Does the Cross Machine Tool UPUR-1LH Billet Left work with the Aero Precision 5.56 BCG W/C158 Bolt?

Upper Receiver
Cross Machine Tool UPUR-1LH Billet Left Handed
from $198.00

Bolt Carrier Group
Aero Precision 5.56 BCG W/C158 Bolt
from $148.99
upper and Aero Precision bolt carrier group compatibility
Yes, they fit
The Cross Machine Tool UPUR-1LH Billet Left Handed works with the Aero Precision 5.56 BCG W/C158 Bolt. Our compatibility rules found no conflict between them.
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 upper and Aero Precision bolt carrier group
Backed by thousands of qualified builds that have both an upper and a bolt carrier group.
Share of builds with the Aero Precision 5.56 BCG W/C158 Bolt and any upper
Cross Machine Tool UPUR-1LH Billet Left
Not in enough builds yet to report.
Aero Precision 5.56 BCG W/C158 Bolt
- Of bolt carrier group picks
- 8.4%
- Median paid
- $132
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 upper and Aero Precision bolt carrier group
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
Lower Receiver
Gas Block
Stock & Brace
Pistol Grip
Barrel
Cross Machine Tool UPUR-1LH vs Aero Precision 5.56 BCG W/C158: specs and prices
| Cross Machine Tool UPUR-1LH | Aero Precision 5.56 BCG | |
|---|---|---|
| Best price | $198.00 at AR15 Discounts | $148.99 at KY Gun Company |
| Stores | 2 of 3 in stock | 0 of 6 in stock |
| Assembly | Stripped | n/a |
| Platform | AR-15 | n/a |
| Receiver Type | Billet | n/a |
| Cartridge | n/a | 5.56 NATO |
| Finish | n/a | Black |
Both for $346.99 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.
Cross Machine Tool UPUR-1LH Billet Left Handed
Price history, last 90 days
- Cross Machine Tool UPUR-1LH Billet Left: lowest $198.00 on Jul 5, highest $198.00 on Jul 5 over the last 90 days.
- Aero Precision 5.56 BCG W/C158 Bolt: lowest $131.53 on Jul 6, highest $149.99 on Jul 12 over the last 90 days.
Bolt Carrier Groups most paired with uppers
The Cross Machine Tool UPUR-1LH Billet Left is not in enough builds yet, so these are the most picked next to any upper. Only parts our rules say fit the Cross Machine Tool UPUR-1LH Billet Left are listed.
Upper Receivers frequently paired with the Aero Precision 5.56 BCG W/C158 Bolt
Most picked next to it in real builds. Only parts our rules say fit the Aero Precision 5.56 BCG W/C158 Bolt are listed.



















