Is an 8 twist too fast for a 22-250 with 50-55 gr bullets?

[Rtheurer]

How fast are you thinking?

Also, with a twist faster than is necessary for the bullet length you will hit pressure limits at a lower MV and you would with a slower twist.

No Disrespect, But is that really true or just an old Wives tail that keeps getting passed down generation to generation. If it does, How much will it create pressure and how early? Experts ( scientists/ Engineers) say its not enough to tell.

 

[SmokinJoe]

Maybe look at the new Hornady varmint bullet which requires 8 twist.

 

[Coyotefurharvester]

Have you called Ragged Hole, see what they have on hand?

 

[SteveOak]

No Disrespect, But is that really true or just an old Wives tail that keeps getting passed down generation to generation. If it does, How much will it create pressure and how early? Experts ( scientists/ Engineers) say its not enough to tell.

@Rtheurer

Here is what I am thinking.

Let's say we have two different rifles which are in every way perfectly identical except for the twist of the barrel. Not possible of course but this is to limit the discussion to the physics of the question and not the idiosyncrasies of an individual rifle. We also have precisely identically prepared cartridges. Again, not possible but a necessary hypothetical for this illustration.

The bullet leaves the barrel spinning. The bullet fired from the barrel with the faster twist will be spinning faster. Changing the state of the bullet from not rotating to rotating is work which requires force. Since a body at rest will remain at rest unless acted upon by an outside force and the bullet will resist being made to spin, the resistance to being made to spin will be greater in a barrel with faster twist. As the result of this increase in force required the bullet will accelerate more slowly

The rate of increase of chamber pressure as the powder burns will not change. As the result of the faster twist the bullet will not accelerate as quickly so the expansion of the 'combustion chamber' will be delayed resulting in a higher peak pressure.

Whether it will affect what you are doing depends on several things. If you are a casual shooter, it probably won't make a difference to you. If you are you near the peak pressure for the cartridge/case and trying to eek out the next node, then it may.

There is more to it than that but I think it covers the basics.

VV N5XX series powders may be (at least somewhat of) an exception as they are formulated to remain at peak pressure longer.

 

[Rtheurer]

@Rtheurer

Here is what I am thinking.

Let's say we have two different rifles which are in every way perfectly identical except for the twist of the barrel. Not possible of course but this is to limit the discussion to the physics of the question and not the idiosyncrasies of an individual rifle. We also have precisely identically prepared cartridges. Again, not possible but a necessary hypothetical for this illustration.

The bullet leaves the barrel spinning. The bullet fired from the barrel with the faster twist will be spinning faster. Changing the state of the bullet from not rotating to rotating is work which requires force. Since a body at rest will remain at rest unless acted upon by an outside force and the bullet will resist being made to spin, the resistance to being made to spin will be greater in a barrel with faster twist. As the result of this increase in force required the bullet will accelerate more slowly

The rate of increase of chamber pressure as the powder burns will not change. As the result of the faster twist the bullet will not accelerate as quickly so the expansion of the 'combustion chamber' will be delayed resulting in a higher peak pressure.

Whether it will affect what you are doing depends on several things. If you are a casual shooter, it probably won't make a difference to you. If you are you near the peak pressure for the cartridge/case and trying to eek out the next node, then it may.

There is more to it than that but I think it covers the basics.

VV N5XX series powders may be (at least somewhat of) an exception as they are formulated to remain at peak pressure longer.

You might want to talk to Brian Litz about this, He says otherwise.

 

[SteveOak]

You might want to talk to Brian Litz about this, He says otherwise.

Please provide a link to where he says otherwise.

 

[3-300s]

I have a 9 twist, know you ask about an 8. It shoots 55 gr ballistic tips at 3800 (by chrono)
with great accuracy. I didn't know if my rpm's might somehow help you.