enjoys the shooting sports. I read a lot and have a great interest in ballistics and what makes bullets fly better. From all my research I believe that the new 6mmARC is a superior cartridge in the AR15 platform. I hope to live long enough to purchase  the ammo as I cannot find any for sale on the planet. NO, I have not purchased a upper or bolt gun yet because there is no ammo with which to shoot it.  

Just spent the morning breaking in my new ARC!  Very pleased with its performance.  Only problem I have is that I’m new to the AR and I’m trying to be as fastidious as reasonable. Unfortunately, no one seems to be producing a chamber brush for the ARC, nor for the Grendel.  What are folks using?

Received the new Monster 20" 6 Arc barrel, it is a beauty (SND but still plenty good lookin!).
I have it assembled in a spare upper and set up on the existing 6 Arc lower, hope to do the break in routine this weekend.
The handguard is a generic (Matrix arms) and the "black" doesn't match the black of the aero upper, but all in all the critters in the woods won't be close enough to notice!!

I haven't seen a 6 or 6.5mm RDF for sale in at least 6 months. 0.280 G7 BC included.

https://www.grafs.com/retail/catalog/pro...ctId/74115

Note - these are about 1.26" long and I've found they work best 0.03" off the lands in other calibers. I don't know if a long throated barrel will present a problem.

Hi Gents,
I just got the email that my backordered PR 18" 6mm ARC barrel is on the way from Midway.  For anyone interested I checked the website and it appears they still have some in stock.

Pricy but they are a premium, cut rifled barrel.  My 6.5 Grendel PR barrel would shoot most anything MOA or better.  Hopefully their ARC barrel will be the same.

Hurry. They had 26. 11 left after I got to them. $20.30/100
https://www.outdoorlimited.com/featured-...00-pieces/