bedding

[billy]

What is the diffence in glass and pillar bedding and is free floating or tip pressure better for a barrel?

[John Traveler]

Billy;

"Glass bedding" is the use of fibreglas-reinforced resin to perfectly mate the metal parts of a barreled action to the stock.  The traditional machine or hand-cut inletting of a wood stock is less than perfect unless meticulously done by a skilled craftsman.  It's cheaper and faster to bed an action using fibreglas.  Glas will not by itself, make a rifle shoot better.  It only makes it EASIER to achieve and keep perfect bedding.

"Pillar" bedding is the use of vertical cylindrical metal or plastic spacers ("pillars") to provide solid support for the barrelled action, usually at the rear and front ends.

The choice between free-floating a barrel or using foreend pressure is mostly due to the individual dimensions of the barrel and it's shooting characteristics.  Both work fine, but usually one is preferred over the other for heavy or light barrels.

HTH
John

[gunnut69]

'Glass bedding involves supporting the metal in certain areas with a polyester resin(usually) matrix.  This provides a solid but not stressed platform for the action(and barrel?) to lie on.  Some time the bottom metal is also bedded into the compound.  
Pillar bedding involves either inserting metal cylinders or pouring reinforced resin cylinders to keep the screw pressure from the action screws from causing the wood to colapse and alter the bedding.  
Glass bedding is a modifying process, try to inprove the accuracy of the weapon.  Pillars essentially are trying to preserve the status quo.  It's a pretty subjective thing among guncranks as to which is best, forearm pressure or free float.  Or the 3rd alternative which is full length bedded barrel.  Pressure usually generates the best accuracy as the vibration frequency generated in the barrel by firing is raised as the vibrating length of the barrel is essencially shortened.  Free floated barrels are generally more stable and less effected by changes in the wood stock or pressure on the stock from tight slings, etc..  Also a pressure bedded barrel tends to move it's point of impact as the barrel grows with heating during a long string.  Full length bedded barrels tend to be very stable and consistant and are a good choice for a mannlicher stock..they die tend to move shots during long strings of sire.  I usually try to free float a barrel first and if I can get the level of accuracy I'm looking for great.  If not a pressure point is easy to add.  I have done several full length bedding jobs and while a pain they are very consistant.  One, a 300 mag on an enfield hasn't chnaged it's zero in more than 20 years unless it was removed fromt the stock and most times not even then!!  Thru rain or shine, hot or cold always the same place..  This year 2 shots to verify it had not moved and the first morning a coyote at about 100 yards.  It was still alive and the finisher was delivered with ease, a shot to the back of the ear!!  These were the 3rd and 4th shot fired since November of 2002.  Great rifle...loves the 200 grain partition...