New 6BR barrel and new brass case prep

[michaeljp65]

Just got my Tikka T3 rebarreled to 6BR, 26"barrel 1:8 twist .272 neck. All I've done was trim the case to 1.553's and deburred the mouth. I tried to uniform the primer pocket with a Sinclair 6PPC/BR tool but very little was cleaned up. I made up a dummy round with a Berger 105 Hybrid target that measured .269 with virgin brass.
My questions are,
1. do i need to full length size the brass first before loading?
2. should i turn the necks down .001 to give a bit more clearance now or wait till brass has been fired?
3. do i need to form the brass before any serious load testing is started?
I have some Berger 105 hybrid targets that i got cheap but the box says 1:7 twist. I am going to use these to run in the barrel in as i form the brass.
4. I'm going to start loading at 29grains of AR2208/Varget up to 31gn. Is this a good start and end point for the 105gn Berger? Going up in .3gn at a time using BR4 primers. I also have Fed 205M primers.

Most of my shooting will be at my local 200 yard range. Any advice would be much appreciated.

Cheers Mick

 

[Buzz]

I expand the necks and then full length size new brass so I have consistent neck tension. I don't know that it needs a full length size but I use my full length die for consistency. Sizing should be done prior to trimming, but I doubt the sizing will grow the new brass any in your case since it's virgin brass. I wouldn't worry about turning the necks at all - 272 is usually the spec for a no-turn chamber.

I would start load development immediately. At the bare minimum you'll be able to get an idea of where you start seeing pressure and about where your max is. There's no sense in just burning components for the slight brass expansion the new brass will have. If I were you I would sell those hybrids and buy bullets you think would be suitable. Most say the hybrids shoot fine in 1:8 barrels until you get back to 1000 yards or so. I have a few hundred to try but I'm waiting on my BRX barrel. Berger 105 vld, Sierra 107 SMK, or Hornady 105 amax are probably a good place to start for the straight 6br. I personally like the SMK and honestly had some decent success with Nosler's 105 as well. At only 200 yards the 80 and 90 grain bullets might be a better option depending on freebore.

I don't use Varget but I think you may want to start a little lower, especially with a new barrel. My RL15 load started showing pressure right at 30.0g, but I've seen other people use loads around 31.0g. Starting off with a ladder with each of the bullets will give you a place to start with loads, an idea of the max load without pulling a bunch of rounds apart, and will "form" your brass all at once.

 

[michaeljp65]

I expand the necks and then full length size new brass so I have consistent neck tension. I don't know that it needs a full length size but I use my full length die for consistency. Sizing should be done prior to trimming, but I doubt the sizing will grow the new brass any in your case since it's virgin brass. I wouldn't worry about turning the necks at all - 272 is usually the spec for a no-turn chamber.

I would start load development immediately. At the bare minimum you'll be able to get an idea of where you start seeing pressure and about where your max is. There's no sense in just burning components for the slight brass expansion the new brass will have. If I were you I would sell those hybrids and buy bullets you think would be suitable. Most say the hybrids shoot fine in 1:8 barrels until you get back to 1000 yards or so. I have a few hundred to try but I'm waiting on my BRX barrel. Berger 105 vld, Sierra 107 SMK, or Hornady 105 amax are probably a good place to start for the straight 6br. I personally like the SMK and honestly had some decent success with Nosler's 105 as well. At only 200 yards the 80 and 90 grain bullets might be a better option depending on freebore.

I don't use Varget but I think you may want to start a little lower, especially with a new barrel. My RL15 load started showing pressure right at 30.0g, but I've seen other people use loads around 31.0g. Starting off with a ladder with each of the bullets will give you a place to start with loads, an idea of the max load without pulling a bunch of rounds apart, and will "form" your brass all at once.

Thanks for your input Savage6.5
I do have some Berger 87gn VLD and some Berger 88gn FB. I'll start using these first up, as you say the 105's are more for long range. 200yds is a bit close for a ladder test do you think? I'll start with the 87's and 88's. Do you think 27gn of varget is a good start and go up in 0.3's gns or 0.5's grains?

 

[Buzz]

I think 28ish would be a good start. I just wouldn't be surprised if you run into pressure before you get close to 31. I use .3 for the BR case sizes. 200 isn't ideal for a ladder but I don't think it's pointless.

 

[comagutsa]

i run 105gr hybrids in my 28" 1:8 6BR barrel with good results at 500m (less than 2 inch groups when i do my bit, one example)


, i also run a .272 no turn neck with CCI BR4 and varget , start to get pressure at 30.8gr in both my old kreiger barrel and this new Hart barrel
new brass i expand the necks to get rid of any imperfections and new brass has to much neck tension and then size .002 below a loaded round with my bushing die (i use a .267 bush)
i do my load testing at 300m but if conditions aren't great then 200m
i've been shooting it without touching the necks for years with no problems but i think i'm going to skim the necks .001 to see if it makes any difference ..
i found my barrel speed up over 150 rounds so i had to start load testing all over again

 

[michaeljp65]

I think 28ish would be a good start. I just wouldn't be surprised if you run into pressure before you get close to 31. I use .3 for the BR case sizes. 200 isn't ideal for a ladder but I don't think it's pointless.

Thanks mate.

 

[michaeljp65]

i run 105gr hybrids in my 28" 1:8 6BR barrel with good results at 500m (less than 2 inch groups when i do my bit, one example)


, i also run a .272 no turn neck with CCI BR4 and varget , start to get pressure at 30.8gr in both my old kreiger barrel and this new Hart barrel
new brass i expand the necks to get rid of any imperfections and new brass has to much neck tension and then size .002 below a loaded round with my bushing die (i use a .267 bush)
i do my load testing at 300m but if conditions aren't great then 200m
i've been shooting it without touching the necks for years with no problems but i think i'm going to skim the necks .001 to see if it makes any difference ..
i found my barrel speed up over 150 rounds so i had to start load testing all over again

Thanks for your comment mate, i wish i had a 300 -500m range close by. but at the 200 yard, i can sit at the bench all day if i like. I know of a 300 yard one but the ssaa only get a few targets so if theres a line up of blokes wanting to shoot you don't get much shooting done.
cheers