6mm barrels ?

F

Frankr

Member
What is the most accurate groove and twist for a 6mm barrel for 100/200 yard
benchrest competition? Do you remember when allmost every 6mm ssm barrel was a
14 twist? now it seems there are all kind of groove,twist and land and groove dia.

What groove/twist & dia has the most accurate barrel been,that you have ever owned?
And if say that was a what ever, was that the next barrel you bought?


The most accurate 6mm barrel that i have ever owned has been a 3 groove 14 twist
not sure what the groove dia was.
 
Best one i ever had was a Hart. Jack told be it was about 13 5/8 twist with a 236 bore.
I have had others shillen bartleins even a lilja But over all my best shooter ever was a hart with a 13 5/8 twist.
Right now I do have a Bartlein Gain twist fro 1/14 exiting at 1 13 1/4 that is awsome. I guess its the luck of the draw at times. the bartlein is a 237 bore.
 
mark-x said:
What is the most accurate groove and twist for a 6mm barrel for 100/200 yard
benchrest competition? Do you remember when allmost every 6mm ssm barrel was a
14 twist? now it seems there are all kind of groove,twist and land and groove dia.


.
Click to expand...
The current "flavor-of-the-month" is probably a 237/243 1:13.5 Krieger or a 237/243 1:13.75 Bartlein.
 
Ok thanks, the reason i ask is im going to order two barrels here soon and i know i have to try another 3groove but
the other one im kind of up in the air about, i dont get real concerned about groove and bore dia(should i ?)
im more concerned about number of grooves and twist, becauce i think im going to try 1-13.5, or 1-13.75 but it seems you can go 4 groove
5R, 6 ect and i really have no idea what that will do if anything to accuracry. have had a few ssm barrels and at one time was only ever
concerned with what twist it was. Then someone,i wont say who, reccomended i try this 3groove and it has shot very well for me.
so just wanted to see what you fellows thought about it and what was shooting good in the 6bore.
 
mark-x said:
Ok thanks, the reason i ask is im going to order two barrels here soon and i know i have to try another 3groove but
the other one im kind of up in the air about, i dont get real concerned about groove and bore dia(should i ?)
im more concerned about number of grooves and twist, becauce i think im going to try 1-13.5, or 1-13.75 but it seems you can go 4 groove
5R, 6 ect and i really have no idea what that will do if anything to accuracry. have had a few ssm barrels and at one time was only ever
concerned with what twist it was. Then someone,i wont say who, reccomended i try this 3groove and it has shot very well for me.
so just wanted to see what you fellows thought about it and what was shooting good in the 6bore.
Click to expand...

I'd recommend staying in the 237/243 4-6 groove range. I've had 3 groove barrels and 8 groove barrels and they are harder to tune IMO. Oh, in 2004 I went through some Spencer 5 groove barrels. That would be a good compromise if Clay has some more of the 5 groovers.

The main trouble with a 3 groove is that the lands are very short. The ones I had took a 0.2386 pilot for the reamer. This does not give very much grip on the bullet jacket....but you can have too much grip also..oh well!

Bottom line, stay with the basics. Get them chambered by someone who does great work and stay with that configuration for 2-3 years at least. Don't go less than 13 twist or greater than 14.5 twist. Stay in that range and they will shoot 0.750, 0.790 and 0.825 jackets well. You just gotta' learn to tune what you have.
 
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