SG551 Clone Project

Last UPDATED 05/18/08
Directions for this project have changed radically with the release of the SIGARMS 556 Semi Auto Rifle!!
No longer do you need to find US made parts, as SIGARMS is now making these parts in the development of their new offering!

Here are the latest pics of my gun to date
(05/18/08)
I think this project is FINALLY complete.
This update marks the addition of the
Samson Manufacturing Star Sig 556 Rail
Wow.. this is an awesome product!
Easy to install. Fit/Function is fantastic. If you want the most from your 556, then this is a MUST HAVE!!
Samson makes great stuff and the price provides a GREAT VALUE!
This system, will allow you to use bascially ANY sighting system currently available.

It really opens up your sighting/lighting/accessories options!
IMHO, it balances the rifle very well!!

I hope you enjoy these pictures!
As Always...... (Click any pic for a LARGER IMAGE)

This is an actual SIG SG551 with a Custom Made 16" Barrel and SWAT Furniture
(Click the pic for a LARGER IMAGE)

Here is an image of the new SIGARMS 556.
(Click the pic for a LARGER IMAGE)

Here is an image of a SIGARMS 556 with a SWISSARMS 550/551/552 Semi Auto Lower Assembly attached.
(Click the pic for a LARGER IMAGE)

This is a pic of the latest variant of the SIG SG551LB

Believe it or not ALL the furniture AND the SwissArms 551 lower was originally GREEN.
I like BLACK, so I did my Thermal Dye Sub routine to the furniture and sent the lower out to Top Gun Enterprises for their
Stealth Tec Polymer based self lubricating Black Finish. It took Top Gun about two weeks (round trip) to do the lower.
I REALLY like this finish and have had it put on every one of my projects that require any refinishing work!

DATED 02/03/07
If you decide to add a 550 Lower to your 556 and retain the original 556 forearm you
MUST make a slight modification to the forearm to allow the 550 folder to lock into place.

Below is a pic describing the procedure:
(Click the pic for a LARGER IMAGE)

How to Convert a Full Auto 550 Lower to Semi Auto

1) Remove long disconnector lever on right side.
2) Cut auto sear - hook 1mm (now this sear cannot catch the hammer)
3) ....semi sear on left still in working....
4) Block selector in semi position with pin or weld closed selector auto-notch.
5) Remove 3-burst plate complete and attach small distance-bushing over hold-pin.
6) Outside marking S-1-3-20: remove pin on left, attach small metal plate over the 3-20 position and fix with glue and pin.
7) Now you see only S-1 (3-20 covered). Both sides. This metal plate also works as selector stop.

Below is a list of parts counted on the SIG SG550/551/552 for 922 Compliance Purposes
(1) Frames, receivers, receiver castings, forgings or stampings (2) Barrels (3) Barrel extensions (4) Bolts (5) Bolt carriers (6) Operating rods (cocking handle) (7) Gas pistons (8) Trigger housings	(9) Triggers (10) Hammers (11) Sears (12) Buttstocks (13) Pistol grips (14) Forearms, handguards (15) Magazine bodies (16) Followers (17) Floorplates

If you replace the existing 556 Lower assembly with a 550/551 Lower assembly,
here is a list of the imported parts on your weapon.

(1) Trigger housing
(2) Trigger
(3) Hammer
(4) Sear
(5) Buttstock
(6) Pistol grip
(7) Follower
(8) Floorplate
(9) Magazine body

Since you are allowed 10 Imported parts, you are certainly compliant.
If you used a Swiss Forearm, you are STILL OK.
Keep the US made Pistol Grip and you've got "room to grow".

SIGARMS did an EXCELLENT job duplicating the internals and functional parts of the
SwissArms 550 Series Firearms! For this reason, I do NOT suggest replacing any of these parts
with Swiss made parts. I cannot see any increase or enhancement if your rifles performance.

The gun feels great when firing.
Very similar to the Swiss guns, and MUCH better than any AR, for sure!!
My desire to use the 550 lower with the 556 was for aesthetic purposes only.
(Plus, I had a box of 550 mags I needed to be able to use)

Since the Thread pitch on a 556 Receiver/Barrel is different from a 550/551/552,
You would NOT pursue adding a swiss barrel to the mix.
Besides, it would be MUCH cheaper to allow a competent gunsmith to
change the profile of your US made barrel to better resemble that of an actual 551.

Some folks have expressed an interest in using a 551 forearm on this rifle.
If you were to do this, you would still remain compliant with Sec 922(r),
but IMHO, the 556 forearm seem sturdier and better sized for a typical US American sized hand.
The 556 forearm also seem to better insulate the hands from the heat of the barrel than a typical 551 forearm.

SIG SG 550 551 551 Barrel Changeout Procedures!
Many thanx to Larry @ Capital City Firearms for this wonderful PDF file.
If you wish to swap out the barrel on your SIG SG Rifle, then you also need this document. Adobe Acrobat Reader is required to open the file, so click the logo if you need a free download of this utlilty

If you find this document useful, please thank Larry via email and give him your support!!

Click below for the
SIG SG 550 551 551 Barrel Changeout Procedures PDF File (518k)

In Addition, Larry has been gracious to show how to make Vise Clamping Jaws for SG55X Barrel removal. CLICK HERE for details!

Click Here
for instructions to
Dismantle/Assemble the SG55X REAR SIGHT ASSEMBLY

Cool 55X Related Links

55X Projects.com

Sigforum.com

Aurora Industries LLC

Biggerhammer SIG AMT and 550 Discussion Board

Sig-550.com Website and Discussion Boards

Capital City Firearms

RemTek's SIG SG55X Page

http://www.sig552.com/

email me

If you have any info that needs to be posted here
PLEASE email me with the pertinent information!!
Thanx, KB

Site established 07/23/02
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