Barrel compatibility with different ARs in 308

[svxwilson]

I have 2 different 308 ARs, is it possible to swap to a higher end barrel on these guns or am I stuck with using the barrels from the factories in which they originated? I have a Smith and Wesson M&P10 and a Black Rain Ordinance PG15. Both are 18" now. It is my understanding that the 308 style is proprietary to the company it came from
I am interested in 6creed, 260, and 6.5creed should I buy a new barrel or a whole new upper?
Which leads me to the next question I tried to swap the rifles around (the BRO has a much better trigger than the smith) and smith would not fit on the BRO lower and the BRO upper would not work on the smith lower. At least without modifying either upper.
If I were to order a upper from somewhere where is the most recommended and what would I need to do to insure it will all fit together. I am trying to avoid sending the lower to the upper builder due to the amount of time my AR-15 build is taking(I sent my smith M&P15 lower to match it up with a Grendel upper as this was the recommendation from the upper builder).

 

[Flyfishit]

I am curious about compatibility as well. I have a 20" sr25 and want a 16" setup. I want to keep my other upper as it is. Does anyone know what uppers will work on what lowers. I know LMT and Larue but neither are available alone, I have tried to purchase them many times from people selling complete rifles but have not found one. I would like a LMT but it will be a long time before they are releasing uppers only. I can't get an answer from mega, another one I thought might work. I didn't know if anyone has a list or individuals can post what they know to work on what, and maybe the compilation of poeples input can become a resource on this thread for others with this question in the future. Also if anyone has a LMTor KAC upper, please contact me. Thanks, Steven

 

[Paulyr450]

Mega uppers and lowers will only work with mega. Fulton armory and dpms are the same but im not sure about your sw mp10. Im not sure about lmt or larue. You will get a response from the pof lmt larue guys shortly but a bet they havent tried beating them together to fit.

 

[Ballista One]

"AR-10" pattern barrel assemblies are interchangeable as are complete bolt groups but that's where it all ends... Wouldn't changing out the barrel assembly be a more cost effective method for obtaining the barrel configuration you want?

 

[jjrgr21]

you can use whatever barrel you want, but you have to use the corresponding bolt and gas system. Armalite uses a different length tube.

 

[Strykervet]

Your absolute best bet is to call the manufacturers and find out from them what pattern they use. Some folks use DPMS patterns, others something else, still others even more proprietary, such as Larue's OBR. Asking online is good for getting opinions, but for this you kind of want perfect fact, and to be honest, I know very little of both of those rifles mentioned (though I think I've heard good things about Black Hole?).

So if they modeled their rifle after a popular design, particularly the upper and barrel and barrel extension along with the bolt/gas system, then switching to a barrel from the original maker of the design (say it was DPMS) then you could get a barrel from DPMS, or you could order a "DPMS" barrel from a barrel maker of your choice for your rifle patterned on a DPMS.

Basically, if it is patterned on a more popular design, then finding parts is easier and finding aftermarket parts is much easier.

But it all starts with calling the manufacturer, getting someone on the phone that knows this stuff, and asking the right questions. They can usually help you out a lot with regards to what fits and what doesn't, and especially if it is patterned on another AR10. Find out all the parts interchangeability on the phone, get 'em to email a list if they have one.

No matter what you get, you should get plenty of spare parts, bolt or two, springs, pins, etc. just to have on hand. They can get hard to find. Hope that helps. Good luck!