The R1 will now accept our 5, 8, and 11 slot rails. It will more than likely allow the use of any other manufacturers rail you may want to use of appropriate length that utilizes #10 screws for attachment as we  have added slots in addition to the location holes. Bolt hole patterns in .394 intervals will fit up to our forend as long as the farthest spread centerline to centerline of bolt holes are 3.152 or less. If your alternative rail does not come with usable hardware and uses #10 bolts for attachment our 10-24 grommets may be purchased for use. The flathead screws we use for locating our rails may or may not work as many other rails are not countersunk for flathead screws. If not than more than likely they would use buttonhead screws which should be available at most hardware stores in 10-24 in a variety of lengths.  Below is a diagram of the rail mounting locations to help you see if your alternative rail may work. This option was mainly added to meet requests to use Magpul polymer rails which would save considerable costs to using our rails. The hardware that comes with the Magpul rails will work with our forend. Any length Magpul rail 11 slot and under will fit.

Uses 11 slot rails (4.515 Long).
Prices  (Include Shipping):
R1 PLR16 Forend
Complete with 3 full rails (11 slots)                                 $140.00 (comes with rails assembled)
Body only (no rails)                                                         $  80.00
(1) 11 slot picatinny rail with hardware                           $  23.50
(1)  5 slot picatinny rail with hardware                            $ 17.50
(1)  8 slot picatinny rail with hardware                            $ 19.00

(1) 10-24 grommet (possibly needed for those using alternative rails other than ours, our rails come with these)                                               $    .95

PLR16 Aluminum Forend Info

Features:
-Main Body and Rails CNC Machined From 7075 T6 Aluminum Stock(60% Stronger Than 6061)
-Mil Spec 8625 Black Hard Anodized
-Mil-Spec Picatinny Dimensions
-Free Floating
-Blackened 416 SS Screw Posts for Rails and Clamping Bolt
-10-24 Grade 8 Screws
-Rails Precisely Located With Bugle Type Flat Head Screw In Combination With Screw Post
-Extended Clamping Screw Post For Increased Thread Engagement/Strength
-Does Not Interferr With Gun Stripping
-Virtually Full Length Barrel Nut Contact For Solid Lockup
-Easy Installation
-Weighs Approx. 8 ounces
-Made In USA

Installation Instructions:

Tools required:1/8" allen wrench and flathead screwdriver.

Remove magazine and make sure gun is unloaded by checking chamber.

Remove clamping screw post and button head screw from forend.

Slide forend over barrel and onto and over barrel nut all the way back.

Orient forend and place screw post in place and then place button head screw and tighten.