Certainly not a Glock Guru; but will offer a couple experiences with Glocks and reloads. I, too, was hesitant to shoot reloads; especially, lead cast bullets through my Glocks. I have read on other gunboards of how dangerous it could be. Well, I have this problem owning several Glock pistols that will not shoot cast bullets - economy is the name of the game to me.
After a lot of reading, I learned - from more than one source - that the factory barrels used in Glocks (Polygonal rifling) were not designed to shoot cast bullets and they were prone to barrel leading and/or accumulating lead residue in the barrel. I posed this question on another forum awhile back. Here are a couple good threads on the subject -- http://castboolits.gunloads.com/showthread.php?t=33855&highlight=glock
Since there was no real consensus on the subject, and after reading many post like the one sigman
offered above, I did not feel it worth it to take a chance. I ordered three Lone Wolf barrels from Dillon -- a 9mm conversion barrel for the Glock 22, a 40S&W replacement barrel for the Glock 22, and a replacement barrel for the Glock 21. Problem solved - now I can shoot cast bullets through my Glocks without worry -- SO I THOUGHT!!
Off to the reloading bench to load up some for use in the Glocks. I have loaded thousands of 9mm, 40S&W and 45acp for use in my Beretta, Smiths, Colts, and Springfield without problem. I did nothing different as I have always done!! After loading about 50 of each, I headed to the range. To my dismay about 10% of the 9mm, 5% of the 45acp, and 60% of the 40S&W would not fully chamber in the Lone Wolf barrels. The weapons would not go into full battery - a dangerous situation; especially if the weapon would fire -- I have read that the Glock will fire out-of-battery if it is close enough. I scratched my head, loaded up my stuff, and headed back home …
In working out this problem, decided to use the 40S&W since I had the most trouble with it and felt that if I could find the problem with it, the others would follow. Since I was using the exact same set of sizing dies as I have always used, I did not think that was the problem -- maybe the Lone Wolf barrel had an extremely tight chamber and the cast bullets were sized too large for the Lone Wolf barrel. The bullets were sized at .401. I slugged the bore -- no problem there. Maybe the bullet is seated too long for the Lone Wolf barrel -- loaded a few more at a shorter length and went back to the range (I consider myself lucky in that the Magnolia Rifle/Pistol range is 3 miles from my driveway). Problem solved? -- NO!! Still had the same problem and another more serious problem developed. Looking at the rounds that did fire, the primers were punctured from the blowback pressure. Want do that again!! Be careful not to short seat 40S&W bullets!!
Well, I have all these gages sitting on my reloading bench - why not use them? I took several of the rounds that would not fully chamber and placed them in my case gage -- they would not fully seat into the case gage. I could not understand what was causing this … since I have not had any problems in my Beretta and Smith 40S&W. I posed the question on several other gun boards and the answers that came back were all the same -- I HAD GLOCKED BRASS!! The factory Glock barrels are not fully supported in the chamber area - also the 40S&W is somewhat a high pressure load. When ammo is fired through a factory, unsupported Glock barrel, the brass is overly expanded at its base. Here are a couple of pictures of the situation:
Brass that fully seats into the case gage after sizing:
GLOCKED Brass - After sizing will not fully seat into the case gage:
Back to the reloading bench -- did some adjustments on my sizing die, and cranked out a few more. After the adjustment, I was able to use most all of the GLOCKED brass. However, I still run into some of the 40S&W that I can not get down to size for use in the Lone Wolf barrel. Additionally, this has added another step in my reloading process. In order to avoid FTFeed issues with aftermarket barrel, I must check each sized case with the case gage -or - barrel in order to cull those that will not fully fit. However, this seems to have cured my problem -- couple hundred rounds with no FTFire and no FTFeeds in all three calibers.
As a side note, I will add that the use of a good tamper crimp also helped ….