Does the PSA Lower Safe/Fire work with the Cross Machine Tool Ultra Precision?

Lower Receiver
PSA Lower Safe/Fire
from $79.99

Upper Receiver
Cross Machine Tool Ultra Precision Stripped
from $198.00
Palmetto State Armory lower and Cross Machine Tool upper compatibility
Yes, they fit
The PSA Lower Safe/Fire works with the Cross Machine Tool Ultra Precision Stripped. Our compatibility rules found no conflict between them.
No one has built this exact setup yet, but Palmetto State Armory lowers with Cross Machine Tool uppers are a common pairing.
Counted from real GunPartPicker builds: parts lists people put together while planning to buy.
Checked by the same rules the AR builder runs on every part you add: caliber, frame size, receiver pattern, thread pitch and gas length.
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.
How often builders pair the Palmetto State Armory lower and Cross Machine Tool upper
Backed by tens of thousands of qualified builds that have both a lower and an upper.
Share of builds with the PSA Lower Safe/Fire and any upper
PSA Lower Safe/Fire
- Of lower picks
- 0.2%
- Median paid
- $65
Cross Machine Tool Ultra Precision
Not in enough builds yet to report.
How we count ⌄
These shares come from GunPartPicker's build data: real parts lists people put together while planning a purchase, not sales or surveys. A build counts a part only when it is the final pick for its slot, so parts that were swapped out never count. Fit never comes from these numbers; it comes from our compatibility rules alone.
Frequently built with the Palmetto State Armory lower and Cross Machine Tool upper
The part builders pick most often in each slot alongside these two, checked against both. Parts that conflict are left out.
Charging Handle

Aero Precision Breach Small Levers
Fits both
Pistol Grip
Bolt Carrier Group

PSA 5.56 Full-Auto Nitride MPI
Fits both
Stock & Brace
Rifle Scope
Gas Block
Barrel
Handguard
PSA Lower Safe/Fire vs Cross Machine Tool Ultra: specs and prices
| PSA Lower Safe/Fire | Cross Machine Tool Ultra | |
|---|---|---|
| Best price | $79.99 at Palmetto State Armory | $198.00 at Primary Arms |
| Stores | 1 of 1 in stock | 1 of 2 in stock |
| Assembly | Stripped | Stripped |
| Platform | AR-15 | AR-15 |
| Receiver Type | n/a | A4 |
Both for $277.99 at today's best prices.
Today's best prices and 90 day price history
Every store we track for each part, cheapest in stock first. Prices are checked through the day.
Price history, last 90 days
- PSA Lower Safe/Fire: lowest $74.99 on Jul 12, highest $79.99 on Sep 4 over the last 90 days.
- Cross Machine Tool Ultra Precision: lowest $198.00 on Jul 7, highest $209.99 on Jul 6 over the last 90 days.
Upper Receivers frequently paired with the PSA Lower Safe/Fire
Most picked next to it in real builds. Only parts our rules say fit the PSA Lower Safe/Fire are listed.
Lower Receivers most paired with Cross Machine Tool uppers
The Cross Machine Tool Ultra Precision is not in enough builds yet, so these are the most picked next to any Cross Machine Tool upper. Only parts our rules say fit the Cross Machine Tool Ultra Precision are listed.


















