Benefits of the #50M-CV:

• Entire S.I.R.® front-end can be installed in less than 5 min. directly to the standard barrel nut without Delta ring. Totally Free Floating.
• Front sight, gas tube, and front handguard retaining cap do not need to be removed.
• Barrel does not have to be removed.
• Standard barrel nut does not need to be removed.
• Perfect alignment with the receiver can be accomplished via built-in alignment anti-rotation locking tabs.
• No special tools required. S.I.R.® standard sling swivel is useable for installation.
• The system weighs only 8.6 oz. The weight will increase depending on what selective rails are chosen to be utilized plus the weight of the sling swivel.
• Hanguards complete with QD indirect airflow heat shield.
• The S.I.R.® selective rails at 3, 6, and 9 o'clock positions can be exchanged, repaired, or replaced without removing the main top rail.
• Super-cool offset heat venting.
• The optional S.I.R.® rail also provides a modular means to cost-effectively upgrade into future integral electronics, and provide a solid platform, can eliminate the need to use high, less-stable, mounting devices, plus protects the top of the aluminum upper receiver at the same time protecting the receiver; can eliminate replacement of a damaged receiver.
• The #50M-CV allows the M203 launcher to be free float attached with no modification whatsoever to the launcher's receiver.
• The #50M-CV allows the A.R.M.S.® dual QD 1913 M203 attachment brackets to install to the S.I.R.® upper handguard just like the polymer handguard.
• The #50M-CV launcher QD attachment brackets provide a built-in 1913 dovetail rail along the length of the handguard at the 3 and 9 o'clock positions, multiple position attachment of grenade launcher sights.

A.R.M.S.® PIONEERED THE FREE FLOATING RAIL SYSTEMS.

No other system keeps the weapon as cool during firing as the A.R.M.S.® S.I.R.® System. No more hot, uncomfortable dovetail rails you must deal with like on other systems. The A.R.M.S.® S.I.R.® System has a true free float barrel that does not require the barrel to be removed during installation, like on other tube designs. A unique quick change polymer hand-guard allows easy access to clean the barrel without removing the system or barrel.

The #50, and #59 S.I.R. ® Systems are each available in Civilian and Military versions. Neither the civilian or military models require any modification to the rifle/carbine except removal of your current hand-guards and the Delta ring on the military S.I.R.® model.

The S.I.R.® System works with any type front sight you may have. No special tools are required to install. A coin is all that is needed.

 

The popular #50 Bi-Level S.I.R.® System shown above with the new #40L Stand Alone Flip up Sight.

 

 

The S.I.R.® allows for the attachment of different sized rails to customize your S.I.R.® system. The S.I.R.® System comes stock with 1 each of the #1,#2, and #3 rails which can be interchanged into many different configurations on the hand-guard. If a rail is not being utilized, simply remove it until needed to save on weight. The longer #4 rail is also available. The S.I.R.® System allows multiple attachments tailored to the needs of the users mission.

The S.I.R.® System is designed to fit mil-spec flat top receivers from Colt, Armalite, STAG, Rock River Arms, Barrett, CMT and Bushmaster in the 5.56 or 6.8 cal. carbine, mid, and rifle lengths. The #51 S.I.R.® Allows mounting to the carbine A1/A2 carry-handle. The new #53M AR-10 in 7.62 cal. is available in Rifle length. There may be other flat top receivers manufactured that the S.I.R.® may fit to properly, but we do not guarantee or warrantee S.I.R.® on any flat top receivers other than those listed above.

This modular receiver sleeving system is a hand guard universal mounting system that leaves the barrel totally free-floating while providing a rigid ultra-light platform on which to mount virtually any mission specific accessory.

 

 

Installation of the S.I.R. system is very easy and can be done in less than five minutes using the small flathead screwdriver built into the bottom of the included sling swivel.

 

 

The system attaches both to your flat-top upper receiver using the crossbar rail and to your barrel nut using the provided yoke and screws shown below. These multiple attachment points ensure rock solid, no movement mounting to your weapon.

 

 

 

The S.I.R.® System is available in other styles and calibers;
#50C, #50M, #50M-CV, #51C, #58M-CV, #58M-CV MOD, #59C, and #59M now available.