mv variation off sometimes in shooter app

[mikebob]

Has anyone else noticed that sometimes in certain temps the mv variation in shooter is off and other times it is dead on. i mean one day it is off and the very next day same temp its dead on. I didn't see it in groups just from the chrony reading velocity compared to the corrected velocity in the app. I assume if shooting long range on the time it was off would cause some missed shots maybe making a guy think he pulling one. Just something i noticed shooting through the chrony.

 

[ShtrRdy]

What distance were you shooting at?

How were you tying mv in shooter to mv from the Chrono?

 

[mikebob]

What distance were you shooting at?

How were you tying mv in shooter to mv from the Chrono?

i was shooting some groups at 200 yrds from the ladder test i did the other day.

i always put temp in for powder when running shooter. i know at 38 deg it runs 2405fps verified by chrony, while i was shooting some groups the other day. then shot again yesterday it was 38 deg so i put in 38 deg powder temp and it showed 2425 but chrony read 2405 again. grouped the same on target at 200 but im sure at 1000yrds it changed my elevation adjustment. this was testing my 215gr and varget. im working up some with h4350 also but almost out of it and it is hard to find these days.

 

[ShtrRdy]

Okay. If you look at your cartridge parameters what do you have for a temperature coefficient of the powder? (called MV Variation) Also what is the Powder Temp entered into the Cartridge Parameter page? This is also the spot where you will want to enter your measured 2405 fps and 38 degrees.

Then on the main calculation page there are two spots to enter temperature. This would be the temperature you're at when you're making a shot. There's the atmospheric temperature and then there's the Powder Temperature. Or could could un-check the box that says to "Enable" Powder Temperature.

 

[mikebob]

the temp i have saved in the app is 32 deg that is what temp was day i sighted it in and done ladder test with chrony. i think the saved fps is 2403. when my phone is charged i will hit the edit button and see what zero velocity was at 32deg.

varget .19 for 308win
h4350 .29 for 308win
retumbo .49 for 300wm
rl17 1.4 for 308win

vatget and h4350 input is from a few test firings so may be off a little just what i came up with trying these 2 powders out with this load so far. i have tried both of these and both shot very consistent at 825 with different bullets. never noticed it change then but again was not looking for it.

retumbo i have never noticed it change but never really looked either. i have shot it for years and this lot .49 matches perfect. .31 lot before this one

rl 17 just a few shots also but from the 32deg day to a 65 deg day i came up with 1.4. i have not shot this one other than working loads seating depth at 47gr from ladder test. this one might have to be my alternate until i can get my hands on h4350 again. i am out of my last 8lb and can only find a few 1lbs around with different lot#

It may not amount to a hill of beans it just something i stumbled upon one day at the range. i have never had a problem with it in the field hunting or shooting targets always seems spot on. i could have made a mistake in one of the setups i was doing varget and h4350 on same day and got one mixed up.