G48 MOS

[leathermaneod]

Hey all,

Just bought a G48 MOS and got finished sighting in my Holosun 507Kx2. It went pretty well, although I’m certainly no Aaron Cowan when it comes to my 25 yard grouping. I can keep the dot in the window during the recoil and get a very respectable group at 10 yards while shooting quickly. Definitely a big improvement for me over irons. I was just about done with my 250 rounds of 115 grain Freedom munitions and about 20 rounds of Federal HST 124 grain and all had been boringly reliable. On my very last mag of the freedom munitions, I dropped the side and had a dead trigger. I looked down and realized the slide was just slightly out of battery. I couldn’t get it to go into battery. I dropped the mag, cleared the chamber, and released the slide from lock on an empty chamber. This time in went into battery like normal, and I fired my last ten rounds quickly and without incident. I did a quick field strip to inspect, but nothing jumped out at me. It is dirty though. Anyone ever experience something like this? Anything specific I should check for? Or just shoot it more and be on the lookout?

Thanks in advance!

[breakingtime91]

Hey all,

Just bought a G48 MOS and got finished sighting in my Holosun 507Kx2. It went pretty well, although I’m certainly no Aaron Cowan when it comes to my 25 yard grouping. I can keep the dot in the window during the recoil and get a very respectable group at 10 yards while shooting quickly. Definitely a big improvement for me over irons. I was just about done with my 250 rounds of 115 grain Freedom munitions and about 20 rounds of Federal HST 124 grain and all had been boringly reliable. On my very last mag of the freedom munitions, I dropped the side and had a dead trigger. I looked down and realized the slide was just slightly out of battery. I couldn’t get it to go into battery. I dropped the mag, cleared the chamber, and released the slide from lock on an empty chamber. This time in went into battery like normal, and I fired my last ten rounds quickly and without incident. I did a quick field strip to inspect, but nothing jumped out at me. It is dirty though. Anyone ever experience something like this? Anything specific I should check for? Or just shoot it more and be on the lookout?

Thanks in advance!

Freedom is usually good but sounds like it could of been an ammo issue, I have stopped using any non main stream ammo manufacturer after a really bad experience with reman.

[Leroy Suggs]

breakingtime91 is right. Freedom ammo sucks sweaty balls.
It is some sorry shit.

[breakingtime91]

breakingtime91 is right. Freedom ammo sucks sweaty balls.
It is some sorry shit.

I was being nice but ya, I wouldn't touch the shit

[leathermaneod]

Thanks for the info guys. This was reman ammo too. Hopefully it was only an ammo issue. I need to start being more slow and deliberate when dealing with a malfunction like this so I can recall exactly what happened in what order.

[Up1911Fan]

I shot over 20K of FM 9mm about 7-8 years ago. The QC went to shit and I haven't bought any since.

[breakingtime91]

Thanks for the info guys. This was reman ammo too. Hopefully it was only an ammo issue. I need to start being more slow and deliberate when dealing with a malfunction like this so I can recall exactly what happened in what order.


I would just grab some factory loaded ammo from a big name and run it to get the confidence back in the gun. My g48 was very reliable but I used only factory loaded ammo. Reman is often over sized and not loaded hot enough.

[SwampDweller]

For the most part, I pretty much only run Speer Lawman or Federal American Eagle through guns I want to actually trust my life to. QC is always great and it almost completely removes the variable of the ammo being at fault in a malfunction. Not saying the ammo never does it (I've had a dead primer in one AE 124gr round that wouldn't even go off in another gun when tried), but it's as close to 100% reliable as it gets in my experience.

Now in dedicated trainer pistols, I'll shoot whatever's cheapest. Except reman. That's where I draw the line.

I would agree with the others that it sounds like an ammo issue, given Freedom's poor QC.

[paherne]

Watched my buddy have two dud Freedom Arms 9mm 115 grain FMJ during his IDPA Classifier, yesterday. He probably would have made Master if not for shitty Freedom Arms ammo. I'm betting ammo.

