Does the Lewis Machine & Tool MARS-L SOPMOD work with the Daniel Defense MK18 RIII?
Lewis Machine & Tool lower and Daniel Defense upper compatibility
Yes, they fit
The Lewis Machine & Tool MARS-L SOPMOD works with the Daniel Defense MK18 RIII. Our compatibility rules found no conflict between them.
This exact setup has been built more than once on GunPartPicker.
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 Lewis Machine & Tool lower and Daniel Defense upper
Backed by tens of thousands of qualified builds that have both a lower and an upper.
Share of builds with the Lewis Machine & Tool MARS-L SOPMOD and any upper
- This pairDaniel Defense MK18 RIII22%
Share of builds with the Daniel Defense MK18 RIII and any lower
- This pairLewis Machine & Tool MARS-L SOPMOD12%
Lewis Machine & Tool MARS-L SOPMOD
- Of lower picks
- 0%
- Median paid
- n/a
Daniel Defense MK18 RIII
- Of upper picks
- 0.1%
- Median paid
- $1412
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 Lewis Machine & Tool lower and Daniel Defense upper
The part builders pick most often in each slot alongside these two, checked against both. Parts that conflict are left out.
Lewis Machine & Tool MARS-L vs Daniel Defense MK18 RIII: specs and prices
| Lewis Machine & Tool MARS-L | Daniel Defense MK18 RIII | |
|---|---|---|
| Best price | n/a | $1454.00 at Primary Arms |
| Stores | n/a | 5 of 5 in stock |
| Assembly | Complete | Stripped |
| Platform | AR-15 | AR-15 |
| Caliber | Multi | 5.56 NATO |
| Length | n/a | 10.3 |
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
- Daniel Defense MK18 RIII: lowest $1259.99 on Jul 21, highest $1527.00 on Aug 2 over the last 90 days.
Upper Receivers frequently paired with the Lewis Machine & Tool MARS-L SOPMOD
Most picked next to it in real builds. Only parts our rules say fit the Lewis Machine & Tool MARS-L SOPMOD are listed.
Lower Receivers frequently paired with the Daniel Defense MK18 RIII
Most picked next to it in real builds. Only parts our rules say fit the Daniel Defense MK18 RIII are listed.






















