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Durkin Tactical Franklin Armory
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Posted: 6/28/2017 11:35:57 AM EDT
Hello All, I just wanted to post about the build I am working on at the moment. I am cheap so I am making my own lightweight receiver set.

Both are works in progress and I need to mill more off each. If something sticks out as completely dumb or dangerous, please let me know.

I also have an AIM lightweight bcg, and a Larue PredatAR barrel. (won the barrel, or I probably would have gone with a Faxon Pencil bbl.)

The stock I am not sure about yet. anyways, here are the pics.









Thanks for looking!
Link Posted: 6/28/2017 12:12:15 PM EDT
[#1]
Are you going to re-anodize the receiver?

Looking forward to see the weight when done.
Link Posted: 6/28/2017 12:19:00 PM EDT
[#2]
Not sure yet. It will at least get durakote
Link Posted: 6/28/2017 5:54:18 PM EDT
[#3]
You can shave more weight by milling down the shell deflector so it looks like an early slick side upper. The lower can have the reinforcing rib above the mag release button on the right side mag well shaved too. Make it a short rib front to back. The spring channel is not that deep for the detent.  Couldn't tell from the pics but did you remove any material fron the front of the mag well?
Link Posted: 6/28/2017 7:01:37 PM EDT
[#4]
that is interesting! would have never had the idea of shaving the rails down.
Link Posted: 6/28/2017 7:15:33 PM EDT
[#5]
Very jealous of your ability to mill. Hoping to have one next year.
Nice work!

Did you weigh the receiver set after milling?
Link Posted: 6/29/2017 9:41:00 AM EDT
[#6]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
You can shave more weight by milling down the shell deflector so it looks like an early slick side upper. The lower can have the reinforcing rib above the mag release button on the right side mag well shaved too. Make it a short rib front to back. The spring channel is not that deep for the detent.  Couldn't tell from the pics but did you remove any material fron the front of the mag well?
View Quote
I had planned on drilling as big of a hole as I can in the brass deflector. I would still like it to function as a deflector.

As for the front of the magwell, I wanted to mill some slots in it like the sides. The problem I have is that my vice is too big and I don't have the clearance with upper and a bit. I have a smaller vice I will probably set up once I am done with everything else.

Funny you should mention the ribs above the mag release. I got the bulk of the work done on the lower, and milled most of that off.

Link Posted: 6/29/2017 9:44:59 AM EDT
[#7]
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Quoted:
Very jealous of your ability to mill. Hoping to have one next year.
Nice work!

Did you weigh the receiver set after milling?
View Quote
not the set, but I did weigh the lower after milling most of it.
7.72oz (looks like 1.72 in the pic. that would be awesome!!!)

Link Posted: 6/29/2017 10:09:00 AM EDT
[#8]
I would second that part on the shell deflector. Being milling out the inside of the shell deflector, so it's kind of hollow. The shell deflector doesn't really need that much support, as it's not getting beat on. You might even think about making it smaller.

Other than that, I don't see much that you can do to make it any lighter. Maybe making more lightening cuts near the fcg area, but that would seem hard to do and make it look good. maybe some cuts near the front of the mag well
Link Posted: 6/29/2017 10:25:54 AM EDT
[#9]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
I would second that part on the shell deflector. Being milling out the inside of the shell deflector, so it's kind of hollow. The shell deflector doesn't really need that much support, as it's not getting beat on. You might even think about making it smaller.

Other than that, I don't see much that you can do to make it any lighter. Maybe making more lightening cuts near the fcg area, but that would seem hard to do and make it look good. maybe some cuts near the front of the mag well
View Quote
I think I am going to finish the milling on the upper tonight and will decide then if I want to re-prefile, drill a hole in, or omit all together the deflector.

should have pics tomorrow.
Link Posted: 6/29/2017 12:10:08 PM EDT
[#10]
Amazing that the LW billet receivers weigh so much less that forged from the onset.

I took a pic of my BAD lower next to a Spikes forged I had in the safe for comparison. The billet has a larger FCG pocket toward the rear and then the pocket continues over the grip area. Then there is the hole for the receiver tightening set screw also.



Seems like this could be done to drop quite a bit of weight from the lower
Link Posted: 6/29/2017 4:03:58 PM EDT
[#11]
interesting, might see if I can hog out some more of the material.


best pic I have at the moment.
Link Posted: 6/29/2017 6:31:49 PM EDT
[#12]
OP...that is some seriously nice work.

