Diana Model 48 / 52 Barrel Twist ??

[Miguel Ingles]

Can anyone tell me the "Barrel Twist" of the Diana Model 48 or 52 ?? I'm trying to input that info into my Strelok Pro ballistic calculator.
I emailed Diana and searched everywhere with no luck... I'm thinking 1:16 twist, but wanted to be certain.
Thanks in advance

 

[bdzjlz]

I think it is likely 1:17 but not totally certain.

 

[Ryden]

Doesn't really matter for an air gun. spin drift will be negligible at the distances we normally shoot so just leave it blank.

Unless you're pushing for 100y or so, then add approx .3 MIL vertical deflection