Glock locking block question

When do you know a locking block has to be replaced?

My brother got a good deal on a Gen 4 G17 and asked me to check it out. Minor finish wear on the slide near the muzzle. Offhand, the slide stop needs to be replaced. Am leaning towards getting all springs and spring cups replaced too.

The reason why I asked about the locking block is that both the locking block pin and the trigger pin didn’t require much effort to push out. Trigger feels nice so I assumed the gun was shot a fair bit. My brother says the seller claims that the gun has seen about 20k rounds give or take, and that the recoil springs were replaced twice.

Are there other bits that need to be refreshed at this round count?

Quote:

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Originally Posted by CarloMNL

When do you know a locking block has to be replaced?

My brother got a good deal on a Gen 4 G17 and asked me to check it out. Minor finish wear on the slide near the muzzle. Offhand, the slide stop needs to be replaced. Am leaning towards getting all springs and spring cups replaced too.

The reason why I asked about the locking block is that both the locking block pin and the trigger pin didn’t require much effort to push out. Trigger feels nice so I assumed the gun was shot a fair bit. My brother says the seller claims that the gun has seen about 20k rounds give or take, and that the recoil springs were replaced twice.

Are there other bits that need to be refreshed at this round count?

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I am not a certified armorer, but I would probably replace the trigger spring if it's seen ~20k.

ETA: unless the locking block is quite worn, cracked or damaged or the gun has accuracy issues... I would not replace it.

Unless it cracks or breaks I consider locking block to be good for the life of the gun. The locking block and trigger pins need to be checked periodically for sure. They get easier to move over time, and the more times the gun is detail stripped, but that does not imply replacement. I would replace the recoil spring assembly just because (they are cheap and you don't know how many rounds are on it). Replacing the trigger return spring, same reason. That is all if it were me. (multiple graduate of factory armorer and also the factory advanced armorer classes).

Striker spring and new spring cups are never a bad idea either. Check the safety plunger and make sure you cannot push the striker past it. That is another part that wears in gen1-4.

So essentially, if it isn't broken, function should still be ok. Does the locking block impact accuracy in any way? I don't think it will matter much since my brother rarely gets to shoot but the geek in me is curious to find out.

Quote:

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Originally Posted by CarloMNL

When do you know a locking block has to be replaced?

My brother got a good deal on a Gen 4 G17 and asked me to check it out. Minor finish wear on the slide near the muzzle. Offhand, the slide stop needs to be replaced. Am leaning towards getting all springs and spring cups replaced too.

The reason why I asked about the locking block is that both the locking block pin and the trigger pin didn’t require much effort to push out. Trigger feels nice so I assumed the gun was shot a fair bit. My brother says the seller claims that the gun has seen about 20k rounds give or take, and that the recoil springs were replaced twice.

Are there other bits that need to be refreshed at this round count?

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Replace locking blocks when cracked, broken, or chipped - necessity is rare.

A G17 with 20k of unknown origin/unvetted owner would be fine as a shooter, replace the RSA. For EDC or life support I'd replace internals just for confidence. But, likely not necessary if parts are okay and previous owner didn't "improve" the gun.

20k is a high round count for many, but still isn't much for a G17.

Quote:

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Originally Posted by CarloMNL

Does the locking block impact accuracy in any way?

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Yes it can, but the wear is probably insignificant. Accurizing the Glock seems to usually be changing out the barrel, getting a tighter fit in the hood (e.g. Barstow) which can also negatively impact reliability if it is not fitted completely. There is also twist rate, crown, etc. in play. For whatever design change reasons, I get tighter groups at distance with the factory gen 5 barrels than any previous generations.

At a regional match where I was RO'ing some time ago, I was told by a member of the old/past crews of Glock sponsored shooters that they changed out their guns around 35K-40K rounds, and that there was just something related to accuracy that started to deteriorate at that point, at a level that made a difference to them. Frame rails, barrel fit, etc. that caused accuracy to fall off a little past that point with any particular gun. The person who told me that said the team changed out their guns at least once a year, 30-40K being very close to a yearly average for the professional shooters then.