Do Sharps Bros lowers fit YHM uppers?
Sharps Bros lower + YHM upper: yes, they fit
Yes. Sharps Bros AR-15 lowers fit Yankee Hill Machine (YHM) 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 Sharps Bros Showdown Stripped lower with the YHM A3 upper.
About 1 in 25 Sharps Bros lowers in our builds carries a YHM upper.
Sharps Bros makes billet receivers with bold styling like the Livewire, plus AK receivers and pistol grip modules.
Founded 2012
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
Sharps Bros lowers and YHM 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.
Checked on this Sharps Bros lower
Sharps Bros Showdown Stripped Lower Receiver$284.95and this YHM upper
Yankee Hill Machine A3 Upper Receiver$121.75Most built Sharps Bros lowers and YHM uppers setups
Ranked by how often builders pick the exact pair. Only pairs our rules pass are listed.
#1Yes, they fit56% of these buildsCheck fit
#2Yes, they fit18% of these buildsCheck fit
#3Yes, they fit6% 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 Sharps Bros and YHM 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.
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.
YHM: YHM's stripped A3 upper comes without the forward assist and dust cover, while the A3 upper assembly includes both.
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
- Sharps Bros lowers + PSA uppersThird most picked
- Sharps Bros lowers + Daniel Defense uppersFourth most picked
- Sharps Bros lowers + Geissele uppersFifth most picked
- Sharps Bros lowers + Aero uppersSixth most picked
- Sharps Bros lowers + Sharps Bros uppersEighth most picked
Other lowers under YHM uppers
- Aero lowers + YHM uppersSecond most picked
- PSA lowers + YHM uppersThird most picked
- YHM lowers + YHM uppersFourth most picked
Sharps Bros lowers and YHM uppers: questions builders ask
Will a YHM upper fit a Sharps Bros lower?
Yes. Sharps Bros AR-15 lowers fit YHM 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 YHM 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.