I've created 3 articles on in-progress and completed projects:

1. Rear-Velocity Adjuster (RVA) for MacMurray bolt-action
2. [another] wooden stock refinishing
3. Sling mount for Hurricane stock
4. KP2 restoration - Refinish, repair valve, add stock
5. Wooden stock refinishing

Please see below for the information on these projects!  For the How-To projects, a DIY guide, check out the How-To page I've created.

A common problem with old Sheridan based paintball markers is velocity control.  The velocity is controlled by the amount of spring force that slams that hammer into the valve stem during each shot.  Somewhere along the line, some genius figured out that if you could 'adjust' the spring tension, you could change the velocity.  Since playing conditions varied all the time (temperature, paintball size, CO2 or HPA source), the velocity varied all the time.  This genius decided that you needed to be able to adjust the spring tension without taking the whole marker apart and without 'clipping' springs with a pair of wire cutters.  So, the rear-velocity adjuster, or RVA, was born.  Simply put, it's a set screw you install at the rear of the spring to control spring tension on-the-fly.  My MacMurray bolt-action Marauder had only one spring setting, and I decided it was time to bore out the KP trigger group housing and install a set screw of my own.  Here are the results:

When I first used my Hurricane, I lugged it around the field and found that it is extraordinarily heavy!  Without a hopper, paint, or air, I estimate the weight to be about 7-8 pounds.  Add those things in, and you have one heavy paintball marker.  To alleviate the stress on my arms and shoulder, I decided to add a sling.  There are many slings available for modern rifles, but these are usually too long and the attachment points too larger for a paintball stock.  I chose Uncle Mike's 1" sling swivel mounts and a Butler Creek padded sling with 1" nylon webbing.  The two attachment points are significantly closer than on normal rifles, and in particular, the front attachment point is too close to the trigger assembly.  This makes it difficult to carry the Hurc.  However, with a little patience and care, you can have a decent sling that will help relieve the weight every now and then.

The installation process was actually quite simple.  I used a 5/32" drill bit to bore the main hole for each screw, and then countersunk the head area with a 5/16" bit at a depth of 1/8".

Next, I used a crescent wrench to insert the self-tapping swivel mounts and aligned them properly (holes pointing directly perpendicular to the length of the stock).  This will ensure that the padded sling will travel from the front to the back of the paintball marker without getting tangled or cause an imbalanced carrying posture.  Here are some pictures of the finished product:

caption:  (L) This is a closeup of the sling swivel mount.  (R) This is the full length of the attached sling.

The KP2 body that I removed from its stock was in need of serious repair!  12 grams repeatedly get stuck in the lower tube, it doesn't fire correctly, and the finish was appalling.  The gun was originally a KP2SC or KP2 Stock Class.  As you are probably aware, stock class markers are defined simply by 4 criteria:  Pump-action single shot; Horizontal feed tube with no feed-assist mechanisms; Only 1 ball stacked above the loading chamber at any one time; 12 gram CO2 cartridge as the propellant source.  However, someone decided to remove the stock feed tube and make this a KP2DF or KP2 Direct Feed.  I haven't decided whether or not to return this marker to its stock state, or leave the feed tube on, but I know that the body is certainly in need of a restoration.  Since I used the wooden stock for my Hurricane, I'll be needing a new one for this marker.  Thankfully, I also have a Sheridan Blue Streak pellet gun, so this will share the stock with that gun, as it is easily removed with one main mounting screw.  Below, I'll be going through the restoration process of the body and what I do in each step.  I hope you enjoy, and learn something.

1)  These first photos show the KP with all the parts removed.  I completely stripped the body down and removed all internal parts.  The last picture shows the internal bore.  It's nice and smooth on this KP, which means although the previous owner didn't take care of the outside, they kept the part that mattered crystal clear!

