Reamer Spec's for New 6BR Lapua brass

[signut]

Looking at purchasing a new 6BR reamer from PTG. Currently running a no turn .272 with .140 freebore . The new lapua is slightly different, what are your thoughts on reamer od and freebore for a new reamer ? This will be running 107 SMK's and 108 Bergers . Any info appreciated !

 

[tclaunch]

I just got 40 boxes of new 6BR brass in where i work, purchased a box in anticipation of receiving my first ever 1.250" Bartlein chambered in a 6BRX with .269 Nk. I was planning on turning the cases to a .0115" wall thickness. Upon inspection the necks, these ran from an average of low side .0112" to .012" kind of right on both sides of my goal. I decided to shoot them first before I go to all the trouble. as my math figures these will avarage a .2662" loaded neck diameter for the .269" neck. I have a good supply of Gold box for my .272" reamer, and with the looks of this my .269" may just be my new no-turn for the blue box brass.

 

[fdshuster]

Recently sent my PTG 6BR reamer back for a chamber neck dia. regrind, (cost $25), from the .272" no turn for the "Old" thicker neck wall brass, to .269". for the newer in the blue plastic box. Do a very light outside turn if using the older, load & use as is with the new. Old brass was .013"/ .0135", new is .012"/ .0125".

 

[dreever]

In my opinion the only way to tell if you need to turn the necks or not is to make up a dummy round with the bullet, or bullets you intend to shoot and mic that round on the neck. In my .269 neck chamber a loaded berger 105 VLD does not give enough clearance per side to be considered safe (loaded round mic'd .26810 which only gives .00045 per side). I needed to lightly turn the necks removing about 60-70% to get the desired .001 per side clearance. I would consider a .270 neck to be the absolute minimum to be considered a "no turn" neck with the new Lapua Blue box brass.

As far as freebore goes a lot of guys use .105. Myself I like them shorter .060. Gives me more room to chase the lands. .060 with 105 VLD's has worked fine for me.

Danny

 

[johara1]

One other thing, the length of the blue box brass is shorter by .010 so i reduced my chamber by .010 also. 1.560 is now my chamber length reduced from 1.570.........jim

 

[fdshuster]

Good point Jim: With some other ctgs. we could just let them stretch 'til they reach that longer chamber length, but with a properly sized 6 BR: no stretching, so it will never "grow" in length. Before I cut another chamber with that reamer it will probably be sent back for another regrind, maybe as short as 1.555". By keeping a very minimal gap at the case mouth I never see a ring of carbon buildup there. Just no room for it to develop.

 

[johara1]

Frank, If your making Dasher brass it's at the top of the list, the blow length is now 1.550 if your lucky. Lapua is making the reamer people happy with the short length and the neck wall going .012 or less......jim

 

[fdshuster]

Jim: My 6 BRX brass is a little shorter than normal after blowing the shoulder forward the 1/10", but only by .005" or so. Maybe it's the difference between the 40 degree Dasher shoulder & the 30 on the BRX. Ya, I wish they would have left the brass alone, but we're stuck with it. Wonder how Norma 6 BR would foreform?

 

[johara1]

Frank, I'm old fashion, i really don't want to change at this point. I am still shooting Dashers with 30 loads on them,i just had to get a reamer to fit the brass they make now. I use a .266 neck now and 1.560 length and and had the shoulder set at .460 and guess what, factory dies work great. The die sizes .001 at the shoulder and the brass is not over worked and i am only sizing .001 at neck. I now anneal every time, this really helps with longevity ......jim