[Nephrology]

Hey all,

Just bought a G48 MOS and got finished sighting in my Holosun 507Kx2. It went pretty well, although I’m certainly no Aaron Cowan when it comes to my 25 yard grouping. I can keep the dot in the window during the recoil and get a very respectable group at 10 yards while shooting quickly. Definitely a big improvement for me over irons. I was just about done with my 250 rounds of 115 grain Freedom munitions and about 20 rounds of Federal HST 124 grain and all had been boringly reliable. On my very last mag of the freedom munitions, I dropped the side and had a dead trigger. I looked down and realized the slide was just slightly out of battery. I couldn’t get it to go into battery. I dropped the mag, cleared the chamber, and released the slide from lock on an empty chamber. This time in went into battery like normal, and I fired my last ten rounds quickly and without incident. I did a quick field strip to inspect, but nothing jumped out at me. It is dirty though. Anyone ever experience something like this? Anything specific I should check for? Or just shoot it more and be on the lookout?

Thanks in advance!

I've found my G48s to be less tolerant of weakly loaded ammo. One of my pair came from the factory having issues with failure to return to battery even with full power 124 +P. Over time the issues became less and less frequent so I am forced to conclude it was probably some aspect of the slide/frame/internal parts tolerance stacking. Maybe finish was a bit thicker than normal, stock spring a little weaker than normal, not sure. However after about 1000 rounds the gun shoots fine. I use it as my trainer backup for the more reliable of the two pistols but would probably trust it after another 500-1000 rounds issue free

[HCM]

Prior posters comments re: the poor quality of Freedom Munitions ammunition and the G48 being intolerant of weak ammo are correct.

That is a knock against FM, not remanufactured ammunition in general, there are quality Remanufactures such as Black Hills, Precision Delta and Atlanta Arms.

The bigger issue is the G48 is very sensitive to grip and ammunition that is too weak or too hot.

The slim line Glocks (43, 43X,48) are on the bleeding edge of reliability and it only takes one thing, grip, ammo, adding an optic, light or aftermarket mags, to push them into failure.

It’s important to understand the G48 uses the G43 recoil spring assembly. So it is not a “slim” G19 but a stretched G43 modeled after the G47/34. That means a reduced operating / timing window vs full size Glocks.

If better ammo does fix your issue, try removing the optic and see if the added weight of the optic is a factor.

RJ had such an issue with a G48.

[Nick B]

breakingtime91 is right. Freedom ammo sucks sweaty balls.
It is some sorry shit.
^^^ For sure . The joke at our gun club was “Friends don’t let friends shoot Freedom Munitions.”

[leathermaneod]

Thanks again for all the helpful replies everyone!

Just to clarify, the problem here happened when dropping the slide on a full mag, not while shooting. Just pointing that out because some of the comments about weak ammo really wouldn’t apply to this particular issue. I’m not arguing the point that weak ammo or grip issues may cause similar malfunctions, just pointing out that was not the case here. Maybe out of spec on dimensions, but I’ve never had any similar issue while shooting this G48 or my G43X with the same ammo (granted I have not put more than 1k of the Freedom through these guns though and won’t be buying any more). Again not arguing with anything anyone has said, just clarifying this particular instance.

[breakingtime91]

Thanks again for all the helpful replies everyone!

Just to clarify, the problem here happened when dropping the slide on a full mag, not while shooting. Just pointing that out because some of the comments about weak ammo really wouldn’t apply to this particular issue. I’m not arguing the point that weak ammo or grip issues may cause similar malfunctions, just pointing out that was not the case here. Maybe out of spec on dimensions, but I’ve never had any similar issue while shooting this G48 or my G43X with the same ammo (granted I have not put more than 1k of the Freedom through these guns though and won’t be buying any more). Again not arguing with anything anyone has said, just clarifying this particular instance.

