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Swap handguards stock and grip from 522 to 556 & vice ve

5295 Views 15 Replies 9 Participants Last post by  moses
Hi -

I have a 556 and love it, however, it has the "fishgill" handguards/stock and I don't love those. I bought it before the green classic came out, and that would have been my choice if it were available then.

Now, the 522 is out and available with the all green plastic for only $440 "street price". I was thinking of freshening up my old beat up 10/22 but I figured for the price of the green handguards ($80+) the grip ($20 if you can get one (?)) and stock ($110+?) plus all the shipping and hassle, I may as well buy the whole rifle and get a cheap, awesome rifle in the bargain. :D

My question before I go spending almost $500 after shipping/FFL/etc, is whether I can be sure that I will be able to put the 556's fishgills front and rear and pistol grip onto the 522, and put the 522's green plastic onto the 556. Are we sure this is possible? I am not against a little dremeling here and there, but I want to be sure it is almost a no-brainer and won't require all kinds of surgery or just not work.

Thanks for your help.
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I have the same question.

Plus, I noticed that the newer "SWAT" 522 has quad rail. But I am not sure if it's the same as the one on SWAT 556. The one on 556 is sold at $300ish, so I think more likely the one on 522 is different--nobody would put a $300 rail on a $600 gun.  
The hand guards are the same, I havn't bothered to look very closely at the grip or buttstock since the 522 will keep it's folder (I don't want it on my 556), but I believe they should be interchangeble based on the shotshow video. If anything a call or email to sig should answer the question about the stock.

One big thing from putting the swiss guards on my 556, the fishgills on a 522 will make it really nose heavy and not as nice in the hand imho. I'd personally get a set of swiss hand guards and swap the other parts.

I don't have quad rails so I can't comment on those.
As far as I can tell the handguard grip and stokc are the same between the 556 classic and the 522. The Handguards from the early version 556 work on the 556 classic so they should also work on a 522. Of course the early version 556 stock (M4 type) won't go on a 556 classic so neither will it go on a 522.

As for the railed "SWAT" hanguards, there are two versions. One with the top rail that is integral with the rail on the receiver and one that is separate from the receiver rail. Since the receiver rail on the 522 is integral with the receiver, then the early version railed handguards should work on it, but the newer railed handguards with the extended top rail wouldn't cecause the 522 top rail can't come off to accept the long top rail form the handguards.

Does that answer your questions? Does it make as much sense written out as it did in my head?
C Swimm said:
As far as I can tell the handguard grip and stokc are the same between the 556 classic and the 522. The Handguards from the early version 556 work on the 556 classic so they should also work on a 522. Of course the early version 556 stock (M4 type) won't go on a 556 classic so neither will it go on a 522.
Could you expand on this? To be clear, my 556 has the folding fishgill stock, not the non-folding expandable one. The bases look similar to me but it was hard to tell without having them side by side.

Thanks for the info guys.
i have a classic 556 and a 522 i have swapped them and they both swap fine the 522 forearm fits my 556 alot tighter than the classic handgaurds bot i have changed it all back and forth
I have both the 522 and the 556. I put the fish gill guards on my 522 when I upgraded my 556 with troy rails. There is no modification necessary!
awesome, thanks! A 522 will be on the way to me shortly...
Hate to be a pain and belabor this, but I want to be sure:

Will my 556 fishgill folding stock swap out with the 522 "smooth triangle" folding stock?


Thanks!
ibuprofen said:
Hate to be a pain and belabor this, but I want to be sure:

Will my 556 fishgill folding stock swap out with the 522 "smooth triangle" folding stock?


Thanks!
I highly doubt it.
:? Can someone confirm whether or not the end of the 522 stock looks like this?

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racenet said:
No it doesn't. Not even close.
True that.
Crap. (thanks for the info though.) Is there a 'Sig green' folding stock I could put on this if I do swap the handguards and pistol grip? I could paint the fishgill one but I like the smooth better.

Irritating that they couldn't just keep all the stocks the same and allow us to customize them.
The older stocks and the classic stocks do not interchange, the lowers are different.
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