G551K build. A G3 and Sig 551 love child

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[ARCHIVED THREAD] - G551K build. A G3 and Sig 551 love child

Posted: 10/17/2018 9:45:56 PM EDT

Here's a custom pistol I built. Pieced it together with HK G3, G3k and Sig 551/556 parts. It uses a RTG flat, g3k cocking tube, RCM 12.7" barrel and #18 50* locking piece. Sig 551 sights, 556 grip, handguard and gas block. Still waiting on a airsoft 551 to steal the "gas tube and regulator" parts. Added a picatinny rail, case deflector and AR buffer tube adapter and brace. Had to mod the grip housing alot to fit the Sig grip and take up some of the dead space behind the grip. Bith HK and Cetme mags work great and I prefer cetme mags because they are curved. Shoots good and recoil is really manageable. I can post a build tutorial if anyone is interested. Also have it posted on weaponsguild.
Painted with parkerizing grey and od green aluma-Hyde ll from brownells and cured overnight in a box with a space heater blowing inside. Here's it completed under my Sig P556/553 clone with its converted 35rd Galil mag. Enjoy and let me know what ya think.

G551k test fire. 20rds

Posted: 10/17/2018 9:59:29 PM EDT

[#1]

Golf clap*

That’s cool.

Posted: 10/17/2018 10:17:24 PM EDT

[#2]

Heres a few closer pics. I have a 2nd handguard I'm going to make thr cutout for the cocking handle better, after I get a new hk21 style cocking handle (broke the cheap one I bought)

Posted: 10/18/2018 11:22:51 AM EDT

[#3]

Very cool

Posted: 10/18/2018 10:07:28 PM EDT

[#4]

Nice!!! Must get lot of stares when you shoot it at a public range.

Has that uncanny look to it and makes one squint to do a double take!

Posted: 10/18/2018 10:13:07 PM EDT

[#5]

Yeh, ok.

I kind of like it.

Gun nerds will give “WTF is that,” looks.

Posted: 10/19/2018 7:11:25 AM EDT

[#6]

Wow! Incredible!

Tell us about the lower group- How did you make it? Modify an existing steel G3 housing or?

Posted: 10/19/2018 7:15:49 AM EDT

[#7]

Is that a Galil magazine in the 553 ??? does that work?

Posted: 10/19/2018 7:44:37 AM EDT

[#8]

Quote History

Quoted:
Wow! Incredible!

Tell us about the lower group- How did you make it? Modify an existing steel G3 housing or?

View Quote

I modified a steel G3 housing. Cut the grip mount off, shortened the trigger guard and welded metal on the back side to take up the huge gap because of the different grip location. And welded a box to fit in the grip to support it.

Posted: 10/19/2018 7:46:47 AM EDT

[#9]

Quote History

Quoted:
Is that a Galil magazine in the 553 ??? does that work?

View Quote

Yes works pretty good. Goes through all 35rds without any jams and locks up tight. Had to relocate the front and rear lugs, thin the body a little bit and thin the top of the feed lips.

Posted: 10/19/2018 7:51:17 AM EDT

[#10]

I am stuck at WHOA & NEAT!

Posted: 10/19/2018 8:05:28 AM EDT

[#11]

Skills....OP has them.

Awesome build, I'd be proud to own and shoot it.

Posted: 10/21/2018 6:44:45 AM EDT

[#12]

Quote History

Quoted:
I modified a steel G3 housing. Cut the grip mount off, shortened the trigger guard and welded metal on the back side to take up the huge gap because of the different grip location. And welded a box to fit in the grip to support it.

http://i.imgur.com/DaLyI57.jpg

http://i.imgur.com/sfFD3pz.jpg

http://i.imgur.com/eoZA89X.jpg

View Quote

Superb workmanship and creativity on that. That is a fantastic looking firearm!

Posted: 10/23/2018 3:16:23 PM EDT

[#13]

100% complete now. Installed the fake gas tube and regulator and swapped out thr SOB for a KAK blade and put a KAK 2.0 blade on the Sig. Happy with it so far.

