When in bear country it is recommended that in a 10mm a 200 or 220gr solid bullet is used for deep penetration. Now I hear that a solid lead bullet should not be used in a Glock barrel. Any insight for me? Could always back off to the 180gr if need.

“Solid” bullet—made of what? Are you referring to a lead bullet with no copper or gilding metal jacket?

My understanding is its ok once in a while if you clean after shooting lead in a glock w polygonal rifling. If you get an aftermarket barrel with standard rifling you are fine.

Thanks for the cleaning advice.

Until just this morning I never looked into the question of why unjacketed bullets should not be shot in Glocks with barrels having so-called “polygonal” rifling. In doing so, however, the consensus seems to be that the barrels are subject to accumulating excessive lead deposits (“leading”) from bullets without a harder metal jacket. On the other hand, the reason(s) is/are debated. I always assumed it was because the lack of sharp, distinct lands and grooves allowed soft bullets to “skid” as they traveled down the bore rather than being firmly engaged by the rifling. (The SIG pistol barrels I’m familiar with have conventional rifling, but it’s notably shallower than some other manufacturers’, and that may be the reason that SIGs don’t have a good reputation for unjacketed bullet accuracy.)

If heavy leading builds up in a barrel it can be very difficult to remove and that can be one reason to avoid it. More significant, however, is that enough leading can act as an obstruction, and that can lead to excessive chamber pressures. Excessive pressures are bad enough, but with unsupported chambers, case ruptures are even more likely and that is dangerous to gun and shooter.

The other supposed reasons I found for the leading problem in Glocks with polygonal rifled barrels are undersized bores and/or rough bore surfaces. Regardless of the claimed reason(s) and regardless of how valid they are, though, there are a few things to consider.

Harder lead bullets are less prone to causing barrel leading than soft bullets. I have heat treated cast bullets to the point that they were extremely hard, but a pure lead, untreated bullet will leave a deposit if rubbed across a piece of paper. That’s why pencils are said to have lead in them: At one time they did, but now it’s graphite.

Second, leading is a progressive process. Firing a few rounds is unlikely to cause enough leading to be a hazard. It can also be reduced or slowed by using harder bullets that are sometimes available as handloading components or in loaded ammunition. Keep in mind, and as I mention above, however, that once leading accumulates, it can be very difficult to remove completely. Even if a little is safe, it can still be a nuisance to deal with.

If I were relying on a Glock for protection against a large animal, I wouldn’t hesitate to use unjacketed bullets. I would be careful to remove all leading after firing however many practice shots were advisable and not worry about the effects of a few more in a defensive situation. But I’m not advising that for anyone else because it’s not my gun, eyes, or fingers that are involved.
(I also wouldn’t be relying on a 10mm autoloader; in my case it would be an S&W model 29 loaded with really hard and heavy bullets, but that’s also a hypothetical at this stage of my life.)

There are those who choose to put aftermarket rifled barrels in Glocks for lead, and there's a persistent myth that lead causes glock "kabooms."

I've shot a lot of lead out of Glocks. Despite the rumor that if you shoot lead and then copper, you'll incur some kind of earth-ending explosion, everyone who passes on this counsel has never seen it happen and has heard it from someone else...and those who claim it happned to them offer little more than guesswork as to the cause.

Shooting soft lead, especially improperly sized lead, can incur cutting action where expanding hot gasses blow past the bullet in the barrel, and can cause leading as the lead is further softened, leaving deposits. Proper hard cast lead, properly sized for the specific barrel in question, is not a problem, regardless of whether it's polyagonal or rifled.

I used to shoot nothing but cast lead in just about everything. No problem. If I'm shooting unjacketed bullets, I usually use coated bullets now; polymer coatings that bond to the lead and leave the barrel virtually deposit-free even after thousands of rounds.

Bear in mind that a given barrel may have several sizes of bullet fired through it. The correct size should be determined by "slugging" the barrel. This is useful if you're loading your own ammunition. If you're buying off the shelf, then you're restricted to what's offered commercially.

I wouldn't hesitate to run an autoloader against dangerous game today; we carry them against the most dangerous of opponents on the planet (two legs). Carrying them for bear or another threat makes sense. Especially given the higher capacities, speed of reload, etc. Conversely, how many people do speed reloads on a charging bear?

Hot powders, insufficient loads, improper bullet alloy and hardness, and undersize bullets (for the specific barrel) can lead to gas cutting and additional leading of a barrel.

quote:

Despite the rumor that if you shoot lead and then copper, you'll incur some kind of earth-ending explosion