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SIG 556 to 550/551/552 Conversion

3773 Views 17 Replies 11 Participants Last post by  armakraut
This is what SIG should have made in the first place. I came across their ad in the latest SGN Treasury. MFI is a good company with great customer service. I don't own a SIG 556 but I would love to have one with these conversions.

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Ha ha, bitchin.

Mine is done and ready for pickup. :twisted:
I assume you have either do the conversion yourself or have them do it.
Call Mike Frost at MFI to make sure, but I think you will be able to do the conversion yourself.
My conversion, w/the 55X lower, and w/the 556 lower... Hehe :wink:

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love that folder! :razz: i just ordered from ace their fold. adapter for my 556 with the push-button release and was thus able to keep original stock! the fold. mech. is really great and 100% tight both fold. and unfolded, i did have to cut buffer tube 1 inch shorter to make up for the
length of the adapter! i am still looking for a ft. and rear sight havent found either that i really care for! hopefully those items in the ad at top of page will be avail. soon! :hail:
One thing that works/looks really good on the 556 rifles is the ACE M4-7 buffer tube with the magpul stock. Much more substantial than the standard AR tube, and it has a QD adapter. Good combo if you want an original-ish look, but don't want to spring for a folder/551 lower.
j-rod said:
w/the 556 lower...

j-rod, Did you do the converstion yourself or send your upper to them? I'm actually interested in the 556 with a fixed rear sight and rail combo like yours now...
PM sent
j-rod, id love the info on that set up too. thx
i would love to know where you got that ft. and rear sight? and how much? thanks! :dance:
Nice Rifle, I have a 556, and 1 more en route. I got on the list to get the sight set you have. I might make a 551 clone, and then just a beater for the truck.
Why do they say you can't use the original SIG scope mount with their rail?
Because the rail (on SAN mfg rifles) is welded to the receiver - how I had mine done. IIRC, the earlier SAN/SIG rifles have a bracket on the front of the receiver and there is a hole at the front of the rear sight base. The SAN scope mounts have a dovetail (for lack of better description) on the bottom/front of the mount, and a spring-loaded "spike" at the rear. To mount, you compress the spike into the front of the RSB, and lower the front "dovetail" onto the bracket - tension holding it in place.

If you wanted to mount the scope on the rail-model, you could get the ARMS STANAG adaptor, but you may need the riser-version. I have been contemplating doing this with a G3/Hensoldt scope - set the scope on the 300m setting (.308 cam), dial it in at 300m, and just leave it until I can locate the .223 cam... All the ground in between will be covered :wink:
does anyone know where to buy the mags for the 550/551/552 series of guns?

Is that a 556 in the picture? that has been converted
Is that a 556 in the picture? that has been converted[/quote]

Yup... :grin:
Mine's done, put the list of improvements in a separate thread.

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