Break Me Off A Piece Of That….

Last week, I’m crankin’ out some 40S&W, minding my own business when suddenly…..

It was sudden, but not violent. No snap, no pop. The handle just twisted a little weird. My first though was that the nut had worked loose, but I put a little pressure on it to test that and there is was, swinging in the wind by the handle.

I contacted Dillon about the replacement part, which even if I had to purchase it would only be $40. Of course, they intended to replace it under warranty. The only question was which version I had. One connects with E-clips, which you can see in that picture above. The other has locknuts.

While I had him on the line, I asked about their (legendary) refurbishment service. It’s only $68 to send them the whole press and they will repair and update everything on it, with about a 3 week turnaround. I’m in!

During the week, I removed it from the strong mount, removed the bits that they didn’t need for the work and boxed it up. It actually shipped on Thursday.

Meanwhile, a friend has a spare RL550 that needs a little work of its own. I arranged to borrow it in exchange for the work it needs. He learned the hard way that you can’t keep your reloader in the same enclosed space with pool chemicals.

The rust on the main shaft was enough to prevent it from operating. I used carburetor cleaner and steel wool to remove most of the surface rust.

I put it in the ultrasonic.

I love the way the muck flows off the parts.

Unfortunately, I was in a bit of a rush from this point forward and did not take any more pictures of the progress until it was finished. Really, it was just more cleaning except that there was still some dimensional enlargement from the rust on the end of the shaft. I used a fine file to gently draw file the part, being very careful to avoid causing any flat spots.

I put it all back together, with my handle, dies and shell plate.

I loaded 4 rounds just to test it out and it’s ready to go!

When I get my own press back from Dillon, I’ll just swap it around and return this one better than when I got it!

A Practical Application of the Conservation of Momentum

There are two main reasons to hand load your own ammunition. Most people approach reloading for reasons of economy. All situations being otherwise equal, reloaded ammo designed around cost tends to run about half of what commercial ammo might cost. There are firms selling commercially remanufactured ammunition for close to what you can load your own for, particularly if you watch for sales and/or free shipping is offered, so if you are reloading for economy only, reloading may not actually be your best option. After all, for $600+ investment in a press, accessories and reloading components makes that first box of ammo run at least $12 a round. It gets much better from there, though.

The other, perhaps even more compelling, reason is to customize ammunition performance. Action shooters benefit from controlled recoil for faster followup shots and consistency. While economy *is* a factor, it is custom performance that drives my reloading/handloading efforts.

There are revolvers and other semiautomatic cartridges in use, but the majority of action shooting competition is done with semiautomatic pistols in 9mm, 40S&W or 45 Auto. The focus of this blog article is about the effects of customizing recoil in semiautomatics for the competitive shooter.

There are energies released and absorbed throughout the operation of a semiautomatic pistol (or just ‘pistol’ from here on). One could go completely crazy plotting them all. The displacement of a 1911 in reaction to the swinging hammer would be mathematically predictable and physically measurable. It would likely be buried in the noise, but it could be accounted for. Indeed, sniper rifle design accounts for dampening or reacting such forces because in that application, it can matter.

The forces that matter most to action shooting reloaders are the actions and equal but opposite reactions that are initiated by firing the cartridge. These are also the big forces, big enough that we can largely ignore everything else.

Power Factor is a simple measurement that action shooting sanctioning bodies use to ensure their competitors meet a minimum expected level of power. Power Factor (PF) is calculated simply by multiplying the bullet weight in grains by it’s velocity in feet per second, dividing by 1000 then discarding the digits to the right of the decimal. For example, a 165g bullet going 900 fps would be 165 x 900 = 148,500. Dividing by 1000 and discarding the digits to the right of the decimal is practically the same as just dropping the comma and those digits, PF = 148.

Common minimum power factors are 125 and 165. For example, in IDPA, all semiautomatic divisions except CDP is 125 and CDP is 165. In USPSA, PF is a scoring modifier in some divisions, like a golf handicap. Shooting major PF (165 or more) reduces the penalty of non-A zone hits.

Power factor, or momentum, is a simple and linear method that is adequate for comparing different ammo between different shooters. Recoil is a more personal effect, felt by only the shooter. Less recoil generally means an easier to control firearm. Ideally, you have the least possible recoil while meeting the minimum required power factor.

Recoil is really the reactive force to the bullet’s acceleration. The easiest way to measure that is by the velocity of the bullet, presuming it has lost a negligible amount of energy between the muzzle and the measuring field. Scientifically, they are different things. Practically, they are close enough.

Momentum is derived from a fixed mass moving at a fixed velocity. Muzzle energy is derived from the acceleration of the mass. Remember that acceleration is any change in velocity, not just speeding up but also slowing down.

Unlike momentum, the relationship between muzzle energy and velocity is thus not linear.

Bullet weight (in grains) X (velocity ^ 2) / 2 X 32.174 X 7000

The 7000 is to convert grains to pounds and 32.174 is the acceleration of gravity in fps. Note importantly that the velocity is squared.

The same 165g bullet above at 900fps has 296.7 foot pounds of energy.

