Nick, I just take Dr. Ken's word for it, since we have discussed it a couple of times.
The determination of shot speed is a function of the instrument used as much as the shot speed itself. Take the 35P. As choke increases, so does shot speed (and this is probably true, at least for some of the pellets near the front of the cloud.) Take an (industry standard) inductive chronograph and tighten the choke and the speed goes down, probably due the the different shape of the shot cloud.
All in all, it makes little difference. You'd be amazed by the variation in average speed between similarly-marked shells of any brand. With an inductive chronograph, which tells you best what's going on, if you test seven lot numbers of lights and seven of heavies, any brand, you are going to get at least one "crossover," that is a light that is faster than a heavy or the other way around. That's why you can't "standardize" a chronograph with an example factory load.
But it makes little difference. Really, if you follow some recognized reloading guide, and use some standard powder (I use Red Dot) and use brand-name stuff and a scale and care, in an evening you can make all the "standardization" loads you will ever need in a decade of testing. Before you start some test, just shoot a few and they will be about like they were last time. If they aren't start again. Or another day. Sometimes light-operated chronographs just don't work right and you just have to wait until next time.
My version - the long one - is at the above link. But no one need to do all that.
If you follow a guide, you will get about what you expect. If you test your product made according to some text with a cylinder choke and everything chronowise works about right, you will confirm your expectations. If you shoot a full choke instead you will get higher speeds and so much variability that you won't be able to pick up reloading problems which sometimes creep in which is why cylinder choke is better if you have one available. Mod is borderline. Full is useless (for testing variability) and my tests with two good chronos mounted in a line, clocking the same shot, confirm this.
A couple of shots, full choke - which is what practically everyone does, face it - is a waste of time and shells; shoot them at targets instead and don't worry. If you follow a guide, you'll be OK an any case.
In other words, the few FPS differences I get are just what you'll - or anyone - get. They are no problem. The shot, after all, doesn't know its speed is being tested and if it's OK, that is, nothing tricky, then I just run with it.
But, you ask, how about when I want to do something tricky?
Don't. There can be some surprises at the upper range of pressures which don't show up as changes in speed. This trips up the occasional factory; for the home loader with a consumer chronograph and no pressure pressure barrel it's just an invitation to show up here in another, unfavorable, context.
Neil
The determination of shot speed is a function of the instrument used as much as the shot speed itself. Take the 35P. As choke increases, so does shot speed (and this is probably true, at least for some of the pellets near the front of the cloud.) Take an (industry standard) inductive chronograph and tighten the choke and the speed goes down, probably due the the different shape of the shot cloud.
All in all, it makes little difference. You'd be amazed by the variation in average speed between similarly-marked shells of any brand. With an inductive chronograph, which tells you best what's going on, if you test seven lot numbers of lights and seven of heavies, any brand, you are going to get at least one "crossover," that is a light that is faster than a heavy or the other way around. That's why you can't "standardize" a chronograph with an example factory load.
But it makes little difference. Really, if you follow some recognized reloading guide, and use some standard powder (I use Red Dot) and use brand-name stuff and a scale and care, in an evening you can make all the "standardization" loads you will ever need in a decade of testing. Before you start some test, just shoot a few and they will be about like they were last time. If they aren't start again. Or another day. Sometimes light-operated chronographs just don't work right and you just have to wait until next time.
My version - the long one - is at the above link. But no one need to do all that.
If you follow a guide, you will get about what you expect. If you test your product made according to some text with a cylinder choke and everything chronowise works about right, you will confirm your expectations. If you shoot a full choke instead you will get higher speeds and so much variability that you won't be able to pick up reloading problems which sometimes creep in which is why cylinder choke is better if you have one available. Mod is borderline. Full is useless (for testing variability) and my tests with two good chronos mounted in a line, clocking the same shot, confirm this.
A couple of shots, full choke - which is what practically everyone does, face it - is a waste of time and shells; shoot them at targets instead and don't worry. If you follow a guide, you'll be OK an any case.
In other words, the few FPS differences I get are just what you'll - or anyone - get. They are no problem. The shot, after all, doesn't know its speed is being tested and if it's OK, that is, nothing tricky, then I just run with it.
But, you ask, how about when I want to do something tricky?
Don't. There can be some surprises at the upper range of pressures which don't show up as changes in speed. This trips up the occasional factory; for the home loader with a consumer chronograph and no pressure pressure barrel it's just an invitation to show up here in another, unfavorable, context.
Neil