Long Throat

[deertroy1]

So I'm building a new rifle on a Savage M11 action and a McGowen 6mm Rem. prefit barrel. The barrel arrived the other day so I headspaced it to my action andmeasured a few bullets for COAL. I only tried a few bullets but in those I tried it is obvious this barrel has a lot of free bore. Bullets are going to have somewhere in the neighborhood of 0.100" of jump to the lands. While I prefer to be around 0.020" - 0.030". I have a new Cooper in 7mm-08 Rem. that has a fairly long throat and so far I can't get it to shoot worth a ****.

I would be interested in hearing some experiences people have had with barrels chambered with this kind of free bore vs those where you are able to seat out close to the lands?

 

[Gene]

What bullets? Longer, less streamlined, loaded with base near half the neck, might work.
You will need to be careful that your reloads do not cause tip of the loaded round to strike the loading port when withdrawn.
Consider using tangent ogive bullets.

 

[deertroy1]

Hornady 100gr SP, Speer 105gr SP and Hornady 58gr V-Max are the only ones I've measured so far.

 

[Dosh]

1, the freebore on factory Weatherby rifles run from .378 in the .257cal to .756 in the .378 and .416Wby. I shoot the Berger VLD 115gr n the .257 and the Berger 215 and 230gr in the 30/378. Near or a bit less than mag length on all. The .270Wby and the 300Wby shoot best even farther off with the Bergers.

 

[deertroy1]

1, the freebore on factory Weatherby rifles run from .378 in the .257cal to .756 in the .378 and .416Wby. I shoot the Berger VLD 115gr n the .257 and the Berger 215 and 230gr in the 30/378. Near or a bit less than mag length on all. The .270Wby and the 300Wby shoot best even farther off with the Bergers.

I got some 140 Berger VLD's I guess I should get around to trying them in the Cooper?

 

[J E Custom]

Freebore is not a problem if you have good case prep and uniform neck thickness. if you don't over size the brass and size only enough to close on the bolt with little pressure the cartridge and bullet will stay on the bore centerline and shoot no matter how much freebore you have.

If the case does not fit the chamber, the cartridge will lay in the bottom of the chamber even if you touch the lands with the bullet. This non-concentricity condition launches the bullet off center and can cause accuracy problems.

The best rifle cant make up for poorly loaded ammo, so try your best to load great ammo and you will be amazed at the difference in accuracy. I find that if I turn the necks when the brass is new, that it fire forms true and sizing it the minimum keeps it performing at it's best. After it is fire formed, I like to check the concentricity of every round to make sure I am loading good ammo. I like to stay below .002 thousandths run out in concentricity (I prefer .000 but cant always get it.

J E CUSTOM

 

[deertroy1]

I size my brass in a Redding S type full length die for about 0.002" clearance at the shoulder. Are you saying I'd get better results if I had zero clearance and the rounds chambered with a little resistance?
I'm talking about clearance at the shoulder and not run out. I realize zero run out is the goal.

 

[Longtooth32]

1, the freebore on factory Weatherby rifles run from .378 in the .257cal to .756 in the .378 and .416Wby. I shoot the Berger VLD 115gr n the .257 and the Berger 215 and 230gr in the 30/378. Near or a bit less than mag length on all. The .270Wby and the 300Wby shoot best even farther off with the Bergers.

I am shooting the 170 Bergers in my 270Wby with a .3...(yes a .3") jump...I have a long mag box...Mausingfield long action...running less than .5 MOA @ 3225 fps...COAL 3.5" Drops confirmed to 925 yards...

 

[J E Custom]

I size my brass in a Redding S type full length die for about 0.002" clearance at the shoulder. Are you saying I'd get better results if I had zero clearance and the rounds chambered with a little resistance?
I'm talking about clearance at the shoulder and not run out. I realize zero run out is the goal.

I personally don't bump the shoulder on any of my precision rifles unless they wont chamber, and then only enough to close the bolt. I also use bushing dies on these rifles to help get a perfect fit
and save the brass. when sized this way the round never moves in the chamber and primer ignition
remains very consistent by eliminating any case movement when the firing pin strikes it. (Different firing pin travel produces different primer results) the difference is minimum but everything helps when you are trying to squeeze every bit of accuracy out of your rifle.

Of course on Simi auto's some sizing may be necessary for the rifle to function, and for certain hunting situations sizing smaller than the chamber may have advantages over minimum sizing (especially on dangerous game)

Just the way I prefer to load ammo for accuracy.

J E CUSTOM

 

[deertroy1]

Thanks for responses guy's! A few things to try.