Reloading

Quick Guide
Reloading for Glocks
Lead Bullets
Semi-Wad-Cutters
Maximum Reloads
Expansion Measurement
kB! Information

The Glock manual does contain a warning against using reloaded ammunition. However, this is generally viewed as an industry-wide practice done to prevent lawsuits:
"The use of reloaded ammunition will void the Glock warranty, due to the unpredictability of the standards (SAMI/NATO) adhered to, since reloads of poor quality ammunition may not meet (SAMI/NATO) specifications, may exceed limits, and therefore may be unsafe."
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Can I shoot lead bullets in my Glock?
This has been debated on rec.guns and GlockTalk about 10,000 times. There are basically 2 schools of thought:

School #1: Don't Do It
Glock barrels use special polygonal rifling not found in most handguns. This rifling is one of the main reasons Glocks are extremely accurate guns. However, the same rifling can cause a high degree of leading when not using jacketed bullets. In other words some lead from the bullet sticks to the inside of the barrel when it is fired. Too much leading can quickly lead to high pressures which can cause the barrel and/or gun to break or even explode. Most people who weigh in on this subject fall into this category including Glock Inc.

School #2: Don't Worry About It
If you clean your barrel well and do it every time you shoot there will be no significant leading. Many, many people use lead bullets almost exclusively in their Glocks and do not have any problems whatsoever.

Additional notes from Hoss:
Not all lead is created equally. You can shoot lead in your Glock (probably) but you should use a hard lead from a reputable manufacturer. The homemade lead bullets made from wheel weights and other recycled lead should be avoided! Just becuase one type of lead bullet and load shoot fine in one glock does not mean it will be safe in others. Each barrel is different and must be carefully checked when first using lead.

Additional notes from JT:
You *can* shoot lead in a polygonal barrel, as many Glocksters do. But you need to be aware of some potential dangers in using lead bullets, not to mention voiding your Glock warranty if you use non-factory ammo.

First, if you decide to use lead bullets, use hardcast bullets at medium velocities for best results. This will reduce potential leading of the bore. Theoretically, polygonal rifling allows the bullet to seal the gases better than traditional land and groove rifling, thereby increasing velocities but also increasing potential problems with bore-leading-induced pressure spikes. Lead particles from the bullets have no where to hide in polygonal rifling as in the lands and grooves of conventional rifling and with better bullet-to-bore sealing, serious pressure spikes can develop when the bore is fouled.

However, note that some dismiss the purported velocity increases with polygonal rifling. Mike Orrick (GlockTalk's "BrokenArrows") has pointed out that his chronographed results of identical loads in conventionally-rifled barrels versus same-length polygonal barrels yielded higher velocities in some of the conventionally-rifled barrels.

Secondly, absolutely get all the lead out after at least every 200 rounds to avoid lead buildup, pressure spikes and potential corresponding kBs! With the tighter seal of the bullet, pressures can increase significantly in polygonal barrels. There have even been reports of Ranier-type bullets shedding bits of copper jacket in polygonal barrels, causing the same pressure spikes that are caused by excessive leading. Just be sure to use hard-cast lead bullets or good-quality jacketed bullets and keep the velocities down to earth.

Thirdly, polygonal rifling doesn't get the same grip on the bullet as conventional rifling. This may affect accuracy with some loads, especially hot ones. Even with using copper-jacketed bullets, some LEAs have reportedly banned the use of polygonal barrels in duty guns because of the potential difficulty in forensically identifying the rifling patterns on a bullet shot from a polygonal barrel. IOW, it's sometimes impossible to identify which polygonal barrel a particular bullet was shot from. Who shot whom?

Another recommendation is to moly-coat your lead bullets and/or treat your barrel with one of the spaceage lubricants, such as TW25B spray from Kleen-Bore. This will definitely help the cleaning process and may even increase velocities slightly and help with accuracy.

