M4-ish build

Had a devil of a time finding a quality carry handle sight assembly and the skinny handguards, I never liked the standard double heat shield ones. On another note I have heard the finish on Anderson lowers is crap, now I know the upper is a Cerro but Im not sure who finished it but it looks pretty damn even with the lower.
 
Nice build! ... Given that you are running a non-collapsable stock, it appears to be a MA-compliant carbine ... I'm wondering what the muzzle attachment is. Is it a faux-birdcage? I'm in RI, so we can still do the normal builds ... except for the magazines, but I was wondering what would fly 5 miles north or east of me.

Thanks,
CC
 
cookiecutter said:
Nice build! ... Given that you are running a non-collapsable stock, it appears to be a MA-compliant carbine ... I'm wondering what the muzzle attachment is. Is it a faux-birdcage? I'm in RI, so we can still do the normal builds ... except for the magazines, but I was wondering what would fly 5 miles north or east of me.

Thanks,
CC
Click to expand...
Yea stuck in MA, I won't put a collapsible stock just to have to pin it in place, it's the correct look but it's dumb IMO. I've always liked the Magpul stocks so I used that. The brake is a Bravo Co. Gunfighter mod 0, it kind of has that birdcage-ish look besides being a good unit and it was pin and welded by Public Safety Armory in Rehoboth.
 
1903Collector said:
Yea stuck in MA, I won't put a collapsible stock just to have to pin it in place, it's the correct look but it's dumb IMO. I've always liked the Magpul stocks so I used that. The brake is a Bravo Co. Gunfighter mod 0, it kind of has that birdcage-ish look besides being a good unit and it was pin and welded by Public Safety Armory in Rehoboth.
Click to expand...
I do like that stock. They're nice.

I understand the desire for good irons. And I love the A2 front sight post. Curious as to what inspired your choice to go with simply a carry handle instead of a red dot or holographic sight with an iron sight behind it? I do love the look of the carry handle. Its a nice looking carbine.
 
LakeTrout said:
I do like that stock. They're nice.

I understand the desire for good irons. And I love the A2 front sight post. Curious as to what inspired your choice to go with simply a carry handle instead of a red dot or holographic sight with an iron sight behind it? I do love the look of the carry handle. Its a nice looking carbine.
Click to expand...
I too like the look of a carry handle on an AR, although my eyes really appreciate magnification the older I get. @1903Collector what brand carry handle did you go with?
 
LakeTrout said:
I do like that stock. They're nice.

I understand the desire for good irons. And I love the A2 front sight post. Curious as to what inspired your choice to go with simply a carry handle instead of a red dot or holographic sight with an iron sight behind it? I do love the look of the carry handle. Its a nice looking carbine.
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I think its important to keep up with the basics so i like to shoot irons from time to time, and I'll be the first to admit my groups open up a lot with irons. And you have to admit they are reliable. I was surprised the carry handle is in 1/2 clicks so I have it set at 6/3 - 4.
 
Romokid said:
I too like the look of a carry handle on an AR, although my eyes really appreciate magnification the older I get. @1903Collector what brand carry handle did you go with?
Click to expand...
I got it from AIM Surplus but its made by Aero, I tried to find a Colt but they are big bucks. The forging on this one is from a known company and the quality is pretty good.
 
1903Collector said:
I think its important to keep up with the basics so i like to shoot irons from time to time, and I'll be the first to admit my groups open up a lot with irons. And you have to admit they are reliable. I was surprised the carry handle is in 1/2 clicks so I have it set at 6/3 - 4.
Click to expand...

I am curious where you got the "6/3 - 4" setting from and it's the same source I am thinking of.

Also, what is that connector between the stock and the rear of the receiver? The one that came with my Magpul MOE does not look like that.
 
FPrice said:
I am curious where you got the "6/3 - 4" setting from and it's the same source I am thinking of.

