chrony results ?

[Barrelsniffer]

I have just chrono my hand loads using my new CED Millennium 2 Chronograph System,i also thought while i had my old chrono,the cheap but useful Shooting Chrony F1 Master Chronograph i would check the 2 against each other.

 

My load was 25grn vit 133 with 60 grn v-max

the millennium gave a reading of 3085 fps av spread

F1 master gave reading of 3200 fps av spread

 

All rounds were same batch same cases all new.

 

Any one had similar differences and which reading do i go with ?

 

Mick

[Ronin]

Test the load on target at distance increments of 50 yards to the farthest you shoot.

 

 

Work out a drop table.

 

Use the "real data" to compare with the two FPS measurements in Exbal or similar prog - you will get something that resembles and accurate FPS by "back calculation"

 

 

Alternatively change to a reliable chronograph with proof channel (tests each measurement twice before it gives you the reading) - Oehler 35

[Andrew]

If you didn't do it this way in the first place, I would set up both chronos and alternate shots from one to the other. See how that works.

 

I have three Chronys and each of them gives readings within a few fps of each other; this is a necessity as I calculate BC with multiple chronographs and a big error on one will really toss a ballistic coefficient.~Andrew

[Guest varmartin]

I bet the problem lies with your CED crono.

Sounds to obvious, but make sure the two

sensors are pushed on the bar correctly

as if one is not on all the way to the stop

it will give wildly incorrect readings.

[Barrelsniffer]

i did try them both,alternating from one to the other this is how i got both diff in the reading. 1st time i used the mill chrono,brand new out the box.

 

Mick

[sir-slots-alot]

Micky

Both myself and Dave G , use that load , From our chrono results ( seperate chono's )

 

you should have a velocity of around the 3200 fps mark ( out of a 24 inch barrel. )

 

This velocity is also back in the field from the expected drop the of the bullet at a given ange.

 

 

Another way to test this , is to put a few subsonic rimmy rounds through it

 

You know they will be around the 1050fps mark ( + 0r - 30 fps )

 

If the result from either chono's shows velocitys excessively wide of that mark , i would be suspicious of it .

 

 

Alan

[Barrelsniffer]

Micky

Both myself and Dave G , use that load , From our chrono results ( seperate chono's )

 

you should have a velocity of around the 3200 fps mark ( out of a 24 inch barrel. )

 

This velocity is also back in the field from the expected drop the of the bullet at a given ange.

 

 

Another way to test this , is to put a few subsonic rimmy rounds through it

 

You know they will be around the 1050fps mark ( + 0r - 30 fps )

 

If the result from either chono's shows velocitys excessively wide of that mark , i would be suspicious of it .

 

 

Alan

 

 

Cheers Alan,

 

Only just seen your reply.

 

Mick