I guess I don't need help just opinions.

I am at a loss as to what SIR to purchase.  The 46C, 50C, 50M, or 50MOD.  It will be going on a BM 14.5" M4 with attached phantom and I will be using a Aimpoint ML2 in a ARMS #22M68 mount.  I will be ording this upper from Bushmaster so I can have them leave out the delta ring assembly and/or handguard cap if necessary.  

Are there any added benefits from the M models over the C models.  I know the C models would allow you to change back to "normal" if you like.  Also I have found a diagram of the weights of all the types of handguard, FF tubes, SIR's etc but I have yet to find the weight of the 58MOD.  Anyone know?

I really like the extended rail of the 46 because I can mount my aimpoint farther out but I also like the 50 and the 58MOD because it will give me flexibility to mount a Eotech should I ever aquire one.  I think I saw a rail that attached to the 50 and 58MOD that would make the rail the same height but I can't find any info about it (price, availibity,etc.) Plus, is this rail as sturdy as the 46 would be?  

Any input would be appriciated.

Thanks.
JBritt

If only the ability to raise the forward rail to the receiver rail ht. is your concern, never fear a rail that raises the forward rail exists,

[url="http://www.hunt101.com/?p=72430&c=500&z=1"][img]http://www.hunt101.com/img/072430.jpg[/img][/url]

the #50 SC.Ex, and yes, its as sturdy as the #46, its the same basic design, and it works w/ the #58MOD too (pic.'d above).

/S2

Thank you very much.  I knew I had see such a rail.  

Thanks,
JBritt

Oh yea, does anyone know the weight of the 58MOD?  I am interested in how much more it weights that the 50C and 50M.

Thanks again,
JBritt

I don't have the exact 58-mod weight but the 58 weighs 23oz and I'm sure the 58-Mod is very close to this.  The 50c weighs in at about 16.1 oz and the 50m weighs 18.7 oz but since you cut off the delta ring and the tension rings it probably evens out.

Take a look at the "Rail FAQ" that's tacked near the top of this forum for more info.

Thanks for the info.  I guess I will have to rack my brain to figure out which one I want.

Thanks,
JBritt

As noted on several threads there are lots of co-called C-Models on Army weapons, I got mine off the tail end of an Army buy a couple of years ago.  Installs in minutes.  And luckily for me dis-installs just as quickly.

The SIR sytem adds a good pound and a half the the M4 and that's before you start adding "stuff."  If you really have an IR laser, IR filtered flashlight, M68, and AN/PVS14 to mount there then the rails are helpful (if heavy).  

Otherwise "the weight" will quickly negate "the look."  [;)]

-- Chuck

I believe the top selective rail that goes in the #50, also fits into the 58MOD, and prob. the other models two. It certainly is a very modular system.
Jack