Do you think twist rate has a measurable effect on pressures?

If you are pushing the limits so far that the rate of twist puts you into the danger zone, then you have already pushed the limits too far.

I have never seen ammo that warns against using it in a certain twist barrel except when a slow twist may not stabilize a long bullet. I have never seen pressure warnings associated with rates of twist.
 
Not at all. the amount of twist helps in stabilization or not of the projectile in the atmosphere.

The quality of the cut chamber is 1000x's more important then any other factors in a barrel.

All things to quality control, that is.

The ammunition components, ratios in the load, burn rates of powder and wall thinkness of the brass matter.

Also if the chamber is polished or coated this plays afactor
 
Curious if a tight or loose twist has a measurable effect on pressures.

Thoughts?

It kinda does.

But if I have learned anything, your lands in combo with twist will really screw with things. Least thats what I have learned while messing with the 6.8

The OG 6.8 chamber remington fubar, have a short throat, 1:10 twist and I think a 6 land rifling. Pressure sign happened early, like in the 40k range

The SPC II chamber that Harrison came up with made the throat longer and he slowed the twist down to 1:11/11.25 and now the pressure range is up around 60k.

Now he has switched over to 3r rifling and back to the 1:10 twist and the speeds have went up with no affect on pressure.

He is coming out with a 224 Valkyrie barrel that has a 1:6.5 twist to stabilize the 90/95 smk with no velocity change.

I'm pretty sure that info is spot on.

Now to answer your question, I think a faster twist can show over pressure signs sooner than a slower twist. But unless the the twist rate is wrong and the chamber design is fubar then I think the affect are minimal

But like mention, bullet stability is were twist rates really come in to play
 
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Yes, but the difference should be very little.....as in next to nothing.
 
ALL else being equal, if you could keep pressures the same, the faster ("tighter") twist barrel would have a slower MV. However, us average folk cannot measure chamber pressure, and if you tried to load to the same velocities, you would create higher pressure in the faster twist barrel. At the far deep end of the rabbit hole, when bullet RPM gets too high (a combination of twist and velocity) bullets will come apart as they exit the barrel. (Not normal stuff, more like trying to push a .22-250 to extreme velocities.)
 
Here's the scoop. I talked to Mike last night, my partner in B&M Rifles. He said for an example...223.....1In 16 twist....1 in 8 twist. Pressure is LESS than one half of one percent difference. Thank goodness he keeps all this stuff. My lack of knowledge about this is only exceeded by my lack of interest. BUT not him, he loves this stuff.
 
push a .22-250 to extreme velocities.)

I know when I can't make a hole in a target at 25 yards with my 22-250 the bullets aren't making it there. The limit for my gun seems to be around 4300 or so. My pet load runs around 4150 or so but if I bump it they just don't come out of the barrel....
 
I know when I can't make a hole in a target at 25 yards with my 22-250 the bullets aren't making it there. The limit for my gun seems to be around 4300 or so. My pet load runs around 4150 or so but if I bump it they just don't come out of the barrel....

Tried solids?
 
I had heard that faster twist would erode the throat quicker. I thought that was the reason for some AR barrels going to 1:8 instead of 1:7.
 
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