Choke gauge

[Benelli m2]

Them brass choke gauges that you drop in the end of barrel
Are they really that accurate and give a true reading

 

[takbok]

They're just measuring the diameter at the muzzle so pretty simple really. You could always use a vernier caliper instead if you don't have one of those gauges.

The choke is relative to the bore diameter (which can vary from gun to gun, and then some are backbored too) so the gauge will never be 100% accurate.

Here's a bit of info:

Understanding shotgun back bore rifleshooter.com

 

[McKenzie]

Them brass choke gauges that you drop in the end of barrel
Are they really that accurate and give a true reading

No.

 

[enfieldspares]

As above +1. They only measure the width of the hole in the muzzle.

Choke is defined difference in thousandths of a inch between the diameter of the constriction and the diameter of the barrel immediately (usually) behind that constriction. So you could have a cylinder bore gun with a barrel that was .719" behind and .719" at the "choke" and, yet a tightly choked gun that was .739" behind and .729" at the choke.

Yet...the brass gauge would have you believe that the .719" muzzle gun was a tighter choke than the .729" muzzle gun.

 

[Benelli m2]

As above +1. They only measure the width of the hole in the muzzle.

Choke is defined difference in thousandths of a inch between the diameter of the constriction and the diameter of the barrel immediately (usually) behind that constriction. So you could have a cylinder bore gun with a barrel that was .719" behind and .719" at the "choke" and, yet a tightly choked gun that was .739" behind and .729" at the choke.

Yet...the brass gauge would have you believe that the .719" muzzle gun was a tighter choke than the .729" muzzle gun.

Thanks all I'm going to get it measured properly at a shop