my new project would be a full ambi lower, then lightweight. are ranier arms or arfcom good lowers?
Rainier Arms would get my money first. My interactions both online and in their storefront have been fantastic. Get the 45* BAD ASS too. Great parts!
Of those two I prefer the Rainier, however neither is a true Ambi lower as you can not lock the bolt to the rear with the right side lever.
If you are looking for a true Ambi lower look at the Aero Precision Gen 2 ambi, or the San Tan tactical.
Your gonna come on the M4C and ask if you should get a Barfcom lower?.. Your F’ing with us right??
If your wanting true ambi I’d save up for a KAC SR-15 E3. Once you add up what you spend to make your rifle ambi the KAC will about the same price and a better rifle.
The AP gen 2 Ambi & san tan will lock the bolt back from the right side? I thought the only 2 true ambis were AX556 & LWRC IC lower…
Just train to shoot the RIGHT way, no ambi needed
Yes they will. And you can have a machinist mill any lower for the PDQ lever which will make any lower ambi and able to lock back from the right side.
Figure out which ambi features you actually need/will use. Ambi selectors are awesome (if done right); I have Norgon ambi catches and SR15IWS Lowers, but I tend to just use the normal magazine release anyway. I run BAD levers on my stuff (haven’t encountered issues with them yet) which serves as an adequate ambi bolt manipulation solution, so FWIW just about any lower will do for most purposes with the addition of something like the BAD-CASS and maybe adding an AXTS/BCM Ambi CH.
AXTS, SanTan, and KAC still have some of the best setups if full ambi suite of features is really required, but you could take a ‘boring’ forged Rainier (or AeroPrecision, MEGA, PSA, BCM (Blem/non), Noveske(Chainsaw/non), DanielDefense, LMT, or other) receiver and just run that without issue for less money using a few smartly chosen aftermarket pieces.
I was just asking myself the same question. I ended up going with Rainier’s matched set. I’ll let you know how it is once it comes in.
There are only three fully ambidextrous lowers available on the market right now for 5.56 (most of the brands mentioned in this thread only have a right-side bolt release, not a manual bolt catch):
LWRC M6 IC
AXTS AX556
AP Gen 2 Ambi
As far as the Rainier Arms and ARFCOM variants go, the one from Rainier Arms is a derivative of the Mega GTR-3 lower and the one from ARFCOM is a derivative of the POF P415 lower.
Isnt the arfcom version an exact copy of the magpul lower, just a different logo? Also seems that the ranier lower has a similar frame. Hence the reason i narrowed the two down to my choices.
The Magpul lower is made by POF, just like the ARFCOM one. The Rainier Arms lower is made by Mega.
The form and function of the two are almost identical.
I have a San tan grenade - not quite sure what the blem was. Works quite well.
Take down pin detention spring needed to be clipped due to the addition of sling swivel sockets.
Rainer or KAC lowers. I still think ambi is a gimmick and not really needed
Unless you’re left handed 
However most righties do see the advantage of being able to lock and release the bolt using an ambi colt catch lever.
how is the aero lower true ambi? theres no left side mag release lol
Just like with every lower, you install one from Norgon, Troy, KAC, or a few others. The mag release is the easy part. It’s the right-side bolt stop/release that you can’t just buy and install in 30 seconds…
I shoot lefty and much rather have the conventional layout. its a muscle memory thing
then its not a true ambi lower if you need to install aftermarket parts in it.If we arent calling kac a true ambi lower or rainier a true ambi lower you cant give a pass to aero.A bad lever is no more difficult to install than adding the parts to the mag release on an aero