SCD "Gadget" related malfunction

[Hunter Osborne]

Let me preface this by saying I am in no way being critical of the SCD or of Tau. I am a big fan of the SCD and will continue to use them on all the Glocks that I carry for serious purposes. I have already emailed Tau via their website informing them of the issue.

The gun is a Gen 4 G19 MOS. It has the following modifications: RM07, as well as a KKM comp and barrel, it also has a OP Poly DAT trigger. It was wearing an X300U at the time. Other than that the gun is completely stock. The gun has 8,650rds on it, all with the SCD installed.

Yesterday during a practice session, I had just shot the last round of the GWS when the gun felt weird. I took a look and found that it had failed to return to battery. I attempted to "bump" it back into battery, to no avail. I cleared the gun and "sling shotted" the slide, thinking maybe the RSA was hung up on the comp (which has never happened with my gun, but I've seen it happen with others.) When that failed, I attempted to depress the take down lever and pull the trigger to get the slide off the frame, which also didn't work. For some reason I looked at the rear of the slide and saw the issue. The SCD had slid down in it's raceway enough to contact the frame, preventing forward movement of the slide. This locked the gun up completely and would have been fight/stage ender had it occurred somewhere other than the practice range.

I can say in all honesty that I've never seen an end plate slide out of position like that, nor have I heard of that happening. In the heat of the moment, this would not have been something I would have thought to check.

I pushed the SCD back into the intended position and heard/felt the click of the end plate locking into place. I fired an additional 200rds or so after that and had zero issues.

The last cleaning for the gun was at 7,100rds. The slide was not disassembled at that time. I can't say definitively when the last time the slide was stripped down, but it has been at least several thousand rounds. I inspected the striker sleeve and found no visible defects.

This post is for informational purposes. At this point in time, I cannot say whether it is a gun issue, an SCD issue, or a freak confluence of events. I'm going to keep an eye on it and will update this post if any new information becomes available.

[YVK]

Talk to Tom, he'll help you troubleshoot it.

[Hunter Osborne]

Talk to Tom, he'll help you troubleshoot it.

Already emailed them.

[STI]

I'm sure Tom's on it, but I'd wonder if the extractor spring and/or "spring loaded bearing" plastic end piece are in good condition. Seems like those are what ends up keeping the backplate or Gadget from falling down.

[Tensaw]

I'm sure Tom's on it, but I'd wonder if the extractor spring and/or "spring loaded bearing" plastic end piece are in good condition. Seems like those are what ends up keeping the backplate or Gadget from falling down.

This, and I wonder if when the back plate was most recently installed, it was completely seated/clicked in. I know that in the past, I failed to get a factory piece fully locked in. And it felt like it was seated, but it was canted/cocked and just did not want to move any further due to that. It is subtle. I guess I would ask how many rounds since that piece was last installed.

[echo5charlie]

Let me preface this by saying I am in no way being critical of the SCD or of Tau. I am a big fan of the SCD and will continue to use them on all the Glocks that I carry for serious purposes. I have already emailed Tau via their website informing them of the issue.

The gun is a Gen 4 G19 MOS. It has the following modifications: RM07, as well as a KKM comp and barrel, it also has a OP Poly DAT trigger. It was wearing an X300U at the time. Other than that the gun is completely stock. The gun has 8,650rds on it, all with the SCD installed.

Yesterday during a practice session, I had just shot the last round of the GWS when the gun felt weird. I took a look and found that it had failed to return to battery. I attempted to "bump" it back into battery, to no avail. I cleared the gun and "sling shotted" the slide, thinking maybe the RSA was hung up on the comp (which has never happened with my gun, but I've seen it happen with others.) When that failed, I attempted to depress the take down lever and pull the trigger to get the slide off the frame, which also didn't work. For some reason I looked at the rear of the slide and saw the issue. The SCD had slid down in it's raceway enough to contact the frame, preventing forward movement of the slide. This locked the gun up completely and would have been fight/stage ender had it occurred somewhere other than the practice range.

I can say in all honesty that I've never seen an end plate slide out of position like that, nor have I heard of that happening. In the heat of the moment, this would not have been something I would have thought to check.

I pushed the SCD back into the intended position and heard/felt the click of the end plate locking into place. I fired an additional 200rds or so after that and had zero issues.

The last cleaning for the gun was at 7,100rds. The slide was not disassembled at that time. I can't say definitively when the last time the slide was stripped down, but it has been at least several thousand rounds. I inspected the striker sleeve and found no visible defects.

This post is for informational purposes. At this point in time, I cannot say whether it is a gun issue, an SCD issue, or a freak confluence of events. I'm going to keep an eye on it and will update this post if any new information becomes available.

Since the Firing Pin Spacer Sleeve is what retains the Slide Cover Plate (and thus SCD) I would look for abnormal wear at the rear contact surface. Another possible culprit is a worn or broken Firing Pin Spring. The Extractor Depressor Plunger likely has little part in the retention of the SCD just as it does for the OEM SCP. Eliminating parts breakage/wear the only other possibility I can think of is that your initial failure to return to battery may not have been SCD related but "bumping" the rear of the slide dislodged the SCD and created a new failure. I know that's a real long shot, but it is remotely possible.

Tom will have much better insight as to the possible cause and I'd love to know the outcome - it'll help me diagnose the problem quicker if I ever encounter it myself.

[powell556]

Is this really an SCD specific malfunction? It sounds like if you were using a factory slide plate and it got loose, due to the same underlying reason, then the glock slideplate might have caused the same malfunction. Just a guess, I’m not a glock armorer.

[10mmfanboy]

That is interesting, I had the same thing happen on my gen 4 29 once. I just chalked it up to not fully clicking the scd in place right, but maybe it wasn't that. My g29 is bone stock other than a 6" barrel. Luckily I noticed it pretty quickly when it didn't return to battery and could simply drop my mag and clear chamber, then locked the slide back and pushed it into place. I have a gadget on 7 glocks and that was the only one time it happened.

[Hunter Osborne]

Is this really an SCD specific malfunction? It sounds like if you were using a factory slide plate and it got loose, due to the same underlying reason, then the glock slideplate might have caused the same malfunction. Just a guess, I’m not a glock armorer.

Seeing as it is the SCD itself that moved, it seems a possibility. I never speak in absolutes, which is why I titled the post "...related malfunction."

It may not be the SCD at all, it may be any number of different things. In the 70k I've put through Glocks in the last few years, I've never seen this happen. The fact that it happened with an SCD installed might just be coincidence.

[Hunter Osborne]

Tom is on it and has been very gracious with his time and an offer to replace the SCD. He mentioned it may also be a worn out striker spring, so that will also be replaced.