Last, but not least, most experts recommend getting a conventionally-rifled barrel from replacement barrelmakers such as Jarvis or Bar-Sto if you shoot a lot of lead. These barrels generally offer more case support than stock Glock barrels as a bonus. Use your replacement barrel for practice and the stock barrel for carry.
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Can I shoot SWC bullets in my Glock?
In all calibers but .45 ACP SWC's shoot fine. In .45 ACP most shooters report problems with SWC bullets but some do not. This even varies between guns of the same model.
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How can reloading make more powerful loads than commercial ammo?
The difference is that every combination of gun/chamber and the lots of reloading components being used is a law unto itself...

There are so many variables involved, that rounds have to be loaded down somewhat by the factories to be guaranteed safe in every gun.

Some of the variables involved are:

  Thickness of the web of the brass
  Overall internal volume differences in brass
  Brass longer (esp. if too long for the chamber)
  Primer Strength (esp. magnum vs. standard, but even different manufacturer's primers of "same strength" have different force and effect pressures differently)
  Lot-to-lot variation in powder burning rate
  Lot-to-lot variation in diameter of bullets (even of the same make, weight, and style)
  Lot-to-lot variation of exact weight of bullets (even of the same make, listed weight and style)
  Overall-length the rounds are loaded to
  Variation in the amount of crimp applied
  Neck tension variables due to thickness of the brass as well as expander die dimensions

We haven't even talked about the variations in different guns regarding the length of chamber, size of feed ramp/case head support, and diameter of chambers. Need we go on?

This is why handloading is a way to maximize performance for your gun, with your lot of components, and why McNett's published figures here are academic ONLY -> Showing us what HE got with HIS components in HIS barrels!

I've bettered some of the loads of some people here, but, on the other hand, I can't come up to some of the loads some people post here. MY barrels and components are better in some combinations and worse in others.

It's important, that if you choose to handload for performance gains like these, you know how to read pressure and thoroughly understand reloading safety procedures.

I hope this explains why loads such as these aren't generally available and why we discuss them so much. I also hope this explains why you shouldn't EXPECT to get the exact same performance. Like I said, in some examples I've done better, and in some I haven't been able to match them. The point is, getting more than factory, but SAFELY! [MakeMineA10mm]
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Determining Comparative Pressure Through Expansion Ring Measurement
Here's yet another article from our favorite author MakeMineA10mm.

1. Obtain and fire factory loads for the cartridge in question and measure the cases at the appropriate place (explained later) in order to determine the exact pressure ring expansion measurement for factory loads in your particular chamber.
2. Size and reload the cases with your selected load in increments up to the book maximum.
3. Fire the loads, starting with the lightest loads first, and measure the cases at the appropriate place. When you find expansion equal to or greater than the expansion of the factory loads, STOP!

• If you've ever had a case head separation, it was probably at the pressure ring where it happened.
• Feeling/looking at a fired case, look at the point where the case is still bulged from firing, and then below that point, where it is not bulged. The lowest and widest bulged point is the pressure ring.
• If I've still managed to lose you, get one of the reloading manuals and look at the pictures in the front of them. They almost always have illustrations or pictures of cut-away cases and you can see quite easily that the case's head is solid for some distance ahead of the extractor groove. It will also be apparent where the powder chamber starts.
• If you are still absolutely not confident in your ability to find the pressure ring, you can section a case with a Dremel Tool and then you'll know for sure, exactly where it's at.

When measuring around the pressure ring of the fired case, I like to "mic" the diameter at any point around the pressure ring. Then, I open the micrometer up .0005" to .001" and rotate the case. In this manner, I am able to find the absolute largest measurement of expansion around the entire circumference of the pressure ring.

Now that you know where it's at and one way to do the measuring, it's time to measure your once-fired factory loads. Make sure you record the largest measurement of each case on a sheet of paper, or directly into a spreadsheet, if you wish. Once you have done that with all 40-50 of your factory loads, you can look at the list of measurements.

If you find one or a few cases that expanded much more than the rest, ignore those measurements and set those cases aside, or throw them away. They probably were not annealed properly and are of soft brass, which will this method off and they would be dangerous to load with hot loads anyway.

