I have a Sig 556 Classic SWAT, and I'd probably play with it a lot more if I could ditch the 50 lb cheese grater hung off the front. The usual places that would have these things are drying up, figured the Sig brain trust might have an idea I hadn't thought of!

A 551 handguard will fit, assuming you are not talking about a "patrol" model. The front end of the 551 handguard will be a smidge loose in the gas block; this can be remedied by swapping to a Swiss gas block or shimming the handguard perimeter with something like a piece of zip tie.

quote:

Originally posted by KSGM:
A 551 handguard will fit, assuming you are not talking about a "patrol" model. The front end of the 551 handguard will be a smidge loose in the gas block; this can be remedied by swapping to a Swiss gas block or shimming the handguard perimeter with something like a piece of zip tie.

I have the same issue with my 551-2 SP clone. I have just lived with it.
I noticed the inside of the gas block of my JDI 550P has some sort of white colored insulator which appears to be heat resistant which also maintains a snug fit between the gas block and the front end of the hand guard. At one time I had a piece of black rubber in place but eventually, it loosened up.

If one uses a zip tie or a piece of rubber, I am concerned that the shim will start to melt during heating up from shooting.
What do you think?

I have used zip tie in the past without issue. Some gas blocks gave the insulator layer you're referring to, and some don't. A 553 doesn't have it, nor does the US 556. The 553 handguard retainer will not fit on a gas block with that layer. So, as an addition to my earlier comment, if the OP gets a Swiss gas block and 551 handguard, he needs to ensure it's a 551 or 550 gas block, intended for use with plastic handguards, and not the 552/3 retainer.

Wil,thanks for your response.
Mike

To clarify I’m looking for the Classic length and not the shorter Patrol length.

Well, I reckon you need to further clarify whether you want the US or Swiss handguard. If you want to go the Swiss route, I may be bale to help you; refer to my post in classifieds.

https://sigforum.com/eve/forum...730011384#4730011384

Good question on US vs Swiss. What’s the difference?

Google it, for images and such. The overall contour and venting differs.

Well crap. Upon closer inspection my factory quad-rail hand guard seems to have a one piece top rail, which makes the idea of a swapping out appear to be a no-go.

I may have a top rail and rear sight that would allow you to switch. I'll look.

I sent you an email.

This message has been edited. Last edited by: KSGM,

Hey KSGM what do you have left for an early 556.

It has the M4 collapsable stock and the cheese grater handguard.

Thanks
Needabiggersafe

Think I saw one on GB, if you do an Sig 551A1 search

quote:

Originally posted by KSGM:
I may have a top rail and rear sight that would allow you to switch. I'll look.

I sent you an email.

KSGM, sent you another email!

quote:

Originally posted by Malysh:
If one uses a zip tie or a piece of rubber, I am concerned that the shim will start to melt during heating up from shooting.
What do you think?

550 cord stuffed in there becomes 'custom fit' PDQ. I assume a zip tie would be similar. It won't hurt anything.

I like shooting my 556, but it's one of the worst purchases I have ever made, 2009 paid ~double what I should have. Going to use it today for some rookie shooters. It's heavy enough that the pencil thin ladies won't mind the recoil.

I have chopped the 1-pc integrated top-rail/quad rail into two pieces to allow use of a normal set of handguards. I get wanting a monolithic rail for front sights but that's irrelevant on the 55x.