Farmerbrown32
Well-Known Member
I was wondering if anyone has shot the 195 berger out of a 7 RUM with a 9 twist? And what kind of accuracy, speeds, and ballistics you are getting?
Thanks!
Thanks!
7 RUM 195 berger
- Thread starter Farmerbrown32
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If you are talking about a factory barrel the twist is going to be 1 in 9.25 or 1 in 9.5. According to Berger's stability calculator either barrel doesn't have enough twist for proper stabilization.
Twist Rate Stability Calculator | Berger Bullets
Twist Rate Stability Calculator | Berger Bullets
TheDerkster
Well-Known Member
So in general, your twist rate is somewhat based off RPM. So velocity definetly comes into play here, but not totally. I dont wanna get reamed for saying something incorrect...
But Im running a 1:8 28" krieger on a 7mm Sherman shortmag and I was getting great results with the 195 considering I had no load developement. Probably running 2800 ish FPS but I haven't chronographed it yet. I was cloverleafing or leaving one jagged hole at 100.
My point is that 1:8 is sufficient, but Ive never heard anybody say 1:9 is gonna perform like you want it to. Especially when velocity starts to drop off and you get out to long range. You may waste your time developing a good load that wont hold its own at range.
But Im running a 1:8 28" krieger on a 7mm Sherman shortmag and I was getting great results with the 195 considering I had no load developement. Probably running 2800 ish FPS but I haven't chronographed it yet. I was cloverleafing or leaving one jagged hole at 100.
My point is that 1:8 is sufficient, but Ive never heard anybody say 1:9 is gonna perform like you want it to. Especially when velocity starts to drop off and you get out to long range. You may waste your time developing a good load that wont hold its own at range.
Farmerbrown32
Well-Known Member
Ya thats what im afraid of. I will try some and see what happens. If they wont work ill shoot the 180s out of it i guess. They should do real well. Just was hoping someone would chime in that has tryed it before. Just hoping the big 7 rum can push it hard enough to stabilize.
barefooter56
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- Nov 10, 2014
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Farmerbrown,
Go to our website and run your data through the TWIST RATE CALCULATOR. Be sure to enter the correct altitude(s) you will be shooting at. Also read the article by Bryan and Eric found in the BERGER BLOG on how to interpret your results on the twist rate calculator.
Go to our website and run your data through the TWIST RATE CALCULATOR. Be sure to enter the correct altitude(s) you will be shooting at. Also read the article by Bryan and Eric found in the BERGER BLOG on how to interpret your results on the twist rate calculator.
Farmerbrown32
Well-Known Member
Thank you sir! At my altitude it is right on the edge of marginal and full stability. Im gonna shootum and see how it goes! gun)
barefooter56
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- Joined
- Nov 10, 2014
- Messages
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Great! Let us know how it goes.
Take care,
Take care,
Farmerbrown32
Well-Known Member
Thank you to everyone for their help!