With the remaining case measurements, you should have a very consistent trend of measurements, and you should be able to average them without any of the measurements being more or less than .001" from the average. This average is now your factory load expansion measurement. You need to write this down someplace that it will never, ever be lost, because you will be referring back to this dimension a lot in the future.

Now, pick the powder, bullet, and primer that you want to load. It doesn't matter if it's the same or totally different from the factory load's as any combination will work. Go to a reloading manual and find a starting load for your combination (or as close to it as you can get).

Now is also a good time to measure the length of your cases. If you need to trim them, do so. It will not effect the PR measurement in any way, and if you don't, it could effect you adversely. In addition, this is also a good time to recommend that you find the cartridge OAL you are going to load to, since changing that, will require that you start these tests all over again as well…

With the cases you just used for the factory load measurement, load 5 rounds with your starting load. At this point, Ken Waters and I depart slightly, because in my experience, every starting load has given lower pressures than the factory load. Some day, this may not be true, but so far, it has been for me. Therefore, I proceed to load 5 additional cases with the next step up in powder.

The size of step depends on what you are loading. If I'm loading pistol cartridges, I use steps of .2 grains. If I'm loading large-capacity rifle cartridges, I use steps of 1 grain.

Assuming you did not have to discard any cases with out of the norm expansion with the factory load, with your 40 cartridge cases, you can continue on until you've loaded 8 steps. Even if you can only load 7 steps, due to bad cases, you will probably be able to load from starting to at or near the listed book maximum load. Keep the cartridges for each step separate or sorted somehow including a label, both before taking them to the range and after, so that you can measure case head expansion as you get done firing each step.

You want to do this at the range, as you fire each step up in powder charge, because, you may find you've reached the maximum load before you get to the book maximum. (On the other hand, you may be able to exceed the book maximum quite a bit with your combination of case, bullet, powder, seating depth, and chamber. In addition, you COULD find that the starting load is too hot, and that you have to go home, and pull all the bullets on the other steps you've already made up…)

If you are loading for a strong, modern, bolt-action rifle, Waters suggests that you can exceed the pressure ring measurement of the factory loads you fired by as much as .001".

If you are loading for a cartridge that has weak factory loads due to old guns, such as the 45-70, you can exceed the factory PR measurement by quite a margin, but you must also be very careful to watch for the other, less specific signs of excess pressure, such as stiff action, ejector marks, loose primer pockets, pierced primers, etc.

If you are loading for an auto-loading action, I recommend you do not exceed the factory PR measurement by anything, or, at the most, .0005". This is because, depending on the action, all semi-autos to some degree or another still have residual pressure left in them when they are extracting the case. This becomes even more sensitive on a blow-back action locked by no mechanical means, such as an Uzi, or Mac. With the Browning-style of mechanically delayed opening, this is less sensitive and I feel it is quite safe and appropriate to exceed by as much as .0005".

As long as you find your PR measurements are equal or below the PR measurement of the factory load in the same case, you can continue to increase your load in steps. I reduce the size of the steps once I go beyond book maximum however. For pistols, I use steps of .1 grains, and for rifles, I use steps of .3 grains.

Once you've found your cases with PR measurements that are at the recommended limit (.0005" to .001" above the factory load), STOP! This is your maximum load.

You can determine your most efficient load with a chronograph. Chronograph the load you've found to be your maximum. Now load backwards down the steps used to get to this max. You may find that a load with slightly less powder provides almost the same velocity and is a little more accurate to boot. This of course varies from gun to gun, and even from load to load.
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What is a kB! and how do I prevent it?
kB! is short for KaBoom! It is a general term describing a failure that results in a small explosion. Here are 2 excellent writeups on Glocks and kB!s from 2 of our resident experts.

The original Glock is the 17, and it was designed around the 9mm cartridge package. It is completely and totally engineered to be absolutely safe with that round, and the 9mm seems to be the Glock with the least kaBOOMs, even though it has, by far, the largest number of pistols made for it's caliber (world-wide -> in the US, the 40 is catching the 9mm, maybe even surpassing it). Why is this so?