It sure is refreshing to see someone actually building stuff in the build it yourself forum....as opposed to most asking for help on creating a shopping list, or where to buy the cheapest parts.


Can't wait to see the completed build.


.
Link Posted: 7/15/2017 6:31:56 AM EDT
[#13]
Any updates?
Link Posted: 7/15/2017 7:15:59 AM EDT
[#14]
Interesting project.  I still don't know why ARs are built to be lightweight.  99.9% won't carry an AR all day under CBQ/SHTF scenarios.  I just question how good the structural integrity of a lightweight is.
Link Posted: 7/15/2017 11:56:47 AM EDT
[#15]
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Quoted:
Any updates?
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Havent had much time to work on it. Was on vacation last week and helping a buddy move this weekend. I milled out the back area of the upper where the CH goes. Will post pics when home later.
Link Posted: 7/15/2017 11:59:29 AM EDT
[#16]
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Quoted:
Interesting project.  I still don't know why ARs are built to be lightweight.  99.9% won't carry an AR all day under CBQ/SHTF scenarios.  I just question how good the structural integrity of a lightweight is.
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This is just a range toy. I like building different ARs. I have built a few plain jane ones, an SPR, 300 BO pistol.

Next one i would like to be a side charging 9mm pistol.
Link Posted: 7/18/2017 5:41:51 PM EDT
[#17]
You could have milled lengthwise down the middle of the rail. DS Arms makes one like that. Probably remove a lot more material that way. I've looked at ARs and thought there's a lot of places you could mill out and it's still function. The original design was probably built to survive being run over by a truck. I've never done it just because I'm not real that into the lightweight thing.
Link Posted: 7/18/2017 5:50:46 PM EDT
[#18]
Tag.
Link Posted: 7/19/2017 5:54:14 AM EDT
[#19]
Nottooslow

What was the total weight reduction on the lower and upper, separately?
Any plans for front of mag well?
And deflector block?

I plan to steal your ideas.

Thanks Nitro
Link Posted: 7/19/2017 9:52:24 AM EDT
[#20]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
You could have milled lengthwise down the middle of the rail. DS Arms makes one like that. Probably remove a lot more material that way. I've looked at ARs and thought there's a lot of places you could mill out and it's still function. The original design was probably built to survive being run over by a truck. I've never done it just because I'm not real that into the lightweight thing.
View Quote
I might still do something like this in spots. I plan on using a PA micro dot only.
Link Posted: 7/19/2017 9:55:04 AM EDT
[#21]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Nottooslow

What was the total weight reduction on the lower and upper, separately?
Any plans for front of mag well?
And deflector block?

I plan to steal your ideas.

Thanks Nitro
View Quote
not sure yet. Upper is still mounted in the vice and I am still working on it. also, I will be removing some more material from the lower. I will post up numbers when its done.

Front of the mag well will get a few slots milled out if I can get it mounted in my smaller vice. If not, I will probably leave it alone.

Brass deflector will get some treatment. Not sure yet if I want drill a hole through it, or something else.
Link Posted: 7/19/2017 4:02:57 PM EDT
[#22]
Thanks

Please post progress pictures.

Nitro
Link Posted: 7/21/2017 10:08:53 AM EDT
[#23]
haven't had much time to work on it lately.

Link Posted: 8/23/2017 5:02:26 PM EDT
[#24]
bump to keep out of archives.

haven't had much time, and its been too hot to be in the garage. I did work on the brass deflector a little. I am going to get it built and see how much it weighs, if it is too heavy I will go back and remove more material.

Also cats are assholes.






this is on the bottom of the brass deflector
Link Posted: 8/24/2017 6:49:11 PM EDT
[#25]
Nice! Really like your milling work.

If you want to drop a quick ounce + go to the new Hogue 15° poly grip.
Link Posted: 10/19/2017 10:18:55 AM EDT
[#26]
Bump to keep out of archives.

I ordered a lightweight stock and handrail.

I should have everything I need to get it assembled. I am going with a standard LPK but will eventually upgrade to all V7 parts.

Still need sights. Wanted Leitner-Wise (SP) buis, but have heard that he is a shit bag. Should I just go with Magpul BUIS?

went with the Guntec stock and hand guard. Hand guard is a mod-lite skeletonized.