Here is where the handloading magic starts to happen. Raise the bullet weight to 180g and obviously the PF and the muzzle energy will also rise, 162 and 323.7 ft/lbs respectively. However, now you can keep the heavier bullet, but slow it down. At 825fps, the 180g bullet still makes 148 power factor, but now the muzzle energy is only 242 ft/lbs. Keep reducing the velocity to 695 fps and you get exactly 125 PF but only 193 ft/lbs energy. That translates to 35% reduction in recoil while still meeting minimum power factor.

Now, shooting for exactly 125 PF doesn’t allow for the inevitable differences in powder drops or ambient temperature, either of which can make any given bullet run faster or slower. It will likely be the ones that the match officials chronograph that will be slower, so it’s best to build in a little margin to allow for that.

You can also reverse that logic and load up a 9mm bullet hot enough to be major PF. A 147g bullet at 1125 fps meets 165 power factor, but at the cost of 413 ft/lbs of recoil (and probably dangerously high pressures in the cartridge). You can go nuts and push a 115g bullet at 1440 fps for 165PF, but a whopping 529 ft/lbs energy, which is at the lower end of the 357 Magnum neighborhood. Plus, I’m pretty sure neither your warranty nor health insurance will cover that.

The other thing to consider is that unless you are shooting a Desert Eagle, your semiautomatic pistol is probably *powered* by recoil. Turn it down too much and there may not be enough energy left to operate it, especially if some of that energy is also lost in a loose grip.

There is a reasonable solution for that: lighter recoil springs. I had to tune the recoil spring weight in my Glock 20. Using a LoneWolf 40S&W conversion barrel, heavier bullets and lighter loads, I was able to greatly reduce recoil while meeting power factor, but before I could get all the way down, I started having stovepipe jams or sometimes, it would just fail to extract at all. The stock spring on the G20, and I think all base models, is 17 pounds. The G20 and G21 have heavier slides, as well. So the stock spring and big slide took more energy than was left after throwing a bullet downrange. I ordered a 13 pound and an 11 pound spring, each with a stainless guide rod. Turns out the 11 pound spring runs best with my softest 180g handloads, which is 4.2g Winchester 231 (or Hodgdon HP38; they are essentially the same powder from the same manufacturer, with different labeling). I can sometimes run the pistol on as low as 3.9g W231, but with the occasional jam and it’s only about 119PF.

One should be be able to determine mathematically what weight spring would be needed to run a given slide with a given ammo power. I may tackle that just for the fun of it.

 

Triggered!

The stock trigger on my Glock 19 can be fairly described as harsh. The measured pull is only about 6 pounds, but the feel is not nice, particularly compared to the G20 and G21. To me, it feels like you are bending a piece of plastic inside and it finally breaks. All three are Gen 3 pistols, with only the slightest trigger work done, replacement of the connector. The G20 and G21 have had many thousands of rounds through them, so there is probably some degree of surface polishing having thus been done.

I decided to try an aftermarket trigger. I ordered a Pyramid trigger from GlockStore.com.


I chose the Complete package for $180 because it included alternate striker springs and the firing pin block plunger, but no lightened striker. Personally, I am not sure the addition of a lightened striker is worth $70 more. Perhaps one day I will add that, but that package is roughly half the cost of the pistol.

The installation is pretty straight forward. The trigger assembly itself requires driving out the three pins for the locking block, the trigger and the trigger housing and basically dropping the replacement parts in and putting the pins back.

This kit also comes with a replacement firing pin block plunger and spring and a selection of striker springs. I opted for the lightest, a 2 pound spring. Again, installation is pretty straight forward, especially if you have ever taken the slide apart for deep cleaning, which is a good idea while it’s apart anyway. There are many resources online describing the details. It is not difficult, but there is a tricky first step to it.

Once the striker is out, there is a delicate operation to removing the spring. It would be wise to consider doing this with the striker within a plastic bag to retain the spring retainer cups. Assembly is basically in reverse order.

The black trigger with a red safety pawl just looks right to me. The trigger is available in a large variety of color combinations.

The pull weight of the trigger is not much less, 5 pounds compared to the stock 6 pounds, but the feel is a thousand times better. Much shorter pull, much sharper release and a short reset. The trigger shoe is wider and flatter than stock, so it feels like less than 5 pounds. I am looking forward to shooting it.

While I was working on the pistol anyway, I decided to address a minor irritation that is not necessarily caused by this pistol, but it did bring it to my attention. Until I got this pistol and shot it in a match, I had not noticed that frequent shooting has caused an accumulation of terminally undifferentiated keratinocytes in the outermost layer of the skin on the middle finger of my right hand.

Since it does what a callus is supposed to, protect that spot from repeated friction, I had not noticed it. However, the Glock 19 grip is smaller than the G20/21, so that spot lands a little differently. The same spot on the bottom of the G19 trigger guard hits the edge of the callus and it’s kinda uncomfortable by the end of a match. Rather than wait however long it will take for the callus to expand, I decided to smooth off the trigger guard.

Although the mold seam is clearly visible here, that’s not what causes the discomfort but rather the nearer edge of the trigger guard.

I used primarily 1 inch wide 150 grit sanding strips to reform that edge, then smoothed and polished it with finer strips and sanding pads.

I haven’t fired it yet, but it certainly feels better in the hand.