Pillar bedding a rifle

A well bedded stock is an essential part of an accurate rifle.  Pillar bedding helps ensure accuracy as conditions change.

Historically, when rifles were equipped with wood stocks, as the wood expanded and contracted with changes in humidity and temperature, the point of impact and accuracy of the rifle was effected.  Bench rest shooters would use torque wrenches to ensure action screws were at the appropriate settings between strings.  Drilling the action screw holes over sized and filling the voids with bedding compound, improved accuracy.  Some of these shooters figured out that placing sleeves made out of metal tubes, or pillars, in the action screw holes would allow the action screw torque to remain constant and provide superior results to those stocks without them (check out this article from McMillan the history of pillar bedding and how it works).

Pillar bedding is common in wood, fiberglass and plastic rifle stocks.  In addition to helping the rifle maintain accuracy, the pillars provide consistent spacing between the action and bottom metal which is necessary with modern detachable magazine systems.

g10 bedding pillars

Bedding pillars are found in different materials and thicknesses.  Aluminum is the most common, but steel, G10 and epoxy can be encountered.  While most are 9/16″ or 5/8″ in diameter, some, like those found on some factory Savage rifles, can be thin tubes.

Bedding pillars are a big help in wood stocks.  Some fiberglass stocks can benefit from them as well.  If the material in the core of the stock can compress, it would benefit from pillars.  Pillars are not needed if a stock has a metal bedding block- occasionally you’ll hear about a smith trying to do this, I wouldn’t.

In this post, we will be pillar bedding my friend’s Remington 700.  Assembled from an old Remington 700 action that was screwed to a newer 700 take-off barrel chambered in 22-250, it is a little rough around the edges.  The fiberglass stock is a used Bell and Carlson that was previously bedded.  Not an ideal scenario for a bedding job, but one that can work.

Pillar bedding a wood stock is a similar process to the fiberglass stock shown here, but some of the techniques and materials would be different.  I’ll explain the differences in the techniques needed for a wood stock throughout this post.

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For this project, I ordered the following parts from Brownells:

pillar bedding dry fit

The first thing I like to do is see how all of the parts fit.  To do this, I assemble the unloaded barreled action in the stock to make sure the clearances are appropriate.

pillar bedding test fit 2

To check the fit of the barrel in the barrel channel, I moved some paper down the barrel channel.  Note in the image above it caught on a high spot.  This will need to be taken down a bit.

pillar bedding barrel channel work

I use a barrel bedding tool (shown above) and sandpaper to clean out the barrel channel.  If you don’t have the specialized tool, simply wrapping sandpaper around a dowel or socket will work.  Since this is a used stock, any existing compound from the previous bedding job should be removed at this stage of the process.

pillar bedding pillars

Take a look at the Brownells catalog and you will see a wide variety of pillars.  Some are adjustable, some are synthetic, some are precut.  The aluminum pillar we will be using in this post are sold as Brownells pillar bedding sleeves. Note these 9/16″ diameter pillars have a radius cut in the top to match the bottom of the rifle’s action.  I coated the bottoms of the pillars with some red Dykem so I can mark their length later in the process.

pillar bedding fixture

There are a few options to drill the holes for the pillars.  In this post, I’ll be using the Score-High fixture (above), however, a hand drill with a piloted counterbore, drill press or milling machine would all work.  A fixture like this would only be worth buying if you had a few different rifles to work on.

pillar bedding tapered alignment

The fixture sits inside the top of the stock.  A tapered pin is used to locate the front action screw.

pillar bedding drilling hole

The bottom plate is installed in the bottom of the stock and a 9/16″ drill bit is used to cut the rear pillar hole.

pillar bedding drilling front

The process is repeated from the front pillar hole.

pillar bedding hole

The finished hole for the pillar.

pillar bedding long pillar

These pillars need to be cut to length.  Note the excessive protrusion.

pillar bedding pillar aligned

To mark the pillars to length, I need to make sure they are properly seated against the action.  I place them in the stock and ensure the concave surface of the pillar is in line with the action.

pillar bedding push down pillars with action

The action is placed in the stock so the pillars are seated against it.

pillar bedding mark pillars

The stock is flipped upside down and a scribe is used to mark the pillars to length.

trim pillars pillar bedding

I cut the pillars to length on a lathe.  A hacksaw and file would work as well if you don’t have access to one.

pillar bedding trim lug

The rifle can now be prepped for bedding.  The bolt and trigger are removed from the barreled action and the steel is degreased (I wipe it down with alcohol on a clean rag).  Only the rear surface of the recoil lug should contact the bedding.  The sides and front of the recoil lug are taped to accomplish this.  I use 3M fine line tape for the sides.  This is an automotive painting product that works extremely well for this task.

pillar bedding pack voids

Voids in the rear of the action are packed with modeling clay.  I spray release agent BEFORE packing it with clay.  This will make clean up easier.

pillar bedding trim clay

The clay is cleaned up with a razor blade.  This will help prevent a mechanical lock when the bedding compound is applied.  I also make a small clay “snake” to place in the stock, just in front of the recoil lug area to prevent epoxy from flowing forward.

pillar bedding release agent

The metal parts are coated in more release agent.  I have found Acra-Release works the best.  Alternatively, clear shoe polish or paste wax can be used.

mix compound pillar bedding

All stock surfaces are degreased prior to applying the bedding compound.  I prefer to use Marine-tex for fiberglass stocks.  For wood stocks, I prefer Acraglass.  To mix the Marine-tex I purchased some mixing cups from an automotive paint store that work well, they cost about $0.30 each and are certainly worth it.  Note the clay “snake” (mentioned earlier) on the stock in the background.

pillar bedding coat pillars

The surfaces of the stock and pillars are coated in Marine-tex.

pillar bedding glue up

The bottom metal is taped to the bottom of the stock and the action is set in the compound.  I normally use the factory screws to attach them.  Long bedding screws are sold if you don’t want to use the ones that came with the rifle.  I would only use the bedding screws if the action screws had a slotted head.  The hex head screws (coated in release agent) are easy to remove from most bedding jobs.

pillar bedding clean up excess material

The excess epoxy is cleaned up with cotton swabs, a razor blade and some alcohol.  To allow the epoxy time to cure, I hold the rifle’s barrel by a padded vise and let it sit overnight.

dried marine tex pillar bedding

The screws are removed and the action is tapped with a block of nylon to remove the barreled action.  This is what the surfaces look like.

trim pillar bedding in mill

I clean up the excess bedding material on the mill, however, sand paper and files work just as well. Again, you don’t need the fancy equipment I am using here.

pillar bedding finsihed 2

This stock is ready for paint and final assembly.  Soon, it will be hammering away at the range!