Finally...my 607 project begins! Update: all done! - Page 1

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[ARCHIVED THREAD] - Finally...my 607 project begins! Update: all done!

Posted: 5/25/2022 2:40:32 PM EDT

It's been too long...thinking back, I've owned a 607 upper and a 607 lower with pinned stock in the past ..both at separate times and both sold because "I can get another anytime." Well now is finally the time. Just bought a pretty complete kit from a nice gentleman here on the site and will be doing it right. Everything will be here tomorrow but here are the pics I got from the seller.

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Now I've never installed a 607 stock myself. I know the NDS Lowers have a roll pin hole for the rod, but the rod is also threaded. Do I need to thread the back of my lower for that rod? Or is that just another mounting option?

I'll document my build here. Super excited to finally get started. Oh, by the way, primary arms has chrome BCGs (albeit with FA cuts) on sale for $100 right now...I picked up one for this and one for my XM177E1 project.

Posted: 5/25/2022 3:01:01 PM EDT

[#1]

You’ll need to drill out the lower, tap it, and drill a cross pin for the rod. The hole in the NDS lowers are not for that but the pin size is the same. Probably going to have to open up the rod for the buffer detention spring as well.

I would not recommend trying to do it without a mill.

Also, the cross pin intersects the takedown pin spring hole. It’s what keeps the spring in place after the mod. I had to chop a few coils off of the spring to get it to fit as well.

Posted: 5/25/2022 4:25:37 PM EDT

[#2]

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Quoted:
You’ll need to drill out the lower, tap it, and drill a cross pin for the rod. The hole in the NDS lowers are not for that but the pin size is the same. Probably going to have to open up the rod for the buffer detention spring as well.

I would not recommend trying to do it without a mill.

Also, the cross pin intersects the takedown pin spring hole. It’s what keeps the spring in place after the mod. I had to chop a few coils off of the spring to get it to fit as well.

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Yikes....I might have to see if John Thomas can do it when I send my barrel to him. I'm hoping he can chop the handguards down too.

ETA man I have been out of the retro game for too long...I remember now that the pin hole on the NDS lower is for the buffer tube and the 607s had two pins.

Posted: 5/25/2022 7:13:17 PM EDT

[#3]

Handguards are an easy chop - remove the heat shields (maybe not, if you're comfortable doing it all at once - I wasn't), measure from the end you're not cutting and add a bit just to be sure, sand/dremel to the fit you want. (I did it for my LaFrance clone - biggest issue was when my boss decided to "help" and shortened the (nicer) handguards too much.) Modify the heat shields to fit, reattach and celebrate the circumcision!

Posted: 5/26/2022 11:25:58 AM EDT

[#4]

I made a wooden jig for the hand guards that fit inside a miter box and used a hack saw to cut them. It was simple, a couple of screws and some markings on piece of wood. I used a dremel to trim the heat shields and remove the support ribs from the cut end. I had some pictures of a real one to tried to get as close as I could.

Posted: 5/27/2022 8:33:19 AM EDT

[#5]

The 607 cross pin does two functions. It keeps the threaded rod from coming loose of the lower and it intercepts the hole for the rear takedown pin detent and spring. Without a lower endplate there’s nothing to keep the takedown pin spring in place. Placed far enough back to perform this secondary function it should not interfere with the buffer retaining pin and spring. The stock rod threaded into the lower will intrude into the buffer retainer hole. After Matt (607 stock) threads the lower and screws in the rod locating its final position with the cross pin, he then recuts with a mill the buffer retaining pin hole.

Installation of the 607 stock isn’t difficult, but it does require a mill if you want to be sure it doesn’t all go pear shaped.

I threaded the rear takedown spring hole and screwed in a set screw. I didn’t want to wrestle with holding that all in place as I tried to drive in the cross pin. I positioned the set screw just deep enough to clear the cross pin.

https://www.ar15.com/forums/AR-15/Retro-Show-off-thread-/123-747212/?page=3#i8039492

Posted: 5/27/2022 9:17:07 AM EDT

[#6]

Thanks for the explanation! Yeah, sadly I don't have a mill. I think I have Matt's email so I'll see if he's still offering that service.

In the meantime, I need to figure out which bolt release I want to use

I'm leaning towards the transitional one. And yes, they're both original. I have some original deep dimpled takedown/pivot pins I'll be using, just need another dimpled selector. My original 3 pos one is on my 601.

