v 15.4 - 3 / 5 / 2008
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 Reloading Can I reload for my Glock? Yes. As with all reloading: be sure to follow published SAAMI guidelines very carefully.
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:
Can I shoot lead bullets in my Glock?
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?
Determining Comparative Pressure Through Expansion Ring Measurement
The question has come up quite frequently about how to determine the maximum safe handload for XYZ cartridge/bullet/powder combination. This is one of the most neglected areas of reloading, even in the manuals. I have for several years used and advocate the method that was first widely reported by Ken Waters in a September, 1982 Handloader Magazine article. The exact same article and description of method is also the first chapter in Volume I of Waters' book "Pet Loads". Both Handloader and Pet Loads are available through Wolfe Publishing, and they are excellent resources. Below is a brief description of Waters' method, and to reiterate, this is brief and not as thorough as the description available in the referenced sources above. I encourage the reader to obtain one or both of these resources. Waters' method involves three steps:
The first prerequisite is that we have a micrometer that can measure in ten-thousandths of an inch. There are numerous ones available, including easy-to-read digital ones from Brownell's among other sources. A chronograph is a handy addition, however, it is not absolutely necessary. The second prerequisite is to assemble factory loads for testing/measurement. There are several things to be careful of here. First, for calibers that are loaded to wildly different power levels (such as the 10mm Auto), make sure you get "full-power" loads. For calibers that are down-loaded by the factory due to old/weak actions (such as the 45-70), you must look for specialty ammo (such as Buffalo Bore) or use the weak factory ammo, and then compare your handloads to data available in reloading manuals, and determine a maximum PR measurement that way. Also, factory ammo that is designed for semi-auto actions should not be used as the factory maximum for, say, a bolt-action rifle. Next, once we've determined one or more good, full-power factory loads for our caliber; we must get enough of them to do pressure testing. (We use the same cases from the factory loads to make our measurements on until we determine what the safe maximum in our firearm is.) Usually, about two or three 20-round boxes, or one 50-round box of ammo is enough. I recommend you do all of this testing during the Summer on a nice hot day (because that's when pressures are highest in the chamber), but whenever you fire your factory ammo, you must do all of your comparison of measurements of any handloads in the future at the same ambient temperature. So if you do your testing and measuring of factory loads in the winter on a 20oF day, your pressure ring measurement for comparison purposes is only valid on another 20-degree day. Now, before we can measure, you must know where the pressure ring is. I'll give you a hint: It is near the base of the case. : ) If you get a multiple-reloaded, fired case and follow along, it may be much easier to visualize this. Starting at the very base of the case and moving forward along the outside of the case, we have the rim, the extractor groove, the head of the case (where the brass is solid all the way through, except for the primer pocket), and then the pressure ring. The pressure ring is the point where solid case head ends and the powder chamber on the inside of the case begins. On a case that's been fired and resized multiple times, it is usually apparent as a slightly brighter ring of brass around the outside. Some other ways to find it:
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? Glock Kabooms...Myth or Not? - MarkCO I have read the reports where folks say they have 500, or even 5,000 rounds through their Glock with no problems. That is nice, but by no means is it significant scientifically. I bought the first Glock .40 the local gunshop sold and started shooting IPSC with it. That first G22 went about 23K rounds before it failed. The reason it failed, and documented by myself through exhaustive metallurgical testing, and concurred with by Glock, was due to overpressure caused by lead bullets. Funny thing is that, as I write this, sitting right here at my desk, is a page full of numbers, numbers that luckily I recorded prior to the failure. I was shooting over a Chronograph when the gun blew and had over 120 rounds individually recorded. Each round had been measured and each powder charge individually weighed. I know EXACTLY what the loads, powder charges and velocities were. I look at the numbers now and wonder how I did not pick up what was occurring. But hey, I was young. This was almost 10 years ago. As I write this, I have a G22 with over 80,000 rounds through it, a G35 with over 15,000 rounds through it, a G27 with over 20,000 rounds through it and I sold a G24 with 15,000 rounds on it, a G23 with 6,000 rounds and a G35 with 2,000 rounds on it (does not count since a KKM barrel) So I have fired 159,000 rounds of .40 through Glock factory barrels. I have pressure tested lead bullets fired in actual Glock barrels with controlled test conditions and the same loads fired in conventionally rifled barrels. Then I fired jacketed and copper plated bullets in the same conditions to test for pressure increases there. Conclusion is that lead bullets, yes, even the 24 BHN variety, increase pressure after only a few rounds fired. When the pressure reaches an unsafe level has to do with the powders pressure curve, temperature, bullet hardness, bullet grain structure. Weak cases do let go, but do not result in the same type of damage. When a Glock is overpressured, the shooter is rarely injured beyond a few cuts or bruises on the shooitng hand, none that I have seen have been permanent. And how many have I seen? To date I have personally inspected over 40 blown Glocks that were the result of overpressure. I have reviewed documentation on over 120 others. And, yes ALL calibers were represented. And how would I know what I am doing, besides just being a shooter? I am a forensic engineer (mechanical) who investigates accidents and failures for a living. I have been qualified in court, as an expert (which is not easy these days). And for the record, the firm I work for does more defense work than plaintiff work. We work for who hires us and, sometimes, our clients do not like our findings, but that is the breaks, facts are facts, evidence is evidence. Glocks are not perfect, nothing man-made is, but I trust my life to their reliability. I reload (couldn't afford to shoot if I did not). For me, I choose to shoot plated bullets which cost me a few dollars a thousand more than lead. I save on the cleaning stuff and the cost is about the same as lead. I also use the factory barrels, exclusively now (I sold my KKM barreled G35). The overwhelming majority of blown Glocks are from lead or poor quality reloads. A few are from bad factory loads and a few from defective aftermarket parts. I must beleive that there are a scant few that have had manufacturing defects, but I have not seen one yet that casued a KB. If I do, Glock will surely be hearing from me, and I believe they will do the right thing. Hope this helped. Glock kaBOOMs - MakeMineA10mm 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
Sorry this is so long, but attempting to explain complex concepts takes some
room. :-) [MakeMineA10mm]
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Thickness of the web of the brass