6BRA Reamer Help

[a-dog]

I am shooting a 6BRA for F-class midrange. My gunsmith, who chambers my barrels, has his own reamer that I use. I have been very successful with it. I will be moving shortly and am kicking around the idea of buying my own reamer. His reamer that he uses on my barrels is a .272 chamber with a .104 freebore. These are the only specs my gunsmith knows about his reamer. Doing research, I want to keep it a .272 neck but have a longer freebore, likely a .120, based on my research. I mostly shoot 108s and 109s and Lapua brass. Does this sound like a good idea? Also, no reamer manufacturers I have found make this as standard. Can I custom order this? Would I need both a rough and finish reamer? Any help would be appreciated!

 

[swd]

You only need a finish reamer. Reamer makers make custom spec reamers all the time. Call JGS and tell them what you're doing and they'll help you make the right decisions on specs.

 

[Ccrider]

Look into a zero freebore. That way your smith can set the freebore at whatever you want.

 

[Clancy]

Just call JGS and tell them what you want. Super easy.

I’d probably ask for a wheeler no turn with the freebore increased to .120, but Alex may have a .120 print anyway.

 

[varget204]

Might check if 4Dreamer Rental is still renting reamers,they used to sell them too!

 

[boltfluter]

Buy your own reamer and take good care of it. JGS would be my first call. Manson makes a very fine reamer as well. No surprises from chamber to chamber is always a good thing. Shoot straight.
Paul

 

[SKWERLZ]

JGS and Manson will make whatever you want.
Bruno’s often has a few 6BRA reamers in stock with various neck and FB options but they are mostly PTG.

That said the reamer I got from Bruno’s worked well for me.

 

[Jeff Porter]

I am using the Manson 0.272 no turn with 0.104" free bore and shooting great in a Bartlein 5R with 105,107,108, and109 bullets.

Edit to add- these bullets seat with the boat tails at the neck shoulder junction so you wont be gaining much of any capacity seating them out further, only more donuts.

 

[a-dog]

I am using the Manson 0.272 no turn with 0.104" free bore and shooting great in a Bartlein 5R with 105,107,108, and109 bullets.

Edit to add- these bullets seat with the boat tails at the neck shoulder junction so you wont be gaining much of any capacity seating them out further, only more donuts.

View attachment 1662116

So you would recommend sticking with a standard .104 reamer if I am shooting 108s and 109s?

 

[Jeff Porter]

It is working for me with Bergers, SMK and ELDMs and Ray Gross designed it for those bullets.

 

[SKWERLZ]

So you would recommend sticking with a standard .104 reamer if I am shooting 108s and 109s?

I shoot the 108 with a .104 reamer as well.

 

[Jeff Porter]

I just did some math with the 105 Hybrids I am loading today. The brass is 1.555” OAL, the case neck is 0.310” long. From the reamer print and my brass, case base to shoulder junction is 1.119”base to neck shoulder junction is 1.245”. Subtracting the bullet length from a round seated 0.020” off touch, I calculate the base of the bullet is 1.130” from the case base.

This tells me that the bullet is 0.115” into the shoulder area. The boat tail on the 105 is 0.213” so about 1/2 a boat tail into the shoulder. My load of H4895 that gives me 2920 fps fills just up to shoulder so not compressed at all. I checked and I can get another grain and a half of H4895 in the case to be starting to hear crunch.

Even a 110 Atip will fit in this profile.

 

[LVLAaron]

Call JGS: Ask for the alex wheeler BRA. Ask to adjust the neck diameter.

 

[WSnyder]

Call JGS: Ask for the alex wheeler BRA. Ask to adjust the neck diameter.

 

[64Rambler]

This is how far a Vapor Trail 103 sits in the neck with a 0.120" FB at touch (contact circled). Criterion 6BRA, 0.272" neck. Critical body dimensions are the same as Alex's. JGS made the reamer.

 

[SKWERLZ]

Here you can see how a 108 sits in my .104 FB with .010 of jump.
You can barely see the expansion line from the bullet a bit above the neck/shoulder junction.

 

[ELR LVR]

I am shooting a 6BRA for F-class midrange. My gunsmith, who chambers my barrels, has his own reamer that I use. I have been very successful with it. I will be moving shortly and am kicking around the idea of buying my own reamer. His reamer that he uses on my barrels is a .272 chamber with a .104 freebore. These are the only specs my gunsmith knows about his reamer. Doing research, I want to keep it a .272 neck but have a longer freebore, likely a .120, based on my research. I mostly shoot 108s and 109s and Lapua brass. Does this sound like a good idea? Also, no reamer manufacturers I have found make this as standard. Can I custom order this? Would I need both a rough and finish reamer? Any help would be appreciated!

You can get a Finish Reamer
Short freebore
then I'd get a Throater Reamer additionally
That way you can set your freebore to whatever you like
inch it out a little a time if you want even and test.
If you ever change to a different bullet you can reset your freebore by setting the barrel back if need be
or just throat it longer if need be.
----------------------------------------
Or if you are positive in your specs and are never going to change bullets
Go with a Finish reamer spec'd out to your freebore
Manson can do this for you

 

[varget204]

I am shooting a 6BRA for F-class midrange. My gunsmith, who chambers my barrels, has his own reamer that I use. I have been very successful with it. I will be moving shortly and am kicking around the idea of buying my own reamer. His reamer that he uses on my barrels is a .272 chamber with a .104 freebore. These are the only specs my gunsmith knows about his reamer. Doing research, I want to keep it a .272 neck but have a longer freebore, likely a .120, based on my research. I mostly shoot 108s and 109s and Lapua brass. Does this sound like a good idea? Also, no reamer manufacturers I have found make this as standard. Can I custom order this? Would I need both a rough and finish reamer? Any help would be appreciated!

Believe .272 No Tun neck .104 to .135 freebore are the way to go in 6 BRA ,have posted pictures with Bart's bullets in the past 600 to 1000 yards. Fireforming got some zeros quite afew.1's..2's @100 &some.2's.3's at 1000 yards.using Lapua & Peterson brass & Rem 7 1/2's

 

[Clancy]

This is how far a Vapor Trail 103 sits in the neck with a 0.120" FB at touch (contact circled). Criterion 6BRA, 0.272" neck. Critical body dimensions are the same as Alex's. JGS made the reamer.

That is absolutely perfect. Everything I have is set up just like that.