Building a 6.8 upper assembly

[Robin]

I have a 6.8 and after a lot of thought I decided to put my money into building an upper assembly rather than going for an AR-10 in .308, been chewing on this for a long time, it feels like a relief to have finally made up my mind. Now that I'm reloading again I want to see what kind of performance I can get from this cartridge and end up with a very accurate deer rifle that will give me hours and hours of fun at the range as well.
I know absolutely nothing about what I need, and how it is done so any and all help will be greatly appreciated.
I want to make it left handed and side charging, this eliminates quite a few options already, Seems there are two places that offer them, GIBBZARMS and Rainier Arms. Are they good outfits?. I want a 20"-24" barrel, which means it probably has to be stainless, which hurts my old school affinities, hah! Anderson Manufacturing makes a 24" fluted, stainless, 416R barrel. Are the considered to be really good barrels?
Well, its a start, is there a good book on the market for this?
Robin

 

[ManrisFrack]

Left side charging uppers are out there but they get expensive pretty quick. Eisenach Arms lists an ETA of 1/15/18 for theirs. Then there's American Spirit Arms and the Matrix one that Rainier sells and the similar Gibbz. Bear Creek has a left charge, left eject upper that's probably the cheapest you'll find but I don't know where you're gonna find a 6.8 bolt set up for left ejection. I've always thought you could mill a slot in a regular forged upper, buy a charging knob from someone like Eisenach Arms and drill and tap the carrier. Probably not that simple though, cause no one sells one anymore.

That Andersen is probably the cheapest 6.8 barrel you're gonna get that's even close to that length. I have no idea what the quality is. Other options are AR15 Performance (out of stock on 20" and no TC but seems to be one of the few non-stainless options), Wilson Combat (18" is the longest, can get coated with "Armor-Tuff"), Bison Armory (20 or 22", can be coated and ordered with TC), Satern (20" "Liberty" with no coating and no TC but does include a matched bolt in the price), and Black Hole/Columbia River Arms (Stainless but the most configuration options of the bunch). All my AR barrels are ARP and I like them. Wilson, Bison and Satern have good reputations. Black Hole seems a little hit and miss - I know @meketrefe wasn't impressed with them.

You absolutely need some way to hold the barrel or upper when you torque the barrel nut on. There is the Giessle reaction rod or a barrel vise if you want hold the extension/barrel and there are a bunch of different clamping blocks for the upper. I use No-Mar vise blocks.

Install the ejection port door before the barrel nut. It's not usually a necessity but it's easier.

Many people use blue loctite on the OD of the extension to take up any play between the receiver and the extension. It's not necessary if you don't want to.

Many also lap the very front of the receiver (the bearing surface that seats against the extension's shoulder) so it's square to the axis of the receiver. Again, not a must - your choice.

The wrench used to torque the barrel on depends on the free-float tube you pick. Several of them will have proprietary barrel nuts. Usually they provide a wrench if it isn't standard. Wrenches for standard barrel nuts are widely available. Grease the threads before you torque. Tighten, then back off before final torquing. If I remember correctly, it's 35ft-lbs min and then whatever extra so that the gas tube can be slid into the four-leaf clover at the top of the receiver without touching the barrel nut.

I'm sure YouTube can show you start to finish 1000 times over. It'll be child's play for you.

 

[Robin]

Thank you Manris!!!
Robin

 

[JamieZ]

18 inch is the optimal length for a 6.8 barrel. You won't gain jack shit with a 24 inch barrel compared to an 18, except for weight. I have a 16 and a 14.7.

As far as manufactures, you could get lucky with the Anderson but they seem to make the cheapest AR parts out there. I dont own one of their barrels but do have one of their uppers and one of their lowers,,,those are decent. The barrel Im using is a Wilson Combat. I personally would look at Black Hole Weaponry, ARP, Wilson Combat. I would say Lilja, which I would of bought like I did for my other builds but they dont make one.

As far as tools to put it together, take a day and drive up here with your 4 wheeler in tow. I have the tools and have a shit ton of places to ride 1 min from my house.

What size bullets are you using in the one you have now? Are you reloading? I have a bunch of 90gr Sierra hollow points loaded up but loade up some 100gr accubonds for Deer season. Shot a Doe with one. First shot at the Doe while it was on the run at 175yds, deer dropped but got back up. So then I unloaded the other 4 at it. It dropped at about 200yds +. Went over to it and soon realised that the other 4 shots I took,,,,missed on every single one.

 

[Robin]

I didn't realize that 18" was a maximum effective length. There is a lot I don't know having immersed myself in primitive archery and muzzleloading for so many years. Thank you, these things may seem second nature to you guys but its new technology to me.
Years ago I belonged to a huge gun club and the rifle range was full of young guys with AR's, and me with my muzzleloaders. They were always very nice young men, excited to share their interest with the old guy, many times offering me a opportunity to run through a magazine or two. Now I never mentioned that I had probably fire thousands of rounds through similar guns and many on full auto. I would humbly accept their offer and fire off however many they had loaded up for me. I found out something very interesting in that after all those years, these guns are just as much fun to shoot as they were decades ago!!! I went ahead and bought one, in 6.8 SPC II, I never did like the .223. I am getting up to speed reading as much as I have time for but the lessons learned on this site are the best!!!
Jamie, right now I'm loading sierra pro-hunters, 110 gr. and took my first ever deer with a centerfire rifle this year using it. About 120 yards, hit exactly where I aimed and it went about 80-100 yards. I got gifted 1000, 115 gr., ball ammo, bullets and will be using them up in my reloading this winter. I may just take you up on your offer, and while I haven't tools to offer, I do have miles of ATV trails right out the back door, so you got a standing offer. Thank you for the sourcing!!!!
Robin