Also, what is that connector between the stock and the rear of the receiver? The one that came with my Magpul MOE does not look like that.
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Yea the improved BZ. The stock is the MOE fixed carbine stock, it comes with two different spacers, the standard and the other one is designed to be used with one of Magpuls end plates, you have to use one of them or you cannot secure the stock. The last few MOE stocks have all had the same spacers.
 
Some sweat looking carry handles.👍

You May appreciate this one I built
www.northeastshooters.com

XM177E2 clone build of a MAC-V-SOG CAR-15

I’m a military history buff, and I have been reading and listening to podcasts lately about MACVSOG Spike Teams running recon on ”The Trail” in Laos and Cambodia during the Vietnam war. Many of these guys carried XM177E2 CAR-15s, and I have been motivated to combine my love of guns with my love...
www.northeastshooters.com www.northeastshooters.com
 
Took the build to range Friday, fired 100 rounds of 855 with no issues, all my empties were in a nice pile around1-2 O'clock. Only issue I had was the bolt not locking back on the last round, checked with different mags as well. When I got it home I took it apart and noticed the buffer spring was short, shorter that a standard carbine spring..about 6-7 coils short, granted this was a cheapo kit I had hanging around. I had a BCM kit so I swapped everything over , I'm gonna head back over the range today to confirm and see if it resolves the issue. Otherwise very satisfied with this build, got it sighted in at 50yds, just need to confirm at 200yds.
 
Finally got to the range yesterday, still a no go on locking back, was only shooting PPU and LC ammo and using a 20 and 30 round GI mags. I had one time when the bolt locked back. Kinda stumped on this one so I'm going to go back, re-check all components but its certainly looking like a gas issue. I did read on another forum that an over gassed gun can have the same malfunction, IDK. It's gonna suck if I have to remove the front sight base to check the gas port. The bolt locks back every time when you do it manually.

On a good note, finally got to fire my 450 Bushmaster build, had a couple of issue of dropping the fired cases as they were extracted but after about 25 rounds everything worked perfectly. This is a great round!!
 
The 1-2 OClock brass pile can indicate an over gassed scenario or a buffer system with too weak of a spring or too light of a buffer. How far away is the brass being ejected?

One way to help narrow down the issue is to use a much heavier buffer and see if it now locks back. If it didn’t lock back before but locks back now with the heavier buffer than you know the issue wasn’t due to too little gas/too slow bolt speed. Because now you’re slowing the bolt down.
 
LakeTrout said:
The 1-2 OClock brass pile can indicate an over gassed scenario or a buffer system with too weak of a spring or too light of a buffer. How far away is the brass being ejected?

One way to help narrow down the issue is to use a much heavier buffer and see if it now locks back. If it didn’t lock back before but locks back now with the heavier buffer than you know the issue wasn’t due to too little gas/too slow bolt speed. Because now you’re slowing the bolt down.
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This is exactly what I read on another forum, I have heavier buffers to try. Brass is ejecting around 4-5 feet away at 2:00. I did swap out the bolt catch and that didn't help, Carrier key seems nice and tight. But I'm gonna break it down again and triple check everything as well. The rest of the cycle is fine, no double feeds, no failures to extract, fired brass looks good. IDK but I like the challenge of figuring this out.
 
I'd try an H3 buffer with a known-good buffer spring before I took anything apart.

Failure to lock back on known-good mags can absolutely be caused by an overgassed conditon--the bolt is cycling faster than the mag spring can lift the bolt-catch.

Damage Industries makes good springs.

$9.95 for two, free shipping through midnight tonight.

2 Pack CARBINE LENGTH Enhanced Recoil Buffer Spring, AR-15 M4

2 Pack CARBINE LENGTH Enhanced Recoil Buffer Spring, AR-15 M4
damageindustriesllc.com

Recoil Spring Material Guide

Recoil Spring Material Guide
damageindustriesllc.com
 
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So got back to the range today tried H, H2, and H3 buffers and bolt still wont lock back on the last round. This gun runs great except for this problem, no failure to extract, eject, no double feeds, nothing except for not locking back. I'm stumped here. Next trip I'm going to bring a couple different buffer springs and a complete BCG and see if that does anything....just grabbin at this point, don't know what else to do?
 