I think what hcm said is spot on. Could be the optic unfortunately. I decided against getting a g48 because it uses a g43 recoil spring. Wish they would of done it right.

[leathermaneod]

I think what hcm said is spot on. Could be the optic unfortunately. I decided against getting a g48 because it uses a g43 recoil spring. Wish they would of done it right.

I haven’t heard about this issue, so I won’t argue wether or not it’s a thing, but I really don’t think it’s the case here. I’ll say again just to clarify, this G48 with Holosun 507k x2 ran absolutely flawlessly through 250 rounds of Freedom Munitions 115 Reman and about 20 rounds of Federal HST 124 grain, with the exception of the last mag. I loaded it, dropped the slide, and realized it was not in battery. I could not push it forward. Something stopped it and nothing I did could get it the last 1/8” into battery. After I removed the mag and round in the chamber, I dropped the slide on an empty chamber and it was fine. I then put the round back in the mag and dropped the slide and fired the ten rounds in the mag without incident. Something prevented the slide from going into battery and it was not a weak recoil spring. Hopefully it was an issue with ammo sizing, or something like that and not an issue with the gun, but it was definitely not caused by a weak recoil spring.

[leathermaneod]

Just to update for anyone who is interested, I did a complete strip and clean of the pistol including slide internals, except for channel liner. Also verified extractor plunger moves freely. Reassembled everything clean and dry except for a drop of clp on the slide rails, connector, and barrel hood. Only interesting things I found were some brass shavings, just two or three, a burr on the inside of the safety plunger depressor, and a manufacturing mark under the extractor.

[DpdG]

Just a FYI- the slimline slides (42, 43, 43x, 48) do not have channel liners.

[leathermaneod]

Just a FYI- the slimline slides (42, 43, 43x, 48) do not have channel liners.

Thanks for the info! I would have swore I saw one in there. Any issue with that little burr on the trigger bar safety plunger depressor?

[SW CQB 45]

Thanks for the info! I would have swore I saw one in there. Any issue with that little burr on the trigger bar safety plunger depressor?

if you are referring to the build up at the bottom of the depressor part on the trigger bar, it may be low enough and not make contact with the safety plunger. If it did, I would feel it at the beginning of the trigger press.

Any offending roughness, if it were my gun would be addressed with a jewelers file and finished off with a stone.

if you can't feel any roughness through the trigger press, it's not making any contact with the safety plunger.

[leathermaneod]

if you are referring to the build up at the bottom of the depressor part on the trigger bar, it may be low enough and not make contact with the safety plunger. If it did, I would feel it at the beginning of the trigger press.

Any offending roughness, if it were my gun would be addressed with a jewelers file and finished off with a stone.

if you can't feel any roughness through the trigger press, it's not making any contact with the safety plunger.

Thanks for the reply. Im talking about that little burr, right on the rear corner at the the top of the part that depresses the plunger…

As far as how it feels, almost the same as my g43X, maybe just a little heavier…

[SW CQB 45]

just so we are on the same page

this is the only roughness I see

if you cannot feel roughness on the initial part of the trigger press, the first contact between the "ramp" part of the depressor and the safety plunger is above that jagged area.

Me, I would have stoned it smooth.


https://i.imgur.com/ROesDwsh.jpg

[SW CQB 45]

I am disappointed in my decision to buy a G48 MOS as for some dumb azz reason, I thought the direct mount SCS Holosun optics were made for the G43x/48.

When the SCS became available for purchase, I found out the SCS MOS line was for the standard size glocks, not the slimline.
So, I am plastic sight, optic free and 10 round at this time. I dont want to cut into any tabs just yet but I was looking for a reputable optic thats not oversized and bolts directly to the slide.

I don't want to pay or the added height for a plate and want the optic low enough to use the plastic sights for back up. I communicated with Holosun and they have nothing on the drawing board for the G48 MOS direct mount.

So, when I don't feel like packing my G19 off duty, I throw the plain G48MOS on.

I might sell it is the reason I don't want to cut on any tabs.

