30BR — Barrel, Load, Case Forming?

[bobcat93]

If you're doing that approach, there's some areas that need some rethinking. The throat length on competition level 30BR reamers will be so short that the base of a 150 will be waaaay below the neck/shoulder junction. With a small case like the BR and a bullet like the 150's, you can't afford to give up any powder space. As to neck diameter, once you expand the necks of a 6BR case to .30, there's a lump at the bottom that will measure about .337. So, the chamber neck diameter needs to be at least that for a successful no-turn chamber that won't end up giving you funnel shaped inner case necks. See the pic below re: the lump.

Truly, for what you've semi-outlined you're wanting, my recommendation for an excellent 30BR... is the 308W.

Good shootin' -Al

How did you form that case?
did you use a 30 neck expand mandrel for neck turning, then a full length 30 br size die?

 

[AlNyhus]

How did you form that case?
did you use a 30 neck expand mandrel for neck turning, then a full length 30 br size die?

That is right after being necked up with a tapered 6MM to .30.expander mandrel and before any sizing. The necks then need to be turned and full length sized.

 

[bobcat93]

I see..now its sinking in..thank you..
Some times my mind is slow. It takes a few moments for me to visualize it in my head first.
So a no turn neck 30 br will really only work with light flat base bullets.
Because your kind of committed due to barrel chamber and twist.
From what ive been reading
Dont i want to shoot the 150's in 30br. @ 100?
I thought thats supposed to be the sweet spot.

So what do the guys do who shoot the 150's fire form with a light bullet that doesnt match the barrel twist.

 

[Shooter13]

Do you find this chambering to stay in tune well?

Pete, Just got it at the end of last year and have shot maybe 200 rounds and it has done really well. Will know more after the start of the season. I'll be shooting it in April. Just put a new 12-42 NF and have to zero that in the next few weeks. Will try to remember to post back.

 

[Shooter13]

200 yards 5 shots, seems to hold together pretty good.

 

[AlNyhus]

So a no turn neck 30 br will really only work with light flat base bullets.

Not necessarily. The throat length needs to be appropriate for the bullet being used...regardless of the bullets length. To use a 150-ish bullet, the throat will need to be much longer than what a 30BR competition level chamber will be.

The whole 'no turn' thing is seperate from the above.

Because your kind of committed due to barrel chamber and twist.
From what ive been reading

The chamber and twist rate are seperate pieces of the whole puzzle.The twist rate you need has to be adequate to stabilize the bullet length you will be shooting. The chamber needs to have a throat length compatible with the bullet length to be used (weight is secondary).

 

[AlNyhus]

The no turn 30br I just put together has a .339 neck. I left the lump as my 125s stayed out of the donut area. I thought about it, chided myself for being lazy and turned the lump off. Now my cases are .333 all the way to the shoulder.

And there's the rub on 'no turn' 30BR chambers.* By the time the 'lump' is considered in the reamer neck dimension, you end up with .006 neck clearance.

*Using brass that has been mechanically necked up from.6 to .30.

 

[Pete Wass]

Pete, Just got it at the end of last year and have shot maybe 200 rounds and it has done really well. Will know more after the start of the season. I'll be shooting it in April. Just put a new 12-42 NF and have to zero that in the next few weeks. Will try to remember to post back.

Thanks for the report.

 

[RossL]

Interesting information Al!

Thought I'd share some particulars on my non competition 30BR.

Using a 24" #7 profile SS 1 in 10 twist barrel, I had PT&G make a .045" freebore no turn neck .332" 30 BR reamer after talking to Dave at least 25 years ago. It is Remington 700 in its original brown laminate stock with an opened up barrel channel.

This package will shoot up to 175 gr Sierra MK seated into the lands accurately without the bearing surface going getting near the "lump".

For load data I use an old Sierra loading manual that lists loads for bullets weighing up to 200 grains!
I acquired a large inventory of 168, 175, and 200 gr Sierra MK from an 1000 BR shooter who stopped shooting due to old age. I thought it would be fun to have a lighter recoiling rifle than a standard 308 with barrel life being a bonus. I may never consume all those bullets. Lots of fun working up new loads for a particular bullet.

It is fun to shoot and is one of the intermediary rifles I use to help Jr hunters acquire their shooting skills.
The usual load is a 168 Sierra MK @ 2490 fps. When the 168s get consumed, I'll most likely start shooting the 175 MKs.

Ross

 

[moorepower1]

I am a bit surprised that Alpha has not made a run of .30BR with all the different brass they make.