PGS today

The last portion of the recoilless shotgun project to be completed has little to do with the actual recoil of the gun.  The only mechanical advantage it gives is by adding a few ounces to the completed weapon. 

Instead, what I steered toward was how well the shooter was able to interact with the weapon.  One of the problems my mom had was that she was unable to properly shoulder this shotgun.  Guns are not built for people with compromised mobility.  They are built so that someone who is physically much more flexible than some people are.  Just look at high-power rifle competition (or Marine Corps known distance rifle qualification).  It’s like a sadistic form of yoga with extra noise. 

People who are “different” have always had problems with guns.  Perhaps the most common difference, if you’ll pardon the oxymoron, is left-handedness.  The perhaps one in eight folk who are more capable with their left hand have a terrible time trying to get a weapon that doesn’t eject hot brass in their face, or where the controls are properly placed, even today.  Folks have an even worse time if their dominant eye they use for aiming is on the other side of their body than their dominant hand.  When that happens, you end up with things like this:

Looking at the stock, we can discern that the shooter in this case was right-handed, but was left-eye dominant.  So the stockmaker made a stock that allowed the gun to be fired from the right shoulder, but put the sighting plane in front of the left eye.  It may look a bit curious, but it’s a mechanical solution to a biological problem.

And these are the same problems that plague people today.  This isn’t even compensating for injury yet.  What about someone who has had an accident and only has one good hand?  What about someone who has a torn shoulder and can’t take the constant pounding on the skeet range?  Again, we have to design the machine to accomodate the body.

In this instance, a series of circumstances gave me a path to follow.  First, my mom can’t bend very well at the shoulder anymore.  Trying to aim with the existing bead sight  forced her to contort into a cramped, uncomfortable, unstable position.  Recoil was amplified as a result.  Second, my mom sometimes has a hard time picking up the bead as her eyes age and especially without corrective lenses.  Last, this shotgun is to be used as a defensive arm, probably in poor light.  Based on these existing conditions, the solution that I arrived at was a red dot sight, in this case, a Vortex StrikeFire specifically.

A sighting system such as this gives us a solution to all the above problems.  First, it will sit higher off the gun than the original bead sight, allowing a more relaxed, more stable shooting position.  As long as you can see the dot, that’s where the shot is going.  The bright red dot helps compensate for bad eyes and can be fired with both eyes open.  The dot is illuminated, and visible in any light condition. 

So now that we’ve got a sight, how do we get it on the gun?  The mounting system is a Weaver-style 30mm ring, but there was no provision for any sort of sight attachment on the Winchester 1200.  So, I drilled and tapped the receiver for 8×40 screws (used for extra strength in high recoil applications over the standard 6×48 sight mounting screws) through the bolt guide rib in the receiver, mounted a sight base, then repainted the receiver. 

With that, the recoilless shotgun project’s component parts are done.  All I have to do now is put it back together and give it back.

PGS today

On top of all the many other projects that are progressing at approximately the same breakneck pace as a Dodge Omni with two cylinders gone and trying to burn diesel, I had to take care of one of my father-in-law’s pistols today.

This is a Kahr Arms E9.  A small, double-action only 9mm, it started experiencing some primer drag issues.  Primer drag is caused mainly by spring fatigue, and it looks like this.

These are some of the cases left from this actual pistol.  The centered crater is the firing pin strike, which fired the pistol.  However, what is happening is that the firing pin can’t get out of the way fast enough.  The slide is recoiling so fast that the empty cartridge case is dragged over the protruding firing pin as the case is ejected.  That is why the extra gouge is there.  That’s where the tip of the firing pin dragged.  In severe cases, the gougle will extend into the brass head of the case.  While the gun will still run like this, it’s certainly not good, and may be indicative of other problems, and will cause premature wear on the weapon.  Because the springs can’t work right, the gun will literally start to beat itself to an early death. 

To service this problem, it required spring replacement.  This is a regular maintenance item for an autoloading pistol.  Springs should be replaced every 3,000-5,000 rounds.  Even if the gun runs fine, you still need to change springs.  It’s like changing the oil in your car.  When I pulled the gun apart, the need for this maintenance was clear.