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Posted: 5/27/2022 3:52:45 PM EDT

[#7]

Ok so I just got everything in my hands. It looks like the stock rod is threaded, but still meant to be pinned. My question is...do I need to deepen the pocket on the lower so it sits flush before pinning? Or will the rod go farther into the stock once it's fixed to the lower? Right now, I can't unlock the stock to extend it because I have no way to hold the rod steady, so it's just spinning with the locking sleeve when I change the lever from open to locked.

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Also just got my echo arms chrome BCGs from Primary arms. Absolutely insane how quickly they shipped..I ordered Wednesday! Only $100 so I got one for this project and one for my XM177 project

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Posted: 5/27/2022 4:06:08 PM EDT

[#8]

You need to deepen that hole all the way through the other side and thread it with the appropriate tap before you even think about drilling a cross pin.

Refer to this: 607 Receiver Stub

Posted: 5/27/2022 4:27:24 PM EDT

[#9]

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Quoted:
You need to deepen that hole all the way through the other side and thread it with the appropriate tap before you even think about drilling a cross pin.

Refer to this: 607 Receiver Stub

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Even though the rod is smaller in diameter than the recess in the receiver? I'd have to drill and tap at a smaller diameter than the current hole, so threads would only behind where I start drilling to deepen the hole. Is that correct?

Posted: 5/27/2022 4:56:38 PM EDT

[#10]

Yes, that’s correct.

The only way to have it threaded fully would be to start with a raw forging. It’s just a concession that has to be made when working with an off the shelf lower.

I would also recommend not trying to do this with a power drill and probably not with a drill press either.

Posted: 5/27/2022 5:44:01 PM EDT

[#11]

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Quoted:
Yes, that’s correct.

The only way to have it threaded fully would be to start with a raw forging. It’s just a concession that has to be made when working with an off the shelf lower.

I would also recommend not trying to do this with a power drill and probably not with a drill press either.

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Yeeeah I think I'm going to see if John Thomas can take care of it for me. I would just hate to mess it up.

Posted: 5/27/2022 7:46:54 PM EDT

[#12]

Ok spoke to JT and the barrel work and all that is no problem but no go on the 607 stock mounting soooo...what are my options? Is there anyone out there that does the work?

Posted: 5/27/2022 8:45:56 PM EDT

[#13]

You could probably drill the hole with a drill press if you can securely clamp it and get it square in both directions. You’ll drill all the way into the firing control pocket, then tap the hole. I’d then play around with how deep the rod will thread. Work it until it functions properly. Then you drill for the cross pin. Another solid fixture will be needed since you’re not drilling a flat surface. Start the hole with a drill point so it won’t wonder, then finish with a regular drill bit. Finally you machine the buffer retainer hole. It’s something like 6° off square so the mill will clear the top of the extension hole.

Good news? There are lots of lower fixtures available. It isn’t difficult, you just need to go slow and use the proper tools. The mill may be a problem but most machinists are gun guys and would probably be glad to help.

Matt can’t do it since he’s not an FFL and you’ve got a finished lower. Don’t get discouraged. You’ll get there and once finished will be glad you worked through it all.

Here’s an install with a 607 using an interference fit rod. He drilled the hole in a vise and plain old drill. https://www.ar15.com/forums/ar-15/How-To-Install-A-607-Stock----Pics-/123-420062/

https://www.mcmaster.com/starter-drills/high-speed-steel-drill-point-countersinks-for-lathe-centers/

Posted: 5/27/2022 8:51:49 PM EDT

[#14]

Quote History

Quoted:
You need to deepen that hole all the way through the other side and thread it with the appropriate tap before you even think about drilling a cross pin.

Refer to this: 607 Receiver Stub

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That link BTW was an absolute gold mine of authentic info.

Posted: 5/28/2022 10:15:39 PM EDT

[#15]

Ok so it's definitely seeming like the stock mounting is going to have to be done by myself. I do have a drill press and vise I can use, so that helps. But I really want to get all this right. I'm an aircraft electrician and an amateur blacksmith, but not much of a machinist so please excuse my dumb questions

I measured the threaded portion of the rod. Excuse me if I'm wrong, I had to Google these terms, but from my measurements the crest of the thread measures at .432" and the root measures .410". I'm not sure what the thread pitch is yet. My questions are: a. How do I figure out the thread pitch to tap the hole at? And b. What diameter hole do I need to drill to make sure I can still tap it for the threaded rod? It'd be pretty easy if it was a plain rod like in the linked 607 mounting thread, but the diameter of the threaded rod is a good bit smaller than the recess in the receiver.

