DIY AR10's

[Kyohte]

Ammunition selection should play a larger role in AR-10/7.62 NATO firearm choicemaking than it seems to. KAC makes the nicest AR-10, but you'll extract maximum value from that KAC SR-25 by shooting FGMM or similar. If you've got a pile of M80 and your mission is to blast steel out to 600 using irons, the SR-25 is a premium option, but perhaps not an ideal fit.

Honestly, M80 is for M14s and FALs. I wouldn’t buy or build a modern large-frame AR with the expectation of getting any good results out of M80 ball. Its external and terminal ballistics are pretty much inferior to similarly priced 5.56.


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[rpoL98]

I built up an Aero .308 and have shot a KAC. I wish I just saved up some more money for the KAC and gone that route. I will just have to find a 16” barrel with a rifle gas length system for the Aero. The KAC is just a soft shooter.

not only the barrel, but if you really want to duplicate the KAC characteristics as closely as possible, you should research the gas port dia, the buffer weight, and find out what kind of buffer spring (i.e. equiv aftermarket spring). also, muzzle brake, if any. barrel length & gas length is only part of the equation.

[Firefly]

The problem with rifle length 16" 308 barrels is that they are not at all easy to make. I had to get my cheater barrel specc'd just so because I kept hearing "Dwell Time" over the phone.

It's an ancient Chinese art and everybody gotta know their part. mine turned out okay but I paid for it money wise.

IIRC not even LMT uses a true rifle length gas 16" and they don't have to. To be fair, done properly it really does mitigate recoil. Coupled with a MAMS even moreso. I just want the QDC on my M110K1 solely to eke out more accuracy.

[ABNAK]

Without Googling, is there a decent chrome lined 18" or 20" barrel out there? One that could interchange with another brand's upper? (or is that a weakness of 7.62 AR's, i.e. not compatible?).

[Firefly]

Short answer is yes. Price varies. I'd point people to Rock Creek, Criterion, Faxon, BA, or Noveske.(in no order)

I'd also say that Chrome Lined is sorta unnecessary unless you just wanna shoot dirty surplus ammo all day long and not be too anal on sub MOA accuracy.

The compatibility really was Armalite had a different receiver for M14 magazines. most current barrels which are non-proprietary will be compatible.

[36trap]

Criterion makes a 16" rifle gas 308 barrel. I have one on my Maten.

I have one of those barrels in my Armalite. Converted the barrel / bolt to DPMS pattern.

[Danus ex]

Honestly, M80 is for M14s and FALs. I wouldn’t buy or build a modern large-frame AR with the expectation of getting any good results out of M80 ball. Its external and terminal ballistics are pretty much inferior to similarly priced 5.56.

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Exactly! There's always that guy who expects sub MOA slinging Wolf FMJ and Syrian surplus out of his LMT MWS.

I own most available semiautomatic 7.62 NATO models and they pretty much divide into two groups: those that shoot M80 well but shoot M118 types better, and those clearly meant for M118 and beyond. The FAL might be the only exception—I've never had one shoot FGMM any better than M80.

[dlrflyer]

I’m new to building in general, and especially Ar10’s, however I did manage to grab a couple of the Mega sets from JSE before they were all gone. While I can appreciate a built gun, and have 3 different ones, I don’t know that I’d like a factory 6.5, because the barrel life is, at best, half of a 308 and KAC wants too much to rebarrel on a regular basis. I’m still trying to figure where I am going with the 6.5, either straight on replacement for a 308 16”, or strictly long range. I’m leaning towards the latter given the price I can get for quality 308 ammo to use in high volume carbine, either way, building using the Mega receiver sets allows for very easy barrel replacement.

[mark5pt56]

dirfiyr, I would look at how you are going to use the gun? Consider ranges it will be shot at and intended use. In my opinion, there's not much advantage inside of 600 or so between the two, slight recoil difference, huge barrel life difference. Ballistically, past that yes the 6.5 has an advantage. Be careful about a "do all" rifle, although a 16-18" .308 or 18-20" for a 6.5 would work well within typical ranges you may use it in.

Hope that helps. Oh and I'm asleep at the wheel, this has to go to "beyond 5.56"