I expect that this is going to run me around $2-2.5K when all is said and done.

So far, here's what I've put together.  Some parts are new, some are used.  My intent is not to use vintage parts, but to use parts that look correct to provide the proper look, but has better reliability than an original would have had.  It'll also be my first AR that uses the "grey" receivers.  A benefit is that essentially all of the 607's were "parts-bin" builds by Colt, so they vary.  Some have the full A1 grip, some are cut.  Some have the FA, some are slickside.  I've opted to go with the FA and will use a full A1 grip.  Another decision is that I am attempting to use an 11.5" barrel instead of a 10" barrel, with a slip-on XM177 moderator that will go over the barrel so that it appears to have a 10" barrel.  We'll have to see how that turns out.

What I have so far:

NDS/Brownells "retro" A1 receiver, lightly used (grey) w/teardrop FA and no bayo lug on FSB.  Proper .625 profile.
H&R GX-5857 grey receiver from PSA
Grey slip ring
11.5" Colt barrel assembly (used) - has a non flared end of the barrel, but was not "cut down"
Carbine triangle handguards (trying to decide if these are OK, or if I need to go the route of cutting down real ones and using the proprietary end cap, but will begin with these.
607 stock assembly from Ordnance Research - ouch - that one hurt, badly...  $810 by itself
H&R LPK from PSA - proper for grey lowers
A1 grip (vintage, mottled)
phosphate BCG
standard charging handle
SBR tax stamp (of course)

Still trying to work out the moderator...

Sherluck has the 607 handguard caps for $25. He is the only one I know who has any. They are not the proper ones but they work. I grabbed me a couple a while back. Just mentioning it incase you want to grab one before they are all gone. https://www.sherluk.com/m16e.php

I grabbed me a couple real handguards from Numrich for mine. I cut them down on the miter saw at 3 degrees. 6 3/8" long. I found an old thread on here that said as such. (see below) No idea if this is right but it worked for me. The carbide tip blade spinning at 4k rpm went through them like hot butter. (cut slow. wear safety glasses) The angle and length worked out great for me. I pulled the slip ring back as for as it would go and they slipped in with about 1/16" - 1/8" to clear. The slip ring seems to sit pretty straight too. https://imgur.com/a/JXmQA8O

The carbine handguards look fine on the 607 but just throwing this out there incase you decide to go the original route.




"Handguards 6 3/8" length ***NOTE:  Model 1 sales cuts them to 6 1/4 inches."


"When you get to the miter saw part...

Put the bottom of the handguard against the miter saw fence with the receiver end facing the blade.

Lower the blade and slide the rear of the handguards until they touch the blade.

Adjust the miter so that the saw makes full contact with the flat part of the handguard where the slipring will go.

This will be the angle for the cut.

Same for the other side of the handguard, just the miter will be the opposite direction."

I built a lower for a customer using one of those repro stocks (original stock body, new other parts and hardware I guess). It was a very complicated process. Threading the receiver, threading the slide rod to match, drilling the cross hole that retains the slide rod AND the takedown pin detent & spring, and cross drilling the slide rod for the buffer retainer and spring.

I would suggest having the stock fitting work done before stamping the lower, that way in the event something happens, you're not totally out a stamp.

You don't have to do any of that with the stock I got.

I'm still not convinced that I want to do that cap.  Is the only way to get that cap on by removing the FSB (the forward triangle cap is already on), or can it slip over the barrel nut if the slip ring assembly is removed?

It will slip over the barrel nut.

Do the handguard cap. I think those ready made triangle handguards look terrible.

Sweet! Dude must have changed the design since I built that one.

If you find a moderator like that, please let me know. I'm using an 11.5" barrel, and with the moderator it's right at 15.5". Looks too much like a ghetto pin and weld job for my likes.

Agree 100%.

Does heat beat still make the HG caps? That is who I got mine from.

I took my mutt 607 clone to the range to sight in and test for function today.

It likes lube. Lots of it. I only shot about 100 rounds.

If you go with the Ordnance Research stock, they are cool.

Stake it at the buffer tube. Small stake.

Can you stake them without a stake notch? I did the airsoft stock guts for mine but same set up as Ordinance Research I think as far as attaching. I had to use a strap wrench to tighten. I feel like it needed to be tighter or staked or something. Did you cut a notch or just stake? You got a close up of your staking? https://imgur.com/a/86lAi0Q

I didn't realize that some of the 607's had a full-fence lower.  Though I guess his could also be a lower from an M16A1 or an XM177E2...