Posted: 5/28/2022 10:38:14 PM EDT

[#16]

Take the stock to your local hardware store and test fit nuts onto the rod. Once you find the correct size, note what size it is, then google "correct drill bit to use for a ?? size tap."
The tap you need will obviously be the same diameter and thread pitch as the nut you pick up that fits the rod.

https://www.bing.com/search?q=drill+bit+tap+size+conversion+chart&form=ANSPH1&refig=4b74f31ae12e44c4a8bfdfa7a5e3061a&pc=U531&sp=1&qs=NM&pq=conversion+chart+drill+bit+and+tap&sk=PRES1&sc=2-34&cvid=4b74f31ae12e44c4a8bfdfa7a5e3061a

PS, if you have or can borrow one of those 80% jigs from someone, it makes it a whole lot easier to drill that hole with a drill press. It's how I did mine years ago.

Posted: 5/29/2022 1:29:01 PM EDT

[#17]

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Quoted:
Ok so it's definitely seeming like the stock mounting is going to have to be done by myself. I do have a drill press and vise I can use, so that helps. But I really want to get all this right. I'm an aircraft electrician and an amateur blacksmith, but not much of a machinist so please excuse my dumb questions

I measured the threaded portion of the rod. Excuse me if I'm wrong, I had to Google these terms, but from my measurements the crest of the thread measures at .432" and the root measures .410". I'm not sure what the thread pitch is yet. My questions are: a. How do I figure out the thread pitch to tap the hole at? And b. What diameter hole do I need to drill to make sure I can still tap it for the threaded rod? It'd be pretty easy if it was a plain rod like in the linked 607 mounting thread, but the diameter of the threaded rod is a good bit smaller than the recess in the receiver.

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7/16" diameter either 7/16 - 14 unc or 7/16 - 20 unf

use a rule and measure the number of threads per inch then check with a nut as suggested by m1

These are handy thread pitch gauge

Posted: 5/29/2022 2:36:40 PM EDT

[#18]

If you are not confident in your abilities start calling some local machine shops, or ask around at work. Lots of aerospace/machinists have mills in their garage.

If you stay there while they drill it and the firearm doesn’t stay overnight you don’t need a shop with an FFL.

Posted: 5/31/2022 8:45:33 AM EDT

[#19]

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Quoted:

7/16" diameter either 7/16 - 14 unc or 7/16 - 20 unf

use a rule and measure the number of threads per inch then check with a nut as suggested by m1

These are handy thread pitch gauge

View Quote

So 7/16" would be the diameter of the bit I'd need to use to drill the hole prior to tapping it? Or just the diameter of the tap I'd need to use?

Posted: 5/31/2022 9:08:47 AM EDT

[#20]

7/16 is the size of the tap. The hole will be smaller. Probably... 25/64 if I remember right.

For example if your threads are 1/2 x 20, you drill a 15/32 hole and the tap cuts the 1/2 part.

Posted: 5/31/2022 9:58:03 AM EDT

[#21]

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Quoted:
7/16 is the size of the tap. The hole will be smaller. Probably... 25/64 if I remember right.

For example if your threads are 1/2 x 20, you drill a 15/32 hole and the tap cuts the 1/2 part.

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Got ya. Just googled it and it looks like if it's 7/16-14NC then it's 23/64“ but if it's 7/16-20NF then it's 25/64". Thanks!

Posted: 6/3/2022 1:29:43 PM EDT

[#22]

Just wanted to put a shameless plug for John Thomas out there...dude is amazing. I totally crapped the bed on shipping my 607 stuff to him for work (barrel chop, FSB smoothing and bayo lug removal, install handguard caps, parkerize moderator). Forgot the front handguard cap, the money order, and the note for requested work. John still had the work done the day he got it and send back out to me same day. Meanwhile I just waited almost 8 months for my simple FAL build

. Can't wait to send him my XM177E1 stuff too.

I'll update again when I get the barrel back and upper built. Stopping by the hardware store today...I may do the stock install myself. I'm pretty sure I can pull it off.

