I picked up a Sig P522 and was curious if there is any knowledge in this group about any aftermarket off-brand parts (e.g. airsoft, etc) that would fit the 522 to dress it up more as a 552. Yes it would be a sin, but its not a real 55X.  Nor will it be a very accurate representation clone being a rimfire bolt area etc.

Seems like most MFIAP Sig 55x dress up parts are sold out.  Any other sources?

I feel like I can't be the only person who has considered this, and thought to ask before I buy higher end airsoft guns/parts to experiment with.

Many of the higher end Sig airsoft clones are as much or more than I paid for the pistol.

What are you trying to do with it?  The top rail is molded in so an MFI diopter rail won't work anyways

I've had a couple of 522 pistols, intended to SBR them but sold them (still have a 522 rifle). As mentioned, the rail is cast into the upper unlike the 556's so no options there. I bought one of the MFI MAD rear sights for my 522 rifle and one of their thin blade front sight posts (had to file it down in order to match the rear sight height).

I also have both rifle and pistol (SBR'd) versions of the 556. The rifle length quad rail SIG handguard will interchange between the rifle versions of the 556 and 522, but the pistol length rails were different and wouldn't swap. Also, if you SBR it and try to put a factory folading stock on the 522 be aware that the latch buttons are differeent (due to the receivers being different material)...the notches in the button are different. You'll either have to find a 522 button (pretty impossible...I've never seen one for sale anywhere, and I looked for awhile), or Dremel the notch in a 556 button (worked fine with some trial and error "BrrrRRrr"ing and some Aluminum Black). The grips are interchangable if you wanted to swap for a Hogue or a Manticore (if you can find one). As far as Airsoft interchangability, I have no idea...but understand that the 552/553 handguards (which the short airsoft guns replicate) don't fit on the 552/556 pistols as they are shorter.

I was hoping to add:
- diopter sight - looking at HK-like made for picatinny rails
-Possibly some 552/553 clone (even Airsoft)  handguard might just be willing to cannibalize an airsoft clones to get the parts -

As the gas block on the 522 is without purpose - it could possibly be swapped for a metal airsoft one and allow the 552 style handguard.

I was sort of hoping someone may have tried - it but evidently not an easy project - especially for an out of production gun.

One issue you'll run into is that Sig has made at least three different height front sights for the 556/522's (at least that's how many I've encountered on the three 556's and three 522's I've had). The "Easy Button" may be to find a pistol-length railed handguard and then pick the matching F/R sight set of your choice and mount the front on the handguard top rail (this is what I did on one of my P522's...I used the HK-style diopter set off a Walther/Umarex HK416 .22lr).

The front "gas block" on the 522 is secured to the barrel with a set screw rather than roll pins like the 556's...it may be possible to use an airsoft gas block (or even the original) and just re-dimple the barrel in the new location of the screw.

Thank you for the info.  I recall that front sight height issue with my Sig556 SBR. I think I will be looking at airsoft stuff carefully - Some parts are surprisingly well done - as these airsoft guns can cost more than the 522 did!  Well, This will give me something to putter on and try.  Had I thought about it, I should have invested in an HK416 to SBR - far more supporting parts, etc to use with those.  But I had to like that 55X look of the Sig!!

Nice score and what great "blank canvas" for sure.

I vote a FDE pistol with as much tanodized stuff as possible

Skeleton brace?

Thinking SBR with stock - But will see how possible parts look for some form of compatibility and time/cost permits.

I never thought of tan/FDE but hmmm.

Oh yea, stock makes it. Dead Sexy !

Just an interesting note on the 522 is that the M16/AR15 style magwell that extends in front of the trigger guard is not entirely necessary - the mag catch is above it - in theory one could cut it (its polymer) and create a 550, 552, 553 look - but would need some fine reshaping in front of the trigger guard AND it might leave the black dog 22 mags rather wobbly and perhaps unreliable = not worth trying unless I had some spare lowers.

UPDATE - Can't remove the flash hider with Mapp gas and holding the barrel in a vice - I suppose it could be "permanently attached" state compliance models that were out there as some states did not allow pistols with threaded muzzles and Sig offered that version - I can't see a blind pin.

Anyone know about how or where the pin should be IF its pinned?

I thought it was not pinned but I could be wrong.

It does not look pinned - I might have to have it cut and re-threaded if it cannot be removed.

Updating on the permanent attached Flash Hider - There are factory threads underneath it.  It appeared to be welded at the base - very well!

Took it to a friend with a lathe and removed the hider - It wasn't pinned and appeared to be welded at the back.  Once we cut through it ahead of the base it would unscrew.  the back had to be re-faced a little.

Sig did not make it easy to restore threads!

Now I can run a suppressor on it which is Nice for a 22!