Kaos AR Build #2: Defensive Carbine

[Kaos]

So many of you may remember the garbage 15 project I worked on late last year.

This time I decided to chronicle/discuss my new build here. Partly I think threads like these are a great resource of information because quality information will be shared.

I bought a complete lower from another member here for this build. I'm likely going to swap some stuff out and cange a few things, but it will be a good base for my carbine.

So what I have so far is a DPMS lower. He told me it was a DPMS kit inside it, but compared to my other 2 dpms lpk's this one has MUCH better build quality. So it's likely the game where they just play leapfrog with their suppliers and who knows where it came from.

Two things it has that no other AR I've ever had on it were a "tactical" bolt catch lever, and a tactical oversized safety/selector. I had to remove the hammer pin because the hammer spring was incorrectly installed (not sure if it was assembled factory or not).

First thing I learned:

Removing a hammer pin while the bolt catch is in the way is a PAIN IN THE ASS. Adjusting the Mag catch is impossible without removing the tactical bolt catch.

Solution, Im getting rid of the tactical bolt catch.

The oversized safety/selector isn't something I thought I would like, but it's built out of solid metal and makes manipulating the safety pretty damn easy in no/low light (I've been playing with my lower).

This is also the first time I've owned a collapseable stock. Initial impressions are that it's different and that Im not used to it. I will say that maneuvering through doors is much better with it. I'm not going to instantly replace it with a fixed stock but I will explain my thoughts for the rest of the build below.

So now I present my plans for the build:

• Replace stock with a Milspec Magpul CTR
• Replace standard buffer with heavy buffer
• Replace grip with Magpul MIAD
• Replace trigger guard with magpul winter guard
• Add KNS Gen 2, Model 2 non rotational pins
• Add KNS push button pivot and takedown pins
• Add rear sling plate (hook and strap type)
• Add Midwest Industries 9" Mid length drop in 4 rail handguard
• Use Magpul XTM covers to cover empty spaces
• Pick a quality flat top upper
• Pick a quality (likely chrome) carrier and bolt
• Add quality flip ip BUIS (troy likely)
• Add EOTech or Aimpoint sight
• Add VFG (Tango Down or LaRue)
• Add flashlight mount (daniel defense offset) and light
• 2 or 3 point sling

This is going to be a much more expensive build than the last time, but I want it to be something that I will like very part going into it. I decided that for a defensive carbine I didn't need it to be free floated. I went with mid length for a softer gas pulse and more handguard area.

Oddly enough AIM surplus has this image on their site, which is pretty much what I'm going for



Thoughts?
(ill get some receiver pics ASAP)

[MTechnik]

14.5" barrel, lightweight profile, with permanent flash hider? I like less weight up front, and since you'll likely need a flashlight....

Also, think now about your flashlight, it may affect your foregrip choice.

[mojo]

I like it ... I really love that stock.

I've been giving this same thing a lot of thought. This is what I was thinking.

Lower: Any quality mil-spec will work
LPK: G&R tactical LPK
Stock: Magpul CTR
Grip: Not sure yet
Upper: BCM 16" mid-length
BCG: LMT
Handguards: RRA Half Quad Aluminum FF
BUIS: Not sure yet

I'm new to ARs and haven't owned one yet ... so I'm not sure if I missed anything or not.

[synergy]

Your build ideas are very similar to mine.

I sacrificed a middy barrel for a carbine because I was having a hell of a time finding one, and a carbine barrel fell into my lap at a good price. When this barrel gets changed, it'll be middy for me.

I'm free floating anyway, just for the heat benefits, and getting the sling off the barrel.

While I prefer the EoTech reticle....I'd still say go w/ an Aimpoint.

It honestly sounds like the blaster I'd build, with the exception of the FF...and a stubby length VG.

[Kaos]

Your build ideas are very similar to mine.

I sacrificed a middy barrel for a carbine because I was having a hell of a time finding one, and a carbine barrel fell into my lap at a good price. When this barrel gets changed, it'll be middy for me.

I'm free floating anyway, just for the heat benefits, and getting the sling off the barrel.

While I prefer the EoTech reticle....I'd still say go w/ an Aimpoint.

It honestly sounds like the blaster I'd build, with the exception of the FF...and a stubby length VG.

Im still debating the FF though, the new YHM black diamond FF tube looks appealing to me, I might have a source on a middy in about 2 weeks, but not looking good at the moment. If necessary, I will just keep using the 16" CAR barrel I have, and just rebuild the rest of it around what I want it to be. I would just use the longer tube from YHM and get a rail mounted front sight. The gas block would then be "captive" under the FF tube. I like the pulse of the middy barrel a lot more than the CAR. I had a friend mention that I should go with an adjustable gas block and then tune it to my needs, but eh...not sure I wanna do that.

At any rate, Im going to start buying up parts now, the upper might end up getting pinned to my anvil lower, so I may get an anvil upper as they mate very tightly together.

