Perhaps not directly, but barrel length affects MV.
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Barrel length and twist rate
- Thread starter mkk
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No it affects velocity, not RPMs. And if you spin the bullet to fast at to high a velocity a light bullet with a low SD can potentially explode. However, if you increase velocity by lengthening the barrel you do not increase rpm's because the twist is to slow, therefore heavier bullets will not necessarily stabilize. I hope that made sense.
I am not trying to start an argument, just trying to learn more.
So if I shoot a lite bullet with too much twist it will still over spin not matter what barrel length
So if I shoot a lite bullet with too much twist it will still over spin not matter what barrel length
He just showed you the RPM calculation, which has velocity in it. If you change valocity, you change RPMs.
Mikecr
Well-Known Member
No
Stability is not related to TIME per turn. Nothing to do with RPMs.
It is related to the twist rate, which is DISPLACEMENT per turn.
Thinking that velocity or RPMs will solve your stability deficits is wrong thinking. Doesn't work that way.
Find me a stability calculation that does not include Muzzle velocity
Yes your right. I never thought of that, but if you play with a SC you will see that velocity has a very small effect on stabilization. at least according to the calculator
Mikecr
Well-Known Member
Find a stability calculator that includes RPM.
If you manage it, you've found one that absolutely doesn't work.
I understand that but we are talking about inches in barrel length and stabilization of heavier bullets. In theory if you could increase the number of revolutions a bullet took before it left the barrel while increasing the speed you could stabilize a heavy bullet in a long slow twist barrel but the barrel say in a 1/10 twist would need to be 30 inches or longer and you would need to push it extremely fast which would also increase the barrel length. For practical purposes say barrels less than 30 inches you need to increase the twist not the barrel length. Barrel length is about velocity and when you increase velocity you increase rpm's but not significantly enough to effect stability in a slow twist barrel. I understand the formula I am just trying to put the cookies on the bottom shelf so he can understand that increasing barrel length with in usable perimeters does not increase stability which was the question.
Generally speaking yes. The construction of the bullet comes into play here if it's a cup and core with a thin jacket which most light bullets are they can come apart in mid air.
Solid bullets don't care if they are over spun.
Velocity has very little effect on stability if you look at the formula the twist rate is the divisor it has way more effect.
I agree. That is why I said going from 20" to 22" might not change velocity enough, but going from 16" to 24", depending on the bullet, might be enough to go from unstable to stable.
That was what I was trying to ask in my original question. So with that answer, barrel length does impact stability?
