I greatly enjoy your techniod Q&A. While I have found a lot of info on free recoil, I haven’t found exactly what I was looking for. I wanted to know (assuming a standard O/U shooting a standard target load) what the free recoil differences were by gauge:
Or if you could tell me some where else to look.
Free recoil, the kind you measure mathematically, is not a function of gauge. It is a function of shot load, shot speed and gun weight (plus a fudge factor or two).
Example, you might think that a 12 gauge would kick more than a 20 when shooting standard target loads, but if that 20 were a real light gun and the 12 was a real heavy one, the 20 would kick more.
However, lets assume that you are using an 8 pound four barrel skeet set (to keep the gun weight constant) and were using standard 1200 fps skeet shells of the maximum payload permitted. Free recoil numbers would be as follows:
12 ga 1-1/8 oz load is 17.63 foot pounds
20 ga 7/8 oz load is 10.5 ft/lb
28 ga 3/4 oz load is 7.78 ft/lb
410 bore 1/2 oz load is 3.6 ft/lb
The above might vary very slightly with different weight wads and types of powder, but you get the idea. Remember too, the gauge doesn’t govern recoil. A 12 shooting 7/8 oz will kick just about the same as a 20 or 28 throwing the same load if the guns weigh the same.
I hope that this is what you are looking for. Now if my computer would just quite smoking. Formulae are so much harder on it than mere excess verbiage.
The Technoid writing for Shotgun Report, LLC
(Often in error, never in doubt.)