[diananike]

The Holosun K models will direct mount to the MOS slide if you file down 2 of the locating posts on the slide.

I opted for a CHPWS plate so I wouldn’t have to modify the slide. After more research I may remove the plate and direct mount instead.

It cowitnesses the irons sufficiently to see about half the sights on the plastic Glock ones.
They are usable but I really only use the dot anyway.

I have had no reliability issues with my G48 407k TLR7 equipped gun.
If I remember correctly it went through around 1500 rounds of mixed reloads and cheap 115gr without cleaning before it had a malfunction.

I had similar results with my original silver slide G48 which is still bone stock.

Why yours didn’t run I’m unsure. Maybe the ammo and gun don’t like each other.
Or maybe your particular pistol needs a fluff and buff.

[SW CQB 45]

The Holosun K models will direct mount to the MOS slide if you file down 2 of the locating posts on the slide.

I opted for a CHPWS plate so I wouldn’t have to modify the slide. After more research I may remove the plate and direct mount instead.

It cowitnesses the irons sufficiently to see about half the sights on the plastic Glock ones.
They are usable but I really only use the dot anyway.

I have had no reliability issues with my G48 407k TLR7 equipped gun.
If I remember correctly it went through around 1500 rounds of mixed reloads and cheap 115gr without cleaning before it had a malfunction.

I had similar results with my original silver slide G48 which is still bone stock.

Why yours didn’t run I’m unsure. Maybe the ammo and gun don’t like each other.
Or maybe your particular pistol needs a fluff and buff.

I have been looking at the Kmodels and not quite there to break out the files.

correct me if I am wrong, completely shave off the rear tabs, and minimize the front tabs?

thanks in advance

[diananike]

I believe it’s remove the rear posts with a file.
And the front posts need to be shortened slightly.

Even the kitchen gunsmith like me shouldn’t have any trouble with that if you go slow and check the interface as you file.

I haven’t checked it on my gun yet as I’m satisfied with the plate interface. No loosening yet after around 2000 rounds.
I used vibratite and some thread locker when I installed it.
I saw a slight zero shift over the course of the first 500 rounds. Rezeroed and it’s been good to go.

[TC215]

I have been looking at the Kmodels and not quite there to break out the files.

correct me if I am wrong, completely shave off the rear tabs, and minimize the front tabs?

thanks in advance

Maple Leaf will do it for you for $50 and mount the optic. Their turnaround time is pretty quick.

https://www.mapleleaffirearms.com/43xmosconversion

[paherne]

I've had the Holosun K mounted to my G48 for almost a year with the CHPWS plate and I carry, daily, IWB. It's gotten banged around, been to a couple of range sessions and it has held zero with no issues. I did use Loctite blue, I degreased the slide and threads before assembly, torqued it properly using a $30 in-lb torque wrench set I bought on Amazon and let it sit 24 hours before I zeroed it. Keeping schmutz and fuzz off the optic is the biggest problem I've had. Wished I'd waited for the closed-emitter EPS to come out, but I'm not pushed enough to change.

[Paul Blackburn]

The closed emitter windows get dusted over too from carrying.

[leathermaneod]

just so we are on the same page

this is the only roughness I see

if you cannot feel roughness on the initial part of the trigger press, the first contact between the "ramp" part of the depressor and the safety plunger is above that jagged area.

Me, I would have stoned it smooth.


https://i.imgur.com/ROesDwsh.jpg

Yep that’s the burr I was talking about. I don’t notice anything in the trigger pull. I guess I was just grasping at straws checking for anything that could potentially have caused or contributed to my issue the other day. As I’ve been thinking about it now, it doesn’t seem like that surface would touch anything because, iirc, it’s on the side, more than the top. So it doesn’t seem like it could have anything to do with my malfunction. I’m certainly tempted to polish things up or at least remove the burr like you mentioned, but I’m too scared of changing internals on a carry gun. I know I could also just replace it myself. I’ve done it a couple times before on a G43 that had a trigger safety pin that kept walking out. Unfortunately, it seems these triggers are out of stock everywhere right now. Does anyone think that little burr could affect operation other than in the potential feel of the trigger? Would a imperfection like that keep you from carrying it? If I don’t have any more malfunctions with it?

