Do Aero lowers fit PSA uppers?
Aero lower + PSA upper: yes, they fit
Yes. Aero Precision AR-15 lowers fit Palmetto State Armory (PSA) AR-15 uppers. Both are AR-15 size receivers. A real mil-spec keeps AR-15 receivers from different makers close, though not exact, and fit problems show up most when the upper and lower come from different makers. We checked them with the rules the AR builder runs.
One exception: Aero AR-15 lowers are a smaller frame and do not fit PSA AR-10 (.308) uppers. One catch: AR-10 parts aren't standardized between makers, so ask Aero Precision and Palmetto State Armory if this lower and upper fit before you buy.
Fit comes from the same rules the AR builder runs on every part you add. Build data only ranks the setups; it never decides fit. Checked October 31, 2026.
Our take
Most built setup: the Aero M4E1 Lower with the PSA 16in Mid-Length 5.56 NATO upper.
About 1 in 15 Aero lowers in our builds carries a PSA upper.
Aero makes forged AR receivers, mainly the M4E1 line, with a billet look that still takes standard mil-spec parts. They also make complete uppers, charging handles and rifles.
Founded 1994, Tacoma, Washington, Made in USA
PSA sells affordable AR lowers, uppers, BCGs and complete rifles, and it makes them in house from forging to finished part.
Founded 2008, Columbia, South Carolina, Made in USA
Aero lowers and PSA uppers by platform
Each row is checked on the most built part of that platform from each brand.
| Platform | Fit |
|---|---|
| AR-15 | Yes, they fit |
| AR-10 (.308) | They fit, with a catch |
| AR-15 lower + AR-10 (.308) upper | No, they do not fit |
AR-15: yes, they fit
Both are AR-15 size receivers.
Checked on this Aero lower
Aero Precision Stripped M4E1 Lower Receiver$154.99, out of stockand this PSA upper
PSA 16" Mid-Length 5.56 NATO 1/7 Nitride Timber Creekout of stockAR-10 (.308): they fit, with a catch
AR-10 parts aren't standardized between makers, so ask Aero Precision and Palmetto State Armory if this lower and upper fit before you buy.
Checked on this Aero lower
Aero Precision AR-10 Stripped Lower Receiver Anodized$120.99, out of stockand this PSA upper
PSA GEN3 PA10 20" Rifle-Length .308 WIN 1:10 Stainless$499.99AR-15 lower + AR-10 (.308) upper: no, they do not fit
The upper receiver (AR-10) is large frame (AR-10) but the lower receiver (AR-15) is small frame (AR-15 / AR-9).
Checked on this Aero lower
Aero Precision Stripped M4E1 Lower Receiver$154.99, out of stockand this PSA upper
PSA GEN3 PA10 20" Rifle-Length .308 WIN 1:10 Stainless$499.99Most built Aero lowers and PSA uppers setups
Ranked by how often builders pick the exact pair. Only pairs our rules pass are listed.
#1Yes, they fit4% of these buildsCheck fit
#2Yes, they fit3% of these buildsCheck fit
#3Yes, they fit2% of these buildsCheck fit
#4Yes, they fit2% of these buildsCheck fit
#5Yes, they fit2% of these buildsCheck fit
#6Yes, they fit2% of these buildsCheck fit
#7Yes, they fit2% of these buildsCheck fit
#8Yes, they fit2% of these buildsCheck fit
What Aero and PSA say
Aero Precision: The M4E1 upper is forged 7075-T6 with a billet style look, and it still takes a standard barrel nut and mil-spec parts.
Aero Precision: The Aero M5 lower is DPMS pattern, but its lower parts kit uses an extended magazine release button to make up for the thicker receiver.
Aero Precision: Aero's M5 lower works with standard AR-308 parts and magazines, but Aero recommends its own M5 lower parts kit, which has custom takedown and pivot pins and an extended magazine catch button.
Aero Precision: The rear takedown pin detent hole on Aero's Gen 2 AR15 lower is threaded for a 4-40 set screw.
PSA: PSA owns its supply chain, including Spartan Forging and DC Machine, from forging the receivers to finishing the muzzle brake.
PSA: PSA's Gen3 PA10 lowers work with Gen1 and Gen2 PA10 uppers, but Gen3 with Gen3 is recommended for the best look and performance, since mixed generations differ on the outside.
PSA: The PSA PA-10 follows the DPMS pattern, so it can use a wide range of DPMS style parts.
PSA: The AR-10 has no common design across makers the way the AR-15 does, so use only PSA PA10 parts in PSA's PA10 receivers and not other makers' parts.
Fit is judged from the specs retailers list, which can be missing or wrong. Confirm with the manufacturer before you buy, and have a qualified gunsmith check any build before you fire it.
Other uppers builders put on Aero lowers
- Aero lowers + Aero uppersMost picked
- Aero lowers + BCM uppersSecond most picked
- Aero lowers + Geissele uppersThird most picked
- Aero lowers + Wilson Combat uppersFourth most picked
- Aero lowers + Daniel Defense uppersSixth most picked
- Aero lowers + Radical uppersSeventh most picked
- Aero lowers + YHM uppersEighth most picked
- Aero lowers + TacFire uppersNinth most picked
Other lowers under PSA uppers
- PSA lowers + PSA uppersMost picked
- Smith & Wesson lowers + PSA uppersThird most picked
- Wilson Combat lowers + PSA uppersFourth most picked
- Spike's lowers + PSA uppersFifth most picked
- Sharps Bros lowers + PSA uppersSixth most picked
Aero lowers and PSA uppers: questions builders ask
Will a PSA upper fit an Aero lower?
Yes. Aero AR-15 lowers fit PSA AR-15 uppers. Both are AR-15 size receivers.
Do I need a matched upper and lower?
A real mil-spec keeps AR-15 receivers from different makers close, though not exact, and fit problems show up most when the upper and lower come from different makers.
Does an Aero AR-10 lower fit a PSA upper?
Aero AR-10 (.308) lowers fit PSA AR-10 (.308) uppers, with one thing to check. AR-10 parts aren't standardized between makers, so ask Aero Precision and Palmetto State Armory if this lower and upper fit before you buy. Aero AR-15 lowers are a smaller frame and do not fit PSA AR-10 (.308) uppers.
Why might a PSA upper feel loose or tight on an Aero lower?
Some play between an AR-15 upper and lower is common, but it can get excessive when the two come from different makers, and a tension screw or an Accu-Wedge takes it up.