Link Posted: 10/19/2017 7:40:27 PM EDT
[#27]
Looking good, won’t be long now. Have you got a final weight yet?
The Bobro Lowriders are the lightest flip up irons as far as I know. They are a bit pricey.
Link Posted: 10/21/2017 9:06:10 PM EDT
[#28]
Looks awesome! I really like the F/A mod

If you get a chance, what is the weight of the guntec buffer tube and stock plate alone?
Link Posted: 10/22/2017 9:25:43 AM EDT
[#29]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Looking good, won’t be long now. Have you got a final weight yet?
The Bobro Lowriders are the lightest flip up irons as far as I know. They are a bit pricey.
View Quote
Will probably go with the bobros.

Should know close to final weight today.
Link Posted: 10/22/2017 9:26:58 AM EDT
[#30]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Looks awesome! I really like the F/A mod

If you get a chance, what is the weight of the guntec buffer tube and stock plate alone?
View Quote
Attachment Attached File
Link Posted: 10/22/2017 5:54:05 PM EDT
[#31]
Thank you for weighing those. How do you like the LOP? Pretty good price point considering a lightweight buffer tube and stock would cost considerably more.
Link Posted: 10/22/2017 5:55:47 PM EDT
[#32]
Oh man, this thread is dangerous for me to see.  I've been known to terrorize engine parts with the Dremel...
Link Posted: 10/22/2017 6:15:13 PM EDT
[#33]
I think there is room for more machining

Link Posted: 10/23/2017 9:22:24 AM EDT
[#34]
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something is going to have to go. I am at 4.921 lbs and haven't put the adjustable gas key, or sights on it yet.

I think I am going to have to ditch the PredatAR barrel for a Faxon. Or send the PredatAR to Adco. Not sure which yet.

Also, I plan on replacing much of the LPK with lighter parts from V&7.

78.73 Oz so far.




Also, I removed the weight and milled some material off the buffer. Will this be ok? I am kind of scared to try this. I am going to start with the adjustable gas key not letting any gas through and slowly open up the port until it cycles. then play with it from there.



Link Posted: 10/23/2017 11:27:48 AM EDT
[#35]
Discussion ForumsJump to Quoted PostQuote History
Quoted:


something is going to have to go. I am at 4.921 lbs and haven't put the adjustable gas key, or sights on it yet.

I think I am going to have to ditch the PredatAR barrel for a Faxon. Or send the PredatAR to Adco. Not sure which yet.

Also, I plan on replacing much of the LPK with lighter parts from V&7.

78.73 Oz so far.
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Quoted:


something is going to have to go. I am at 4.921 lbs and haven't put the adjustable gas key, or sights on it yet.

I think I am going to have to ditch the PredatAR barrel for a Faxon. Or send the PredatAR to Adco. Not sure which yet.

Also, I plan on replacing much of the LPK with lighter parts from V&7.

78.73 Oz so far.
I think you're right that you'll get a pretty big reduction with the barrel swap, although I was hoping you could achieve your goal with Larue's superb barrel.  I hear Faxon's pencil barrel or Gunner barrel make a good shooter, but I would find it difficult to swap out that PredatAR.

How about your muzzle device?  Weight versus function considered? (I'm sure you did)

You'll get about a 60% reduction in weight using all VSeven lower parts versus a mil-spec LPK.  Not a whole lot for the amount of money, but VSeven parts are really top quality.


Also, I removed the weight and milled some material off the buffer. Will this be ok? I am kind of scared to try this. I am going to start with the adjustable gas key not letting any gas through and slowly open up the port until it cycles. then play with it from there.
I think that given you will sneak up on the gas adjustment to just allow the rifle to cycle, you'll be ok with the skeletonized buffer.  I use Taccom's ultra lightweight buffer system and you have that beat on weight by 0.3 oz.  Based on my tuning experience, I think you'll be surprised how sensitive a super lightweight action is to even small gas adjustments.  For example, applying a light coat of grease on the buffer spring made a difference on whether the bolt locked back or didn't on the same gas setting and same ammo.  Really surprised me.
Link Posted: 10/23/2017 11:33:18 AM EDT
[#36]
Discussion ForumsJump to Quoted PostQuote History
Quoted:

I think you're right that you'll get a pretty big reduction with the barrel swap, although I was hoping you could achieve your goal with Larue's superb barrel.  I hear Faxon's pencil barrel or Gunner barrel make a good shooter, but I would find it difficult to swap out that PredatAR.

How about your muzzle device?  Weight versus function considered? (I'm sure you did)

You'll get about a 60% reduction in weight using all VSeven lower parts versus a mil-spec LPK.  Not a whole lot for the amount of money, but VSeven parts are really top quality.