You ruled out the bolt catch.

Any chance that you swapped/mistook the disconnector spring for the bolt catch spring?

Or that the bolt catch spring itself is out of spec?

Bolt Catch Spring (8 coils):

Bolt Catch Spring.jpg

Disconnector spring (7 coils)

Disconnector.jpg
 
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Warm_Garand said:
You ruled out the bolt catch.

Any chance that you swapped/mistook the disconnector spring for the bolt catch spring?

Or that the bolt catch spring itself is out of spec?

Bolt Catch Spring (8 coils):

View attachment 776597

Disconnector spring (7 coils)

View attachment 776598
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Nope, already checked that, the catch functions fine when the bolt is drawn back on an empty magazine. I'm really dumbfounded with this one, next range trip I'm going to to bring another BCG, a couple of different buffer springs and maybe try this upper on a different lower because I'm still not convinced 100% that it's a gas issue but I'm leaning that way.

What I really don't want to do is take off the front sight tower to check the gas port size, I've never had to take one off and I’ve been told they can be a bitch to remove.
 
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The saga continues, I bought a cheap borescope on Amazon, I'm sure it's not the best but it's pretty cool. I got a nice shot of the gas port and it doesn't appear to be blocked, only issue is the light can't get up into the port so I'm basically just looking at a black hole. I'll post a picture later once I figure out how to do that lol. If I have time tonight I'll punch out the FSB pins and slide it off and measure the gas port.
 
So the deed is done, got the FSB off and measured the gas port at .078", so it's oversize (at least from what I read on the internet). I could not remove the FSB off the barrel due to the muzzle device being pinned and welded (thank you MA, f*** you MA!) but as best as I could see there were no burrs on anything. One thing I did notice is the gas tube had kind of a mushroomed head (No Jokes please) I compared it to some other gas tubes that didn't appear to be the same, more straight tipped, don't know if that means anything but I put that gas tube in for the hell of it.

So if anything the gun is over gassed so I' going with my previous plan and trying different BCG, buffer springs and such.

Edit:, I take some of that back, the gas port size varies with the thickness of the barrel come to find out. I need to confirm later but if the diameter is .750" that port is within spec. Yikes, whoever thought a tiny hole could be so complicated?
 
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1903Collector said:
So got back to the range today tried H, H2, and H3 buffers and bolt still wont lock back on the last round. This gun runs great except for this problem, no failure to extract, eject, no double feeds, nothing except for not locking back. I'm stumped here. Next trip I'm going to bring a couple different buffer springs and a complete BCG and see if that does anything....just grabbin at this point, don't know what else to do?
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OK. How about going with an A5 Buffer tube, and experiment with stacking tungsten weights?

I think (and somebody please check me on this) you can get more buffer weight into an A5, and you'll still have the necessary overall form factor for your non-collapsable stock.

ETA: Yes, the heaviest A5 buffer available is A5H4 at 6.83 Oz. H3 is 5.4 oz.

VLTOR A5 Buffers....
 

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Warm_Garand said:
OK. How about going with an A5 Buffer tube, and experiment with stacking tungsten weights?

I think (and somebody please check me on this) you can get more buffer weight into an A5, and you'll still have the necessary overall form factor for your non-collapsable stock.

ETA: Yes, the heaviest A5 buffer available is A5H4 at 6.83 Oz. H3 is 5.4 oz.

VLTOR A5 Buffers....
Click to expand...
Here's thing, and I didn't put this in a post. When I was was trying different buffer weights by the time I got to the H3 the guns recoil impulse was very sluggish and I started getting feeding jams. The gas port is within spec, I confirmed that so now I don't think its an over gas issue, I'm missing something however. Also all this time the only ammo this gun has seen is LC M855 or M193. Next range trip I'm going to bring another gun that works to swap upper/lowers. Also going to try a different BCG and buffer springs.
 
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