AR 15 barrel diameter/gas block question

[Mrkeller]

I recently bought a gas block off ebay for my AR build. The listing says it has a .750 diameter. I went to put it on my barrel and it just slides down the whole barrel to the receiver. Is there a chart for diameters somewhere? I don't have a micrometer so it's hard for me to measure it. Any help is appreciated.

 

[Mgderf]

I recently bought a gas block off ebay for my AR build. The listing says it has a .750 diameter. I went to put it on my barrel and it just slides down the whole barrel to the receiver. Is there a chart for diameters somewhere? I don't have a micrometer so it's hard for me to measure it. Any help is appreciated.

.750 of an inch is 3/4". Try putting a tape measure up to the hole and check it.

Sounds like you have a pencil barrel.

 

[Mrkeller]

I did measure the circumference and it was just under 2 inches.

 

[menzzer37]

ok...circumference and diameter are two different things....

sounds like you have a .625" DIAMETER, you know across the circle, not around it, gas block section.

 

[45calibre]

You need a .625 diameter gas block

 

[Mrkeller]

Thanks for the information. It has helped a lot. Looks like I will be shopping for a new gas block. Oh and I have an unused gas block for sale.