needing to learn about crony results

sorry to be a pest, and show my stupidity,

Ive got a HW97kt .22 and have borrowed my friends caldwell chronograph, an have it hooked up to my Note-8,

it gives me FPS readings,

but not FT-LBS

I have 8 diffrent type weight and brand pellets,

Im shooting inside,( because im and oldfart-sissy and I aint going out in the cold,)

at 18ft

every pellet in a 5 shot group can be covered with a dime, some when i do my part are almost a hole in one,

when I use the crony what am i looking for?

what should it be telling me?

is there a secret number? or FPS im looking for?

thank you for taking the time to further my edumacation in the pellet world

cheers

John
 
The "Magic Number" is 671... at 671fps the pellet weight in grains equals the foot pounds of energy. (slower = less, faster = more)

(example) If you shoot a 18.5gr pellet at 671fps, you would be generating 18.5 ft lbs of energy at the distance the pellet crosses the chrony. 

As the pellet goes down range it will loose velocity and therefore energy. 
 
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With your 97 the only thing you can do to affect velocity is to change the weight of the pellet. In theory the pellet that shoots the most consistent velocity should be the most accurate. I’ve got a chronograph it’s an aid in the search but honestly I shoot for accuracy and precision the velocity is just going to give me an idea of energy.

I set the chronograph as close as I can to the gun. Two reasons. Muzzle velocity is typically the number used to compare. Secondly if the chrony is down range you will at some point hit it with a bullet. Ask me how I know
 
5 different chrony's will give you 5 different sets of numbers, so using one to determine true velocity for plotting trajectory is going to put you 1/2" to 2" off......which in THIS GAME is significant.

IMO the only use for them (if you only use the same one all the time) is to compare readings after a "tune", or when comparing different pellets.

As far as I know the only way to ACCURATELY plot trajectory down to pinpoint accuracy is the old fashioned way.....shoot & measure.
 
5 different chrony's will give you 5 different sets of numbers, so using one to determine true velocity for plotting trajectory is going to put you 1/2" to 2" off......which in THIS GAME is significant.

IMO the only use for them (if you only use the same one all the time) is to compare readings after a "tune", or when comparing different pellets.

As far as I know the only way to ACCURATELY plot trajectory down to pinpoint accuracy is the old fashioned way.....shoot & measure.


Yup, that's the way I do it. The old fashioned way, shoot and record my holdovers for a given distance.

John another thing the chrony is good for.....once you get your average velocity write it down somewhere for that particular gun and it's favorite pellet's weight. Then at a later date, say your groups don't look just right? Run a few shots across the chrony to make sure your gun hasn't lost any velocity from your original recordings. Would be a good way to see if there is a problem with the internals?

I know on some of my PCPs, I write the avg velocity and pellet weight for each gun. Sometimes when I go to check a particular gun, say a few months or year later I might notice a slight loss in velocity and then I know to tweak the hammer spring adjuster to get her back on point with the original velocity.
 
The "Magic Number" is 671... at 671fps the pellet weight in grains equals the foot pounds of energy. (slower = less, faster = more)

(example) If you shoot a 18.5gr pellet at 671fps, you would be generating 18.5 ft lbs of energy at the distance the pellet crosses the chrony. 

As the pellet goes down range it will loose velocity and therefore energy.

so when some on here send out there rifles, is this what they do when they say they tune it to a specific pellet?

they find the 671fps for that favorite pellet 
 
I wouldn't say that is the case... Its just that mathematically, when calculating the FPE, 671 happens to be the velocity that the weight works out so perfectly.

So, if I'm shooting away and I see my chrony say that my last shot was at 900fps and I know I'm shooting 18.5gr pellets, I can easily see that I'm shooting quite a bit above 18.5fpe.

Shoot groups with every pellet that you have. Find the 2 or 3 that group best at the distance you would normally shoot at. Pick your favorite and shoot a string of 20 shots. Record your velocity's and average them out. This will allow you to use an app like Chairgun (RIP) or Strelok to find your power curve for that pellet. This will give you better insight on your hold-over values for different distances when out in the field.