ETA:  Yes, I am dumb - it's an XM177E1.  

Attached File

Im not sure where you're getting 607 out of that picture, its clearly a late XM177E1.

You're correct.  

Sweet

See below.

I posted in another thread on accident.

My tube was working loose.

Stake here.

Well, I tried to stick to my plan for keeping the 11.5" barrel and getting a fake OTB moderator, but both of the guys who have made XM177 moderators said that it's not possible to do because it would be too thin.  I'd have to reprofile the barrel thinner than it already is, so I am just going to have ADCO cut the 11.5" down to a 10".  Just sent it in today.  I expect turnaround to take about 2-3 weeks with shipping both ways, and then I can finish this build.

...

@TheYellowThing or anyone with an Ordnance Research stock, I have a question.

I am terrible at explaining things so hope you can follow. A standard A1 / A2 or entry buffer tube is made to normally be tightened down right up against the receiver. This allows the threaded part to barely go over the buffer retaining hole to hold the buffer retainer pin in. When you put a receiver end plate on one, it does not screw in far enough. When I built mine, I spent weeks looking for the correct buffer tube. I just ended up using the standard entry length buffer tube. Then I had to cut about an 1/8" piece off another buffer tube to hold my buffer retainer pin in place. Apparently Ordnance Research are using buffer tubes with longer than standard threads. Anyone have any idea where Ordnance Research is getting their buffer tubes?

I've sent 2 barrels to JT at Retro Arms Works. Took 3 days for him to get them, he did his thing the day he got them and shipped them back that same day.

Question about the Ordnance Research 607 stock. Is this a rock solid adjustable stock? Tight lock up? Easy to extend/retract?

Yes. The lock up is solid both closed and extended. Make certain to lube both the buffer tube and lower guide rod/tube.

I had an issue with mine becoming difficult to slide open and closed after shooting it for awhile. A little oil wiped on the outside of both tubes and it was fine.

Well, I've got the lower together.

I used an H&R GX-5857 gray receiver, an ORI 607 stock, an H&R gray LPK and an A1 grip that matches the stock finish with regard to the level of "mottled".

Still waiting on the H&R upper (w/FA) since the "Colt gray" I have didn't match the lower receiver color very well.  Also waiting for my Colt barrel to come back from ADCO - should arrive late this week.  I got two sets of triangle handguards from Numrich and I'll pick one to cut down per the instructions Shane733 offered above.  I'm a bit nervous doing that, but considering the HG's are fairly inexpensive all things considered, it should be OK.

The ORI stock is actually really cool and well done, though there is a bit of lateral play to it - not much more than an CAR or M4 stock.

The finish on the receiver is a stark difference from the mottled and slightly worn finish on the grip and stock.

I started out building a M16A1 in like 2022. As I was buying parts, I ran across some parts for a 607 so I said what the heck, ill build one them too. So for well over a year I had the fear of cutting 5 decade old handguards up and ruining them in my head. Then somewhere in 2023 I ran across these real USGI right handguards for $2.49 (Think they were dated 1984) - https://armysurpluswarehouse.com/m16-triangle-forearm-right-side-only/

I think I ordered 6 of them. Didn't want to get greedy so left some for other retro builders. I figured I would start with cutting one them to see how it fit and set in there. Not long after I ordered a set from Numrich. The left one was ok but the right had broken teeth. Few weeks later I ordered another 2 sets. Same thing. Lefts ok but rights had broken teeth. Numrich is a no questions asked return place. They even give you a return label to print out. So I ended up sending all them broke right ones back and just keeping the good left ones to go with my NOS right ones. Scuffed the NOS ones up some, they matched the surplus ones ok.

So in the end, I was not going to feel as bad if I messed a couple up cutting them but it worked great for me. First cuts worked great. They did take some work to get in there. Lots of sharp edges and lots of pressure to get them in there. Take your time. Some just use a hacksaw. I went real slow and the miter saw worked great for me.

Rights are the NOS. Lefts are Numrich surplus - https://imgur.com/a/kzxvJ8f

Well, I cut the handguards.  I used reproduction triangle handguards to see how well I did and tried some test cuts toward the rear where I wouldn't be using that part.  They actually came out perfectly when measured with the pre-made carbine triangle handguards when I put the cap on the end.  Exact same size.  Whew - wasn't that bad.  Thank you so much for the instructions and specifics.  The only thing I did differently was I put some masking tape where I didn't want to cut so that I'd make sure to get the perfect cut.

Still waiting on the upper receiver and my barrel to come back from ADCO.