The old spring is on the bottom in both pairs.  The recoil spring, which regulates the slide’s movement, is the top pair.  The striker spring, which actually fires the gun, is the bottom pair. 

While I generally use and recommend Wolff springs*, they didn’t have the springs for this particular model Kahr (discontinued in 2004).  So, I ordered a set of springs directly from the factory.  What has occurred is that through extensive work cycles and constant compression, the old springs had “taken a set”.  While the diameter of the spring wire, the diameter of the coils, and the number of coils had remained the same, the old springs had been permanently compressed to less than their designed length, effectively weakening them to perform at less than their designed strength. 

Where this became evident was in the drag on the primers in the fired cases.  As the weapon fired, the slide was recoiling backward against the recoil spring.  Since the recoil spring was operating at less than it’s designed specification, it was unable to resist the slide’s movement as effectively as it should.  Because of this, the slide was ejecting the fired case faster than the firing pin could retract.  Because the firing pin was still protruding, it was gouging the empty cases.

If you see primer drag occurring on one of your pistols, it’s time for a tune-up.  It’s a simple, inexpensive fix, but it saves wear on the weapon, saves the brass for reloading, and ensures reliability in a weapon for duty or concealed carry.

*FTC disclaimer: no financial or material compensation has been made for this endorsement

PGS today

With Christmas vacation rapidly approaching, the recoilless shotgun project is nearly done.  All of the work on the actual mechanism is done.  As of today, the cosmetics are mostly done too.  All the steel has been Parkerized, and is now sitting quietly in grease.

The wood has been completely sanded down and sealed.  The first couple coats of finish are on, but there’s a few more to go.  I’ve got a couple more days, so I should be able to get it done before I have to leave. 

Pretty much all that’s left is painting the aluminum receiver again and putting the thing back together.  No big deal there.

PGS today

Once I got the stock for the recoilless shotgun done, I switched to the other end of the gun and started working on the barrel. 

The first thing was lengthening the forcing cone.  Once again, altering the internal structure of the barrel will not only produce tighter patterns, but also reduce the recoil of the gun.

Once that was done, I set up the mill and ported the barrel.

The way barrel porting works is by re-directing the combustion gases from a cartridge being fired.  As the shot column passes by the ports, the gas pushing it out the barrel catches the front edge of the ports and is directed vertically.  When that happens, the gas being forced through the ports acts like a rocket engine, forcing the barrel back down on target and keeping the stock from whacking the shooter’s face.

Once the barrel work was done, it was time for a general refinish, both stock and metal.  So the stock will get cleaned up here in the next few days and the metal will get parkerized.  Once that’s done, the third and final part of the recoilless shotgun project can be completed.

PGS today

Today I started on a new project: the recoilless shotgun.

Now, I can imagine when I mention recoilless shotgun that some folks might be thinking of a recoilless rifle, a military weapon that uses a rearward firing charge (usually with a payload of shredded plastic or something) to counterbalance the recoil of a heavy anti-armor round.  Here’s a recent development, a shoulder-fired 75mm version being fired in Afghanistan.  For scale, realize that the main gun on the WW2 Sherman tank was also 75mm.  Notice that you’ve got a fireball on both ends due to the rearward charge.

Anyway, that’s not really what I’m going for.  The weapon that I’m using is a Winchester 1200 Defender shotgun. 

You might recognize this particular weapon from Semester 1.  While I made it nice and shiny there, it didn’t become any more useful.  See, this shotgun belongs to my mom.  She’s a little recoil sensitive, and the shotgun beats her up to shoot it.  Part of that is just because she bruises easily, part of it is that physically she can’t really get into a good shooting stance, and part of it is just that with a 12 gauge shotgun, there’s actually a fair bit of recoil going on (the rifle table is here).  What it boils down to, though, is that she doesn’t want to go practice because it hurts to do so.  She’s not alone in this.  A lot of women, especially ones with slight frames, dislike shooting in general because some idiot at the range decided it would be funny to hand her a .300 Ultra Mag and then guffaw all over themselves when it jumps out of her hands.  Sort of like this video.  I can just about guarantee that woman will never want to go shooting again.  So now, when she has to use some sort of firearm to protect her or her kids, she won’t shoot well at all because she’s scared of the gun and, due to that, she never practices. 

