Twist rate of a BlackHawk?

[FerrumB5]

Hello,

what is the twist rate and the rifled barrel length in our beloved BlackHawks .177?

Thanks!

[dukemeister]

Breach to muzzle, mine is 18-3/4" long.
I don't know how to measure the twist rate, but a guess would be 1 rev in about 8" because it looks like a quarter rev in about 2", but it's a very loose approximation.

[mikeiniowa]

twist should be 1 in 16 inches...

[FerrumB5]

Thanks, Mike! That is the number I had in mind (approximately). So, if we take an average 870 fps with 7.9 gr CPHP we have approximately 650 revs per second!
Math:
1 twist in 16"
barrel length 18-3/4" => 1.17 revs in a barrel in 18.75" / 870 ft/sec / 12 in/ft = 0.0018 sec
So, 1.17 revs / 0.0018 sec = 650 revs /sec 
Not bad!

[Sure Shot Rick]

I just received a referb Blackhawk. After about 100 shots I put it on the Chrony. H&N Sport Field Target Trophy Green 5.56gr 1081FPS, Crossman 7.9gr 970fps. It already messed up my Leapers illuminated recital. It goes red from the recoil and I now need to remove the battery to turn it off and it will not go green. If I shoot anything lighter than 7.9gr the firing cycle sounds different and harsh. But is still very accurate with the lighter pellets. I am planning on a Vortek tune kit for Christmas. It is real hold sensitive as it came. Can I expect these velocities with a Vortek tune?

[Donny]

I just received a referb Blackhawk. After about 100 shots I put it on the Chrony. H&N Sport Field Target Trophy Green 5.56gr 1081FPS, Crossman 7.9gr 970fps. It already messed up my Leapers illuminated recital. It goes red from the recoil and I now need to remove the battery to turn it off and it will not go green. If I shoot anything lighter than 7.9gr the firing cycle sounds different and harsh. But is still very accurate with the lighter pellets. I am planning on a Vortek tune kit for Christmas. It is real hold sensitive as it came. Can I expect these velocities with a Vortek tune?

i never did chrono mine but it shot jsb exact 8.4 very accurate and hard with the vortek pg2