From: Gale McMillan <mcmillan@getnet.com>
Newsgroups: rec.guns
Subject: Re: Barrel bedding vs free floating??
Date: 28 Mar 1996 17:32:21 -0500

Keith MaloneyHuss wrote:
 
# I'm new to rifle shooting and am interested in learning more about
# accurizing.  Could someone explain the theory behind bedding a barrel.  It
# seems to me (naive view follows) that the best bedding would be none at

A good barrel will shoot better when free-floated. That is a barrel that 
has been properly stress relieved and is uniform in dimensions. A 
typical factory barrel will normally shoot better with fore-end 
pressure. The reason for this is that fore end pressure tends to bow 
the barrel upward and as the bullet starts down the bore it wants to 
travel in a straight line which tends to take the bow out. This action, 
reaction reduced the vibration of the muzzle from a circular movement to 
a near constant position. This allows the bullet to exit the muzzle 
when it is in the same place each time regardless of variation of muzzle 
velocity from shot to shot. Being barrel makers we don't always drill 
straight holes. When we get one that is too crooked to sell we set it 
back to use on our rifles. Every world record and national match the 
McMillans have set (and there has been many including the .009 record 
were shot using these crooked barrels. 

Gale McMillan

From: Gale McMillan <" gale"@mcmfamily.com>
Newsgroups: rec.guns
Subject: Re: Barrel Concentricity
Date: 15 Feb 1997 18:06:53 -0500

Bartbob wrote:
 
# There is some effect on accuracy with off-center bores in barrels.  But
# you may need a super-accurate rifle to detect the difference.  With
# hunting
# rifles made in factories in mass production, detecting the difference may
# require several barrels to be worn out.

When drilling a barrel the drill always drills in a spiral.  Some times
it may only be one turn in 36 feet which is virtually straight.  Some
times it is much tighter.  When you turn the taper between centers the
hole is in the center at each end but not toward the center.  This has
an effect on accuracy.  It helps!  Look at it this way.  When a bullet
starts down a barrel it resists turning and at the same time the barrel
tries to unwind.  This causes the barrel to rotate in a circular
motion.  The variation in velocity causes each bullet to exit at a
different point in the arc.  When a barrel has a spiral in it the bullet
tries to go in a straight line straightening the barrel.  This puts the
muzzle at the same point each shot as the bullet exits regardless of the
muzzle velocity.  When we made a barrel that had too much run out to
sell to the public it was set back for our personal use.  I will tell
you that every world record shot by members of my family (and there has
been more than our share) was shot with one of these barrels including
the famous .009 5 shot group.

Gale McMillan