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Chronographing CO2
Posted: Thu Mar 25, 2004 4:52 pm
by Clark
I have used a chronograph to evaluate CF reloads, but I have never used it with my CO2 pistol. Does anyone know if a chrono. can yield worthwhile info. for a CO2 pistol?
Chronograph testing on an AP
Posted: Thu Mar 25, 2004 5:18 pm
by Bill177
A chronograph is valuable in testing a Co2 airgun. You can test the velocity of different pellets, the same pellets at different temperatures, and adjustments made to the valve of the gun.
Be sure to log all your information for future use.
Important - Distance to Chronograph Screen
Posted: Thu Mar 25, 2004 5:23 pm
by Mark Briggs
One important point to note when it comes to chrony'ing Co2 guns... The cloud of Co2 expelled from the muzzle can cause false triggering of the chrony if you're too close to the first skyscreen. To avoid this, make sure the chrony is a yard or so off the muzzle. In this manner I haven't had any trouble getting very reliable results with mine.
Posted: Thu Mar 25, 2004 8:06 pm
by Clark
When testing pellets, I have compared two things:
1. group dispersion, and
2. weight variance.
I have assumed that heavier pellets may travel a bit slower, but velocity is irrelavant as long as the pellets group well and do not tumble/ tear the paper. Just because velocity can be measured doesn't mean it is worthwhile. What is the point of chronograping a CO2 driven pellet?
Posted: Fri Mar 26, 2004 2:21 pm
by Mark Briggs
In some jurisdictions muzzle velocity determines whether or not your airgun is or is not impacted by onerous gun control legislation.
On another front, chrony'ing your airgun gives you a good idea about velocity performance in terms of consistancy across pellet types, as well as consistancy across cylinder fill levels, temperature, etc. I've seen instances where there was very little correlation between grouping performance and consistancy of pellet weight. But a low extreme spread in velocity can have a significant impact on group size. Velocity is just one more variable that's helpful to characterize. But remember, some folks buy cheapo pellets, shoot them out of a rusty old pistol with plywood grips and shoot very well. It's a personal choice.
Mark.
Posted: Fri Mar 26, 2004 4:19 pm
by Clark
Now I am getting interested in using my chronograph on my CO2 pistol. Based upon Marks reply there may be a stronger correlation between pellet velocity and group size than between pellet weight and group size.
A chrono. may also be the best way to choose the optimum pellet diameter, i.e. 4.49, 4.50, 4.51 etc.
Has anyone tested these possibilities?