failure to eject / Converted Glock 37

[BarneyLongden]

20+ years ago I purchased a Glock 37 chambered in GAP 45. This was a bad choice but I still own it & I could use some help.

This year I purchased a GAP 45 to 40 S&W conversion kit from American Tactical. See https://americantactical.us/product...el-g37-45gap-to-40sw-w-extractor-and-follower

It works pretty good but the gun is not quite dependable enough for self-defense. Every few hundred rounds I get one failure to eject.

From what I have read the problem could be:

1. underpowered ammo ( I think I am shooting Federal180 grain but I purchased range ammo in bulk and threw the box away. It could be 165 grain IDK & I already feel very dumb about this)

2. recoil spring is too heavy

3. extractor with insufficient tension (I do not understand this one)

Suggestions on where to start? I guess hotter ammo is the first thing to try?

 

[ikeo1]

I’d start off with a video of you shooting showing the issue. When you’re doing a conversion it could be those things you mention.

Did the kit come with a recoil spring? If not, you could go down a lb or two or get hotter ammo. I usually prefer a softer spring.

It could also be your limp wristing it which the video would help identify. Otherwise maybe a softer spring since it’s meant for .45 but you’re at .40

 

[BarneyLongden]

I’d start off with a video of you shooting showing the issue. When you’re doing a conversion it could be those things you mention.

Did the kit come with a recoil spring? If not, you could go down a lb or two or get hotter ammo. I usually prefer a softer spring.

It could also be your limp wristing it which the video would help identify. Otherwise maybe a softer spring since it’s meant for .45 but you’re at .40

Video is a good idea. Easy enough to set up a gopro at the range.

The stock spring in the 37 is part #5579. A Google search for that spring does not tell me the rating / stiffness. How do I know what I have so I can purchase the spring one step softer? All full size Gen 3 Glocks come with a 17# spring?

I would also need an aftermarket guide rod assembly?

 

[ikeo1]

Video is a good idea. Easy enough to set up a gopro at the range.

The stock spring in the 37 is part #5579. A Google search for that spring does not tell me the rating / stiffness. How do I know what I have so I can purchase the spring one step softer? All full size Gen 3 Glocks come with a 17# spring?

I would also need an aftermarket guide rod assembly?

You'd just get another guiderod/spring. It's like $20, but if its a 40 and uses stock spring, it should be ok. I'd do the video first before buying anything. Might be how you're gripping the gun. .40 is notoriously hard to shoot.

 

[BarneyLongden]

.40 is notoriously hard to shoot.

Can you explain?
My hands are pretty strong but after 50-75 rounds my grip might not be as consistent as the first 10
FYI - I am NOT an expert shooter but I am also not a total beginner.

 

[ikeo1]

Every few hundred rounds I get one failure to eject.

That's the clue. Not quite saying that you are, but doing video is a cheap way to find out. Then move on to buying stuff. It happens from time to time if you soften your wrists. This video is a exaggerated version. It doesn't need to be this bad to happen. Hence, check out if you can catch it on video.

1:15 in the video...

 

[BarneyLongden]

Ok, that is super insightful.

Funny how Ben never seems to have strong opinions about anything

 

[Walmart_AR15]

GAP 45 is basically a shorten 45 ACP. It has the same dimension as the 45 ACP except shorter. Also the pressure is close to that of the 45 ACP then 40SW. Remember just because the round is bigger does not mean it has more "power". The pressure in 40SW is higher, so instead of lowering your spring tension, you may want to increase it. Using the stock Glock 40 spring would be a good start. The weight of the slide also plays a part in the recoil cycle. If the slide is heavier you may need lower tension. Unfortunately, a bit of tuning (trial and error with different spring weight) may be required.

As in the other thread, GAP 45 slide will have a larger breach face compared to the 40 SW slide. Since it is a conversion barrel, it will lock up correctly, and shoot fine, but it is 99% reliable. The extractor is also designed for a larger rim case, so it may or may not grab the smaller case rim correctly, so once in a while it is possible the empty case will eject without being held by the extractor and cause a jam. Pull the extractor and see how it fits the 40 rim.

OEM has gone through thousands of hours of testing and tuning by the manufacturer. So to expect your conversion Glock will run 100% is a bit unrealistic.

 

[AR15barrels]

20+ years ago I purchased a Glock 37 chambered in GAP 45. This was a bad choice but I still own it & I could use some help.

