Coworkers and building .308 ARs...

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Coworkers and building .308 ARs...

Postby Archer » 30 Dec 2022 21:58

There's been a lot of turnover, layoffs, and so forth at my company over the last few years. Contracts, Covid, Internal Research and Development, Proposals etc.. I've been out a couple times and back. Early in 2021 I demonstrated my first Aeroprecision M5 .308 w/ Rainier Select barrel to one of my coworkers as well as my .223 Wylde AR-15 w/ White Oak barrel to a few of my coworkers. As it happened this was immediately before a layoff cycle.

A few months later I was asked to work on another effort and got pulled into several other projects in various capacities. After about a year they brought back another engineer who'd been on staff and had purchased a different kind of business in the interim. He came back and asked me to build him a .308 AR similar to the one he'd shot of mine. We went through the parts required and he'd gotten 'permission' from his wife to spend a substantial amount on the gun. He planned to rack up the parts over Black Friday and take advantage of any sales or cuts in price. This was a plus to me in terms of his purchasing the parts wouldn't be on my dime waiting on reimbursement, although there's always the possibility that he might not get compatible or correct parts. He purchased a scope that was on pretty good sale about a month ahead of Thanksgiving with the approval of his wife.

Come Thanksgiving break he was just getting started on buying parts starting with a LaRue MBT-2S when his wife looking over his shoulder asks what he's up to? When he replies 'Buying parts for my rifle!' she blows up. Apparently she thought he was buying a commercial rifle already assembled and not some shoddy collection of parts... Basically ruined the holiday atmosphere according to my friend.

His rifle is currently on hold. He's got a scope. He wants to use a barrel I've offered to sell him and may want to pick up a set of rings from me as well.
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Re: Coworkers and building .308 ARs...

Postby Archer » 30 Dec 2022 22:23

Meanwhile, the guy I bought the Browning BAR .300 Win Mag from was planning on putting that money toward either a bolt action .308 or a .308 AR. He was expecting a second munchkin and sold the BAR the weekend before the wife was going in to induce so in the excitement of the moment he misplaced the funds for a little while but managed to find them eventually.

He wound up deciding on the .308 AR. NO the BAR sale didn't come close to covering the cost of the new rifle but every little bit does help...

I offered to help and he took a few notes but elected to go mostly on his own.
He purchased parts at a semi-local shop.
Aero M5 receiver set and handguard. BCG. probably Aero lower parts kit. Unitized trigger that the shop had on sale. Magpul carbine stock.
Picked up the barrel from me. (No dimple on the barrel.)
Picked up a generic Armorer's wrench at the shop.

He assembled the gun on his own. No torque wrench for the barrel nut. He didn't dimple the barrel for the gas block but said he thought the block had cup point set screws that should have set into the barrel metal.

After he assembled it he asked a few questions about the recoil system. I mentioned the .308 carbine buffers were shorter than the ones for the AR-15s unless he was using an A5/Armalite AR10 style extension. He said he had a heavy buffer but it looked identical to the AR-15 buffers he was used to. He said it cycled by hand fine.

After the Christmas holiday we talked again and he said he was having some teething problems.
The gun fired ok but would not pick up a second round automatically.
He could cycle it by hand for the second and subsequent shots but the gun would not automatically pick up the next round. After the range session he found his handguard was a bit loose. Turns out it wasn't the handguard so much as it was the barrel nut. He thought he had enough torque on it but he hadn't 'seasoned' the threads by tightening and loosening the nut three or so times before torquing it up for the real deal. That and not having a torque wrench to ensure he had at least a minimum torque on it was a mistake.

He took my advice on getting a new CAR-10 buffer. Wound up getting a new recoil spring at the same time. He said that solved his bolt catch issues.

I ended up loaning him a dimpling jig. That's a rarity as I usually come with any tools I loan.
Offered to help him torque up the barrel nut.

We'll see how things turn out.
I've bought a few tools over the years to make putting ARs together easier and make it more certain the job gets done right the first time. I had a pretty good couple of mentors who taught me basic techniques. I recall one of the issues I had learning from someone who KNEW what they were doing was getting them to slow down enough to follow what they were doing since they almost did it by feel. Books and articles from experienced/professional builders have been very helpful.

I still learn something from time to time as I'm putting one together.
It's interesting to watch other people and their learning experience.
Sometimes it's a good thing to do that from a distance.
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Re: Coworkers and building .308 ARs...

Postby Archer » 30 Jan 2023 22:34

He's asked for me to torque and align the barrel nut. Factory spec on this Aero Precision handguard is 65 ft-lbs. He also wants me to dimple the barrel for the gas block. Seems he was tightening it in a padded vise without any other fixture and without a torque wrench. German ghuddentight was only enough to twist the upper out of the padded jaws and scratch up the picatinny enough to need some needle file to clean it up.

Initially my 308 reaction rods would not go in the barrel extension until I got the barrel out of the receiver and lined it up on the tool. It came with a set of shims. He'd applied one but it wasn't in the right spot. Didn't grease the receiver threads.

I have a sneaking suspicion this one is going to be a bit of a pain.
I may need the big boy vise for this one.
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Re: Coworkers and building .308 ARs...

Postby Archer » 05 Feb 2023 16:58

Got the barrel nut torqued up where it ought to be good to go.
Barely got a dimple on the barrel, small. Very had steel to drill.

I usually like Aero Precision stuff. I don't much like this AP M5 barrel nut. It's ok but you REALLY need an armorer's wrench with a lot of pins instead of the standard mil-spec one with 3 or the DPMS wrench with only 2. The Magpul wrench or PRI's wrench that goes all the way around the barrel would be the best choices IMO.
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Re: Coworkers and building .308 ARs...

Postby golfish » 05 Feb 2023 19:50

Good read brother....

I'm with ya on the Aero stuff. They make a good product and the price is right. I switched over a few of my lowers to Aero.
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