Last year, my three primary practice and competition guns experienced problems with light strikes. To make a very long and boring story short, coincidentally (or fortuitously) between December 2017 and January 2018, a 617 22 commenced a pattern of light strikes that became progressively worse, a GP100 in 38 Special experienced a similar pattern but with my handloads using Winchester primers, and lastly, a Glock 19.4 also started doing so with Winchester primers.
The 617 was returned to S&W four times before it was fixed. It appeared the cylinder gap was reduced and cylinder play (end shake?) was greatly reduced and tightened up. No problems after the final repair. This firearm had about 15,000 or 17,000 rounds (my recollection without finding and checking the log) before it became a problem. Throughout its life there may have been a handful of failures to ignite but it is a 22 and 22 ammo can sometimes be finicky in my experience.
The GP100 had close to 7500 rounds and no prior light strikes. One trip to the factory, and it came back with a very tight cylinder (again, end shake) and was very sensitive to primers not fully seated initially (i.e., cylinder very tight and could bind). No further light strike problems. The gun is probably better than it was new--at least in terms of shootability. I don't believe there had ever been a light strike previously.
The G19 had 7000 rounds when it started acting up. In addition to my hand loads, there were a couple of Winchester White Box light strikes. The recoil spring was changed at 5000 rounds. Upon recommendation from a Glock armorer after the light strikes became more common, the striker plunger tube was cleaned several times and a new striker spring installed. It was OK for about 1000 rounds and then started light striking again at an increasing rating. The striker plunger tube was thoroughly cleaned again but didn't change the increasing rate of light strikes. I finally returned it under warranty for a new gun. I later checked the shooting log and noted there were about two light strikes per 1000 rounds prior to the increasing light strike problems at 7000 rounds.
The new G19.4 worked perfectly until two days ago. At round 400 there was a light strike on a hand load. There was nothing obvious that showed the primer was too high or low or any other problem.
Using hand loads should I expect there will be an occasional light strike with centerfire ammo? Am I expecting too much with the Glock? Many of you reload and shoot far more in one year than I do and would appreciate your perspective. Thanks.