This year I purchased a GAP 45 to 40 S&W conversion kit from American Tactical. See https://americantactical.us/product...el-g37-45gap-to-40sw-w-extractor-and-follower

3. extractor with insufficient tension (I do not understand this one)

Suggestions on where to start? I guess hotter ammo is the first thing to try?

In most auto pistols, the cartridge case sits in the breechface cut of the slide and the extractor pushes the case against the side of the breechface cut.

Because you are using a smaller case head than your breechface cut, this leaves the case head not able to be clamped against the side of the breech cut after the case is partially withdrawn from the chamber and before the case head strikes the ejector.
This happens because the extractor does not have enough travel to move the case over to takeup the 1mm mismatch.
In a native cartridge slide/barrel, the case is held against the breechface cut before the case is extracted.
Since you do not have good control of the case, you do not get 100% reliable ejection.

The solution is to use a slide that is the correct breechface cut to match your case.
Used Glock 22's are readily available and have the correct size breechface for 40 S&W cases.

 

[Korben Dallas]

I’m with many others here. Video in super slow mo and post the link. We can speculate all day long, and you can buy part after part. However, the video evidence will tell all.

 

[Spooky]

Did you ever replace the ejector? I know converting from a 40 to a 9, the ejector for the 40 is different then the one for a 9

 

[BarneyLongden]

@Spooky - The kit comes with a new extractor but not an ejector.

ATI DROP IN CONVERSION BARREL G37 45GAP TO 40S&W W/ EXTRACTOR AND FOLLOWER

<p>Give your Glock 37 new life and new accuracy by replacing the original .45 GAP chambering with this .40 S&W Conversion. The replacement barrel is precision-engineered from 416 stainless steel for flawless performance. Easy drop-in fit, no gunsmithing required. Made in the USA.</p> <ul>...

americantactical.us

I plan to swap the parts back to GAP 45 for home defense - that way the gun is stock and reliable when it matters. Maybe I should be spending money on GAP ammo or saving for a new gun but I have started down this path.

@ikeo1
I will get slow mo video with the 40 S&W next time I go to the range. If I were to want to try different springs do I purchase a standard Glock spring kit with various weights? I am not sure how interchangeable recoil springs are across Glock models. The springs I see online actually seem comparable to the cost of the few hundred rounds I am going to burn trying to get a malfunction on video.

Yes this is a very slow burn thread. I do not get to go to the range enough.

 

[ikeo1]

The springs I see online actually seem comparable to the cost of the few hundred rounds I am going to burn trying to get a malfunction on video.

A spring should be $20 for a Glock spring. Go down to a 15/13 lb NZ on eBay should be good enough

 

[AR15barrels]

@Spooky - The kit comes with a new extractor but not an ejector.

ATI DROP IN CONVERSION BARREL G37 45GAP TO 40S&W W/ EXTRACTOR AND FOLLOWER

<p>Give your Glock 37 new life and new accuracy by replacing the original .45 GAP chambering with this .40 S&W Conversion. The replacement barrel is precision-engineered from 416 stainless steel for flawless performance. Easy drop-in fit, no gunsmithing required. Made in the USA.</p> <ul>...

americantactical.us

I plan to swap the parts back to GAP 45 for home defense - that way the gun is stock and reliable when it matters. Maybe I should be spending money on GAP ammo or saving for a new gun but I have started down this path.

@ikeo1
I will get slow mo video with the 40 S&W next time I go to the range. If I were to want to try different springs do I purchase a standard Glock spring kit with various weights? I am not sure how interchangeable recoil springs are across Glock models. The springs I see online actually seem comparable to the cost of the few hundred rounds I am going to burn trying to get a malfunction on video.

Yes this is a very slow burn thread. I do not get to go to the range enough.

You will do better to buy more 45GAP ammo and skip further testing of the 40 caliber conversion barrel because no change in components is going to make the extractor and ejector 100% reliable due to the case not being in contact with the breech cut in the slide.
You can see this for yourself simply by placing a fired case in the chamber of the conversion barrel and then installing the barrel fully into the slide and looking for light between the side of the breech cut and the case head opposite of the extractor.

 

[BarneyLongden]

@AR15barrels I agree. It is just hard to let go of an idea even when it is a bad idea.

I looked on ebay for springs and am still not sure what to get. Need to get some GAP 45 ammo - retest the gun - put it next to night stand - move on.