Posted: 6/9/2022 11:47:58 AM EDT

[#23]

Can JT install these stocks?

Posted: 6/9/2022 12:29:13 PM EDT

[#24]

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Can JT install these stocks?

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I asked, he said he doesn't do that work unfortunately.

I did just get my barrel back from him and it looks awesome. I'll post pics when I get the upper together

Posted: 6/10/2022 5:00:25 PM EDT

[#25]

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I don't know why, but I had so many issues putting this upper together. I've barreled countless receivers but I could not get the barrel nut to line up, cracked the rearmost tooth of the HG getting it mounted ..just problems. But it's together! Now I need to mount the stock....but.

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Won't fit in my drill press

ETA: I know my drill press is rusty. My brother left it in his shed for a while

Posted: 6/10/2022 5:14:45 PM EDT

[#26]

Paging Doctor Emel...

Posted: 6/10/2022 5:15:48 PM EDT

[#27]

McMaster short bits?

Posted: 6/11/2022 10:07:00 AM EDT

[#28]

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Quoted:
cracked the rearmost tooth of the HG getting it mounted

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Quoted:
cracked the rearmost tooth of the HG getting it mounted

That was actually something the Army documented and complained about during testing. S'why they went to the short rounds.

Won't fit in my drill press

I have that same cooler.

Seriously though, that set up look really sketch. I would want to clamp onto the lower more than that. It doesn't scream "solid" to me. I'd strip it too. All the aluminum chips are probably bad for the action.

As far as drills, I'd start small and work my way up. Hit it with a center drill and then use progressively larger bits until you get to the final size. It's slower but, you're moving less material at a time and can probably keep it more stable.

To echo the above, you can get stubby drills. Probably have them on amazon.

Posted: 6/11/2022 1:24:26 PM EDT

[#29]

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Quoted:

That was actually something the Army documented and complained about during testing. S'why they went to the short rounds.

I have that same cooler.

Seriously though, that set up look really sketch. I would want to clamp onto the lower more than that. It doesn't scream "solid" to me. I'd strip it too. All the aluminum chips are probably bad for the action.

As far as drills, I'd start small and work my way up. Hit it with a center drill and then use progressively larger bits until you get to the final size. It's slower but, you're moving less material at a time and can probably keep it more stable.

To echo the above, you can get stubby drills. Probably have them on amazon.

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Haha! Yeah this was just a mock up to see if it'd even fit. I'll have to look for some stubby bits. I reached out to unclemoak's company to see if they can do the work. If not, I'll try to tackle it myself.

Posted: 6/20/2022 11:38:32 AM EDT

[#30]

Alright well...I tried.

I drilled and tapped the hole, I *thought* everything was straight, checked level constantly. It must have just moved ever so slightly and caused the drill bit to go in at an slight angle. That angle is *just* enough to cause the locking rod to press upwards against the buffer tube when everything is installed. Tried to get the stock on and there's no way, just too much friction. Sigh! Well, luckily I have a second partial fence lower, so I went ahead and swapped my XM177E1 stock and such to this lower and it's like it never happened. I'll be sending the 607 stock and my undrilled lower to unclemoak shortly. Oh well!

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ETA: Is there anywhere that sells DOD acceptance stamps anymore?

Posted: 6/20/2022 2:26:00 PM EDT

[#31]

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Quoted:
Alright well...I tried.

I drilled and tapped the hole, I *thought* everything was straight, checked level constantly. It must have just moved ever so slightly and caused the drill bit to go in at an slight angle. That angle is *just* enough to cause the locking rod to press upwards against the buffer tube when everything is installed. Tried to get the stock on and there's no way, just too much friction. Sigh! Well, luckily I have a second partial fence lower, so I went ahead and swapped my XM177E1 stock and such to this lower and it's like it never happened. I'll be sending the 607 stock and my undrilled lower to unclemoak shortly. Oh well!

https://www.ar15.com/media/mediaFiles/68140/signal-2022-06-17-12-22-01-439_jpg-2424781.JPG

ETA: Is there anywhere that sells DOD acceptance stamps anymore?

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I have to give you credit for trying because I'd have a really hard time messing with a NDS Lower right now knowing it can't be replaced.

Posted: 6/21/2022 9:12:44 AM EDT

[#32]

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I have to give you credit for trying because I'd have a really hard time messing with a NDS Lower right now knowing it can't be replaced.

