Need help determining choke

[jclifton]

Hey Guys, I'm new to THR but have seen this sight in a lot of references.
I just purchased an old Belgian Guild gun and was wanting a little help in the choke department. It is a 16 gauge SxS with 16.4 over 16.9 and 16.2 over 16.9 written on the bottom of barrels. In another place it has 16.4 over 17.0 and 16.2 over 17.0. Any help would be greatly appreciated.


______________________
Jim

 

[machinisttx]

I'm not sure what that means. Most Europeans refer to choke as 1/4, 1/2, 3/4, or 4/4.

Your best bet on determining actual choke is heading out to the patterning board and seeing what the gun does at 40 yards. IIRC, 75-85% of the pellets in a 30" circle at that distance is full choke. Modified would be 65-75% in the 30" circle at that distance. IC would be 50% or so, and cylinder would be about 40-45%.

That's the only actual way to determine how a barrel will perform with load X, regardless of dimensions. FWIW, a full choke should measure(at least in 12 gauge, not sure about others) roughly .040" constriction from bore diameter. A modified would be .020" constriction, while IC measures only about .005" constriction.

 

[Pete409]

I'm pretty sure it's the choke and bore diameters in millimeters.