The terrific chart that KevinB posted on the AR Discussions:
http://appliedinc.com/railsys8.gifI'm wondering if my calculations are approximately correct.
1 pound (Lb)=16 ounces (oz)
First Samco said that their RIS handguards will not noticeably change the weight of the rifle. They are listed between 8.5 and 9 oz. Thus, the standard Bushmaster carbine handguards weigh approximately 8 oz.
Bushmaster Superlite Telestock: 6.25 Lb
Bushmaster XM15 E2S A2: 7.22-7.33 Lb so about 7.25 LB
Bushmaster XM15 E2S A3: 6.7 LB
Thus the carry handle weighs about .5 Lb.
ARMS SIR #51: 21 oz Subtracting the weight of the standard handguards (21 - 8) =13 oz, which is about .75 Lb. Put that on the Superlite A2 and it comes out to 7 Lb, still lighter than the majority of A2 carbines, correct?
ARMS SIR #50C Bilevel: 16 oz or 1 Lb. On the Superlite A3, subtract .5 Lb for the lack of carry handle (6.25 Lb - .5 Lb) =5.75 oz, then subtract 8 oz from the SIR to compensate for the other handguard (16 oz - 8 oz) =8 oz or .5 Lb. This comes out to 6.25 Lb, the original weight of the Superlite A2.
I can see how one of the heavier SIRs might cause weight issues with many AR carbines (unless one is bench firing all the time), but do you guys think that there's much to be concerned about with putting a SIR, particularly a #51 on a Superlite?