Lower recommendations for AR-57

[AshWilliams]

I have a friend that asked me for a lower recommendation for an AR-57 build that leverages top loading P90 mags, so being out of my element as an AK guy who also has ARs that were bought in their entirety, I decided to consult the omniscient god-like firearm knowledge here. He wants to "... buy it once and buy it right."

So my fellow NWF compatriots, what say you?

Read More

 

[Will_White]

Any milspec lower will work, if he wants a complete lower I'm partial to the KE arms KP15.

 

[Stomper]

+1 on any MILSPEC lower... the empty mag well becomes the "ejection port" (more like an ejection "chute")....

 

[AshWilliams]

Thank you. I'll be proxying his questions in this thread.

 

[Bolt_308]

If he wants ambi, the Griffin Mk2 lower is the new cheese wiz. It is very reasonably priced, and has the same exact ambi controls as the much more expensive ADM, of which I bought that before Griffin came out with theirs (they partnered on the design). IMO it is worth it:

MK2 Ambi Stripped Lower Receiver

The new Griffin MK2 ambidextrous stripped lower receiver for ar-15 rifles

www.griffinarmament.com

 

[lucusloc]

Your probably going to want a dedicated lower for it. Tuning the AR-57 upper can be a challenge, and whatever you change on the lower (heavier buffer weight, heavier spring) may not work well with other uppers.

Also it needs a stock profile bolt catch. Many enhanced/oversized catches will not fit in the recess intended for it.

Past that any standard spec lower should work.

Keep in mind that the earlier generations had the possibility for an OOB issue that could rapidly disassemble your magazine/upper. The newest generation does not have that problem. This is only a concern if you are buying used or new-old stock. New-new stock should be the gen3/4* version that fixes that problem.

If you want to save your brass get an old mag body sans all the guts and file off the feed lips. You can seat that into the mag well and capture all the brass.

I am still tuning mine to get it to run suppressed, but I did not have a heavy enough buffer on hand. I just ordered the heaviest I could find online, but have yet to test it to see if it slowed the bolt velocity down enough to keep it from ripping off the case head. If you are not trying to run suppressed you probably only need a standard heavy buffer, but they do seem to be recommended as a general starting point for tuning.

*Generation numbering for the AR-57 is all fubar due to having multiple manufacturers who have owned the design. The current manufacturer lists the latest model as the gen 2, but that is just the second generation for them. In reality it is about the 4th revision of the design I can track down available on the market, depending on how you want to count things. Pint being steer clear of the early revisions, they have some less than desirable "features."