I have had a 43X with a RMSc Shield, direct milled by Primary Machine, for coming up on two years. Other than changing the battery on the RMSc a few times, I don’t recall a single issue with the pistol. I have always carried it with 115 Gold Dot, and used OEM ten round magazines. There have been various threads suggesting that slimline Glock pistols have reliability issues, or are on the edge of having reliability issues, especially with an optic. Since I haven’t kept detailed notes on my original 43X/RMSc, I decided to take an almost new 43X MOS with a Swamp Fox optic, and test it for 2,000 rounds or when I lose interest in the project. Prior to today, I shot 50 rounds through this 43X MOS, doing a rough zero on the optic, and experienced no issues. It has had no lube or other changes, from “as it arrived from the factory condition,” besides installing the optic.
The first thing I did today was shoot ten rounds of PMC 115 ball, which is about 125 power factor in this short of a barrel, support hand only, barely gripping the pistol. No issues. I next asked my wife to repeat the same, and she experienced no issues. Interestingly, she would not have expected her Glock 34 to function with that light of ammo and that sort of grip. Here she is doing the support hand test.
Next, I shot five shots at a one inch square from seven yards. Yarded on the trigger on the first shot, and then gripped harder.
Then I shot a quick group at 25 yards, offhand using the PMC 115.
Then I shot some doubles at seven yards to a skunk target.
Today’s round count was 80 rounds, making a total of 130 rounds, and no issues so far.