Will an optic cut make my Glock less reliable?

[Snidely Whiplash]

I searched and couldn’t find a similar topic ; not sure if my search skills are weak or if it’s a non-issue.

As I explained in another post, I recently purchased an MOS Glock and, assuming the red dot experiment works, I’ll be thinking hard about adding red dots to my current Glocks. I was exploring the slide optic cut option and one reputable service listed a disclaimer indicating that they test and fully stand behind their optic cut etc. but that “any modification has the potential to affect reliability”.

Is this a real concern? I wouldn’t want to chance making one of my Glocks less reliable, they have had zero malfunctions after a couple of thousand rounds each. Maybe this is just legalese and I’m worrying over nothing?

[LockedBreech]

I searched and couldn’t find a similar topic ; not sure if my search skills are weak or if it’s a non-issue.

As I explained in another post, I recently purchased an MOS Glock and, assuming the red dot experiment works, I’ll be thinking hard about adding red dots to my current Glocks. I was exploring the slide optic cut option and one reputable service listed a disclaimer indicating that they test and fully stand behind their optic cut etc. but that “any modification has the potential to affect reliability”.

Is this a real concern? I wouldn’t want to chance making one of my Glocks less reliable, they have had zero malfunctions after a couple of thousand rounds each. Maybe this is just legalese and I’m worrying over nothing?

As a lawyer I have some casual familiarity with CYA language. That's what that seems like. They don't want some dude getting an optics cut and then getting mad because his gun won't eat garbage steel case perfectly.

I'm sure there are ways to screw up a slide with a milling, but that's the likely reason for the disclaimer.

Edit: Based on the posts below, it really can impact reliability. Shows what I know!

[GJM]

Probably won't effect reliability. However, folks on PF have had cases where reliability changed post an optic installation. Sometimes a screw is too long and touches the extractor bearing rod/spring, sometimes it might be a heavy optic, sometimes it might be for a reason unknown. Small probability, though, and that is why we test function while zeroing the optic.

[JCN]

I searched and couldn’t find a similar topic ; not sure if my search skills are weak or if it’s a non-issue.

As I explained in another post, I recently purchased an MOS Glock and, assuming the red dot experiment works, I’ll be thinking hard about adding red dots to my current Glocks. I was exploring the slide optic cut option and one reputable service listed a disclaimer indicating that they test and fully stand behind their optic cut etc. but that “any modification has the potential to affect reliability”.

Is this a real concern? I wouldn’t want to chance making one of my Glocks less reliable, they have had zero malfunctions after a couple of thousand rounds each. Maybe this is just legalese and I’m worrying over nothing?

Yes it is.

If you use a stock (stiff) RSA, add a huge mailbox optic on top, then shoot weak target ammo you might get a stovepipe unless you decrease the strength of the recoil spring.

It’s all just physics. Not a big deal.

[Clusterfrack]

I searched and couldn’t find a similar topic ; not sure if my search skills are weak or if it’s a non-issue.

As I explained in another post, I recently purchased an MOS Glock and, assuming the red dot experiment works, I’ll be thinking hard about adding red dots to my current Glocks. I was exploring the slide optic cut option and one reputable service listed a disclaimer indicating that they test and fully stand behind their optic cut etc. but that “any modification has the potential to affect reliability”.

Is this a real concern? I wouldn’t want to chance making one of my Glocks less reliable, they have had zero malfunctions after a couple of thousand rounds each. Maybe this is just legalese and I’m worrying over nothing?

I think this is a legitimate concern, although as @LockedBreech said the warning is likely just legal ass covering.

I have not observed reliability issues with full-size Glocks milled for optics. My P-07 milled for the Holosun 509t2 has been as boringly reliable as normal. Ejection is still in a neat pile of cases, and limp-wristing doesn't cause malfunctions. I would do significant tests on any gun that's to be used for life safety purposes.

[WobblyPossum]

@RJ had a G48 that was reliable until he had it milled for an optic and then it began having problems. It’s a realistic concern because you’re changing the weight of the slide by removing metal and then adding weight that may or may not be about the weight of the metal you removed. It’s less of a concern on the double stack Glocks than the slimline ones since the slimline guns are often already operating on the ragged edge of reliability with their tiny little recoil springs.

[mizer67]

I comp'ed a G19 recently. It was reliable with the comp. and no red dot. Unreliable with both.

Ejection is marginal with just the comp. alone, so it was riding the edge of reliability (with a 15 lb. spring). Likely solvable with a 13 lb. spring.

[Utm]

I have 6 slides that have been milled and I have not experienced any reliability issues but that's sample size of 1

[757_Magnum]

I have three G19s, one G45, and one G26. All are gen 5 with stock RSA wearing RMRs, milled by Jagerwerks and Maple Leaf Firearms. Two of the G19s have carry comps, and all have more than 2000 flawless rounds through them. I mainly run my own full power 147 gr reloads, but the comped G19s have also gone through a couple hundred rounds of aluminum cased 115s I was given.

[RJ]

@RJ had a G48 that was reliable until he had it milled for an optic and then it began having problems. It’s a realistic concern because you’re changing the weight of the slide by removing metal and then adding weight that may or may not be about the weight of the metal you removed. It’s less of a concern on the double stack Glocks than the slimline ones since the slimline guns are often already operating on the ragged edge of reliability with their tiny little recoil springs.

Correct. The post and related discussion starts here:

https://pistol-forum.com/showthread....=1#post1218805

I subscribe to @HCM's theory there "is no free lunch" with the slimlines, and that Glock's choice of the G43 RSA for the G48 narrows the allowable timing window for some ammo. I had the slide milled, taking out the rear dovetail, so perhaps that was why it did not run well. I was bummed because I liked everything else about that gun. So I sold it.