There is a lot of information on the destruction of Glock pistols (humorously referred to as kabooms) and some H&K brand pistols. Here are a few concepts to consider. Both pistols (H&K depending on model) may have polygonal barrels. These are barrels without traditional rifling (lands and grooves cut into the barrel). Rather they have a smooth barrel that has very shallow longitudinal (lengthwise) shallow depressions hammer forged into them. Likewise there are very shallow sort of rolling hills (so to speak) that are raised barely a couple thousandths of an inch next to these shallow depressions. Like a rifled barrel these are in a twisting form to impart a spiral effect to the fired bullet. The barrel is basically smooth inside with the exception of this light twisting effect.
This means there is a lot of surface friction as the poly barrel tries to reform or squash and squeeze the bullet for the couple of milliseconds it passes through the tube. That is a lot to ask compared to a bullet going through a rifled bullet where the material is “sort of” cut away.
NOTE: Glock has been evolving on this and later models and so called generations have more conventional rifling (lands and grooves). IT IS UP TO YOU THE CONSUMER TO DETERMINE WHO, WHAT, WHERE, WHEN ON THESE GUNS–especially if you plan on shooting lead or solid monolithic copper bullets or even bullets like the KTW (keep reading) through your Glock.
There are many reports that lead bullets should NOT be fired through polygonal barrels-especially the Glocks. The Glock factory also recommends against lead bullets. A solid lead bullet will quickly smear plate the smooth polygonal barrel with a film of lead due to the extensive surface friction contact between the bullet and the smooth barrel as it reforms the solid bullet. Then should a jacketed bullet later be fired without through cleaning, it can stick (for lack of a better term) to the lead some and this may increase pressure in the gun and could blow it up. Also, even firing other lead bullets could cause this to happen as the surface and its resistance is built up.
Back in the early 1980s (before Glock) there were reports on certain models of H&K polygonal barreled pistols blowing up when using the then famous KTW (so-called by anti-Constitution types “cop killer bullets or Teflon bullets”).
The reason found was that the KTW bullets were solid copper alloy and the polygonal barrels simply could NOT squeeze them to fit the polygonal barrel before chamber pressures got so high they blew the guns up. This is a much different effect from conventional rifling cutting grooves into the bullet.
However, a solid relatively hard alloy copper bullet through a rifled barrel that cuts into the bullet material may be no problem, but trying to squeeze and reform it in a smooth polygonal before pressures build enough to blow up things is a problem. As an aside, the green Teflon coating on the KTW bullet did nothing to make the KTW bullet better, it was simply a nifty marketing trick that got lots of free press.
Anyway, the then pioneering KTW and many other light weight solid bullets of that type to follow were loaded hot (fast) as hell so as to easily defeat the intended target. For example the KTWs say in .357 Magnum were 200-300 feet per second faster than the then hot .357 loads of other brands. Also the KTW had a bullet that while round nose was a much more acutely shaped round nose. couple this with the lighter bullet weight allowing for much higher velocities and this bullet could indeed go through soft body armor–but not if their was a beaker plate or even trauma plate in most cases.The all copper KTW was NOT an armor piercing bullet.
Then again the super early variants and incredibly rare to find KTW armor piercing rounds were hard steel, sharp pointed, Teflon coated and fast and who knows what they could do.
The KTW and other special rounds were never available to civilians. They were intended for law enforcement and counter terrorist units to use against armored up bad guys. Never was anyone shot with a so-called “cop killer bullet” from the hands of a bad guy (a few bad guys with body armor on were shot by KTW using cops though). As with so many other things the anti-Second Amendment media and its proponents simply positioned and repeated the lie as a cop killer and It worked. These rare rounds are also highly collectable and much sought after nowadays.
Anyway, back to the discussion. So we have a squeezing/reforming problem if the solid bullet is hard metal; loaded warm or both.
Glocks also have what is called a floating chamber. This is simply a cartridge chamber that holds the loaded cartridge where the bottom portion of the chamber is NOT fully supported or in this case enclosed completely around the cartridge near the base or rim. The effect is that the round is less supported or surrounded on the bottom side of the Glock chamber where the feeding ramp helps to feed/slide the round into the chamber. Early Glocks exposed more of the cartridge case than their newer guns.
