Once I got my can, I couldn’t help but try putting in on everything. Ideas started floating in my head for a suppressed A1. Started reading up on the HEL-E4A and its dimensions. Both cans are 1.5” OD anyway. Saw that primary arms had FN 18” govt HF CL barrels on sale and starting comparing the space between the gas block and suppressor on MK12’s. After a rough sketch it looked like there might be enough room for some sort of collar to mimic an HEL. Mike at 19Charlie tactical had just done a Gordon collar for me and it turned out great. Custom collar butted up to the FSB with a cosmetic clamp. I ran the idea past Mike of doing a similar setup with this. He thought he could make it work so I grabbed the barrel from PA and picked out some machine screws from the local hardware store and sent them his way. Super stoked with how it turned out. Wasn’t going for super clone correct considering the modern can but thought it would be a fun build nonetheless. I requested the barrel turned down to .625 between the gas block just to look better at arms length. Upper is an H&R, handguards are the Colt re-issue that I polished up a bit, and used a T91 port door. This upper shares the lower from my NDS 604 build from 8 or 9 years ago. I guess this makes this a pseudo MK4 Mod 0 clone.




Original HEL-E4A mount vs modern



Some of the materials I referenced. One source shows the HEL having a 9.5” OAL. Mine measures out at 9 5/8ths by shear coincidence. Also I decided to use 10-32 screws instead of 8-32 because the ones I found locally had really short heads and I thought the 10-32 looked better to my eye.  



Some reference pics. The first one is from Small Arms Review article on the HEL. Looks like an XM16E1.











Aforementioned 604 and Gordy



Mike also snuck in a neat stamping of his logo which I found cool as hell.


19Charlie has been awesome to work with and has some pretty rad shit on his socials. Look him up and give him a follow. Can’t wait to get this out to the range.

Very cool!

I had toyed with the idea of doing something like that, but never made any progress towards it.  So I am quite jealous.

Dammit!!!  I was all set to finally have bought or built my last AR, the number that I own is ridiculous, and now you’re tempting me with another build.

Yeahhhh… this is badass

Damn, Ron made me a custom collar for my 18” NoDak 601 setup for a similar look, but you really knocked it out of the park.

- Kirby

That is so awesome. I've been needing to get an AEM5 for a Mk12 and Gordy builds, but had been kicking around the idea of doing an A1 like this as well. Can I ask what the mount ran you?

I'd love to see a pic of that rifle of yours. We considered using a pencil barrel and shaving down the front muzzle flare but decided to go with an A2 profile to give more thread shoulder to work with.

$350 plus shipping. That included FSB prep and mounting, barrel work, re-park, and such.

Saw this gas deflector in an old HEL-E4A thread and took a crack at making one using some 1/16th rubber and an office binder clip. Supposedly they were made to use in conjunction with the HEL





Chopped up the clip, bead blasted it, and rattle canned it with some matte black I had. Pretty crude but I like how it turned out

Yea, so this is one of the cooler builds we’ve had here for a while.

Seriously. I need to do this.

ETA: @--FLEET-- can you take a pic of the barrel and mount with the suppressor off? I wonder if it would work with a light barrel...

Yessir, should be doable with a pencil barrel if you turn down the muzzle flare to allow the collar to slide over. Just depends if you are comfortable with the reduced thread shoulder. We erred on the safe side.

Been trying to find as many pics as possible of MK4’s and HEL’s.
I’m wondering if the rifle on the far left is a MK4 but without the can. Looks like a collar part way down the barrel.

The rifle down in front looks like it might have a collar as well but harder to tell. Anyone else have anymore pics I’m missing? TIA

I'm having a buddy with a machine shop mod a dummy suppressor to replicate an HEL- e4 to pin onto a 10" upper.

I'm REALLY liking the gas deflector!  I'm definitely going to incorporate that on my build!

Mike at 19Charlie is working on my barrel right now. It’s a pencil barrel so it should work just fine according to him.

I’ll post pics when I get it back.

I’m also probably going to try that binder clip charging handle now.

Love this thread.

This thread is missing my detailed photos taken at the West Point museum of their example. This was a spotter’s weapon and was utilized in conjunction with the museum’s accompanying XM-21 sniper.

Fantastic photos!

I guess I’m using my XM-16E1 lower for this project now.

Awesome, can’t wait to see it!

Dang, that’s beyond cool. Thanks for sharing those. Checked out your full thread too. So much killer stuff in there.

FINALLY got my LMT. It won’t live on this gun but I couldn’t resist. For the lolz.

Perfection

Love what you've done, OP!

I'm the one who came up with 9.5" from photos and a Small Arms Review article.  They listed an overall length of an earlier version and the E4A is the same with fewer baffles, so I figured the baffle length and subtracted.





I might have to modify my base cap based on that drawing you have there.

Is there any pics of the front of this thing in the wild?

Did the original collar slip over a standard barrel or one turned down?

What size binder clip did you start with here? I tried replicating this and ended up with a mangled binder clip and a shredded piece of rubber.

Any tips you have for us mortals trying to make one?

Thanks man, cheers!



I'd love to see some if they're out there



The one I used is 1 1/4" long and the closed end where you drill the holes is just over 9/16". I can send you one if you need. I just used a pair of tin snips and a hand seamer to get the shape and then touched up the edges with a file. Luckily my first draft ended up working out but I could probably make another one if you decide to throw in the towel. I ended up doing the RTV gasket maker mod on the charging handle as well but haven't shot it since. Didn't notice a ton of gas to the face with the regular charging handle but I wasn't ripping through mags either.

Saw this on Reddit. Probably my favorite HEL pic I’ve seen so far

I saw that too!

Your post with the M203 and HEL set up wasn't too far off.

Couldn't decide where if I should post separately or keep it all in one thread but I figured having the info in one place would be better.

Anyway Mike at 19Charlie Tactical finished up my HEL collar and I got it all together. Got a real camera out for this one.

Pics:

Looks sick man, turned out beautiful! Great pics too, definitely gunna add them to my HEL album. Let me know how it shoots. I've still only had a few mags through mine to function check and still need to get out and zero my irons an dial in the scope. Great build sir!

So hot

Will do. Hopefully this week.

How was the gas blow back on yours? Did you do the RTV trick on the charging handle?

I was thinking about a brt gas tube too depending on how it goes.

Yea I did the RTV gasket on there under the gas deflector. In the limited shooting so far I didn't notice the gas being any worse than my Mod H with a gas buster CH

Got to the range this week. RTV trick definitely helped.

The spring noise was louder than the shot I think. Is it sacrilegious to put a JP silent spring in this thing?