Do Sharps Bros lowers fit PSA uppers?
Sharps Bros lower + PSA upper: yes, they fit
Yes. Sharps Bros 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 October 31, 2026.
Our take
Most built setup: the Sharps Bros Showdown Stripped lower with the PSA Upper 5.56 16in Mid-Length.
PSA is one of the most picked upper brands on Sharps Bros lowers.
Sharps Bros makes billet receivers with bold styling like the Livewire, plus AK receivers and pistol grip modules.
Founded 2012
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
Sharps Bros 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 Sharps Bros lower
Sharps Bros Showdown Stripped Lower Receiver$284.95and this PSA upper
PSA Upper 5.56 16" Mid-Length Nitride 13.5" M-LOK$219.99Most built Sharps Bros lowers and PSA uppers setups
Ranked by how often builders pick the exact pair. Only pairs our rules pass are listed.
#1Yes, they fit22% of these buildsCheck fit
#2Yes, they fit9% of these buildsCheck fit
#3Yes, they fit5% of these buildsCheck fit
#4Yes, they fit4% of these buildsCheck fit
#5Yes, they fit4% 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
Watch the frame size. Builders also pair parts our rules say do not fit, like these two: Lower Receiver (AR-15) cannot support an AR-10/.308 build.
What Sharps Bros and PSA say
Sharps Bros: Sharps Bros AK receivers have an integrated AR buffer extension, a feature it patented in 2014, so you can run AR stocks.
Sharps Bros: The Sharps Bros Showdown lower works with all mil-spec internal parts and other aftermarket mil-spec upper receivers.
Sharps Bros: The Sharps Bros Gen 2 Hellbreaker, Warthog and Jack lowers take any standard AR-15 lower parts kit and mate with any standard AR-15 upper.
Sharps Bros: The Sharps Bros Showdown takes PMAGs, Hex mags and other standard capacity AR mags, and it uses a threaded bolt catch pin.
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 Sharps Bros lowers
- Sharps Bros lowers + BCM uppersMost picked
- Sharps Bros lowers + TacFire uppersSecond 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 and PSA uppers: questions builders ask
Will a PSA upper fit a Sharps Bros lower?
Yes. Sharps Bros 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 Sharps Bros 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.