SiG 552 to SiG 550 Handguard Conversion

[Rotting]

Anyone have any suggestion where to go about obtaining the SiG 550 handguard set? I'll explain my reasoning just so people aren't totally lost.

My original idea was to throw a 590mm inner barrel inside a SiG 552. A SiG 552, though, normally only uses 247mm barrel. The rest of the distance, of which, would be covered by a silencer (The only silencer I can find of suitable length is 355mm, bringing the total length to roughly 609mm, roughly 1-2cm longer than the inner barrel).

I've gotten a lot of flak from people, though, saying that I'd be better off purchasing replacement parts for a SiG 550's handguard set. This'd end up requiring me to get a new outer barrel part, and new lower and upper handguard parts. This would create more stability and what not, not having a huge silencer, etc. My only problem is I have no clue where to find the handguard parts for a SiG 550 as well as the outer barrel part.

And no, "buy a new gun" option isn't available. I don't have that much cash to dump on a gun just to gut it for parts. I swear I've seen replacement parts for a SiG 550 somewhere, I just can't recall where.


edit: Even a 551 handguard replacement might work.