So, what I’m trying to do is make a shotgun that recoils as little as possible.  Mom decided that she wanted to stay with the Winchester instead of buying another gun, as she’s had it for a long time now, and she’s reasonably familiar with it.  That’s fine.  It’s a reasonably robust platform, made out of decent material.  I don’t like to disassemble the 1200, 1300, and 1400 Winchesters as they are held together with plastic bushings and you literally have to beat the gun apart.  However, I can work with it.

I decided to start with the stock.  The first thing is that it was too long, and the factory recoil pad was way more recoil than pad.  Stock fit is pivotal in shooting comfort, and this one was certainly not helping.  So, I shortened the stock and added a Pachmayr recoil pad.

Yes, I”m refinishing the stock as well, so don’t worry about the scuffs on the old finish.  Once I had the stock to size and with a proper recoil pad, I started working on supplemental recoil reduction.  The way to do this is with mercury recoil reducers. 

Mercury recoil reducers work in two ways.  First, the sheer mass of them dampens recoil.  Together, the two reducers I installed add about 25 ounces to the weapon.  So, just as a car accelerates more slowly when it is loaded down, the shotgun will now recoil more slowly because the mass of the weapon resists the inertia of the recoil.  The second way that these reducers work is because they use mercury, which is liquid at room temperature.  Because the mass is liquid, the recoil response (“kick”) is slowed, as the liquid takes longer to start moving and longer to stop moving than the rest of the gun.  Now, the total amount of recoil will not change, but the time it takes for that recoil to occur will be longer.  Instead of a slap in the collarbone, it’s a gentle shove to the shoulder.

To install the reducers, I needed two 7/8″ holes in the buttstock.  The hole for the throughbolt served as one, but I drilled out another (carefully!) for the second reducer.

Once I had the two large holes drilled, I could fix the reducers in the stock.  When installing them, I needed to make a very snug fit, as I don’t want them rattling around in the stock.  That’s why the ends you see are threaded, so you can thread a bolt into them and use a vise to remove them if it becomes necessary for maintenance. 

Once the recoil pad screws in over the butt, the only indication that these reducers are installed will be the fact that the gun is heavy in the back end.  But that will only become evident when the weapon is unloaded.  When the magazine is full, the balance will be neutral, as the tube magazine on a shotgun puts all the weight from the loaded shells near the muzzle.  The other plus is that now the gun will make an even better club once all the ammo is gone.

PGS today

The next thing to work on was Red’s shotgun.  I know, I know.  I worked on that particular gun back in Semester 2.  Why do I need to work on it again?  Well, I was finally able to afford a new barrel.  When I bought that shotgun for her, it had one of the old “C-Lect-Choke” adjustable choke tubes on it.

I think the first words out of Red’s mouth when I pulled it out of the gun case were “Eww.  You can fix that, right?”  So I cut the barrel down to a plain, 18.25″ , cylinder bore barrel after I made a new stock for it.  While it worked, and Red liked her new stock, she couldn’t hit clays consistently past thirty yards or so with the cylinder bore.  The shot pattern dispersed so much that only infrequently did the clays break at all, and I don’t recall ever seeing one dusted.  So, I bought her a new barrel.  The new barrel is a vent rib, 26″ barrel with screw-in choke tubes.

Where I worked on the new barrel was on the forcing cone.  This is the transitional area in front of the .798″ chamber which, when the gun is fired, guides the shot and wad down into the .729″ diameter barrel.  This might not seem like a big deal, but in a factory barrel the step between the two diameters is very abrupt.  What ends up happening is that as the shot column is forced into the barrel, some of pellets are deformed.  When they leave the muzzle, they don’t fly well due to being misshapen and, consequently, have very irregular trajectories.  This is one of the main reasons that, when patterning a shotgun, you end up with “flyers” and “holes” in the pattern. 

What I did was lengthen the forcing cone.  It still makes the same transition from .798″ to .729″, but now it happens much more gradually.

