Do PSA lowers fit CMMG uppers?
PSA lower + CMMG upper: yes, they fit
Yes. Palmetto State Armory (PSA) AR-15 lowers fit CMMG 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: PSA AR-15 lowers are a smaller frame and do not fit CMMG AR-10 (.308) uppers. One catch: AR-10 parts aren't standardized between makers, so ask Palmetto State Armory and CMMG 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 November 10, 2026.
Our take
Most built setup: the PSA Lower Magpul MOE EPT Edition with the CMMG Resolute 16.10in Upper.
About 1 in 60 PSA lowers in our builds carries a CMMG upper.
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
CMMG makes complete AR rifles, pistols and parts, and it's known for Radial Delayed Blowback, its action for pistol caliber ARs in rounds like 10mm and .45 ACP.
Founded 2002, Boonville, Missouri, Made in USA
PSA lowers and CMMG 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 lower + AR-9 (9mm) upper | They fit, with a catch |
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 PSA lower
PSA Lower Magpul MOE EPT Edition$189.99and this CMMG upper
CMMG Resolute 16.10" Upper 5.56x45mm$403.20AR-10 (.308): they fit, with a catch
AR-10 parts aren't standardized between makers, so ask Palmetto State Armory and CMMG if this lower and upper fit before you buy.
Checked on this PSA lower
PSA GEN3 PA-10 AR-10 Lower .308 Classic EPT$239.99and this CMMG upper
CMMG MK3 Resolute Upper Receiver Group .308 Winchester$880.32AR-15 lower + AR-10 (.308) upper: no, they do not fit
The lower receiver (AR-15) cannot support a AR-10/.308 build.
Checked on this PSA lower
PSA Lower Magpul MOE EPT Edition$189.99and this CMMG upper
CMMG MK3 Resolute Upper Receiver Group .308 Winchester$880.32AR-15 lower + AR-9 (9mm) upper: they fit, with a catch
The lower receiver (AR-15) needs a 9mm magazine well adapter for a PCC/9mm build.
Checked on this PSA lower
PSA Lower Magpul MOE EPT Edition$189.99and this CMMG upper
CMMG Banshee 9mm Upper$716.63, out of stockMost built PSA lowers and CMMG uppers setups
Ranked by how often builders pick the exact pair. Only pairs our rules pass are listed.
#1Yes, they fit10% of these buildsCheck fit
#2They fit, with a catch3% of these buildsCheck fit
#3They fit, with a catch3% of these buildsCheck fit
#4They fit, with a catch3% of these buildsCheck fit
#5They fit, with a catch3% 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 PSA and CMMG say
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: PSA's PX-9 lower takes Glock style magazines, is designed to work with PSA's 9mm Hybrid uppers and has no last round bolt hold open.
CMMG: CMMG's MkGs lower takes 9mm or .40 S&W Glock and SGM magazines and is meant for CMMG MkGs Radial Delayed Blowback uppers only.
CMMG: CMMG's MkG lower takes Glock and SGM .45 ACP magazines and is made for CMMG .45 ACP Radial Delayed Blowback uppers, and other brands' uppers may work but are not guaranteed.
CMMG: A CMMG DISSENT upper fits most of CMMG's BANSHEE, RESOLUTE and ENDEAVOR lowers only after you pull the buffer tube and stock and install the adapter plate that comes with the upper.
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 PSA lowers
- PSA lowers + PSA uppersMost picked
- PSA lowers + BCM uppersSecond most picked
- PSA lowers + TacFire uppersThird most picked
- PSA lowers + Aero uppersFourth most picked
- PSA lowers + Geissele uppersFifth most picked
- PSA lowers + Radical uppersSixth most picked
- PSA lowers + Daniel Defense uppersSeventh most picked
- PSA lowers + Wilson Combat uppersEighth most picked
Other lowers under CMMG uppers
- CMMG lowers + CMMG uppersMost picked
- Aero lowers + CMMG uppersThird most picked
- Smith & Wesson lowers + CMMG uppersFourth most picked
- Wilson Combat lowers + CMMG uppersFifth most picked
PSA lowers and CMMG uppers: questions builders ask
Will a CMMG upper fit a PSA lower?
Yes. PSA AR-15 lowers fit CMMG 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 a PSA AR-10 lower fit a CMMG upper?
PSA AR-10 (.308) lowers fit CMMG AR-10 (.308) uppers, with one thing to check. AR-10 parts aren't standardized between makers, so ask Palmetto State Armory and CMMG if this lower and upper fit before you buy. PSA AR-15 lowers are a smaller frame and do not fit CMMG AR-10 (.308) uppers.
Why might a CMMG upper feel loose or tight on a PSA 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.