Quoted: Guys
Those of you who know me, are aware I have a couple of fat Bob's Speedmasters.
I am fed up with the heavy stainless steel, bull barrell one and want to change the barrell for a lighter weight Military style one.
I want it for 600 yard PR shooting and was thinking of a 20 - 22" Barrell and a 1 in 8 twist. I shoot 69grain bullets and am happy with the load.
Does that sound about right?
At least then in the longer distance comps when I have to use it, I won't be knackered in the standing, closer stages
The current barrell is good but just too heavy for unsupported shooting.
Any advice appreciated
Rgds
Stu
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20" max would be your best bet. There's nothing to be gained from a 22" barrel except unweildiness.
As Matt said, if your current barrel is shooting OK, then just put it on a diet.
My latest barrel is 18" and although I've only shot it to 500yds, I'm more than happy with the performance of it
The problem you will have is restricting it to 69's. They're good, but they're not a 600yd bullet. Better to go with 77's or 75's
BTW, a good 16" barrel can shoot as well as a good 18" or 20" barrel at 600yds. You'll lose a little velocity and have to use a bit more wind, but that's why you have turrets on your scope.
But with that said, a 18 or 20 will be your best bet.
Now, I was having a conversation with a very respected barrel maker some months back (Mike Rock).
He was recommending the "QuickLoad" ballistics program and he did the following calculation for me....
With a round loaded with 24.5gns of Reloder15 and a 77gn Sierra, 95% of the charge is burned up at 16.37" of bullet travel down the bore. Make of that what you will, but it's worth considering.
The extra barrel length doesn't give a lot more velocity.
Derrick Martin did some tests (which are in his book) where they compared the velocities between 20 and 27" .223 barrels and the velocity difference was only 107fps on average.
Mark