Author Topic: 1:6.5 twist rate barrel  (Read 477 times)

Offline dclary12

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1:6.5 twist rate barrel
« on: April 09, 2019, 10:23:00 AM »
Lets see how the twist affects my accuracy. Is anyone else shooting with this twist rate?

Offline Liberator52

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Re: 1:6.5 twist rate barrel
« Reply #1 on: April 10, 2019, 12:45:56 AM »
I love my 1-6.5 but it's a gasser. Shoots from 52ELDs to 95 SMKs well. Still working on loads.

Offline binazone

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Re: 1:6.5 twist rate barrel
« Reply #2 on: April 10, 2019, 04:40:03 PM »
6.5T is my favorite, but I also have a 6.7T. I couldn't get my 7T to work well with the 88s and 95s that I shoot. Yeh, I know that a lot of folks have great success with a 7T and not too many barrel makers/suppliers (at least the ones I've looked at per the list provided on this forum) provide anything other than a 7T. That got me thinking about what is the real difference in spin between barrels of 24, 22 and 20 inches and the various twist rates out there for the 224V. Well, here it is:

TWIST   24   22     20
 7.0         3.43   3.14     2.86
 6.7         3.58   3.28     2.99
 6.5         3.69   3.38     3.08

No great math here. Excel did all the work. The numbers with two decimal places are the number of revolutions the bullet makes in each barrel divided by the twist. In all cases there is only a (more or less) 1/4th revolution difference between a 6.5 and 7 twist barrel. I'm sure the barrel manufacturers know what they're talking about, but the 6.5 is working form me in my 20" Bison with both 88 ELDM and 95 SMK, both loads supersonic and accurate out to 1200 depending on the atmospherics.


Offline trianglevelvet

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Re: 1:6.5 twist rate barrel
« Reply #3 on: May 07, 2019, 10:24:10 PM »
Many would be surprised to learn that 1:7 isn't always actually exactly 1:7.

Its more like 1:7ish depending on barrel maker.

Some 1:7 barrels if measured exactly can actually be 1:6.7 to 1:7.3

Length also matters.
Length effects speed.
Higher speed= more rpm to stabilize the projectile.

So a 24" 1:7ish barrel might stabilize fine, but if cut down to 20" and recrowned, it might not.

 :o

Offline Hammerhead

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Re: 1:6.5 twist rate barrel
« Reply #4 on: July 03, 2019, 05:10:51 PM »
Gas gun 6.5 shoots tangent ogive bullets  lights out. Secant ogive not so much.