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Posted: 3/2/2011 9:03:16 AM EDT
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what is the difference between these 2 rails? Sorry if its a dumb question but i cant figure it out.
http://www.operationparts.com/Kac_Knights_Armament_Ras_M4_Carbine_Rail_System_p/98064.htm http://www.operationparts.com/Kac_Knights_Armament_AR_15_Ris_Rail_System_p/94297.htm |
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Quoted:
Thats it? the only difference is that the RAS has a clip? Yep it's supposed to help with the consistancy of devices (like lasers) that are attached to it. I know there is some data in the Archives about the performance difference between the two, the clip helps, but it's not a giant improvement. ETA: I checked Quarterbore's sight and he has more info on the two: http://www.quarterbore.com/kac/kacrisras.html Note the two products you posted are NOT the 'Free Float RAS' which is a different beast altogether (but is mentioned on QB's website). |
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Quoted:
Wow very intresting.. Thanks for the info. I'm sure the techincal shooting data cant possibly vary greatly at all.. Do you think that $110 shipped for a NIB RIS system is bad? i seen them retail for over $300 Sounds like a deal. Just be sure it's the real-deal (i.e. not a Chi-Com airsoft copy) and it's not stolen US Govt property. |
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Quoted: IIRC It's the RAS that has a 'clp' that more firmly attaches the front of the forearm to the rifle. There are a few differences. The RIS (Rail Interface System) is the first rail system Knight's Armament Company (KAC) released for the M4 weapons system. The RAS is the "updated" version that is still in use on many M4s in the military. Differences discussed here: http://www.quarterbore.com/kac/kacrisras.html They are going to be replaced soon with the Daniel Defense RIS II: https://danieldefense.com/rail-systems/ris-ii.html The short version is that the RIS doesn't secure as tightly as the RAS but it has a greater compatibility with different barrel profiles. I ran the RIS on my BCM 14.5" SOCOM profile barrel (medium weight contour) and it worked great but didn't have a ton of wiggle room. My RIS also had a clip that you tighten with a flat-head screwdriver to "clamp" onto the handguard cap in the front. This was only for the top section of the rail which is the same piece as the left and right sections. At the rear it is held in place by the delta ring. The bottom section was designed to be easily removable for mounting the M203 grenade launcher and is held in only with the handguard cap in front and the delta ring in the rear. My RIS locked up very tight. One tip I would give you is after you install it, grab the gun by the rail and push the delta ring towards the rail to make sure it is gripping it tightly. Sometimes it won't lock completely on there just from the spring tension but the spring tension should hold it in place if you push the ring tighter on. This made my rail lock up extremely tightly even with a KAC VFG mounted on the bottom rail which is the looser of the two. Hope this is helpful. |
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$110 for a new rail is a pretty good deal. I'd check and make sure there is a Knight's Armament logo on the inside of the rail on the heat shield. Also make sure each of the rails has T-marks for accurate and easy re-mounting of accessories. A genuine KAC rail will usually come with a plastic "bag" (of sorts) that has a variety of KAC rail covers included. Mine also came with "pistol grip" (vertical fore grip) but I have seen them come without that. |
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Quoted:
Wow very intresting.. Thanks for the info. I'm sure the techincal shooting data cant possibly vary greatly at all.. Do you think that $110 shipped for a NIB RIS system is bad? i seen them retail for over $300 According to Knight's Armament, The RAS is a much better rail than the RIS. This is a quote from C. Reed Knight himself: "The RIS was the first model and the RAS is an improvement over it. The RIS has the retension screw in the front where the RAS clamps in the rear and has a leaf spring in the front to allow movement for expansion during heavy firing schedules . Even though the units appear the same there is 100s of thousands of dollars and many months of development to make the RAS meet the US Army performance requirement . That req. was as I remember a 2.5 " alignment with the upper over a 70k round firing schedule which was hard to understand because the bbl does not even last that long. I performed the test myself(in the middle of the summer). I would recommend the RAS over the RIS if it will fit your rifle. The front clamp can be modified to fit a wider variety of bbl. diameters." _________________ C Reed Knight III Knight's Armament Company http://www.knightarmco.com/ http://www.lawmens.net/ |
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Quoted: is this what its supposed to look like or could this be a knockoff? http://<a href=http://img810.imageshack.us/img810/3497/railo.jpg</a>" /> That looks like it might be an RAS. I can take some pics for you of my RIS but I do not have an RAS. I'll look at it when I get home. Been awhile since I've examined that rail since I went with a free-float on both of my carbines. |
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Quoted:
is this what its supposed to look like or could this be a knockoff? http://<a href=http://img810.imageshack.us/img810/3497/railo.jpg</a>" /> That looks like my RAS because of the mounting bracket at the right side of the pic, as said before the RIS don't have a bracket. Sometimes it's going to be tough to tell if it's real or fake, here are some markings to look for. Some fake rails are marked with odd numbered rail slot markings, real one are even numbered. On the top rail at slot T15 location (next slot forward of the mounting screw): U.S. PAT. 5,826,363 Real one have these internal markings: KNIGHT'S ARMAMENT COMPANY Titusville, FL or Vero Beach, FL (their old address) Cage No. 1S002 (newer production will have this cage code, older ones don't) On the bottom heat shield internal markings are: Large arrow symbol with "FORWARD" word inside the arrow KAC shield and armor logo Knight's Armament Company Take a look here at the EE, there were pics of a used RAS that was recently sold (not mine). http://www.ar15.com/forums/topic.html?b=7&f=159&t=831209 |
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