In this illustration, you can see the difference between the two very clearly, with the area between the arrows being the actual forcing cone.  A side effect is that lengthening the forcing cone also lessens felt recoil.  So, the gun shoots softer even as it shoots better.  What’s not to like?

PGS today

Well, today was the first day back from Thanksgiving break.  It was nice to be back at the shop.  Apparently everyone survived the onslaught of turkey and stuffing with no ill effects.  My folks came over for the weekend and Red put on quite a spread.

The next project at the shop was re-lining the barrel of the Remington 511.  While it shoots okay to middling fair, I decided to see if I could increase the accuracy by putting a new bore in the rifle.  In addition, it’s kind of a nifty skill to be familiar with, and one that tends to come up fairly often in the shop.

The first thing we have to do is actually get the liner.

The liner is a slim rifled tube made of chrome-moly steel (so it will blue with the rest of the barrel).  What we have to do is first drill out the old bore.  We use a special, piloted, deep-hole drill and cut out the bore completely.  Once we have the bore drilled out, we use Acraglas to epoxy the liner in the bore.

Once the Acraglas sets up, we’ll go ahead and chamber the rifle as if nothing were different.  Once the glass cures, the liner is in there, so we don’t treat it in any special manner. 

PGS today

The way it turned out, I had both Red’s Marlin and the Remington to glass bed at the same time.  So I mixed a big pile up and went at it.  I didn’t need to glass either, as my inletting is tight enough to prevent any slop in the wood/metal fit, but I prefer to.  It helps keep everything stable (non-warping) even with big changes in humidity.  Also, when it comes to Red’s Marlin, it has a lot to do with the design of the weapon.  Almost every lever-action rifle I’ve ever seen has splintered inletting, no matter how carefully they are cut into the stock.  The bearing surfaces are very small to begin with, and once they get a little gun oil on them, tend to crumble out very quickly.  So, this way I’ve got a stable, strong bearing surface.  Not necessary maybe, but it makes me feel better.

The Remington was done first, so those are the pictures for tonight.  I’ve free-floated the barrel along its entire length.  The glass helps to ensure that the stock doesn’t warp up into the barrel, changing how it shoots.  I also bedded the action to the stock so that there is an absolutely rigid recess for the receiver.

PGS today

Along with Red’s Marlin 336, I’ve also been working on my Remington 511.  After I made scope bases for it, I decided that it sure would be nice if it was dressed up a bit.  The rifle was mechanically very sound, but it had seen better days, and that was just a shame, considering how nice these little rifles are.  The area where I started was the stock.

There were a number of things that, once I made the decision to alter the wood, came immediately to mind.  The first was the forend.  I thought the little comma they put on the end of rifle looked a little silly.  I mean, on a centerfire, they normally put a forend tip on, and it looks a whole lot better and–

–idea!  I’ll just add some tip wood!  It’ll totally look better.

The other thing is that the grip is too small for my gorilla mitts.  When I shoot this rifle, I’m doing the two-finger hold like on a sub-compact pistol because my hands don’t smush up into that little grip very well.  But if the grip were a little longer, it would be better.  And since I’m adding a forend tip, it would be nice if I had a matching grip cap too and–

–and so I found some old cast-offs and started in on the project.  I don’t really have any sort of guiding light or goal, I just think of things and start working whenever Red’s Marlin isn’t in the way.  So, I’ll keep you updated as both projects wear on.

PGS today

The next task in stocking Red’s Marlin was getting the barrel bands to screw on correctly.  These hold the stock and magazine tube to the barrel.  While the magazine still had the slots for the screws cut, the new barrel did not, so I had to mill them out quickly in the morning so I could start in on fitting everything else.

Once I got the slot in the barrel cut, the screw passed through the slots cleanly, and holds everything together snugly.

The band above is the front barrel band, up by the muzzle.  The rear barrel band was a little more work.  Not only did I have to cut the screw slot, but I had to inlet the stock as well to accept the barrel band.

Now that the barrel bands are on, though, the structural considerations with the  stock are pretty much done.  Now I can make it a stock, not a couple pieces of wood bolted to a rifle.