More Freebore

L

Lucky Shooter A

Guest
I've started this thread so as not to interfere with the j mckinnie thread, which deals primarily with location of the beginning of the leade angle.

I'm curious as any benefit of the freebore with regard to bullet alignment as it enters the leade.

The SAAMI print for a 223 chamber specifies a minimum freebore diameter of
.224"------possibly smaller than the base diameter of a flat base bullet.

I have some Pacific reamers, all with nominal freebore diameter of .2245", which seems to make more sense than using the SAAMI min diameter-----a small clearance on each side.

I wonder if we can specify freebore lenghths and diameters to provide better bullet alignment going into the lead.

Thanks for any opinions.

Wishing all a Merry Christmas.

A. Weldy
 
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From an old post on the 1K forum. Greg Walley is one of the long-tiime gunsmiths at Kelbly's

Me:
I use .001 freebore diameter. Current fashion, I believe, is to keep the freebore diameter just a whisker over bullet diameter -- but my reamers are set up for .309 in my 30s.


Greg Walley replies:
I think this is a good idea. I've been doing some extensive testing with a 6.5mm wildcat, and I discovered (by accident) that a freebore approximately .0008" over nominal bullet diameter gives lower standard deviation than .0003".

Soo, while "Yes we can" is true, you gotta be careful with the compromises.
 
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Most bullets vary in diameter at the pressure ring, from one brand to another, so when considering freebore diameter...it would be best to know what diameter you plan to shoot...then have a reamer ground with enough freebore diameter to ensure good alignment but enough clearance to enhance standard deviation..

IMO...

Eddie in Texas
 
My 2 c worth

eww1350 said:
Most bullets vary in diameter at the pressure ring, from one brand to another, so when considering freebore diameter...it would be best to know what diameter you plan to shoot...then have a reamer ground with enough freebore diameter to ensure good alignment but enough clearance to enhance standard deviation..

IMO...

Eddie in Texas
Click to expand...

for those using custom bullets only I don't think it wise to have a reamer ground specifically for one certain bullet because Bullet Makers don't last forever. I think it is better to consider where in the neck one wants their bullets to sit. Tune usually can be easily found by simply advancing or retarding seating depth and not by enough to disturb where the bullet will reside in the neck.
 
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