[leathermaneod]

I am disappointed in my decision to buy a G48 MOS as for some dumb azz reason, I thought the direct mount SCS Holosun optics were made for the G43x/48.

When the SCS became available for purchase, I found out the SCS MOS line was for the standard size glocks, not the slimline.
So, I am plastic sight, optic free and 10 round at this time. I dont want to cut into any tabs just yet but I was looking for a reputable optic thats not oversized and bolts directly to the slide.

I don't want to pay or the added height for a plate and want the optic low enough to use the plastic sights for back up. I communicated with Holosun and they have nothing on the drawing board for the G48 MOS direct mount.

So, when I don't feel like packing my G19 off duty, I throw the plain G48MOS on.

I might sell it is the reason I don't want to cut on any tabs.

I’m very new to my G48 MOS at this point, but other than the minor issue in this thread, I am extremely happy with it and the HA507Kx2 I put on it. Im not expert shooting, and I had never shot a pistol with a dot before, but I am mostly able to keep the dot in the window even while shooting quickly, which I am quite please about :-) I’m also unwilling to do any filling on it at this point, so I went with the CHP plate and I’m very satisfied with that as well. The factory plastics are perfectly usable, though quite low, which is what I was hoping for. I don’t want to make this setup any more expensive or custom that it already is. I was planning to add a TLR7 sub as well, but this whole experience taught me about the gap you get around the trigger guard with a slim gun and a wider light, so I’ve decided I don’t need the light on an edc gun.

[breakingtime91]

I’m very new to my G48 MOS at this point, but other than the minor issue in this thread, I am extremely happy with it and the HA507Kx2 I put on it. Im not expert shooting, and I had never shot a pistol with a dot before, but I am mostly able to keep the dot in the window even while shooting quickly, which I am quite please about :-) I’m also unwilling to do any filling on it at this point, so I went with the CHP plate and I’m very satisfied with that as well. The factory plastics are perfectly usable, though quite low, which is what I was hoping for. I don’t want to make this setup any more expensive or custom that it already is. I was planning to add a TLR7 sub as well, but this whole experience taught me about the gap you get around the trigger guard with a slim gun and a wider light, so I’ve decided I don’t need the light on an edc gun.

If you ever want metal sights defoor sights are cheap and should give a very similar co witness

[SW CQB 45]

Yep that’s the burr I was talking about. I don’t notice anything in the trigger pull. I guess I was just grasping at straws checking for anything that could potentially have caused or contributed to my issue the other day. As I’ve been thinking about it now, it doesn’t seem like that surface would touch anything because, iirc, it’s on the side, more than the top. So it doesn’t seem like it could have anything to do with my malfunction. I’m certainly tempted to polish things up or at least remove the burr like you mentioned, but I’m too scared of changing internals on a carry gun. I know I could also just replace it myself. I’ve done it a couple times before on a G43 that had a trigger safety pin that kept walking out. Unfortunately, it seems these triggers are out of stock everywhere right now. Does anyone think that little burr could affect operation other than in the potential feel of the trigger? Would a imperfection like that keep you from carrying it? If I don’t have any more malfunctions with it?

