New M4 build specs

[Hammered_Pair]

So through my search from another thread I have started a build for a "maritime reliability package" M4 for work.

Here are the specs on the rifle so far-

BCM 14.5 w/A2x, Socom profile (M4A1 type) upper (gas tube may get replaced with Inconel tube)
Aero Precision Gen 2 lower (checked fit with several different drop in trigger packs and GI parts, all are true drop in so lower is in spec)
Inconel 600 spring set
BCM Mod 4 charging handle
Ambi safety
Magpul grip, probably get swapped for BCM grip
BCM single point rear receiver plate ( I generally run 2 point slings but like having the option)
H2 buffer
Colt CAR stock, the old N1 type
Carry handle sight for now
Colt M4 handguards for now while I decide if I even want a drop in rail, only run a light usually (MI, KAC are in the running)


Still debating on BCG and trigger group, right now the lower is assembled with a GI trigger group.
Considering Geissele triggers (BGRF, SSA)

So I should have the rifle assembled this weekend using a GI bolt carrier I have on hand while I decide on what BCG I want to use, probably a BCM although a nitride one may be more inline with the program. It's turned into a mostly BCM gun.

Will post pics this weekend of what I have together so far, it will be a basic M4.

[1986s4]

My recent build and now favorite rifle is quite similar to yours. Some similarities:
Colt 14.5 SOCOM profile barrel
Geissele H2 buffer, super 42 spring and tube
Magpull SL handguard, it gives a little extra room for the hand over the M4 type.
I have a carry handle sight but I prefer the Daniel Defense A1 rear.
Ejection is about 4 to 4:30 from the rifle. I've had two failures to lock open so far but only while sighting in so maybe I wasn't holding it firm enough. 100% reliable off hand. My BCG is a Colt but I have a BCM too.

[Hammered_Pair]

I was intending to build the upper, but every time I'd spec one out I kept coming back to BCM.

[1986s4]

I was going to go with a BCM SOCOM barrel but I got a good price on the Colt one so that's what I went with. I consider Colt and BCM to be equal in quality. I did get a BCM blemished upper and it has a blemish but it is a tight fit nicely done unit. I used a LMT stripped lower, I wanted one of their full ambi models but they were out of stock at the time, someday..

[1168]

If you plan on buying a new BCG, Duffy’s FCD NP3 one is awesome. Its going in all my new “builds”. I’m not sure about NP3 vs nitride for corrosion resistance, but it should beat phosphate.

Since you might be buying a trigger, coated triggers such as ALG ACT or Sionics two stage might be worth looking at. I’ve found corrosion on engagement surfaces to be a problem with regular “mil spec” triggers. I haven’t gotten my G SSA wet yet, so I don’t know how it would hold up.

I imagine the stock BCM gas tube would be as resistant as any.

Can we assume you are using a regular stainless action spring with stainless spring mags?

I plan on testing a few sets of lower springs for saltwater corrosion resistance, including that inconel set, which I’ll order tonight. I picked up one of the other sets for comparison today. I’ll let you know how it works out.