I'm going to place an order for my Model 1 Sales kit at the end of the week. It'll be in .300Fireball, Carbine and A3 upper.  Other then that I'm more or less open to suggestions.  Try  to keep it under $700 bucks and keep it  logical.  CAR stock or M4 please, no A2 fixed stocks.  Green furniture is cool but I could live with black. M4 handguards would be nice but I could live with CAR handguards too.  Carry handle is fine as long as you provied a rail under the handguard to store/mount it when it's not in use, I don't want to carry it in my ruck, I want it on the gun.  OR a folding rear sight would also work.  Optics will be Trijicon Reflex II with the 12moa triangle, no option there, I've made up my mind about it. Hit the Model 1 Sales web site and let's see what ya'll come up with.  I've got a couple builds worked out but I'd like more input. Talk to ya'll later.

What, no one want's to help me build up an AR?  Ah, man, guess I'll have to go it alone.

my plans

DPMS 16 inch upper from cmmg
Shave the FSB and put on a MRF10
Ameetec or Stinger lower
Vltor mod stock
and an eotech and call it a day.

Welp, looks like you've pretty much made upi your mind, and $700 doesn't really leave much room for other fun stuff.  Not that I'm a big fan of adding junk to a rifle.

Have you looked at grips?  I have a Hogue and Ergo, in addition to the plain-jane A2.  The right-handed Ergo is just fantastic.  A definite must-have if you haven't tried it.

I'm thinking of on like in the movie SWAT, if I can get me mits on an ACOG

I'm going to shave the bump off of the A2 and make it into an A1, they never put the bumps where I need em', it's always under my fingers, not in between.  Things that I do know are as follows:
16" Carbine
A3 upper
.300 Fireball
Tele stock(CAR or M4, not sure which)
Removable Carry handle(99% sure of this)
Some kind of rail on the handguard to mount the carry handle when not being used.
Trijicon Reflex II

Things I'm not really sure about are:
A1 flash hider or Phantom(is it worth the extra $25 for the Phantom?)
Black or Green furinture(I like the look of the green but $20 bucks is $20 bucks)
Folding front sight($75 dollar option, not sure if I really need it or if it's sturdy enough)
Tactial Forarm(Yankee Hill, CAR length, $125 dollar option, Free Floating, but would also need 3 rail covers at $12 bucks each to make it look right so that's another $36 bucks. The Young Manuf. rail would do the same thing for $19 bucks if it's sturdy enough.)

OK, here's what I've got.

CAR Carbine in.300 Fireball
A3 Upper
M4 stock
M4 Handguards
Black Furniture
A1 Flash Hider
 and
A.R.M.S #40(since it seems to be the standard by which all others are measured.)
But here's the question, with a standard front sight which #40 will work.  the 40L or the standard #40?

TNFrank,
 If your doing a whisper in .300 and using a standard gas port/gas tube you may end up with problems on cycling.  In our testing we found that the presure curve on the .300 whisper is so quick that we had to go to a 7 1/2 inch gas tube(pistol setup) system to cycle properly(JP makes an adjustable system, haven't used it though).  Also order a go/no go headspace gauge and do your reloading based on that gauge.  Assuming that model1sales does a good job of reaming(or who ever they had do it for them) and that your go gauge fits properly........ Otherwise

 the 300/221 is a fun.... fun little cartridge.  I personally like then a fixed stock, it's more repeatable and shifts/moves less the m4/CAR.  Eventually look at a SIR, pof makes, IMHO one of the best ones on the market.  I've had Aimpoint, Eotech, Cmore on mine, with a PVS-14(for a short period) and loved shooting at night.  GG&G makes good BUIS, but I have yankee hill as well and both are great.  Also, look at a tactical/oversized CH latch, tactical bolt stop and an ambidextourous selector.

I plan on mostly loading super-sonic so I should have enough gas pressure with the CAR length gas tube to cycle ok.  I've also heard of problems with the standard gas set up when loading sub-sonic.   I've noticed that M1S has listed this ctg. in their kits for quite some time so I think they'll have all the bugs worked out by now, if not I'll cross that bridge when I get to it.  I really think either the DPMS folding sight or the ARMS #40A would be a good way to go for a BUIS, I know  for sure that I'll not be ordering the ASA sights that M1S offers because I've heard too much bad stuff about them here on the forum. I think the M4 stock will be ok for my needs, part of the reason I'm doing this build is to make a "no ban" gun and a tele stock is part of the fun in doing this build.  

