SCAR go FRT? Yes, it can. We have the technology thanks to Imperial Arms. Nathan P of Imperial Arms was nice enough to send me an updated version of his MTM (Mil-spec Trigger Module) for the SCAR17S. We saw the MTM before along with his virgin SCAR receivers called Cypher X. Well, what makes this new MTM so special? It goes to 11.
Imperial Arms Co. @ TFB:
MTM Now With More FRT
Last February, when Nathan sent out the early version of the MTM, he and I talked about how cool it would be if it could use a Rare Breed FRT trigger. He and I bounced some ideas which basically came down to needing some kind of bar that would slide back and forth. The front end would catch onto the carrier and the back end would trip the locking bar on the Rare Breed FRT. This could also work for FFLs who can make post-sample machine guns. You could use an M-16 trigger and sear with the same trip. To refresh your memory, here is how the FRT operates.
Below is the new MTM before assembly. Notice the track for the trip sled?
Here is a close-up of the MTM trigger pocket. It is a little bit different from the previous iteration of the MTM.
For those not familiar with Imperial Arms Co.’s previous MTM, here they are side by side. Old on top, new on the bottom. But it is a power bottom.
There is a significant difference in the trigger pocket design. There is a spring/detent hole on the right-hand side of the lower, this is for the trip sled.
Imperial Arms Co. will no longer be manufacturing the old MTM lower receiver. From here on out, they are moving forward with the new redesign. The new MTM will still function like the old one. You can use any AR-15 style trigger for your SCAR17S. This project took priority but they are working on an MTM for the SCAR16S. All MTM will come with a takedown pin and spring clip.
If you want your MTM to go to 11, you need the trip sled below. This will be sold separately. It consists of the sled, spring and detent.
Installation of the trip sled is straightforward. Install the spring and detent, then drop the sled on top and slide it forward so the hook-like cut catches the detent.
The trip sled has a vertical protrusion on the left side of the receiver. You need to modify your SCAR17S carrier to function with this trip sled. You can send your carrier to Imperial Arms Co. or they can provide the information like the size of the hole and roll pin needed for the modification. I sent my carrier to Nathan. You can see the modification below. He drilled a hole near the bottom and inserted a roll pin that sticks out the left side of the carrier.
This is similar to a SCAR-H MK17 full auto carrier only that it is mirrored. See the photo below
See the zoomed-in photo below. I circled the area on the full auto carrier that trips on a full auto SCAR17.
If you recall, the CypherX upper receiver has a tab that functions as a denial device. The tab prevents you from installing a full auto bolt.
This tab and the full auto carrier protrusion are all on the right side of the receiver. This is why Nathan has the trip sled protrusion on the left side. However, if you have a post sample SCAR17 converted for use with an FN America full auto carrier, you can request a right-hand side trip sled and an M-16 sear compatible MTM.
How Well Does The MTM FRT Work?
It works rather well. The recoil is significant and constant.
Like using it in an AR-15, the FRT requires a little bit of finesse to get the trigger to work. If you pull the trigger back too hard, you can induce a malfunction. Here is a video where I tried to film the trigger manipulation. It is subtle but you can see the trigger resets and the shooter pulls it as soon as the bolt closes. Once the bolt closes the trip sled presses on the locking bar unlocking it and allowing the trigger to be pulled again thus releasing the hammer for a very quick follow-up shot. But then watch my friend (at the end of the video) he pulls the trigger too hard and stops the return of the bolt. Only when he eases the pressure off the trigger, does the bolt close.
Final Thoughts On The new MTM Utilizing an FRT
The recoil is unceasing when you shoot at SCAR17S rapidly. It is borderline impractical, however, it is a lot of fun. I tried a variety of muzzle brakes but they did not seem to help. Maybe I need a more aggressive muzzle brake? When I was testing to see which of the various muzzle brakes reduced recoil the most, I switched to a HANDL lower receiver that uses a factory SCAR17S trigger and hammer. Unfortunately, there is an incompatibility between the modified carrier and the factory hammer. The bolt will not cycle back all the way. See the photo below.
Nathan is going to look into this problem some more. But for now, you will not be able to use your factory trigger assembly with a modified carrier. But now that you can use a Rare Breed FRT or any other AR-15 trigger in an MTM, why would you want to go back to the factory or even the Geissele SCAR trigger? There is a modification to make FRT three-position. I am looking into that now. Oh, also, according to Nathan, his new MTM works best with a Rare Breed FRT. The Alamo trigger functions differently so it does not work and the WOT has loose tolerances that it does not sit properly in the MTM.