AR different upper and lower

[ruarch]

Hi Y'all,

I'm new to the AR platform. Is it considered a good idea to have an upper and lower made by different manufacturers? Seems to me you could run into compatibility issues...

Thanks

 

[jmartinroe]

I am guessing you are talking about AR15s.
Should be ok, as long as "mil Spec"
I didn't have one that wouldn't fit together.

 

[hikingthehills]

Unless it's a Rock River AR-10 and maybe a couple of others that have proprietary upper and lower sets you shouldn't have any problems. They're all pretty much interchangeable.

 

[BIKER13]

Yes stick with mil spec in case you are on a battlefield in North Georgia and need to swap out one

 

[roydamnmercer]

It’s no so simple. Generally, the answer is yes but the buffer tube on the lower may have a buffer with an “incompatible” weight with the gas system on an upper. So, as long as…
1) the pins fit (ie older Colt’s had larger pins) and
2) you’re using the proper weight buffer respectively compatible with either a carbine, mid-length, or a rifle length gas system, you’ll be fine. Hell, even if they aren’t, you’ll “probably” be fine anyway…but learn your rifle. In other words, it may fit and it may function just fine, but it also may cycle a bit finicky. I used to swap uppers and lowers all the time regardless of gas systems and never had issues…but I also use to never wear a seatbelt either back in the 80’s so…

 

[Reloadhby]

I do it all the time, I just put an accurizing wedge in the lower

 

[BLIP]

I do it all the time, I just put an accurizing wedge in the lower

Is that wedge something you pull off the shelf somewhere? Or is it some kind of sized washer

 

[Reloadhby]

UTG Accurizing Wedge AR-15

The UTG AR-15 accurizing wedge will improve upper and lower fit, and improve accuracy. The wedge is placed in the lower receiver beneath the rear...

www.midwayusa.com

 

[Reloadhby]

it helps it fit tighter in case the upper and lower are not perfectly matched