I think that given you will sneak up on the gas adjustment to just allow the rifle to cycle, you'll be ok with the skeletonized buffer.  I use Taccom's ultra lightweight buffer system and you have that beat on weight by 0.3 oz.  Based on my tuning experience, I think you'll be surprised how sensitive a super lightweight action is to even small gas adjustments.  For example, applying a light coat of grease on the buffer spring made a difference on whether the bolt locked back or didn't on the same gas setting and same ammo.  Really surprised me.
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Good info, thank you!!!

The muzzle device is an Arson Machine A-hole brake. It only weighs .7 ounces and is one of the lightest on the market. Think I stripped it out putting it on there. Pretty sure it wasn't my fault as I barely put any torque on it. I will see what Arson has to say about it.

I think I am going to send the barrel to Adco vs buying a faxon lightweight. I would like to use the Larue barrel as well.
Link Posted: 10/24/2017 10:19:46 AM EDT
[#37]
Discussion ForumsJump to Quoted PostQuote History
That is almost exactly the weight of a Mil-Spec RE and a CAR stock. 8.5 oz.
Link Posted: 10/26/2017 11:23:46 AM EDT
[#38]
You may want to contact John Thomas at retro arms works for your bbl work and see how he compares to adco. He has done a couple of projects for me machining wise and his work is top notch/museum quality. His reputation in the retro forum is unmatched. His turn around time is sometimes under one business week from when you sent it to when you got it back from him. Just an FYI
Link Posted: 10/26/2017 11:31:30 AM EDT
[#39]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
You may want to contact John Thomas at retro arms works for your bbl work and see how he compares to adco. He has done a couple of projects for me machining wise and his work is top notch/museum quality. His reputation in the retro forum is unmatched. His turn around time is sometimes under one business week from when you sent it to when you got it back from him. Just an FYI
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Thank you, I will check him out.
Link Posted: 11/15/2017 3:54:47 PM EDT
[#40]
Stunning work my friend. I know the LW build bug well, but not the skill set in machining as you do... Thank you much for sharing!

Happy trigger therapy,
Jim
Link Posted: 11/16/2017 8:27:51 AM EDT
[#41]
What kind of gas block are you using?  This one from Samson may help shave a little more weight.

Attachment Attached File
Link Posted: 11/16/2017 11:25:33 AM EDT
[#42]
Discussion ForumsJump to Quoted PostQuote History
Quoted:

Also, I removed the weight and milled some material off the buffer. Will this be ok? I am kind of scared to try this. I am going to start with the adjustable gas key not letting any gas through and slowly open up the port until it cycles. then play with it from there.

https://i.imgur.com/aAZGmTB.jpg

https://i.imgur.com/NQfH3ew.jpg
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Mine has been fine.
Link Posted: 11/16/2017 4:59:04 PM EDT
[#43]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
What kind of gas block are you using?  This one from Samson may help shave a little more weight.

https://www.AR15.Com/media/mediaFiles/44835/IMG_2501-363658.JPG
View Quote
I have a LW gas block. Not sure if is as light as the Samson, but it feels like nothing.
Link Posted: 11/16/2017 4:59:39 PM EDT
[#44]
Discussion ForumsJump to Quoted PostQuote History
Quoted:


Mine has been fine.
https://i.imgur.com/NB5cVr0.jpg
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Thanks!! I also see another spot I can hog out some more material. Thanks again!
Link Posted: 11/16/2017 8:09:05 PM EDT
[#45]
Discussion ForumsJump to Quoted PostQuote History
Quoted:

Thanks!! I also see another spot I can hog out some more material. Thanks again!
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What size end mill did you use for the slots in the "buffer", or as I like to call it, spring guide. You may want to consider running a flat wire spring that will provide a higher bolt closed load.

Super jelouse of the work you did on the upper and handguard. Makes me want to order up a mini mill.

keep us posted.
Link Posted: 11/17/2017 3:18:28 AM EDT
[#46]
Looking back through the pics, is there any reason you didn't follow the left side #2 cutout all the way back, passing below the mag catch?  That's the thickest material and the most weight to be saved, and I don't see any structural reason for keeping that space intact and not the other side.  I was going to say "symmetry" at first, but then noticed the two sides differ a bit in cutouts, anyway.

I did some work on mine with drill press, Dremel, and bastard files.  I'm envious of your milling machine!

Link Posted: 11/23/2017 9:27:29 AM EDT
[#47]
I'm just here to say:

1. Awesome machine work man! I love custom stuff and can't wait to get my own mill...

2. If you wanna build a light AR, you need to use the PWD to help select parts. Link in sig.
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