Choke Variances...

[J.B. Books]

The only way to measure choke performance (the only thing that matters) is to pattern the gun by shooting into a 30" circle at 40 yards and determining the % of pellets in the load inside that circle. Every other measure merely tells you the constriction, some tools do it roughly and others do it precisely in thousands of inches. I have mentioned before I have a Remington 1900 KE with .014 and .024 constriction and it shoots 72% and 86% or full and super full yet the measurements suggest IC and Mod. I have a barrel on a Lefever 10ga with .018 constriction and shoots 85%. With .018 in 10ga I expected a light modified possibly IC, not super full. Conversely I have a 20ga Trojan with .005 in one barrel, I expected IC, it shot 33%. The other barrel has .012 and it shot 56% which is what I expected.

[mobirdhunter]

Remember that there is a significant difference between shells made at the time the gun was made and our current offerings, even RST shells. I have found a drop in choke gauge to be *almost* useless. As already posted, constriction is a strong clue, but the pattern board is best indicator. I have found that I can “change” the pattern by a choke designation by changing loads (even without spreader inserts). Always best to pattern the gun with the shells you plan to shoot.