RIFLE TWIST
Hi guys,
Edgun barel have rifle twist ?
If it is how many inches per turn ?
Thanks I need this info for balistic calculator Strelok Pro.
Merou
All Replies
Viewing 11 replies - 1 through 11 (of 11 total)
I’ve got this information : found in russian internet edgun have 4 types of barrels with twist rates
– 450 mm (17,72″)
– 350 mm (13,78″)
– 370 mm (14,57″)
– 390 mm (15,35″)
Mérou.
Thanks to all for your technical answers. (Wingman NZ, Keyser soze, Darryl and others)
Very interest and useful to understand the functioning.
Cool links :
http://www.talonairgun.com/forum/viewtopic.php?f=34&t=31529&p=318799#p318799
Merou
see this thread: http://www.talonairgun.com/forum/viewtopic.php?f=34&t=31529&p=318799#p318799
darryl
I have been told that most air rifles have a 1:16 twist. Skirt size and head size are also important. I do know that Ed’s barrels are made for the 18.1 JSB
Keyser, I ran out of fingers and toes, so a ?. Given your formula, can you see it matching up to the Standard,s twist as applied to the 18 grain pellet?
darryl
The basic answer is the heavier the bullet the quicker the twist. What we are looking for is an SG number of greater than 1. SG is a calculation found by a formula called the miller twist rule.
The following formula is one recommended by Miller.[1]
{t}^2 = \frac{30m}{sd^3l(1+l^2)}
where:
m = bullet mass in grains
s = gyroscopic stability factor (dimensionless)
d = bullet diameter in inches
l = bullet length in calibers
t = twist in calibers per turn
Given those definitions we can expand:
{t} = \frac{T}{d}
where T = twist in inches per turn, and
{l} = \frac{L}{d}
where L = bullet length in inches.
Stability factor[edit]
Using Miller’s formula we can also calculate the stability factor assuming we already know the twist. Simply solve for s.
{s} = \frac{30m}{t^2d^3l(1+l^2)}
Twist in inches[edit]
It is possible to solve for twist in inches directly by solving for T
{T} = \sqrt{\frac{30m}{sdl(1+l^2)}}
or you can go here:
use G1 BC drag model when calculating for pellets. The G7 model is for VLD bullets like the 6mm XC. The calculator I posted is for rifles so the GA drag model is not available. If you are using a ballistic calculator that has a drag option then use the GA profile.
Hello Merou,
I think the video gives part of the answer. I understand the twist part, but there must be another video explaining the relationship of ROT to bullet (pellet) weight, which was mentioned at the start of the video. At least the ROT was explained.
thanks All!
darryl
Ed says it 410mm to translate that 410 mm is 16.1 inches so I think Ed means 1:16 ROT
darryl length involved
Darryl,
The solution is here on yutube :
Merou
I think I read it was stated as 407 or 410mm. Can’t say I understand that expression, unless one knows the barrel
darryl length involved
Viewing 11 replies - 1 through 11 (of 11 total)
- You must be logged in to reply to this topic.
keeping the faith (in Ed). :winkn:
Darryl