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by Dave Street
A broken "locking block pin" with part of it missing from the frame of an officer's Glock 22.
A Full Service Armorer for SIG-Sauer, GLOCK, S&W M&P-Bodyguard-Shield-Sigma, Springfield XD & 1911, Beretta 92-96,Remington 870-1100-1187, Sig P320, Kimber 1911's, S&W Revolvers, Colt 1911's, Rock Island 1911's, AR-15, Ruger 10/22, Mini-14, Mini-30 Rifle, Ruger LCP / LC9 / SR Series, Benelli M-Series Shotguns and many more.
Years ago, I was shooting my Sig Sauer P220 pistol in an IPSC match. The “trigger spring” broke and suddenly my gun was completely inoperable. I was devastated. What if this happened when I really needed it? I expressed this fear to my department armorer and he suggested I replace the gun’s springs every couple of years so this didn’t happen again. He added that Sig Sauer offers a spring kit for this reason and it would make the gun more reliable. I did so and felt a lot better about carrying my Sig.
In 2004 while attending the GLOCK armorer school, I asked if GLOCK offered a spring kit for ongoing maintenance. The instructor said no and not to worry, when the gun breaks, just fix it. In 2008 while attending the GLOCK recertification course, that advice changed. That instructor said that the “recoil spring assembly” should be changed every 3,000 rounds to prevent damage to the gun and assure reliability. He also recommended an armorer inspect / clean the gun, and its magazines, once a year as part of a maintenance program. In 2009, GLOCK revised its recommendation announcing that for .40 caliber Glocks, the “recoil spring assembly” should be changed every 2,500 rounds and for 9mm & .45 caliber Glocks, it be changed every 3,000 rounds.
While many departments maintain weapons for their officers, others do not. I have personally serviced many law enforcement guns and found some that were on the verge of failure. Case in point, I received the above GLOCK-22 from an officer who told me he’d bought it new and had fired about 6,000 rounds over the past 6 years. When I broke it down, I found it had a broken “locking block pin” with half of the pin missing. The gun still functioned, but for how long?
Typically, this type of damage is caused by a weak “recoil spring assembly” for the following reason. When a GLOCK is fired, the slide recoils back ejecting the expended round and inserting a new one into the firing chamber. It’s the job of the “recoil spring” to slow the slide as it recoils back so it doesn’t impact with the frame at full force. The “recoil spring” then accelerates the slide forward causing it to reload the gun and lock it in for firing.
When this spring weakens, it starts allowing the slide to hammer the frame harder and harder. Eventually this repeated impact starts breaking internal parts such as the pins, the locking block and even portions of the frame itself. Below is the picture of another GLOCK-22 with a broken “locking block” and the bent pin that was holding it in. Surprisingly, the gun still fired in this condition, but again for how long?
Locking blocks and pins are easily changed out, but a cracked or distorted frame is a different matter. As the slide functions back, the steel nose of the slide impacts with the polymer frame just to the rear of the dust cover. A weakened “recoil spring” will increase the strength of this impact to the point where the polymer frame will distort inward into the “U” shape channel where the “recoil spring assembly” functions. As this channel folds inward, it starts to interfere with the “recoil spring assembly” resulting in weaker lockup and sometimes “failure to feed” malfunctions. Below are three pictures showing this relationship. The photo of the frame and slide shows where the slide will impact with the frame during recoil. The second shows a normal undamaged frame. The third shows the damage caused by firing over 12,000 rounds on a weakened “recoil spring assembly”. To say the reliability of this third gun was compromised is an understatement.
The key to preventing this type of damage is to change out the “recoil spring assembly” pictured below. Note that you don’t need an armorer to change it out, it’s just a matter of field stripping your weapon and installing the new part yourself. The “recoil spring assembly” is inexpensive and easily obtained through a gun store or Internet gun parts business.
The bottom line is that if the gun had been properly maintained, this type of damage wouldn’t have occurred in the first place, so don’t allow your GLOCK to wear out before its time. Start an annual maintenance program making sure that the “recoil spring assembly” is changed every 2,500 to 3,000 rounds depending on caliber. It’s also important to periodically have a GLOCK armorer completely disassemble your weapon, clean it and inspect it for broken or worn parts. This will keep the weapon functioning reliably so you can have maximum confidence in it during those times of need. Finally, it’s been estimated that the majority of all malfunctions in semi-auto pistols are caused by their magazines or ammo. It's often a matter of a weak spring or damaged feed lips. Make sure your magazines are included in your maintenance program and shoot good quality ammo. GLOCK handguns are phenomenal firearms built to last for years. An annual maintenance program will result in a reliable gun and a lifetime of service with these fine weapons.