M4 Front sight/gas block

[Adam3088]

I'm wanting to swap out the stock front sight on one of these..

..with a railed gas block so I can stick something like another mbus on the front.

Found this on ye olde ebay http://www.ebay.co.uk/itm/75-Cal-223-5-56-Low-Profile-Gas-Block-Top-Bottom-Picatiiny-Rail-For-Rifle-/291259383836?pt=UK_SportingGoods_Hunting_ShootingSports_ET&hash=item43d069801c which is considerably cheaper then the alternatives, would this do the trick? Or should I just spend the extra on something like the madbull one?

http://shop.ehobbyasia.com/madbull-top-rail-gas-block-for-m4-m16-series.html

On the same topic, how do they actually stay in place? I get that the gas tube sticks in the back but how does it stop it from moving around?

My knowledge of M4 customizing is less then rubbish, any help would be appreciated.

 

[team flex]

well, i think the problem with that is that the current sight also holds the two moe handguard parts together, and thats why you need it. I have been looking for a solution to this without putting a rail on, maybe a folding one but I can't find any. let me know if you find anything. I think for gas blocks, when you tighten them they then tighten onto the outer barrel, which means they don't move around, depending on how tight they are. But yeah, I don't think that will work unfortunately, let me know if you come across something.

 

[Adam3088]

I don't think it should have any effect on the handguard, the bit which holds it on at the front is the metal 'cap', which is attached to the front sight via the gas tube (as far as I can tell!).

In theory by replacing the front sight with another gas block the plate should sit in the same place without a problem...maybe.

Edit: had a look at the exploded view on http://www.greekairsoft.gr/manuals/manual.asp?Manufacturer=KING+ARMS&Filename=King+Arms+Magpul+PTS+MOE+Manual.pdf does look to be that way.

My main problem with that ebay gas block is how it tightens on to the barrel, kind of looks like it's just a grub screw which bites into the barrel. If so, nuts to that.

 

[team flex]

oh yeah, had no idea about that, looks like I will be doing the same later on then I guess, cheers for that.

In terms of the tightening, I cannot see how that would possibly work. Honestly, I would buy madbull, for a start they are listing it as 556, which is clearly just trying to bump up what will probably be a crap item. I guess it's "like buy nice or buy twice", only now it will actually be, "be nice or buy then send back for a refund because it didn't fit and was made very cheaply etc"

IF you do please report back on how it works. cheers mate

 

[Adam3088]

Might just give it a go with one of the cheap ones as they have the rail underneath as well, didn't realise but the stock sight is attached via a grub screw underneath the sling mount. So it should connect in the same way.

Annoyingly these all come from China so I'm going to have to wait a couple of weeks before finding out if it works or not.

 

[Adam3088]

It's done, gas block fitted pretty well although as it lacks the two pins to go into the barrel grooves I imagine that a hard enough wack in the right place would skew it round.

Front sight was a pain in the balls to get off, discovered part way through that King Arms make theirs out of some really sh*t quality pot metal (see second picture..), that happened while trying to hammer out the sling pin.

Annoyingly my fakepul front sight wont fold down as the handguard gets in the way, will either modify it or just remove it when I get a T1 installed.

Also for £8, quality of the gas block isn't half bad, it's a solid lump of metal and the finish is decent.

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