6MM ARC teething problems update

[Canuckienns]

A while back I started a thread about cycling problems with my new 6v ARC build. Long time Ar builder here, done many many 15's 10's. I was having problems with a rifle +2 length gas system. Not ejecting and not locking back with any combination of buffer weights and springs adjustable gas wide open. JP high dollar hi pressure bolt in a Fail Zero NB carrier.
Solution at that time was to open up the gas port. That being done it cycled barely.
Turns out that part of the problem was the JP bolt. It was a loose fit in the FZ carrier. JP used a one piece piston ring set up.
I tried a new Palmetto State arms carrier that I had in my spares and the rings seems to engage somewhat better, and kind of cycled better when it got a little fowled up.
I had a new NB bolt carrier from Tool Craft so I put the JP bolt into the new carrier and it was a sloppy fit. The one piece piston ring was not doing anything.
I had a few sets of individual piston rings that I hardly ever get to replace for people and replaced the JP one piece ring with three standard piston ring sections. Now I had a nice snug fit.
Rifle cycles and ejects well and I added a new H3 buffer weight and starting to tune the gas system again.
Always something new??!!!

 

[David Milisock]

A while back I started a thread about cycling problems with my new 6v ARC build. Long time Ar builder here, done many many 15's 10's. I was having problems with a rifle +2 length gas system. Not ejecting and not locking back with any combination of buffer weights and springs adjustable gas wide open. JP high dollar hi pressure bolt in a Fail Zero NB carrier.
Solution at that time was to open up the gas port. That being done it cycled barely.
Turns out that part of the problem was the JP bolt. It was a loose fit in the FZ carrier. JP used a one piece piston ring set up.
I tried a new Palmetto State arms carrier that I had in my spares and the rings seems to engage somewhat better, and kind of cycled better when it got a little fowled up.
I had a new NB bolt carrier from Tool Craft so I put the JP bolt into the new carrier and it was a sloppy fit. The one piece piston ring was not doing anything.
I had a few sets of individual piston rings that I hardly ever get to replace for people and replaced the JP one piece ring with three standard piston ring sections. Now I had a nice snug fit.
Rifle cycles and ejects well and I added a new H3 buffer weight and starting to tune the gas system again.
Always something new??!!!

Early on I read several posts on different forums with people having issues with AR builds in 6MM ARC. Can I assume the +2 rifle length gas system was done to reduce pressure at the port, or does the +2 has system has a larger port for more gas? Obviously I don't build rifles.

The most things I've seen reported were fractured bolts, in every case if I could get enough information I found that there were specific things that the builder and or reloader did.

A build that changed the timing of the cycle, ergo pressure on the bolt lugs during extraction (non standard weight bolts and lighter recoil springs). Reloaders that pushed the limits on pressure with faster powders for the cartridge. I'm interested to see how your gas system fares.

I have zero interest in building AR rifles myself but I'm progressing into reloading an inventory of 103 grain hunting rounds for my 6ARC.

I'm amazed at the varied quality of AR's on the market, therefore the very poor market for used AR's. I have 2, both essentially factory rifles, a Colt 20" A2 and an Aero Precision 16" M4E1, (a complete Aero upper from Brownells and an Aero lower), with the right ammo both shoot sub minute of angle. At tge ranges I attend and on many internet sites 2" 100 yard groups seems to be acceptable. YUCK!

AR's are like a box of chocolates, you never know what you're going to get!

 

[Canuckienns]

I shot 19/25 8 inch steel plates in the wind and mirage at 627 yards last month. I even had to turn the gas down a bit. Cycling like a champ. I hope to do better in the next steel plate shoot in a couple of weeks.