6BR FREEBORE

[BOB LEE SWAGGER]

I am looking to have a reamer made for 6BR. I have both a 1:12 and 1:8 twist barrel on hand. I would like to be able to use the reamer for both. If that is just being stupid I would like to err on the side of the 1:12 twist. This will be a "fun" no turn neck gun to use as far as it will go. I am looking to use the 80 & 88 Bergers in the 12 and (if possible) 105's in the 1:8. What free-bore is recommended? Thanks.

 

[AndyTaber]

Check out Pacific Tool. They have a neat little gizmo called a Uni-Throater that would allow you to spec your reamer with a very short or zero freeborre, and then make the necessary adjustment to the desired size.

 

[Phil]

Yup.....

I would spec the freebore for the shorter bullet and then use the uni throater to lengthen it for the longer bullets.

Talk to your smith first off and see if he is a fan of the uni throater, some smiths aren`t.

Phil.

 

[BOB LEE SWAGGER]

Thank you for the replies. For the cost of the uni-throater it makes more sense to buy two reamers!

 

[Phil]

Hadn`t even checked the cost..... :-\ ............oops.


I personally like a reamer for each individual barrel / rifle / caliber , but some smiths have a uni throater already.

Phil.

 

[Bert]

Both of mine are .101 FB I only shoot the 105 Hybrid out of them now but have shot the 80 gr bergers. Both bullets have worked great with that FB. Now I am sure someone will say that isn't enough for the hybrid. Don't care they work great.

 

[tclaunch]

My last 2 6BR reamers I had made use a .100" freebore. The 6BR neck is soooo long its hard to go wrong! The improveds is where the thinking cap and billfold get used much more.

 

[nmjwolf]

I also have a rather short freebore at .090 and dont have any issues keeping the hybrid out of the donut area.

 

[BOB LEE SWAGGER]

THANKS!!! That is what I needed.

 

[Drop Port]

I am looking to have a reamer made for 6BR. I have both a 1:12 and 1:8 twist barrel on hand. I would like to be able to use the reamer for both. If that is just being stupid I would like to err on the side of the 1:12 twist. This will be a "fun" no turn neck gun to use as far as it will go. I am looking to use the 80 & 88 Bergers in the 12 and (if possible) 105's in the 1:8. What free-bore is recommended? Thanks.

I had one built for the same purpose "fun" no turn gas and go. Used a .98 FB and settled on the 107's, sometimes I forget its a 6 br. We were up in PA shooting rocks across the mountain with 6.5's, 7mm's and 338's for the heck of it I pulled out the 6br and turned it on the 1240 rock the guys laughed and asked what do you plan on doing with that. They almost peed their pants in disbelief when it hit. You will love it, as stated no problems with the 80's and the long neck.

 

[dreever]

I use an .060 freebore in my 8 twist 6BR's. It will handle bullets from 55 gr to 105's. Bearing surface/boat tail junction soft seated into the rifling is at the neck shoulder junction with the Berger 105 VLD huntings that I use for Ground Hog matches. Contrary to popular belief you don't need all that freebore to make a 6BR shoot with the heavy bullets. In my 26 inch Kreigers I'm getting 2940 fps and not killing my brass to do it.

Danny

 

[Bert]

Only reason for much free bore is to keep the bullet out of the donut and not have to ever screw with that. And don't forget the 6 br will feed out of a modified AI mag.

 

[JRS]

I use an .060 freebore in my 8 twist 6BR's. It will handle bullets from 55 gr to 105's. Bearing surface/boat tail junction soft seated into the rifling is at the neck shoulder junction with the Berger 105 VLD huntings that I use for Ground Hog matches. Contrary to popular belief you don't need all that freebore to make a 6BR shoot with the heavy bullets. In my 26 inch Kreigers I'm getting 2940 fps and not killing my brass to do it.

Danny

Exactly

 

[johara1]

I use an .060 freebore in my 8 twist 6BR's. It will handle bullets from 55 gr to 105's. Bearing surface/boat tail junction soft seated into the rifling is at the neck shoulder junction with the Berger 105 VLD huntings that I use for Ground Hog matches. Contrary to popular belief you don't need all that freebore to make a 6BR shoot with the heavy bullets. In my 26 inch Kreigers I'm getting 2940 fps and not killing my brass to do it.

Danny

Sounds good except with soft seating i'm sure you engraved the bullet a little, but if you have to jump them it will push the heel into the donut area. Now for the last ….. never seat heel of the bullet past the sized portion of the neck. I would go no less than the .100 FB…. jim

 

[JRS]

Since the OP references a 6BR, not a Dasher, there is no donut ;D

 

[johara1]

Since the OP references a 6BR, not a Dasher, there is no donut ;D

I'm referring to a 6BR. not a Dasher ………….I sure would not want a .100 Free Bore in a Dasher. Yes you you can get a donut in a BR as in any cases that the brass will flow in but never saw one in a Dasher ……. jim

 

[OIF/OEF]

Mr Swagger Sir,

I used the uni-throater and if I can do it anyone can im teetering on the edge of an extra chromosome. The good thing is its good for 6mm so keep it and use it for future projects ya know. Im pretty sure it'll work on most any 6mm bore. I did mine and didn't borescope it until I was done and man it came out great. Erik Cortina posted about using one and not even removing the scope granted the dude is a master bonediggity smith and shooter but if he did it and said it came out good I believe it. Have a Merry Christmas and if your atheist well still have a Merry Christmas lol. JK

Submitted for your review with the utmost Respect Sir

 

[BOB LEE SWAGGER]

Jim, as usual your advice is extremely helpful. Why is the common seating advice that the bearing surface stays above the NSJ and you prefer that no part of the bullet is below this point?

 

[JRS]

OP:

Call the bullet guru, (Randy) RG Robinett, and ask him what the optimal free bore length should be for the 88 GR - 110 GR bullets

After struggling with my reamer dimensions, a long and educational conversation with the good RG answered my questions. 0.060 free bore

 

[johara1]

Jim, as usual your advice is extremely helpful. Why is the common seating advice that the bearing surface stays above the NSJ and you prefer that no part of the bullet is below this point?

First if you use a seating pressure gauge like i do you can size a case seat a bullet as it slides in you watch the meter and as it approaches the the end of the sized portion of the neck you will see the pressure drop. After the the pressure ring passes the sized part of the neck. If you use a standard die you will see a spike in the pressure when it reaches the shoulder neck junction because the neck is supported by the shoulder and the thickness of the shoulder wall. The only worry is the heel of the boat tail that is the start of the bearing surface. the rest doesn't matter except that you are raising the pressure by lowering the capacity. I would set up for jumping would use a little more free bore to get a better condition and the little bullets will still work good enough, use the long neck to your advantage. The BR. will shoot good 105 bullet as good or better than the light ones. Too much capacity for short range BR bullets or the PPC wouldn't dominate, but put a 8 twist barrel in one one and go to 300+ range they will eat the PPC……. BY the way try some of the BIB 104's in the 8 twist barrel and you will find they will shoot in the mid zero's with a .100 fb……… jim