2)  I used a Leatherman tool to gently scratch off the flaking black spray paint that someone had applied (it worked well, at least, not as bad as it sounds...).  You can see the effect of removing the outer layer of paint in these next photos.  All Sheridan guns came stock from the factory with a "chemically-blackened finish," which means that chemicals applied to the bare brass created a tough black layer of pseudo-paint.  Over time, however, this finish wears off.  The picture on the left (below) shows the entire body after the bulk of the paint was removed.  The picture on the right shows the feed neck.  This is a modification to the marker, as it originally came with a stock class feed tube:

3)  The picture on the left (below) shows the brass pattern where the old feed tube used to reside.  The stock feed tube nestled directly in-between the upper and lower tube for a 'triangle' shape look from the front viewpoint.  The lower right picture shows the sight rail.  The sight rail itself is not in great shape, although it still provides a sturdy mount for a 3/8" dovetail sight.  I mounted my Adco E-dot 30mm sight on there without a problem, and in fact, the central mounting of the sight rail was pretty comfortable for sighting in a target:

4)  After I had removed most of the paint with my Leatherman tool, I decided to really polish the body up.  I used a Medium Red Abrasive pad (~100 grit, not equivalent to 100 grit sandpaper though) from Norton Abrasives.  After sanding for quite some time, the body showed its shiny brass finish!  One thing to keep in mind if removing a chemically-blackened finish at home: it makes a mess!  Make sure you have a cloth, work bench, or something to catch the dust and paint flakes, as they won't come out of a carpet!  The part of the brass that was never chemically-blackened in the first place remained nice shiny and golden in color, however, the rest of the marker retained a purplish-gold hue.  I kind of like the look, and think I'll be keeping the body in this bare finish:

5)  I sent the KP body to Palmers Pursuit Shop for a lower tube repair (valve nut threads were damaged and the nut wouldn't thread correctly), and bought a new chamber face plug seal at the same time.  The chamber face plug seal goes in the front of the valve assembly and seals against the face of the 12gram when punctured.  I made a mistake the first time I aired this baby up and cranked down on the rod that pushes the 12g toward the valve, and ended up squishing the seal too much.  Hence, it wouldn't seal properly!  All fixed now though.  I put this KP in a Sheridan Blue Streak stock that I have from the pellet gun and it fits great.  These old wood-stocked rifles have such a solid and unique feel to them.  I'm looking forward to taking it out on the field:

Updated pictures:  24 Oct 05

This is the project documentary of refinishing an old Sheridan stock.  The marker I'm using is a KP2 model.  Here's the gun as I received it, for a modest sum.  I figured some sweat equity would bring up the value a little bit!  Notice the condition of the entire marker (ugly).  Also, there was some sort of adhesive on the butt of the stock, which caused the splotches, I think it was some sort of duct tape or packing tape.   It was summarily removed.
  
Here are the tools of my trade:  sandpaper (grits: 60, 180, 220, 400, 1000), rubber sanding block, #0000 steel wool, tacking and polishing wrags, red oak color stain, odorless mineral spirits, and boiled linseed oil.

Here she is in barenaked glory.  This was after the initial sandings of 60 and 120 grit.

Here you can see the difference of 400 grit and 1000 grit sandpaper.  On the right side is 400 grit.  On the left is 1000 grit, you can see the grain of the wood and how it shines a bit.

First coat of stain on in these next two pictures.  I liked the color, I just wanted it a bit darker.
  
Here I added the second coat of stain.  The last step is to apply linseed oil.  It protects the finish against water and paint, and is very useful for buffing out scratches and marks!  You need to be careful with linseed oil, as it tends to heat up during the drying process, and can light things on fire...

Hope your own wood-working projects are as fruitful as this one!

The Airgun Designs Automag is arguably one of the most popular paintball markers in existence, along with its nemesis and prime competitor through the 90's, the Autococker.  AGD decided to target a niche market with the creation of the Automag pump kit, as the Automag was designed as a semi-automatic marker from the start.  Now, these pump kits are rare and highly sought after, as they didn't sell many of these.  I acquired a large Minimag package on PBNation and sold off most of the other items included, except for the 'Mag.  I had the body and rail milled by Brad Q. Nestle @ PBMaxx in Houston, TX, he specializes in this work.  After installing the pump kit and getting the parts milled I had 2 remaining steps:  paint the body and install the power source.  I sanded down the original finish with wet/dry 320 grit paper (I wish it could have been finer grain, but this sufficed).  I used Plasti-kote autbody paints for the surface, I started with a coat of primer and finished with 2 coats of black.  Finally, I installed microline fittings and put a WGP pump changer on the ASA for my air source.  I sold the Pump Changer and now use the 68ci/4500 Armageddon as the main air source.  This marker is extremely accurate, even with the stock barrel.  It decimated the competition during an all-Pump Day at SC Village in January '06.

I present... The Ninja Mag!