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Discussion Starter · #1 ·
Goin to start my build thread. Received my kit from APEX and it looks to be unissued or factory refurbished. I demilled the trunnion and rear sight. didn't take pics during but pretty much everyone gets the idea.

here are some pics of my kit

Feel free to ask questions.

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Discussion Starter · #2 ·
Got a barrel from another builder. After inspecting it, it looks like its from the initial APEX offering. The journals were too small. I cut the barrel off right past the front sight journal.

I sent the barrel to Morgan Richey at class 3 machining in Texas. and had him knurl the journals and thread 1/2x28. the barrel is 12 5/6" long there is .55" of thread. very happy with the work

the barrel pressed in perfect and I used a #16 drill bit to drill the barrel pin. right now its standing at .020~ bolt gap, it will change after its welded in the receiver

last pic of barrel mocked up in the kit

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Discussion Starter · #3 ·
Ordered a HMG flat, weldment and disconncetor, its perfect and looks amazing! should be an easy build. Sent it off to 4 bush weapons refinishing systems to get laser engraved, having all the original marking plus my trust info . Borrowed the bending jig from another builder which will help out a lot.
Here is a couple pics of the flat and what images that I sent with it for the engraving

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Discussion Starter · #4 ·
Wanted a 4 prong HK style flash hider but I can only find them in M15x1 thread pattern and I had my LC barrel threaded 1/2x28. I used a 5.5" CAR15 flash hider and cut it down to around 4.5" and cut 4 grooves in it to make a 4 prong flash hider. Happy how it turned out, be better if I had a mill but used a drill press, files and a dremel tool. Cold blued it after. With it hand tight it will make the barrel 16.125" after its pinned. It will be removed after I file a form 1 and SBR it. Pic of my kit as it sits right now. waiting on the flat and jig then will be ready to build in a weekend. Also adding a 5" picatinny rail on top of the receiver to mount optics

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Discussion Starter · #5 ·
While waiting on the flat to get here I started to do the semi trigger mods. cut the housing to clear the blocking bar, and cut up the auto trip to use as the trigger pin bushing. Also pics of the HMG disconnector vs original.

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Discussion Starter · #6 ·
Working on the scope mount, cleaned it up some and blended it to match the rear sight.

Also drilled and tapped the flash hider for a 6-32 set screw and dimpled the barrel. The plan is to fill the top of the set screw with clay or something then weld over it so when I get the Form 1 back I can grind off the weld and unscrew the set screw. (that's the idea anyway)

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Discussion Starter · #7 ·
Got my flat in from engraving. Looks great except that I screwed up on the size and location of the selector markings, they are partially covered by the grip and stock. NOTE: ive welded over then and ground flat, they will be re-engraved when I send it in to be cerakoted.

couple pics of the markings and I cold blued the inside of the flat before I bent it.

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Discussion Starter · #8 ·
I installed the trigger housing and weldment to check the fitment and also locate where the blocking bar will be welded.

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Discussion Starter · #11 ·
HMG bending jig was tightened in the vice and the jig and flat was lubed up with some high temp bearing grease I got from an old job. Tighten one bolt a couple turns then tighten the other sided until it cant be tightened anymore.

A LC receiver is born!

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Discussion Starter · #12 ·
First part of the receiver that I welded was the front of the magwell and where the trunnion welds in.

cleaned up the welds some but still need to clean it up more.

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Discussion Starter · #13 ·
next I installed the rear mag weldment. with the mag catch and magazine installed to locate where it needs to be welded. it fit perfect and cleaned up very well. the mags are a little snug with zero play, but not hard to pull out. original cetme and GI mags fit perfect

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Discussion Starter · #14 ·
next I welded the rear of the receiver and installed the rear weldment. I had to out shelf of the hmg rear weldment so that I could pivot up the rear of the trigger housing so I could remove the safety. I don't really care for the way hmg has the selector hole set up, had to remove some material at the bottom of the hole so the safety would come out easier. I also had to remove a little over a 1/16" from the rear of the receiver and grind down the pad on top of the receiver so that the LC stock would fit.

as you can see I messed up on the selector marking size and locations, they will be welded up and re lasered when I send it in to be cerakoted

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Discussion Starter · #15 ·
next I installed and welded the barrel and trunnion. I did 6 plug welds and welded where the trunnion met the receiver rails. welded on the rear sight block and the cocking tube. had to cut back the top of the receiver about 1/8" for the cocking tube to fit and have the proper gap. Installed the front sight and pinned it in place. also while fitting the handguard I had to remove over 1/16" of the front of the receiver so that it would fit.

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Discussion Starter · #16 ·
welded on the shell deflector and picatinny rail. thought I took more pics but think I was too anxious to finish it

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Discussion Starter · #17 ·
AND ITS ALIVE!! built it as a pistol first. mainly because I wanted to shoot it suppressed. pics of it as a pistol then after shooting the video I welded on the flash hider and installed the stock. feels springy when you shoot it with the stock, its pretty loose like HK stocks, maybe one day ill figure out a way to tighten it up but I like so far. shot ~250rds without any jams. it did double tap a couple of times but never ran away. the pistol video is 30rds after I test fired it with a couple rds to make sure it wouldnt blow up. probably be the only time I shoot it suppressed, seemed to really hammer the endcap, like it was over gassed. I don't want to break or bend something. only sighted in the aimpoint haven't messed with the sights. it ejects the rounds straight to the right about 20 feet. shot perfecta brass and steel tulammo. bolt gap settled at .015"

had to trim some of the bolt carrier so that the bolt hold open would work, seems like the bolt hold open hole was cut 1/8" too far back.

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Discussion Starter · #18 ·
some perfecta and tulammo fired brass. the shell deflector really does a number on them

Cleaned up the welds and hit it with some OD green spray paint. looks good green, just have to save up and send to get cerakoted


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Good for you on tackling this project and documenting it all for us. Kudos on your new rifle!
 
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