PTS Syndicate has been working on their licensed Centurion Arms rail systems since before SHOT Show in February, and they finally released them in September. Centurion Arms is owned by a former Navy SEAL, and their products are designed to deliver accuracy and reliability.
PTS produced both the C4 Free Float Quad Rail, as well as the CMR, the Centurion Modular Rail. We take a look at the C4 9 Inch Free Float rail from PTS provided by Airsoft Outlet NW, and shares both features of the rail as well as installation instructions.
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First off, PTS makes the Centurion Arms C4 rail in both 7 inch and 9 inch versions. Both models include a low profile gas block and reproduction gas tube. With these components, there are a variety of builds that are possible.
The 7 inch C4 rail can be combined with a short 7.5 inch Noveske barrel for an ultra short build, but more traditionally it will be fitted behind a fixed front sight on an M4 CQB or M4 Carbine. The 9 inch C4 rail, which we install in the guide here, will fit over the low profile gas block on a 10 inch barrel.
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The first step in the installation is to remove the original fixed front sight and gas tube. Then, remove the original barrel nut/delta ring assembly. The Centurion C4 rail clamps onto the bare M4 barrel nut, which guarantees compatibility with all brands. Since you’re using your original barrel nut, there’s no worry about varying thread pitches.
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The c-clip can be pried off with a screwdriver, which will release the spring and handguard ring. Reinstall the barrel nut alone.
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The C4 rail features two small tang extensions that fit alongside the upper receiver. These automatically align the rail system, which completely eliminates the need to time the barrel nut or align the rail manually, making installation a breeze.
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You do have to press the upper half into place, as it is quite snug on the barrel nut. Once it is dropped into place, now is the best time to install the low profile gas block. Slide it over the barrel and set the mock gas tube in position, then tighten the set screw. You won’t be able to access it later.
Fit the lower half of the rail in place, carefully sliding it into the upper segment. You’ll now tighten 4 screws at the rear of the rail system. These 4 screws thread into steel reinforced holes, which allow the rail to be mounted with excellent durability. Two allen head screws near the front clamp the lower and upper together and finish the installation.
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If you were installing the 7 inch rail, the front sight could be fitted on with the upper half of the rail in place, or once installation was complete. Beware that the PTS Centurion C4 rail has a block that prevents a full length gas tube from being installed. If you want to put a front sight and gas tube in place, you’ll need to shorten the mock tube slightly to fit.
The PTS Centurion C4 9 Inch Rail fits just past the base of the threads on the 10 inch barrel, allowing for a slightly recessed flash hider. The muzzle device pictured is the PTS Griffin Armament Flash Compensator.
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For anyone wanting to run a QD suppressor, a 10.5 inch barrel works the best, giving space for QD mount hardware like that on the PTS Griffin M4SD II.
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The PTS Centurion Arms C4 rails are undoubtedly one of the best built airsoft rail systems I’ve seen. Finish wise, these are well constructed, with exacting detail and nice touches, like the steel thread inserts. The dimensions are perfect for a precise fit. The PTS C4 rail certainly benefits from the excellent design of the real C4 Free Float RIS, which makes installation straightforward and rock solid.
Both the 7 inch and 9 inch rails sport ambidextrous limited rotation QD sling swivel sockets at the base of the rail. The 9 inch model adds two more at the front of the handguard.
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When a good looking quad rail combines easy installation, solid design, quality materials, and excellent fit and finish, it’s hard to go wrong. With the PTS Centurion Arms C4 Rail, there’s a lot to like, and no real downside. In the end, the only real question is, do you go classic with the 7 inch and a fixed FSP or do you roll a more modern low profile 9 inch variant? The answer to that question is up to you.
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You can get the rails and other awesome PTS parts at Airsoft Outlet NW. Just follow >> this link << To close this review, we want to say thank you to the guys over at Airsoft Outlet NW for providing the product for a test. 
