Install low profile gas block? Which size?

[1Fastrider]

Is it difficult to install a low profile gas block? What tools should I need? I was looking online and I saw different sizes. How do I know what's right for an AR chambered for 5.56 or 2.23? I've also seen adjustable ones like this one on jsesurplus:

http://www.jsesurplus.com/jpadjustablegassystem-blackaluminum.aspx

[DarkSoul]

You can remove your existing gas block and measure the bore, it is probably very common, like .750 or .936 .

Depending on the block you purchase, such as the one you listed, you will probably only need the appropriate allen wrench, and maybe a flat blade screwdriver to "open it up" while installing. It is a very easy thing to install.

You may need to purchase a new gas tube as well, depends on the condition of the existing one once removed.

[1Fastrider]

Thanks. I have two pretty new uppers so likely I won't need to replace them. Thanks for the info, I'm always nervous about doing stuff myself.

[Seesm]

Its pretty easy... .750 is the most common..... There is smaller and larger also but not as common.. I would bet your at .750

[repomanNWP]

I just installed my first low profile gas block and it was a snap. Once you figure out the barrel diameter you have (as said before, probably .750) you just slip it on, you'll probably have to tap it into place as it will be pretty snug. Reuse your existing gas tube or buy a new one of equivalent length. The alignment can be done by eye, you'll probably have a pin that needs to be punched in, make sure you don't bugger your gas block when tapping any pins in. The Brownells punch pin and holder set is awesome for AR-15 tasks (but expensive).

[Nathan Krynn]

Is it difficult to install a low profile gas block? What tools should I need? I was looking online and I saw different sizes. How do I know what's right for an AR chambered for 5.56 or 2.23? I've also seen adjustable ones like this one on jsesurplus:
http://www.jsesurplus.com/jpadjustab...kaluminum.aspx

Adjustables are great for competition rifles but if you want 100% reliability then not so great.

There are two reasons for this.

1) they come un-adjusted
2) when you adjust them you are tuning your rifle for a specific ammo. So if you use a different ammo the rifle may not cycle if the ammo is weaker.