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Haha! Believe me, I thought of that. But then I figured there's no way that I can screw it up so bad as to make it unusable. Now that the CAR stock is on there, it's like it never happened. If I only had the one lower, I wouldn't have even tried it.

Posted: 6/24/2022 5:13:14 PM EDT

[#33]

Okay, the lower and stock are all ready to go to unclemoak. I'll update again when it gets back to me! In the meantime, my form 1 for the XM177E1 was submitted

Posted: 8/2/2022 8:24:04 PM EDT

[#34]

Still waiting to get the 607 stock and lower back...but just got the approved form 1 for my XM177E1 back today!

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This is easily one of the coolest, most handy AR platform guns out there.

Posted: 8/3/2022 10:29:49 AM EDT

[#35]

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Quoted:
Still waiting to get the 607 stock and lower back...but just got the approved form 1 for my XM177E1 back today!

https://www.ar15.com/media/mediaFiles/68140/20220802_155557_jpg-2474833.JPG

This is easily one of the coolest, most handy AR platform guns out there.

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Definitely the best looking AR variant.

Posted: 8/3/2022 11:06:29 AM EDT

[#36]

Too cool for school, and I like the CAR stock.

Posted: 8/3/2022 1:55:41 PM EDT

[#37]

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Definitely the best looking AR variant.

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Quoted:

Quoted:
Still waiting to get the 607 stock and lower back...but just got the approved form 1 for my XM177E1 back today!

https://www.ar15.com/media/mediaFiles/68140/20220802_155557_jpg-2474833.JPG

This is easily one of the coolest, most handy AR platform guns out there.

Definitely the best looking AR variant.

It's a coinflip between XM177E1 and Mk18 Mod 0 for me.

Posted: 8/3/2022 2:22:42 PM EDT

[#38]

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It's a coinflip between XM177E1 and Mk18 Mod 0 for me.

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That is hard..

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Especially when you include the latest gen..

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Posted: 9/12/2022 10:34:54 AM EDT

[#39]

Dave Wilson sure came through! The 607 stock is mounted and now I just need to get the form 1 done, then the 607 will be complete.

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This is probably the most "correct" 607 stock I've seen so far. The locking rod is threaded into the lower receiver and then pinned like an original. Locks up good and tight. I can't wait to get this thing done!

Posted: 9/12/2022 12:06:30 PM EDT

[#40]

Quote History

Quoted: Dave Wilson sure came through! The 607 stock is mounted and now I just need to get the form 1 done, then the 607 will be complete.
https://www.ar15.com/media/mediaFiles/68140/20220912_102907_jpg-2523395.JPG
https://www.ar15.com/media/mediaFiles/68140/20220912_102923_jpg-2523396.JPG

This is probably the most "correct" 607 stock I've seen so far. The locking rod is threaded into the lower receiver and then pinned like an original. Locks up good and tight. I can't wait to get this thing done!

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Wow. Now you need to do a 607/XM231 prototype.

Posted: 9/12/2022 12:51:26 PM EDT

[#41]

I gotta get my tax stamp for my 607 lower done.

Posted: 9/12/2022 2:46:49 PM EDT

[#42]

Does anyone offer a 607 stock other than Ordnance Research? I theirs isn't quite as accurate as some of the previous offerings. My65span is out of business, correct?

Posted: 9/12/2022 2:55:50 PM EDT

[#43]

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Quoted:
Does anyone offer a 607 stock other than Ordnance Research? I theirs isn't quite as accurate as some of the previous offerings. My65span is out of business, correct?

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I honestly have no idea where you could possibly get one these days. I lucked out and found this kit on the ee and had the money at the time. My brother got his the same way, but his was the "bolt on" stock. I think ordnance research is the only option.

Posted: 9/30/2022 9:14:41 AM EDT

[#44]

Form 1 submitted and fingerprints mailed yesterday. Now the wait begins

Posted: 10/18/2022 8:19:08 AM EDT

[#45]

That was the quickest form 1 I've ever gotten back. 18 days! But both carbines are all done

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This 607 is just so freaking cool. I've dreamed about owning proper clones of both of these carbines since we all started the retro forum. So happy to finally have them! Thanks everyone for the help and a special thanks to John Thomas and Dave Wilson!