Do Radian lowers fit Aero uppers?
Radian lower + Aero upper: yes, they fit
Yes. Radian AR-15 lowers fit Aero Precision 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.
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 November 14, 2026.
Our take
Most built setup: the Radian A-DAC 15 Stripped lower with the Aero M4E1 Threaded Upper.
About 1 in 20 Radian lowers in our builds carries an Aero upper.
Radian makes ambidextrous AR controls in Redmond, Oregon, and the Raptor charging handle is the one everybody knows. They used to go by AXTS Weapons Systems.
Redmond, Oregon, Made in USA
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
Radian lowers and Aero 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-15: yes, they fit
Both are AR-15 size receivers. An AR-15 lower takes the upper's 5.56 NATO.
Checked on this Radian lower
Radian A-DAC 15 Stripped Lower Receiver$514.95and this Aero upper
Aero Precision M4E1 Threaded Upper$593.99, out of stockMost built Radian lowers and Aero uppers setups
Ranked by how often builders pick the exact pair. Only pairs our rules pass are listed.
#1Yes, they fit14% of these buildsCheck fit
#2Yes, they fit5% of these buildsCheck fit
#3Yes, they fit5% of these buildsCheck fit
#4Yes, they fit3% of these buildsCheck fit
#5Yes, they fit3% of these buildsCheck fit
#6Yes, they fit3% of these buildsCheck fit
#7Yes, they fit3% of these buildsCheck fit
#8Yes, they fit3% of these buildsCheck fit
What Radian and Aero say
Radian: Radian's A-DAC 15 has a spring loaded plunger called SART that takes up wobble between the upper and lower.
Radian: Radian's A-DAC 15 stripped lower ships with its proprietary parts, including the extended bolt catch, both mag release parts, the right side bolt release paddle and a hammer pin.
Radian: The Radian A-DAC 15 takes mil-spec .154 inch trigger pins.
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.
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 Radian lowers
- Radian lowers + Geissele uppersMost picked
- Radian lowers + Radian uppersSecond most picked
- Radian lowers + BCM uppersThird most picked
- Radian lowers + Daniel Defense uppersFourth most picked
Other lowers under Aero uppers
- Aero lowers + Aero uppersMost picked
- PSA lowers + Aero uppersSecond most picked
- Wilson Combat lowers + Aero uppersThird most picked
- Spike's lowers + Aero uppersFourth most picked
- Smith & Wesson lowers + Aero uppersFifth most picked
- LMT lowers + Aero uppersSixth most picked
- Sharps Bros lowers + Aero uppersSeventh most picked
- CMMG lowers + Aero uppersEighth most picked
Radian lowers and Aero uppers: questions builders ask
Will an Aero upper fit a Radian lower?
Yes. Radian AR-15 lowers fit Aero 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.
Why might an Aero upper feel loose or tight on a Radian 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.