I purchased an Overwatch Precision Falx trigger as I wanted a smooth trigger face similar to factory and while it was nice, it was not worth the $$$ as I only gained a smooth face trigger. I read on this forum that G17 smooth triggers will work on the G48 trigger bar, so I punched out the serrated trigger and installed a G17 trigger shoe on my factory 48 trigger bar. My guess on the hole (to remove the little pin) was a little off, and I ended up chunking a larger piece off than I wanted too.

https://i.imgur.com/xaNulbdh.jpg

So, I gooped it up with Black RTV and let it dry over night. I used a sharp razor to cut the excess smooth and to the untrained eye, nothing to see here!

https://i.imgur.com/XGMrhS0h.jpg

https://i.imgur.com/kBkMAoAh.jpg

I sold the Falx trigger at about 80% recovery and will just stick with this set up. I looked up the Ameriglo Defoor sights, and they are perfect for a plain simple steel sight.

that burr on the trigger bar is not the cause of any issues. shoot quality ammo and carry it. Keep it clean and properly lubed.

[JHC]

I am disappointed in my decision to buy a G48 MOS as for some dumb azz reason, I thought the direct mount SCS Holosun optics were made for the G43x/48.

When the SCS became available for purchase, I found out the SCS MOS line was for the standard size glocks, not the slimline.
So, I am plastic sight, optic free and 10 round at this time. I dont want to cut into any tabs just yet but I was looking for a reputable optic thats not oversized and bolts directly to the slide.

I don't want to pay or the added height for a plate and want the optic low enough to use the plastic sights for back up. I communicated with Holosun and they have nothing on the drawing board for the G48 MOS direct mount.

So, when I don't feel like packing my G19 off duty, I throw the plain G48MOS on.

I might sell it is the reason I don't want to cut on any tabs.

I called Maple Leaf today to ask if they can "cut" their cut to an MOS Glock and the fellow said nope, not standard models, only the 43/43X. Which by extension would mean the 48 too I guess.

[JHC]

Maple Leaf will do it for you for $50 and mount the optic. Their turnaround time is pretty quick.

https://www.mapleleaffirearms.com/43xmosconversion

I replied with quote before seeing this excellent info.

[SW CQB 45]

I called Maple Leaf today to ask if they can "cut" their cut to an MOS Glock and the fellow said nope, not standard models, only the 43/43X. Which by extension would mean the 48 too I guess.

thanks for the info.

I just removed a hardly used Holosun 507C V2 (pre X2) from my 1301 and switched to a Holosun 503C. Not sure if I want to hold on to it or sell it to gain the cash for an optic for the 48.

If I go Holosun, it will be between 507k or the EPS Carry (which still shows coming soon on the website).

they are about the same dimensions, but EPS is closed emitter and limited to a dot reticle.

[RJ]

RJ had such an issue with a G48.

Yes sir. 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.

[leathermaneod]

I purchased an Overwatch Precision Falx trigger as I wanted a smooth trigger face similar to factory and while it was nice, it was not worth the $$$ as I only gained a smooth face trigger. I read on this forum that G17 smooth triggers will work on the G48 trigger bar, so I punched out the serrated trigger and installed a G17 trigger shoe on my factory 48 trigger bar. My guess on the hole (to remove the little pin) was a little off, and I ended up chunking a larger piece off than I wanted too.

https://i.imgur.com/xaNulbdh.jpg

So, I gooped it up with Black RTV and let it dry over night. I used a sharp razor to cut the excess smooth and to the untrained eye, nothing to see here!

https://i.imgur.com/XGMrhS0h.jpg

https://i.imgur.com/kBkMAoAh.jpg

I sold the Falx trigger at about 80% recovery and will just stick with this set up. I looked up the Ameriglo Defoor sights, and they are perfect for a plain simple steel sight.

that burr on the trigger bar is not the cause of any issues. shoot quality ammo and carry it. Keep it clean and properly lubed.

Your work on that smooth face trigger looks great! I would love to have a smooth shoe, or even better yet a flat faced trigger, but I can’t get comfortable with modifying a gun I’m going to carry. Just like I can’t get comfortable with the gaps around a trigger guard big enough to allow for a Tlr7. Even with a quality holster from Tenicor. Probably just a stupid mental block, but it’s the way things are for me right now. Probably good because if I go too far down that road, I’ll be spending more on mods and less on ammo.

Thank you for the advice on the trigger bar and the sights btw.