Posted: 10/23/2018 3:24:28 PM EDT

[#14]

@LRRPF52

Didn't you see something like this at a class once?

Posted: 10/23/2018 3:29:30 PM EDT

[#15]

Quote History

Quoted:
@LRRPF52

Didn't you see something like this at a class once?

View Quote

No. I've only used real Sig550 series guns in courses overseas, mainly 551 and 552s.

Nice work OP. That thing is a beast.

Posted: 10/24/2018 11:35:43 PM EDT

[#16]

Saw that on Instagram. Amazing work!!!!!! Mad skills

Posted: 10/25/2018 8:02:42 AM EDT

[#17]

Quote History

Quoted:
Saw that on Instagram. Amazing work!!!!!! Mad skills

View Quote

Where in instagram did you see it? And thank you

Posted: 10/25/2018 4:05:00 PM EDT

[#18]

Lol, that is awesome!!

Now YOU will be responsible for the next "What was the gun in HEAT" debate!!!

Doc

Posted: 10/28/2018 11:03:15 PM EDT

[#19]

Very cool! Well done.

Posted: 10/28/2018 11:13:09 PM EDT

[#20]

https://www.theflatspot.net/ar-lower-flat.html

Well done, OP.

Posted: 10/30/2018 11:06:31 PM EDT

[#21]

Needs a 550 stock. There’s a photo from the late 90s floating around of a g3k being used in Europe with a 550 folding stock.

Posted: 10/30/2018 11:17:45 PM EDT

[#22]

Quote History

Quoted:
Needs a 550 stock. There's a photo from the late 90s floating around of a g3k being used in Europe with a 550 folding stock.

View Quote

GSG9 had some made for their G3K rifles. (Possibly B&T made them.) They were already operating SIG 551 carbines (before the G36 came out, but they kept them) and the folding 550 stock is way better than the G3A4 collapsing stock.

Posted: 10/31/2018 6:29:52 AM EDT

[#23]

Thats cool.

Reminds me of that video floating around of pakastani children building guns and ammo in caves with almost nothing.

Posted: 10/31/2018 9:35:52 AM EDT

[#24]

Quote History

Quoted:
GSG9 had some made for their G3K rifles. (Possibly B&T made them.) They were already operating SIG 551 carbines (before the G36 came out, but they kept them) and the folding 550 stock is way better than the G3A4 collapsing stock.

http://i9.tinypic.com/43csymx.jpg

View Quote

Never seen those before. Thanks for sharing. The stock has been a issue ive been thinking about and now its time to try and track one down.

Posted: 10/31/2018 9:00:53 PM EDT

[#25]

Quote History

Quoted:
Where in instagram did you see it? And thank you

View Quote

It was under one of the HK gun groups. The person insta is hk_g3_33_mp5_addicts_

Posted: 11/1/2018 3:13:13 AM EDT

[#26]

Last few pics of the G551k. Made an aluminum cocking handle, bought a AAC 51t FH to shoot it suppressed. Pretty violent recoil. Need a #17 LP and heavy buffer. Also cut the original 551 front sight and added 1/8" to bring the sight inline and to get rid of the slanted Sig 556 front sight. Love it so far.

Posted: 11/28/2018 5:42:21 PM EDT

[#27]

Decided to make a 551 stock fit a HK end cap after seening the GSG9 pics.

I used a airsoft sig stock and filled it with epoxy resin. I made a adapter out of two 1/4" pieces of aluminum strap. Tapped the holes for the buffer screws, 4 holes for 2" bolts to act as anchors and drilled a relief for the recoil spring guide. After the epoxy dried I used more to build up the sides to better fit the end cap profile and used a 13/16" drill bit to drill out the space for the buffer. I'm happy with the way it turned out though it could be better/smoother lines. Just have to use it on my G3 clone till I get the stamp back.

Posted: 11/28/2018 5:58:30 PM EDT

[#28]

Looks great!

Posted: 11/30/2018 1:39:57 AM EDT

[#29]

Few pics of the 551 stock on my G3 clone.

[ARCHIVED THREAD] - G551K build. A G3 and Sig 551 love child

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