6BR free bore question

[ARshuter]

How much free bore do you want/need to shoot 105-108 class bullets? Thanks Alan

 

[Phil]

You really don`t need the extra freebore with the long neck, BUT you can use a longer freebore and fill some of the neck with powder.......

How much I don`t know so I won`t even throw out a number, someone will be along with an answer much better than mine......


Phil.

 

[DBLNUT]

How much free bore do you want/need to shoot 105-108 class bullets? Thanks Alan

Mine is a .269 neck with a .115 freebore.

 

[johara1]

How much free bore do you want/need to shoot 105-108 class bullets? Thanks Alan

With what case?

 

[ARshuter]

With what case?

Lapua .272 neck just don't know what to tell him for free bore. He has one on the shelf with .105.

 

[johara1]

Lapua

OK what caliber?

 

[ARshuter]

OK what caliber?

6 BR

 

[johara1]

Depending if you have to jump them or seat them to lands, but .120 is good on a BR. That is why i quit, i can't see any .... LOL. jim

 

[geo.ulrich]

mine is .105 for 1,150 jacket length making a 1.210 long bullet, it would seem what ogive and length bullet you are using would need to be known

 

[ARshuter]

mine is .105 for 1,150 jacket length making a 1.210 long bullet, it would seem what ogive and length bullet you are using would need to be known

I was going to let the gun tell me that, what bullet it likes.

 

[geo.ulrich]

I was going to let the gun tell me that, what bullet it likes.

that's fine but what if bullet wants to be jammed and you have a .135 freebore and 18 ogive bullets won't be much in case or a .135 freebore and 95 gr bullets which use a shorter jacket length

 

[ARshuter]

good point

 

[johara1]

If jump say .020 verse in .020 means more to length of the free bore length. plus if you shoot fat bullets you had better be concerned with free bore diameter. Plus if you jump you need longer free bore than to keep the same powder capacity and you will drop back to the unsized part of the neck...... jim

 

[Dave Berg]

I have two 6mm BR reamers that vary only in neck diameter. The old one is 0.272" and the newer one is 0.2704" for "blue box" brass. Both are 0.105" freebore.

One of the virtues of the 6BR is the long neck. I've shot Berger bullets exclusively including the 105BT, 105 Hybrid and 108BT out of the twenty or so barrels these reamers have been used in. With any of those bullets seated for a 0.020" jump the boattail is well above the neck shoulder junction and plenty of room for max loads with Varget or R-15. With the same bullets 0.020" into the rifling there is still plenty of bullet in the neck.

IMHO a 0.105" freebore reamer works just fine in a 6BR at least with Berger bullets although I have tried Sierra, EPS and a couple others briefly with the same lack of problems. I did run into difficulty when Robinette came out with his "bobtail" that needs about 0.190" freebore. I have a reamer designed for those bullets that I'll make you a really good deal on - only used once.

The freebore diameter was an issue when the original Berger hybrid die wore to the point of turning out 0.2435+" bullets compared to the 0.2428" where it started. That should not have happened in my opinion and I'm not going to have a fat freebore reamer ground with the expectation that it will.

 

[ARshuter]

Thanks Dave that's what I was looking for.

 

[johara1]

Spencer or Vaper trails, EPS and Berger are all over .2435. I haver Bergers .244....... jim

 

[Longtrain]

My Dasher is .123, my BR being built is .100, plenty for a 105ish bullet. BR has a lot of neck to play with, if you want it longer, shoot a bit, it will grow.

 

[noload]

I've shot a lot of 105 Bergers with a .104" FB in a BR, I would not go with less than that because you may feel the donut when seating the bullet in after the case gets some mileage on it. I found the donut to be a nuisance only when seating the bullet, if donuts show up there are penty of ways to remove them, but with the 104 fb it gives you plenty of neck lenght to work with when chasing the lands.
I turn necks and will continue to use that free bore because it shoots 105's... to 80's very well.