I've got two lowers to play with, just going to buy a part here, a part there until I can build it all at once.

[synergy]

Im still debating the FF though, the new YHM black diamond FF tube looks appealing to me, I might have a source on a middy in about 2 weeks, but not looking good at the moment.

If necessary, I will just keep using the 16" CAR barrel I have, and just rebuild the rest of it around what I want it to be. I would just use the longer tube from YHM and get a rail mounted front sight.

I like the pusle of the middy barrel a lot more than the CAR. I had a friend mention that I should go with an adjustable gas block and then tune it to my needs, but eh...not sure I wanna do that.

I'd skip the adj block on the fighting carbine. You can adjust the buffer weight if it has reliability issues....but I don't think the adj block is anything but a liability.

I've been searching high and low on FF tubes recently....I've ruled out YHM. There is a TON of info on tubes on m4carbine.net...I've read dozens of threads on them by now...I'm just not gonna skimp here. The YHM's have been universally considered to be huge, sharp as shit, heavy, and often out of spec.

I've noticed in my shooting that I like being able to wrap around the tube with my grip, so I prefer smaller sized rails. FWIW, I have huge hands, with very long fingers and I still prefer smaller rails. This ruled out YHM for me.

Regarding their weights, yes they have the lightweight tubes, and it looks like you'd poke your fingers through the holes on them and burn yourself too easily. So the lightweight model is a no-go for me.

So for the ~$100 more for the MI or the Troy, I think YHM looses out.

Then when you compare the MI or Troy to DD or LaRue...the DD's are lighter and oval shaped (narrower), and the LaRues come with an integrated QD sling mount ($40 and never coming loose).

So for me, when I like smaller and lighter, for a couple MORE dollars...it's either 1 or the other. The LaRue's are even smaller, have the integrated QD swivel, are built like a brick shit-house, and just plain cool. The DD are just about the lightest thing going, and also bombproof.

The other consideration I had made was the JP VTAC tube with removable rail pieces. Price is good, weight is great when it's bare, diameter is what I want.....but for me, I'm going to want a full length top rail, a piece at 9 o'clock for a light, a piece at 6 o'clock for a shorty VG, and a QD sling mount too. With those pieces on the tube, the price and weight just went up to the LaRue or DD...and the JP has more pieces and screws to monitor shooting loose/ move around as I adjust the weight dynamics/ placement of items.

So, in the process of trying to be a specific but thrifty bastard, I ended up selecting the 10" LaRue rails. Funny, huh?

[Kaos]

I already have the carbine YHM LW FF Tube on my current rifle. It is a bit big as you say, but as far as being sharp or out of spec, I haven't seen anything to that effect as of yet.

It does the job well so far.

My fingers dont go through the holes enough to burn my fingers at all, and I also have giant sausage hands as well. For me, I wouldnt have an issue going YHM again, but more narrow in the same price band would be more desirable. I guess though that with rail covers the bulky-ness would me magnified a bit.

Everything is up for debate at this point, I'm still fighting to find a middy barrel.

[MTechnik]

I have the YHM Rail... I got the magpul ladder covers instead of the other big ones. The rails ARE kinda sharp, but that's why you have covers on them.

The DD rails are now "the" official army rail of choice I think now, so if that matters to ya...

Then again, I use a VFG at this point, and don't normally grab the rails.

[BOHICA]

both larue and DD make awesome rail and both have Qd mounts older models didnt but now do ...i personally like the DD omega rail no need to remove the barrel nut and it still a Free float rail system

as for the KNS Gen 2, Model 2 non rotational pins you dont need them on a semi auto they are designed to prevent ovaling of the pin holes which unless your shooting full auto you need not worry

I also didnt see a trigger upgrade on your list its of the best non cosmic upgrades you can do IMHO

here is whats in my carbine

LMT upper and Lower
LMT 2 stage trigger
Magpul MIAD full kit
Magpul CTR stock
Magpul XTM covers
DD 7" omega rail
larue fug
eotech 553
Troy BUIS rear
badger ord. gen 2 charging handle latch
Cr 123 batts in fug
larue's lil bottle of lube and spare gas rings and firing pin retaining pins in MIAD
surefire scout light

[Kaos]

I didn't pick a trigger upgrade mostly because I'm not sure it needs one. If I were shooting for competition and needed every ounce of speed I could squeeze...I'd go lighter.

I've used plenty of two stages to know how they feel, just prefer single stage for defense. If I had to pick a trigger upgrade I would likely get one of the drop in trigger kits (like timney etc) around 5-6 lbs I'd think.

The KNS pins can provide more than just the benefits you spoke of, in many cases users will have a much smoother trigger pull after using the pins for a bit, of course this happens without non-rot pins but just takes a bit longer.

Every fully auto and SBR AR-15 and M-16 that I've shot (only a few FA, but enough to know) had them. They're a cheap upgrade.