M4 solid build questions

[Tangotag]

I needed to order a friend some small parts and one thing lead to another and now I am building an affordable but durable M4.

BravoCompany had some of the DD stripped barrels, I toyed with the MidwayUSA and Brownell's deals when they were going on. This time I took the plunge and ordered a bunch of parts.

All of my other ARs are 1/9 which have been alright but not really solid.
I got into ARs starting in 86 so most of my stuff is old and my AR have collected dust until recently.
Since joining the board here some have gotten recent upgrades recently like Magpul stocks, TD shorty VFG, and Noveske Pig.


For my M4 I picked up a BC M4 flattop, DD 4150 5.56 NATO 1/7 M4 barrel, "F" FSB, taper pins, other barrel parts, BC BCG, double lined hanguards(I prefer the larger diameter). I had a few extra small parts from previous orders.




I have $506.75 in so far.
I plan on adding, for sure, a ARMS#40L for the rear sight. These I really like.

The barrel assembly is not a problem, I have a well experienced machinest/smith friend.

How durable have been my choices so far? I am looking to build something close to the durability of the 6920 that my friend has.

With the "F" FSB do I use the standard A2 sight post or do I need the taller version? I was thinking the taller post was for A2 FSB and a flattop upper but I am not sure.

To finish it off, I have been thinking about tricking it out like going with a Noveske non-second lower and using a Geissele SSA Trigger. Maybe adding a Norgon ambi-mag release and an ambi-safety. Buttstock might be just a milspec M4 stock, extension and, H buffer. Money, time, parts availability will tell on how this will end up.

I kind of want to go with a higher end lower what others might fit that bill?

[Failure2Stop]

I prefer the MI SPLP and Troy Battlesight over the ARMS 40L, though the 40L is one of the better products that ARMS makes, they still have problems.
For the money, the MagPul MBUS is a really good value for a BUIS.
One thing that makes a difference in BUIS choice is what optic is going to be the primary.

You are correct about which posts go to which FSB, standard post for the "F" FSB.

Getting a high-end lower is kind like putting spinners on your car. Looks interesting, but doesn't do anything different. Of course, if you can get a Noveske for a decent price, jump on it, however- simply saying something cool on the side isn't going to do anything for performance. As long as the receiver is in spec, it will be fine. The next step is to ensure that your LPK is good quality (not a whole lot of them available, but avoid guys like DPMS and M1S for your LPK).

Make sure you stake the places that need it after torqueing to spec.

[Tangotag]

Failure2Stop
What are the known issues with the ARMS#40? I have an older 40L, I like it, so I thought maybe stay with the same but I am open to other suggestions too.

Primary optic will come later, ACOG or T-1 maybe? I would like a solid BUIS since I intend to use it as primary for a length of time first.

Does the board have a list of lower receivers that are mil-spec? I have been burned in the past with 4 lowers that are not mil-spec. I'd like to prevent issues ahead of time for this build.

What are my other options for LPK? I see that Bravo Company sells DPMS LPKs, it makes me wonder if that's in their assembled lowers?

[Mo_Zam_Beek]

TT - I think you are off to a great start.

ARMS - I have had a 40L for about 9 years they don't get used much but I feel just great about having it on there. I also have Matechs and Troys. My recollection of the knocks against ARMS was related to the spring set up. The Troys are super beefy and I think there is a feel good level there for most. The Matechs are definitely the weak sister of the group. The feet are very dainty and will snap if over torqued. In short, if you want bomb proof - get the Troys. If you want a great BUIS that will more than likely do every last thing you want and save you a buck or two find a 40L. I wound up with a set of the Matechs b/c they were $40.00.

Lowers - I am sure you have read that there are only a few companies that are responsible for manufacturing and that the rest just put their roll stamp on them. I completely agree about the 'spinner reference' and see zero up side in it. As far as spec? Somewhere around here 'ScottyRyan' I believe it was, had a post on 'How to do an SBR' (look here in the NFA section or across the street in their NFA section for this post). In the post he makes the point that you are going to be married to this lower forever so you may as well confirm that it is in spec with a micrometer prior to sending in your paper work. Long way around to saying - if you have been burned by out of spec lowers before - chase down that thread, record the data, take that data and your micrometer to the gun shop and mic the actual lower that you are going to buy. It may cost a couple bucks more at your local gun shop but you will have 100% assurance it is in spec prior to purchase. That said, I have built on several DPMS lowers in the last few years - all were in spec.

LPKs - avoid DPMS - had a buddy that had (of all things) a mag catch break recently - can you say 'spear'. If you can find them I can vouch for LMT and CMT.

Also if you aren't left handed 'ambi' translates to 'extra snaggy thing, prone to breaking' - I wouldn't do it.


Good luck

[Tangotag]

Update** Grant@G&R has an order in from me.

I ordered a BCM assembled lower with M4 stock and a Troy Battlesight.
Thanks for the suggestions fellas, I will update with pics and a range report when finished.

[CharlieMike]

I kind of want to go with a higher end lower what others might fit that bill?

I really like the dramatically flared mag wells on the Daniel Defense lowers.

[gman622]

Update** Grant@G&R has an order in from me.

I ordered a BCM assembled lower with M4 stock and a Troy Battlesight.
Thanks for the suggestions fellas, I will update with pics and a range report when finished.

Nice! What optic is that ?

[Tangotag]

Optic?
Troy Battlesight = Troy's BUIS
http://store.troyind.com/Rear_Foldin...fbs-r0bt-0.htm

Or
The pic on top = Trijicon Reflex (No batteries, a early short lived, SOCOM M4 accessory kit dot sight) real hard to see the dot when shooting from a dark shaded area to a bright area.

[gman622]

Optic?
Troy Battlesight = Troy's BUIS
http://store.troyind.com/Rear_Foldin...fbs-r0bt-0.htm

Or
The pic on top = Trijicon Reflex (No batteries, a early short lived, SOCOM M4 accessory kit dot sight) real hard to see the dot when shooting from a dark shaded area to a bright area.

Thanks

[Tangotag]

Barrel is now mounted and the FSB is taper pinned. I held off on installing a sling swivel since I am thinking a DD M4 is in the near future for this rifle. The BCM lower is just what I was looking for.