Glock 19 Gen 4 Hitting Left of POA (and it's not me!)

[einherjarvalk]

My Glock 19 Gen 4 MOS shoots left. It has always shot left. I want to stop it from shooting left.

Yes, part of this has been shooter-related; I've kept targets that I shot at 15 yards since I first bought this Glock and got serious about handgun shooting in late 2016, and the groupings have steadily creeped back towards center over the last two years, and gotten tighter as well thanks to the addition of an RMR and Blacklist threaded barrel. However, it has never quite gotten to center; one of my best groupings with it has had the center of the group about an inch to the left at 15 yards. My current setup features polished OEM fire control parts aside from an Overwatch Precision TAC trigger.

I took a hiatus from shooting this gun to focus on irons for a few months. Since then I've put a couple thousand rounds through a pair of P30Ls, a USP Tactical, an M&P Shield, and, most recently, a Glock 19 Gen 5. The Gen 5 shot just as well as the P30Ls and USP for me with all stock internals.

Success with the Gen 5 convinced me that my issues with shooting Glocks were now over, so I took the Gen 4 MOS out today just for fun. It still shot left at 25 yards, but not only was it shooting left, it was shooting left with remarkable consistency. 10 shots effectively produced a vertical string of holes about 3.5" left of my POA. I rested the gun on my shooting bag and shot another 5 round group, which removed the vertical variation but still landed 3.5" left of POA. I then cranked the windage adjustment about 13 MOA right and I was back on again for the rest of my shooting session.

My question is this - given that I shot left consistently with both freestyle and rested shooting, is it more likely that my RMR was off and I just didn't notice since it was zeroed initially at 15 yards, or is there perhaps something I haven't taken into consideration in play with my gun's accuracy? A friend suggested that I may need to try a new locking block since some factory locking blocks have produced guns that consistently hit left of POA, but I'm not sure how common that is or if it's worth doing. I don't really know if there's anything else I can do to isolate the cause of the left pull, but I'm open to suggestions.

Additionally, the Gen 5 striker safety's ramped design is spoiling me - would a light striker safety spring in the Gen 4 striker safety help lighten the "wall" and bring it more in line with the feel of the Gen 5 without creating a slight "roll" before the break like the minus connector does?

[HopetonBrown]

Give us an idea of your shooting background; your current classification and who taught you how to shoot.

[okie john]

Also post pics of current targets.


Okie John

[GJM]

It will be hard to unwind this with the information provided. As for classification, being a GM doesn’t mean you are a Glock shooter.

When you say that your pistol shoots to the left, I am confused about the RMR part since there is no left and right, unlike a rear sight position in the dovetail. Do you have access to another G4 19, and if so, what happens with it?

[HCM]

Despite all the user induced issues among right handers, some guns just shoot left (or right).

Assuming you have tried the usual diagnostics like shooting it left handed and having another known competent shooter shoot the gun ?

You tried swapping the barrel how about the locking block ? If that doesn’t help I guess you either adjust the sights and live with it or dump the gun and get a gen 5 MOS.

[einherjarvalk]

Give us an idea of your shooting background; your current classification and who taught you how to shoot.

As mentioned, been shooting handguns seriously for two years now, but I don't have a current IPSC/USPSA classification. I was largely self-taught, then instructed by an ex-police officer, and most recently did a couple of workshops and Defensive Pistol 1 with Jeff Gonzalez (which I passed, but shot a P30L V1 in). Part of the reason I don't think it's me causing POI to hit left of POA is that during the initial workshops I did with Jeff, my shooting at 25 yards usually had me pulling high and right, and at the time I had just switched over to the P30L V1 from the G19.4 MOS. I can't help but wonder if I've been unintentionally overcompensating for a zeroing error or mechanical issue on the Glock and just never had an opportunity to see it manifest prior to that.

When you say that your pistol shoots to the left, I am confused about the RMR part since there is no left and right, unlike a rear sight position in the dovetail. Do you have access to another G4 19, and if so, what happens with it?

My thinking is that either there's an actual issues with my Glock's lockup or my RMR was just never actually zeroed correctly since I zeroed it for 15 yards initially. My older 15 yard targets tend to cluster just a bit left as well, but I had always assumed that was my fault and not the gun/optic. I don't have another Gen 4 19, but shooting my friend's Gen 3 19s/26 and Gen 4 17 usually produce good results.

