Twist Rate for 7MM

[montec]

Hi Guys. Plan on having a Rem 700 in 7 MM Mag done up. Action trued,H.S Presision stock, and a new SS bbl installed. I have 2 700's in 7MM. One will be used for short range...160 Accubonds.Best I can get out of a 24" factory bbl is about 2825 fps.The one I plan to have rebuilt will have a 26" SS bbl on it. I only plan on shooting 140-150 grainers out of it. Was wondering if any one has experimented with a different rate of twist. Both rifles are currently factory..only glass bedded wood stocks. BBL's have 9 1/2" twist. Can I get away with a slower twist and if so, what would one recommend???

 

[yukonal]

Standard...and common twist rate for 7MM is 1 in 9. My 6-7MM rifles are all 9 twist, and shoot 120's up to 180's just fine.

What are you trying to gain/accomplish by considering a slower twist rate?

 

[montec]

A little better velocity is what I would like to gain. Many times I see diffferent load recipes in the same caliber but for different twist rates. Not sure if this comment will open a can of worms but in my 22-250, I am getting the velocities that are published. Now my 22-250 is a 26" SS bbl with a 14 twist. Not sure if this is true but I have read/heard many times that you can get higher velocities out of a SS bbl that is same length as a chromemoly bbl???

 

[TonyR]

There is another thread here about the 280AI for F-Open when one of the posters reports that he looses 50fps with a 1:8 versus 1:9. I had a 1:8.5 once that was also noticeably slower than my 1:9s. Some of the difference might be due to normal barrel to barrel variations but it must take some extra force to spin the bullet to higher rpm in the same distance which has to take something away somewhere else.