Bsa ultra

[collieman 45]

Hi guys I have a bsa ultra which had been doing 703 fps using jsb heavies, but today the chrono says 633 anybody got any ideas what might be wrong? Could it be the heat I thought that would have made it faster.

[villaman 9,983]

29 minutes ago, collieman said:

Hi guys I have a bsa ultra which had been doing 703 fps using jsb heavies, but today the chrono says 633 anybody got any ideas what might be wrong? Could it be the heat I thought that would have made it faster.

What chrono are you using  , has it been regged  ,if not what bar are testing it at ?

[collieman 45]

Was tested with cb625 chrono both times it had been regulated before I bought it by airtech I was told, was checked at 200 bar.

The drop at 38 yards corresponds with the same fps speed using the balistic app strelok pro.

[villaman 9,983]

Sun light can effect the readings on the crombo  + if it not lined up properly and some times the batteries if they are a bit low will give false readings .

My regged ultra is running at 712-715 fps with jsb heavies  in the shade .

Is there a big difference  in fps over say 20 shots ?

[collieman 45]

I will try that tomorrow going out to the rabbits in half hour, did have to turn the rifle upside down to get a reading as the shroud gets in the way otherwise it just reads bad.

[villaman 9,983]

25 minutes ago, collieman said:

I will try that tomorrow going out to the rabbits in half hour, did have to turn the rifle upside down to get a reading as the shroud gets in the way otherwise it just reads bad.

Sounds like its not lined up or batteries 

[collieman 45]

Well tried to get readings from chrono today not working except saying bad changed batteries secured and alligned chrono up does not even read bad now just ready before and after shot.

[Deker 3,478]

The CB625 is a cracking bit of kit for the money but it can be a bit fiddly/temperamental. 

I am very pleased with mine just the same, but sounds like yours may have an issue, I seem to remember they offer a repair if required!

[villaman 9,983]

On ‎03‎/‎06‎/‎2018 at 16:31, collieman said:

Well tried to get readings from chrono today not working except saying bad changed batteries secured and alligned chrono up does not even read bad now just ready before and after shot.

Give the 4 sensors a clean 

[collieman 45]

40 minutes ago, villaman said:

Give the 4 sensors a clean 

Took chrono apart today cleaned it and it worked, took 10 readings averaged 703 fps with a range between 698 ang 708 so all good thanks for your input.