Despite all the user induced issues among right handers, some guns just shoot left (or right).

Assuming you have tried the usual diagnostics like shooting it left handed and having another known competent shooter shoot the gun ?

You tried swapping the barrel how about the locking block ? If that doesn’t help I guess you either adjust the sights and live with it or dump the gun and get a gen 5 MOS.

The aforementioned friend who owns the other Glocks I have access to and suggested a locking block swap also shot my 19 and had POI left of POA at 15 yards. He seemed to think that it was the flat-faced trigger I had, but I'm not so sure it could produce such consistency hitting left, especially given that it continues to do that even while shot off a bench rest or when supported by my range bag. He's a better shot than I am for sure, too.

For context, here's the two groups I shot earlier at 25 yards before adjusting the RMR's windage. The first group was shot freestyle with 10 rounds (including one called flyer to the left), the second was a 5 round group shot using my range bag as an ad-hoc rest. POA was the center of the circle within the silhouette's head. Ammunition was S&B 115gr FMJ.

[HCM]

As mentioned, been shooting handguns seriously for two years now, but I don't have a current IPSC/USPSA classification. I was largely self-taught, then instructed by an ex-police officer, and most recently did a couple of workshops and Defensive Pistol 1 with Jeff Gonzalez (which I passed, but shot a P30L V1 in). Part of the reason I don't think it's me causing POI to hit left of POA is that during the initial workshops I did with Jeff, my shooting at 25 yards usually had me pulling high and right, and at the time I had just switched over to the P30L V1 from the G19.4 MOS. I can't help but wonder if I've been unintentionally overcompensating for a zeroing error or mechanical issue on the Glock and just never had an opportunity to see it manifest prior to that.



My thinking is that either there's an actual issues with my Glock's lockup or my RMR was just never actually zeroed correctly since I zeroed it for 15 yards initially. My older 15 yard targets tend to cluster just a bit left as well, but I had always assumed that was my fault and not the gun/optic. I don't have another Gen 4 19, but shooting my friend's Gen 3 19s/26 and Gen 4 17 usually produce good results.



The aforementioned friend who owns the other Glocks I have access to and suggested a locking block swap also shot my 19 and had POI left of POA at 15 yards. He seemed to think that it was the flat-faced trigger I had, but I'm not so sure it could produce such consistency hitting left, especially given that it continues to do that even while shot off a bench rest or when supported by my range bag. He's a better shot than I am for sure, too.

For context, here's the two groups I shot earlier at 25 yards before adjusting the RMR's windage. The first group was shot freestyle with 10 rounds (including one called flyer to the left), the second was a 5 round group shot using my range bag as an ad-hoc rest. POA was the center of the circle within the silhouette's head. Ammunition was S&B 115gr FMJ.

The RMR is an adjustable sight and doesn’t really lend itself to seeing if the dot is “centered” the way iron sights are.

Generally you want to do initial dot zero at 10 yards and confirm at 25.

To see if it is the gun, you want to shoot it with Irons centered and no RMR mounted.

There can be POI shift with irons with vs without the RMR.

[einherjarvalk]

That may play into it a bit - the irons were mounted *after* the RMR was, and were "centered" to the RMR dot once I zeroed it previously.

I'm trying to avoid removing and remounting the RMR unless absolutely necessary as it usually turns into a big fiasco with threadlockers and screws stripping out one way or another. Is there any other way to check and see if it may be a mechanical issue other than to just buy another Gen 4 locking block and seeing if there's a dramatic change in POI

[HopetonBrown]

As for classification, being a GM doesn’t mean you are a Glock shooter.

It does mean the chance of their sights simply being off is greater than a self taught dirt clod shooter.

[HCM]

That may play into it a bit - the irons were mounted *after* the RMR was, and were "centered" to the RMR dot once I zeroed it previously.

I'm trying to avoid removing and remounting the RMR unless absolutely necessary as it usually turns into a big fiasco with threadlockers and screws stripping out one way or another. Is there any other way to check and see if it may be a mechanical issue other than to just buy another Gen 4 locking block and seeing if there's a dramatic change in POI

If the RMR is your primary sighting system I would just adjust it and drive on. That is one of the beauties of the RMR.

If it is still bugging you try a locking block since they are cheap and easy to swap.

If the irons are BUIS to the RMR zero them with the RMR in place but off. Forget about correlating them with the dot.