Over the years thanks to gun destruction this area of potential exposure has been reduced (not yet eliminated) by Glock. So couple this with the use of lead or hard alloy bullets and you get more resistance to the fired bullet trying to form in the poly-barrel and with that higher pressure and the cartridge case exposure near the base of the round the cartridge case will burst first (it’s the weakest link in the chain) and that kaboom can “disassemble” the gun violently. Apparently this is not a problem with other handguns that more fully encapsulate the cartridge case and also have conventional rifling.
The problem is that Glocks ALSO do not like reloaded ammunition due to this floating chamber design feature. Any cartridge case that has been fired and reloaded will/may have “minor and generally very minute” changes to the cartridge case–almost always. These super minor changes in the cartridge case (in most cases) are mostly corrected by the correct reforming process use to resize the cartridge case for reloading and this generally will not affect other pistols. Should the reloaded case be slightly stretched, expanded, weakened, reformed or whatever in the critical area where the Glock chamber does NOT fully support and surround it–that will/could be the bursting point even if the reloader or reloading company does everything correctly. For this reason, Glock recommends against reloaded ammunition in their guns.
Ammunition makers are constantly trying to improve their ammunition through better and more efficient bullet design. Back in the 1970s a guy by the name of Lee Jurris came up with a line of (ORIGINAL boxes and individual rounds are now highly collectable) ammunition called Super Vel. This stuff was 100-250 feet per second hotter than any handgun ammunition at the time and it was loaded with sometimes lighter hollow point bullets (oh my, how cruel).
The popularity of this premium and limited ammunition (they are now back in business by the way) prompted the big ammunition makers to begin to reevaluate handgun ammo. leading up to some pretty hot stuff. You can thank Jurris for the advancements he forced the market to respond to in the premium ammunition we have seen in the last 40 years. Nowadays this original Super Vel ammo would be called +P or ++P, a designation which did not exist prior to Super Vel teaching the ammunition companies a real lesson in performance and marketing.
Then comes Glock with its floating unsupported chamber and poly. barrel that helped retain or even add to FPS velocity over rifled barrels. This was seen as smart marketing at that time as domestic makers were hiring inbred marketers from other gun companies to do their marketing–still continues today, all gun companies just fire and switch each others marketing guys around.
Glock positioned itself differently, hired executives from the FBI and outside the inbred U.S. gun community to run their U. S. operation (Glock was actually an Austrian toy making company). They applied new ideas and convinced law enforcement and the Feds. to reconsider the unconventional and pretty ugly Glock for their use. It all worked the the result is its huge consumer popularity and near 60 percent of the law enforcement sales in the U.S. flat out sells more guns.
The secret to selling self defense guns in the U.S. is and was to get them adopted by federal or domestic law enforcement. Huge discounts and “more” may be offered to departments and agencies to get them to buy guns because the civilian market will follow those sales; it is a proven concept in the marketing of guns to the consumer market.
So now the market is very Glock heavy and ammunition makers will (they have to) tailor their production/consumer ammunition for 99.999 percent consumer use to the most popular gun and (if) it is considered weak in some areas then they must and will comply with that situation and will make ammo that will work in that most popular and weakest gun (lawsuits).
The companies are basically forced into making ammo. (bullets and velocities) for the weakest firearm brand and model–especially if it is the most popular gun to begin with.
BOTTOM LINE AND WARNINGS:
So if you are a Glock user (it is a decent gun by the way) you are best off using ONLY factory brand new never fired (not reloaded) ammunition. You should check to see if your barrel is actually rifled with lands and grooves or is a poly or form of poly barrel (they have different configurations). It would not hurt to check the generation regarding the floating chamber situation. And you should probably avoid so-called +P or so-called +P+ types of ammunition. You should never use solid copper or solid alloy bullet or solid lead loaded ammunition unless this ammunition is OFFICIALLY determined by Glock to be safe for use your model, your gun’s generation and your Glock’s caliber. Check with the factory–they will tell you.