If im reading your question right you were asking if there would be a sight height difference zero wise between the 40's.  As far as thats concerned they are all the same.  The 40 has part of the aperature cut off i think so an acog will fit.  It may have some other use other than making it lower but i dont know so im not going to bs you.  The 40 a has the whole aperature and the 40l is a very low profile one with smaller knob and it will fit under my scope.  On the 40l when you flip it up the small aperature comes up first while on the 40 and the 40a the large aperature comes up first. Thats how it was when i bought mine.          

Quoted: If im reading your question right you were asking if there would be a sight height difference zero wise between the 40's.  As far as thats concerned they are all the same.  The 40 has part of the aperature cut off i think so an acog will fit.  It may have some other use other than making it lower but i dont know so im not going to bs you.  The 40 a has the whole aperature and the 40l is a very low profile one with smaller knob and it will fit under my scope.  On the 40l when you flip it up the small aperature comes up first while on the 40 and the 40a the large aperature comes up first. Thats how it was when i bought mine.

Thanks, that helps out some. So it looks like I'd want the 40a because I like the larger aperature as my primary one.  Is the "low profile" just the sight base more or less?  It's not that the sight is lower when it's popped up, right.  They'd all work with the standard front sight installed.  I think I'm understanding what you're saying about the 40's.  Thanks again.  I'll probably go with the 40a, that sounds like what I'm looking for.  

Yep youve got it there is no height difference when they are folded up.  If i didnt want to use a scope on mine i would have kept the 40A.   I dont really know how to explain it.  the two aperatures are made different where they fold together on the 40l so it will sit lower thats thy the small aperature comes up first.  so it basically a 40 with the protective wings cut down allot and the adjustment knob is smaller.    

I e-mailed a guy on the EE that's got em'. I'm going with the #40A, I think it'll work best for what I want.  I figure I'd throw a fellow ARFCOMer some business rather then buy outside the loop,LOL.  Man, I'll be glad when I get this build done.  I just hope that the chamber from Model 1 Sales works ok with the brass that I'll be using. Like I said, I'll be loading super-sonic so I should have plenty of pressure to work the bolt.  I'll worry about sub-sonic loads when I get the money to order a supperssor, who knows when that'll be.  Here in Tennessee you've got to have a .24cal or larger to hunt deer with and the 6.8 still looks like it'll be some time before stuff is available and cheap enough for me to get into one so I went with the .300 Fireball.  Dies were about half, brass was $120/1K and bullets are cheap if you do like I did and load 150gr FMJ's.  All in all it's a nice little ctg. that'll just about do anything the 7.62x39mm will do and I can hunt deer with it.  Talk to ya'll later.

Ok so let me get this straight.

#40 - large and small apertures, large is default.
#40L - lower profile, large and small apertures, small is default
#40A - large and small apertures, large is default.

What's the difference between the #40A and the #40?

Quoted: Ok so let me get this straight. #40 - large and small apertures, large is default. #40L - lower profile, large and small apertures, small is default #40A - large and small apertures, large is default. What's the difference between the #40A and the #40?

Actually the #40 and #40A are the same except the smaller aperture has had the top cut off of it so a scope will fit over it. The "L" is really the only different one and that's only because it's "low profile" with small adjustment knobs, other then that they all have the same sight level when open so they'll all work with the standard front sight.  I like the #40A, it doesn't look like it's been "chopped".

Well, here's what I ended up with:

Standard CAR kit from Model 1 Sales in .300 Fireball
A3 Upper
YHM Folding Front Sight(Impluse buy,LOL)
ARMS #40A Rear Sight
Trijicon Reflex II 12.9MOA Triangle
Tactical Advantage QD Sling and Mount


At a later date I'd like to add a set of YHM two piece rail mount handgaurds and maybe a vert. grip, we'll see how the standard handguards work out first.  I may or may not add a Phantom FH. Anyway, that's about it.


P.S.
Won't be able to put a Phantom on it because the barrel is threaded 1/2x38(guess that's the same threads as the 9mm barrell) so I'll have to live with the A2 for now.

So does the #40A not have a 500m aperture?

It has a 0-200 that pops up as default, and then a 2-300?

The #40 has same, but the 2-300 has a notch so it can be used for 500m?