Anti-walk pin for AR?

[Mity2]

I'm looking to get one, and it appears that they come in 2 different sizes.
Small - .156" (3.9mm), Large - .172" (4.3mm) diameter.
This is going in to my Anvilarm's lower.

Anyone know which one I need?(I don't have caliper to measure my existing pin!)

http://www.brownells.com/.aspx/pid=7...ANTI_WALK_PINS

[Guns4Fun]

I'm pretty sure that Colt was the only one using large pins in their lowers. They have since started using small pins.

[Lycanthrope]

I'm pretty sure that Colt was the only one using large pins in their lowers. They have since started using small pins.

Yeah, it's small pin.

LycancalipersatHarborFreightthrope

[Konsukah_19]

Small pin size.

I have two on both my AR's. They are not really NEEDED unless you are running some kind of full auto for it, but it helps retain the pins a little better. But make sure you put a LITTLE DAB of blue locktite on there. After a while, the screws WILL come loose if you do not do this.

[Mity2]

Thanks for the heads up on lock tight. My trigger pin keep backing itself out for some reason(I was told that this is sort of common issue with now defunct Anvilarms lower). I Made the habit to push on the pin between every mag change, but I figured it's cheap enough insurance, and I have to order few other small things anyway.

[JayBell]

both you guys check to see if yer hammer spring tails are engaging the pin detent grooves as they should... thats what holds the pin in.

if not, either get teh Eclip type antiwalk, or my fave... the KNS anti walk/rotation pins.

[ithinkimamedic]

the KNS anti walk/rotation pins.

I have a set of these on my Anvil Arms SBR, the only reason is because I use it in 9mm and that is notoriously hard on them.

[Kaos]

I have a set of these on my Anvil Arms SBR, the only reason is because I use it in 9mm and that is notoriously hard on them.

I have a set on my AR as well, only because I got them dirt cheap.

Wasnt really "needed" though, like jay said the grooves are what hold them in place when they're properly installed.

[Konsukah_19]

I have a set on my AR as well, only because I got them dirt cheap.

Wasnt really "needed" though, like jay said the grooves are what hold them in place when they're properly installed.

I will not argue about the grooves on the set. I have mine set there and they work. But, I have fired hundreds of rounds through mine, and the screws just started coming a LITTLE loose. Which is why I went with the blue locktite. I just want to make sure the dam thing does not come apart when I am shooting!

[Mity2]

Thaks for the info. I ordered the small Dia' Eclip type antiwalk pinset(along with YHM Phantom FH, Budgerordenance Tac-Latch.