Do YHM lowers fit PSA uppers?
YHM lower + PSA upper: yes, they fit
Yes. Yankee Hill Machine (YHM) 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.
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 YHM lower with the PSA 16in Mid-Length 5.56 NATO upper.
About 1 in 15 YHM lowers in our builds carries a PSA upper.
Yankee Hill Machine (YHM) makes suppressors, handguards, muzzle devices and gas blocks at fair prices, from a family shop in western Massachusetts.
Founded 1951, Easthampton, Massachusetts, 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
YHM 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-15: yes, they fit
Both are AR-15 size receivers. An AR-15 lower takes the upper's 5.56 NATO.
Checked on this YHM lower
Yankee Hill Machine .223 Rem/5.56 Billet Lower Receiver$245.75and this PSA upper
PSA 16" Mid-Length 5.56 NATO 1/7 Nitride Timber Creekout of stockMost built YHM lowers and PSA uppers setups
Ranked by how often builders pick the exact pair. Only pairs our rules pass are listed.
#1Yes, they fit27% of these buildsCheck fit
#2Yes, they fit8% of these buildsCheck fit
#3Yes, they fit8% of these buildsCheck fit
#4Yes, they fit4% of these buildsCheck fit
#5Yes, they fit4% of these buildsCheck fit
#6Yes, they fit4% of these buildsCheck fit
#7Yes, they fit4% of these buildsCheck fit
#8Yes, they fit4% of these buildsCheck fit
What YHM and PSA say
YHM: YHM sells complete and stripped uppers and lowers, plus its own carbines.
YHM: The lower in YHM's billet receiver set fits all standard parts except a trigger guard, has a built in tension screw and takes every generation of PMAG.
YHM: YHM's A3 upper has M4 style feed ramps and T marks, and accepts standard upper parts and mil-spec lower receivers.
PSA: PSA owns its supply chain, including Spartan Forging and DC Machine, from forging the receivers to finishing the muzzle brake.
PSA: The KS-47 Gen2 bolt has two lugs reshaped so it feeds from AK magazines.
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 YHM lowers
- YHM lowers + YHM uppersMost picked
- YHM lowers + BCM uppersSecond most picked
- YHM lowers + Geissele uppersFifth most picked
- YHM lowers + Aero uppersSeventh most picked
Other lowers under PSA uppers
- PSA lowers + PSA uppersMost picked
- Aero lowers + PSA uppersSecond most 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
- Griffin Armament lowers + PSA uppersSeventh most picked
- LMT lowers + PSA uppersEighth most picked
YHM lowers and PSA uppers: questions builders ask
Will a PSA upper fit a YHM lower?
Yes. YHM 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.
Why might a PSA upper feel loose or tight on a YHM 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.