6br bullet ?

[Tyler_S]

I am getting a gun built and it should be done mid January I hope it is a pierce action 6 br 28" broughton barrel 1-8" twist on a shehane varmint tracker with a Jewell trigger and pierce 20 min ring. I'm not real sure what the primary use for the gun is I guess just something that's not a stock rifle. I will post some pics when it's done.

What will be the lightest bullets I could shoot I beleive pierce said the throat would be cut for 105's. I am just curious this is all new to me any input would be great

 

[dreever]

Tyler,

There are a lot of different opinions on how much freebore you need for a particular bullet. You said the smith is going to cut the throat for the 105's. This could mean a freebore anywhere from .060 to .120 or more depending on the smiths opinion.
Find out exactly what the freebore will be from him.
Personally, I prefer a shorter freebore .060 which serves two purposes. First, it allows me to use bullets from 60-105 grains and still be able to seat the bullets into the rifling. Second as the throat wears it allows me to adjust my seating depth to adjust my OAL to keep in contact with the lands.
Using an .060 freebore the bearing surface and boattail junction is about at the neck shoulder junction of the case. Works fine for me.
Some guys prefer a .104 freebore for the 105's which is not a bad choice either.
Just remember the longer the freebore the more distance to contact the lands. This is magnified by the shorter bullet weights.


Danny

 

[Laurie]

I'd agree with Danny.

I have a middle of the road freebore on my 6BR which lets me seat the 105s out to the rifling while not being overly deeply seated in the case. Mid range weight bullets work fine and I can just get away with 55s even. (Eight inch twist shouldn't cause bullet blow-ups unless the barrel or throat are rough.)

I was with a friend working loads up for 68gn G&C flat-base BR bullets that he normally uses in his PPC bench gun the other week. This rifle is 8" twist but relatively short-throated to suit 90gn Lapua Scenars exactly. The accuracy with the 68s turned out to be superb too with a 0.24" five round 100yd group at 3,561 fps and low ES.

Laurie,
York, England

 

[Tyler_S]

Thanks. I don't know what the freebore is yet but I will find out. Is there any other tips for the 6br that I need to know?

 

[Woody]

Tyler:

Not a tip necessarily other than be prepared to save money right away for the next 6mm. You are gonna like them - alot!

Woody

 

[Tyler_S]

I am already wanting another barrel that does not have as much twist for light bullets

 

[MarkS]

Tyler_S,

I am with Danny on the freebore. Shorter is better. Too far out then you can't shoot some bullets.

Two barrell are very nice all my guns have two or more.

Mark Schronce

 

[ourway77]

New here, so free bore is a mystery to me. Only knowledge i have is Weatherby's?. I just bought a Savage F class 6BR 1 in 12 twist. Would the freebore you speak of apply to it? I shoot 68 grain bergers, they are great. I am sure you can see I am in the dark with all this. At 72 I have always just bought a rifle loaded ammo and hunted so all this is very confusing to me. Ihave always smoke the bullet and when it didn't touch the rifleling I felt I was about right? and if it did I would back off til it didn't. Lou

 

[Laurie]

Ihave always smoke the bullet and when it didn't touch the rifleling I felt I was about right? and if it did I would back off til it didn't. Lou

Lou,

what you've been doing is absolutely correct - you're in effect adjusting the cartridge COAL (overall length) to the freebore or space before the bullet shoulder contacts the start of the rifling.

Most people have had to adjust to whatever the factory or rifle-builder gave them for a long time. For instance, Savage who are clued-in to what keen shooters want will have chambered your 12" twist 12 6BR with a short freebore because owners will handload light bullets 55-85gn say that are short, so COAL is correspondingly short. The other version of this rifle with an 8" twist is in effect the 6mm BR Norma version designed for use with 90-108gn bullets, long thin projectiles that need to be seated with a lot of bullet ahead of the case-mouth to avoid taking up excessive powder space. So, it will have a much longer freebore.

In this day and age though, you can get PT&G or whoever to make a chamber reamer to order to suit whatever you want within reason, so might get a 6BR chambered for a spceific make and model of say 90gn bullet so it is seated a reasonable amount in the neck while its shoulder is touching or just shy of the rifling. This gives us gun nuts as found on this forum endless opportunities for discussion over approaches, the best way of doing things etc. All part of the fun!

Laurie,
York, England

 

[squirrelduster]

I have a Hart barrel 1:8 twist set up for 105 gr bullets and I like the performance of the 75 gr VMAX so much that is all I shoot. It shoots little bitty holes at 100 yards and squirrels to 400 yards are not really a challenge.
I have shot the bigger bullets and for my squirrel irradication the VMAX is better. If you are varmint hunting try them out.