FX Smooth Twist – Twist Rate for Strelok?

Forums Other Parts, Accessories, & Equipment FX Smooth Twist – Twist Rate for Strelok?

  • Views : 939
  • Link

    hollowpoint
    Participant
    Member

    Hey guys, I figured I'd post this in here since it's a question related to ballistic calculators/computers. I'm new to using ballistic software, and I'm trying to get Strelok Pro setup on my phone. I have a few setup parameters I wanted to double check with someone more knowledgeable.

    1) Twist Rate

    Does anyone know what the twist rate is on a fullsize FX Wildcat Smooth Twist barrel in .25 cal? I did some searching and one guy mentioned his Bobcat was 1-32 left hand twist, and another person mentioned he thought it might be closer to 1-40 twist. Assuming either of those numbers are in the ballpark of reality, is this how I would enter 1-32 left hand twist into Strelok?

    2) Determining Scope Height

    I took the following measurements to determine scope height. Was this the right way to go about it?

    • Measure scope diameter and divide by two – 2.21" / 2 = 1.105"
    • Measure barrel/shroud and divide by two – 1.1" / 2 = 0.55"
    • Measure distance from top of barrel shroud to bottom of scope – 0.90625
    • Add them all together to determine scope height – 1.105 + 0.55 + 0.90625 = 2.56" Scope Height

     

    Is there anything else that I might have missed to setup Strelok for airgun use? Thanks for your time!

    Link

    stoti
    Participant
    Member

    I use Strelok for my long range powder burners and was turned on to Chairgun Pro for airguns. It seems to be a lot more user friendly when using air guns and it's a free download. It also already has a huge database of the most common pellets used. It's fast, easy and accurate.  Also, I don't know about your formula for finding scope height but it's much easier to just hold a ruler on the side, center of your barrel and measure to the centerline of your scope. Simple and fast with no math involved.

    Link

    Michael
    Keymaster
    Keymaster

    That twist rate (although probably close) won't work because Smooth Twist (st) is only in the last few inches of the barrel. You should be fine leaving the twist rate at default (12 if I remember correctly).

    Scope height and velocity are more important. Yes you calculated your scope height correctly.

    Link

    Kgphotos
    Participant
    Member

    Thank you for the info regarding measuring scope height. I really do learn something new every day.

    Link

    hollowpoint
    Participant
    Member

    Michael

    That twist rate (although probably close) won't work because Smooth Twist (st) is only in the last few inches of the barrel. You should be fine leaving the twist rate at default (12 if I remember correctly).

    Scope height and velocity are more important. Yes you calculated your scope height correctly.

     Thanks Michael, I changed the twist rate back and forth from 32 to 12, and at least out to 150 yards in Strelok…the holdover calculations look the same. Thanks for letting me know that won't work/doesn't make a difference.

    Link

    Centercut
    Participant
    Member

    I’ve tried the same thing with my .30 Bobcat, and like @hollowpoint says, it didn’t affect holdover at all. I do know that changing the twist rate, along with pellet velocity, affects the gyroscopic stability factor (try changing variables and watch the GSF change). My assumption (question) is if there are algorithms in the app that adjust the amount of hold for windage based on the GSF and BC? Just a thought… Love Strelok Pro by the way.
    Mike

    Link

    txrpls
    Participant
    Member

    BTW Strelok has the GA drag profile available.  I noticed you had the G1 selected. 

Viewing 7 posts - 1 through 7 (of 7 total)

You must be logged in to reply to this topic.