Hi all

Kind of odd question that I haven't seen much on. Looked through the 15 pages here....

My current build is on a Stag upper and lower (left hand upper). I've seen a few people mention that the mirrored bolt and carrier has the bolt's lugs rotate the opposite direction than a "normal" right handed AR. As such, the leading edge of the corresponding cutouts on RH barrel extensions are beveled for standard rotation, not for mirrored rotation, if that makes sense.

Basically, I'm wondering if I would want to find a barrel with the bevels set up for the opposite rotating Stag action. A LH barrel extension, as it were. It wasn't even something I considered when starting my project. Never built using a mirrored operating system before.

This particular AR will be a 5.56/223 pistol build, with an 11.5 to 12.5" barrel, likely LaRue, BCM or similar. It will primarily run suppressed. Probably a 1-4 or 1-6x variable, though I've considered a T31 ACOG. Not sure if the ballistic drop on the T31 would match up well with a 12" barrel.

Anyway, my primary concern is, do I purchase a regular AR barrel and hope the non-beveled edge on the barrel extension doesn't bind up with Stag's bolt, or are there LH barrels (or even just extensions) that would better mate with the setup?

Thanks for the help.

The difference in the lefty bolt is the orientation of the cam pin and the ejector pin and the opposing extractor. The ejector pin is near 7-8 o'clock as opposed to a righty 4-5 o'clock. Get yourself a "normal" barrel and enjoy yourself.

I have 3 Stag lefty uppers.

One of them has the fsb and A2 style guards and delta ring assembly. If the dust cover pin were to slide forward, the delta ring would act as a stop.

My second Stag has a free float. The pin traveled forward and the handguard is too narrow to stop it. The pin in the lefty Stag has no circ-clip by design.

Remedy after a couple of tries to include a pin with a knurled end:

I purchased and modified (dremel) a polymer Spikes AR Enhanced Ultimate Dust Cover. Due to the lefty cover flipping upward, a small mod was needed for the center section of the cover (where the spring is exposed) to clear the part of the upper which juts out above the ejection port. I believe I used a sharp Xacto to expedite the process. Or, you can simply remove the dust cover if you see that your handguard won't act as a stop.

If you have a slim handguard or no handguard, there's nothing to prevent you from pulling the pin fully out (toward the muzzle). Dumbass design. The Spike's retention design is pure genius imo.  Scroll down to the bottom of the link and see the "mechanics" of the dust cover. https://www.strikeindustries.com/shop/products/ar/upper-parts/ar-enhanced-ultimate-dust-cover-223.html

My 3rd Stags is under construction. I just tried it and I'll need to do the same to it. Hand guard is approx 1/16" too narrow.

Thanks Logan.

I hadn't considered the ejection port cover. Good to know.

Good info
Almost done with a LH build on a stag upper.

With this 3rd build, I'm seriously considering cleaning the dust cover pin stop (butt end of pin) and that length of the pin with alcohol, followed by a small drop of super glue on the end of the pin. Just enough to secure the pin but should be able to remove with needle nose if needed. But then again, that Spike's cover is just so damn smartly designed I may still go that route. If ya'll go with anything other than what I consider a super slim handguard, you should be gtg. The pin must travel a decent distance before it allows the cover to hang down like an out of whack window shade. Otherwise, My 3 Stag lefty uppers are very nice in my opinion. I also have a Gibbz lefty side charger which is just to cool. It too uses the Stag lefty bcg.

I built a couple of them and also have a buddy with one. As previously mentioned the barrels seem to present no issues. I too had to notch a standard dust cover but that was the only "issue" I ever came across in building or shooting.

Have fun

Regular barrels and extensions can work fine with lefty bolts, (usually do).
You could always sand the extension lugs, (round the lefty corners of the extension lugs a bit) to help them fit with a lefty bolt, if there was any binding.

Army gave me one of these with my first M16.

Since they have  built in brass defector on uppers,,  I wouldn't even think of using a left handed AR

It be like driving a right sided steering wheel on a car...

Attached File

Same here. You couldn't pry it from me back then. Had 2 actually. Sure would like to find one.

My first AR was a Rock River lefty I bought in 2012. It had a giant gas block and heavy half-quad rail which was awful. I’ve since changed almost everything.

The upper doesn’t have the dumb Stag cover that flips up into your optic. It’s a much better reciever set IMO and despite the RR website saying it’s not compatible with normal righty mil-spec parts, it is.

For any future lefty builds, I highly recommend the RR receiver sets. Toolcraft makes lefty BCGs and I’ve never had a problem getting any parts.

My current left handed AR is running a FN barrel and it works fine with the normal barrel extension. Before that I had a White Oak Armory SPR barrel with an ambi barrel extension and it I honestly can't tell a difference between that barrel extension and the normal one on the FN.

Had no idea they did lefties. I really like the cover flipping down. If I do another I'll likely go that route. Thanks.

Never gave much thought to that; actually no thought. As I reflect, I have noticed when installing a lefty bolt and charging handle, there's a little resistance when fully sending the bolt "home". Same if slowly walking the bolt home. Otherwise, you would never know it.