The 375 RAPTOR was designed for the DPMS LR308, KNIGHT SR-25 and ARMALITE AR-10 platform. In addition, it is an ideal choice for the short action rifles such as the Remington Model 700, Remington Model 7, Savage Model 10 and any other bolt action sized for the 308 Winchester. We are currently working on converting a Browning BLR Take Down Rifle that started life as a 308 Winchester.
THE 375 RAPTOR AR
On the 308AR (generic term describing the DPMS LR308, KNIGHT SR-25 and ARMALITE AR-10), the 375 RAPTOR requires only a barrel change.
- Standard 308 Winchester Bolt
- Standard 308 Winchester Barrel Extension
- Standard Buffer and Buffer Spring
- Standard Upper and Lower Receivers
- Standard Carbine or Mid Length Gas System (16-22 inch barrels), or
- Standard Pistol or Carbine Length Gas System (10.75-12.75 inch barrels)
On barrels, we find an 18-22 inch barrel is the ideal length range to give full combustion of the powder charge which will range between 40 and 50 grains for supersonic loads depending on the powder you use. Using an even longer barrel will not provide additional benefit given the volume and burn rate of the ideal powders. During testing, we have used 10.75″, 16″, 18″, 20″ and 22″ barrels.
On twist rate, if you plan on 10.75 inch to 16-inch barrel, to shoot subsonic loads with a suppressor, go with an 8-twist. If you are going to focus on the supersonic performance capabilities, a 10 twist barrel is ideal. In our development work, we have used X-Caliber Barrels and Krieger Barrels. If you buy a long barrel blank, you can have it cut into 2 barrels, one for an SBR and one for a regular rifle.
If you are going to thread the barrel, we use a 3/4-24 thread so that there is no possibility of accidentally fitting a muzzle brake designed for a smaller diameter bullet. This also matches the threading we use on our larger caliber suppressors.
Would you believe this rifle breaks down to fit into a thick brief including an extra barrel. The DRD Tactical M762 assembles is less than 2 minutes allowing me to switch between the 375 RAPTOR, 308 Winchester or any other 308AR Cartridge.
375 RAPTOR MAGAZINES
On the magazines, the ideal magazine is the MAGPUL PMAG as shown below:
To modify the magazine, you simply want to do the following:
- Take the magazine apart removing the floor plate, spring and follower,
- Using a caliper, measure the magazine thickness on each side including the forward rib (should be .165″-.175″),
- Using a common flat file, file the forward rib along it’s entire length so that the magazine thickness on each side including the forward rib is .140″- .150″. I usually start with a more aggressive file and finish with a fine file. Please don’t try to use a Dremel or power tool, you won’t be even and probably will take off too much too quickly.
- Blow out the dust and reassemble the magazine.
- You are done and the magazine will still work with .308 Winchester.
Here is a video showing the magazine modification process:
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