Andro Corp ACI-15 Partial M4 Lower – Proven 7075 Forged

Description

The Andro Corp ACI-15 Partial M4 Lower is the middle ground between a bare receiver and a finished rifle. You get a serialized 7075 forged AR-15 lower receiver with the fiddly small parts already installed, an A2 grip fitted and a five position buffer tube assembly torqued on, so the only decisions left are your upper, your stock or brace, and whether you keep the mil-spec trigger. The factory catalog entry is Andro Corp Industries ACI15LBP, UPC 736684145415, and MAG5 Firearms has it on the shelf.

What is already done on the Andro Corp ACI-15 Partial M4 Lower

Assembling a lower parts kit is the step that turns most first builds into an afternoon of hunting for a detent spring on the carpet. The Andro Corp ACI-15 Partial M4 Lower skips it. The trigger group, hammer, disconnector, safety selector, magazine release, bolt catch, takedown and pivot pins and their springs and detents are all installed and function checked at the factory.

The receiver on the Andro Corp ACI-15 Partial M4 Lower is 7075 forged aluminum, hard coat anodized black, marked CAL MULTI so it is not tied to one chambering. That multi-caliber marking matters on an Andro Corp ACI-15 Partial M4 Lower because it means you can hang a 5.56 NATO upper on it today and a 300 Blackout or 9mm upper on it later without the rollmark contradicting what you have built.

The five position M4 receiver extension on the Andro Corp ACI-15 Partial M4 Lower is already torqued on with the castle nut staked area and end plate in place. Confirm with us whether your particular unit ships with the buffer and spring inside the tube, because Andro Corp specifies the tube assembly without always itemizing those two parts, and you do not want to discover it missing on build day.

What you still have to buy, and one legal point worth getting right

Three things are missing from the finished picture on this Andro Corp ACI-15 Partial M4 Lower and all three are your choice. A complete upper receiver assembly, a stock or a pistol brace, and possibly the buffer and spring noted above. Nothing else is required to make it run.

That stock or brace decision is not purely cosmetic. A stripped or partial lower that has never been assembled into a complete firearm can legally become either a rifle or a pistol. Once you assemble it as a rifle, turning it into a pistol later is a different question entirely, and the answer depends on current ATF interpretation. Decide which you are building before you buy the upper, and check the current federal guidance and your own state law rather than taking a forum post for it.

The trigger on this Andro Corp ACI-15 Partial M4 Lower is a standard mil-spec unit. It works, it is safe, and it is gritty with a heavy break, which is exactly what mil-spec means. Most people replace it within a year. If you already know you want a flat drop-in trigger, factor that into the budget now rather than treating it as a surprise later.

Andro Corp ACI-15 Partial M4 Lower specifications

• Model: ACI-15 partial lower receiver
• Receiver: 7075 forged aluminum, hard coat anodized black
• Caliber marking: multi-caliber
• Lower parts kit: mil-spec, installed
• Grip: A2, installed
• Receiver extension: mil-spec five position M4 buffer tube assembly, installed
• Stock or brace: not included
• Upper receiver: not included
• Warranty: lifetime
• Part number: ACI15LBP
• UPC: 736684145415

Andro Corp Industries backs this with a lifetime warranty and publishes the component list on the Andro Corp Industries product page. Quote part number ACI15LBP when you order, since Andro Corp also sells a fully stripped version and a complete lower with a stock already on it, and the three are easy to confuse. If you decide partway through that you would rather skip the build, the ACI-15 Bravo 16 in 5.56 is the finished rifle this lower is meant to become, and the rest of our in stock firearms are worth a look.

The Andro Corp ACI-15 Partial M4 Lower saves you the lower parts kit assembly, which is the step that frustrates most first time builders.

A 7075 forged AR-15 lower receiver is the same forging spec the military uses, not a cast or billet substitute.

The multi-caliber marking means one lower covers 5.56 NATO, 300 Blackout, 9mm and anything else that runs on an AR-15 lower.

Buying an AR-15 partial lower with buffer tube already fitted removes the castle nut staking job, which needs a wrench most people do not own.

This suits anyone building their first AR-15 who wants the finished result without the small parts headache, and anyone who already has a spare upper sitting in a drawer waiting for a home. It is also the sensible way to start a second build when you know exactly what upper you want but not yet what stock. Remember that the Andro Corp ACI-15 Partial M4 Lower is a serialized firearm: it ships to a licensed dealer, not to your door, and a transfer and background check apply exactly as they would for a complete rifle.