Well there are many reasons. Ammunition problems are a primary concern, however there is also firing out-of-battery, lead bullets, unsupported chambers, and other factors. To break it down, we have to look at how the Browning locking design works, and this takes quite a bit of explaining.

First, assuming a properly chambered and functioning cartridge, the following occurs:

1. The firing pin hits the primer and the primer/powder ignites.

2. The rapidly expanding gas propels the bullet into the barrel and simultaneously swells the brass case into the chamber walls obturating the breach.

3. The barrel and slide begin moving rearward, in a locked-together position for approximately 3/32 of an inch.

4. How soon and quickly the slide/barrel unit begins moving is determined by the force of the round being fired compared to the inertia of the slide/barrel unit. The heavier the slide/barrel and/or the lighter the force of the round being fired, the slower the slide/barrel open and move.

5. As the slide moves rearward, it is compressing the recoil spring.

6. Just after the bullet leaves the barrel and pressures rapidly drop in the chamber and barrel, the cam on the barrel begins it's thing. This causes the barrel to drop downward, out of it's locked position.

7. The slide continues rearward, without the barrel, and the extractor is hanging onto a segment of the case rim, thereby extracting the now-spent case.

8. The slide, near it's end of rearward movement, draws the empty case into the ejector and the case is pivoted out of the grasp of the extractor and out the ejection port.

9. The slide stops.

10. The recoil spring returns the slide to battery, with the slide's pick-up rail stripping a fresh cartridge out of the magazine and feeding it into the chamber in the process. (The feeding of the cartridge is another process altogether, and doesn't have to do with kaBOOMs, so I'll not refer to it further.)

This leads us to question several things, in a certain order about kaBOOMS:

1. Look at ammunition first, because there's a lot less going on with it. It's either defective in excessive pressure, or weak brass, and that's about it. Two things to check makes it much easier to point at/eliminate first.

2. Look at the bore of the pistol. I have in my possession a Beretta 92 barrel that swelled up when a round was fired immediately after a squib load left another bullet in the bore, obstructing it. It is also relatively easy (in some cases) to see if the bore was obstructed in some way, which lead to the kaBOOM.

3. As a last resort, we have to look at the mechanics of the firearm. This is last, because it is complicated, with many things happening simultaneously, and therefore not an easy yes/no test.

By becoming familiar with the above description of the Browning system and looking at the barrels and slides, you can figure out for yourself, that the metric Glocks (9mm and 10mm) are stronger and safer Glocks from a couple points of view:

1. Barrel walls are thicker on 9mms than 40S&Ws. They have the same outside diameter, but the 40 has a 1mm bigger hole bored through it. Likewise the 10mm and 45 have the same O.D., but the 45 has over a 1mm bigger hole bored through it. Thicker walls means safer.

This is especially true with the 9mm/40S&W comparison. The 9mm, 10mm, and 40S&W all work in the same pressure area: ~35,000 p.s.i. The 40 has a MUCH thinner barrel to contain the same high pressures that the 9mm does with its much thicker barrel. This is not such a big factor with the 10/45 comparison, because the 45 can compensate a great deal for that thinner barrel by operating at lower pressures (~21,000 p.s.i. for +P loads). (This is counter-acted when people convert 45s to wildcats such as the 45Super/40Super/400Cor-Bon, taking away the advantage the 45ACP enjoys here.)

2. Slide mass. Slide/barrel mass (a.k.a. weight) is what gives the slide/barrel unit the inertia to keep from opening too early. The thicker barrels for the metric caliber Glocks, already referred to above, contribute some of the additional weight, but mainly it comes from the weight of the slide.

In the 40/9mm I have not compared slide mass, so I will not comment, other than to only say that, on my 9mm Glocks, I can see that the slide walls are full-thickness for only about 1-1/2 inches forward from the breachface, and I must assume that 40 Glocks have full-thickness slide walls all the way to the muzzle. Still, this will barely compensate for the difference in barrel weight, which means, IMO, slide velocity is excessive in 40S&W Glocks. (This is a major part of the reason MarkCO recommends stronger springs, in differing increments, for all Glocks other than 9mms.)

Likewise, in the 10mm, the slide walls are full-thickness all the way to the muzzle, whereas, in my G-21, the slide walls are thinned very close to the breach. If a G-21 had full-thickness slide walls all the way to the muzzle, it wouldn't function reliably as the slide/barrel unit's inertia would be too high.

This is because the engineers have to pick a slide/barrel unit weight that is as close to the ideal for the middle of the road power-level cartridge as is possible, while still giving full safety for the anticipated (SAAMI max) most powerful ammo to be fired in that caliber weapon. (This is why I am very concerned over conversions of the G-21 to 40 Super/45 Super/400 Cor-Bon, because all of these cartridges operate at higher chamber pressures AND higher slide velocities than the highest level the 45+P operates at.)

These inertia/barrel thickness factors only increase your margin of safety. They do not mean that any Glock/firearm are infallible. Any firearm can be made to fail.

The one factor we have not looked at, yet, is the "unsupported chamber".

This, too, is another cause of many kaBOOMs, and it, again, is connected, at least partially, to caliber. For example, if you looked at an engineer's drawing of the 40S&W case, you would see that the web (the area of the sidewall of the case that begins tapering thicker as you get towards the base of the case) starts much farther down the case than the 10mm, which it was designed from. The reason for this was that when 10mm cases were trimmed down to make the first, wildcat 40S&W cases and bullets of 180gr or heavier were seated in them, the case bulged because the heel of the bullet ran into the beginning of the web of the cut-off 10mm brass. Reamers had to be used to shorten the converted cases' web to allow seating the 180gr bullets desired.

When setting up to make 40S&W brass this was a known problem, and to correct it, the web simply starts lower and thickens more rapidly so that it is still the same thickness as the 10mm by the time you reach the base of the case. This is fine, except on chambers which have relatively long tapers to their feed ramps, such as the Glock. What happens now is that a thinner area of the case is over the beginning area of the feed ramp (the "unsupported" area) and with a case that has too brittle brass, or soft brass, or cracked brass, or an over-pressure load, you can have a kaBOOM.

This is complicated by the factor I cited above: Slide Velocity. The higher the slide velocity, the sooner the slide/barrel unit begin moving rearward, and the higher the residual chamber pressures are while this happens. If residual chamber pressures are too high (from say an over-pressure round), and the case is beginning extraction from the chamber, this only aggravates the unsupported chamber problem.

All of this was likewise aggravated, because several companies rushed production of their 40S&W firearms and/or ammunition. Glocks in 40 cal. were out almost simultaneously to the S&W product! Additionally, there are several lots of Federal 40 ammo that are under recall, because they were loaded to the maximum level and proved to not interact well with guns produced hastily (the first 40 cal Glocks). This is why there was such a rash of 40 caliber kaBOOMs when they first came out. Rushed ammo and guns operating at the edge of the safety margin. It was bound to happen.

So basically, what this all means is, that, barring barrel obstruction, and defective ammunition, the safest Glocks are the ones with the best safety margins (thickest barrels and best inertia to power-level of their cartridges, AKA Low Slide Velocity).

To rank them in this quality of greatest safety margin, I would do so thusly:

1. 9mm
2. 10mm
3. 45ACP
4. 357SIG
5. 40S&W
(and then conversion calibers which operate at higher chamber pressures without compensating for slide/barrel inertia:)
6. 400Cor-Bon
7. 40 Super
8. 45 Super

If one plots out the number of kaBOOMS compared to the number of pistols produced in each caliber, I would be willing to bet that that list would be in the reverse order of my list, meaning the 40S&W has the highest percentage of kaBOOMS and then down to the lowest percentage being 9mm.

Sorry this is so long, but attempting to explain complex concepts takes some room. :-) [MakeMineA10mm]

Here are some links to additional kB! info:
Calibers Glock kB! FAQ http://greent.com/40Page/general/faq-kb.htm
Calibers .40 S&W kB! Report http://greent.com/40Page/general/kb.htm
kB! Pics http://glock.missouri.edu/glock/gkbpix.shtml
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