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Discussion Starter #1
Bob has been working very hard assisting all of us here on the Glock Forum with our technical questions. I thought it was time to create his own corner of the GF. Perhaps by researching this thread we can find the answers to our questions that Bob has already graciously answered.

Thanks Bob! :D
 

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Discussion Starter #2
After cleaning my G17.4 today, given the on-going discussion regarding the benefits and reliability of aftermarket parts (especially titanium), I decided to take some pictures.

The attached pictures show the wear on the striker, striker safety, and extractor with approximately 15,000 rounds.

For our benefit and education, I'd really like to see similar pictures, particularly of titanium strikers and striker safeties, with comparable round counts.








 

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Discussion Starter #3
After 'discovering' the Handi-Racker (http://www.handi-racker.com/), I thought I'd cobble something together from the scrap material in my workshop.

With a 1" board, 1" PVC pipe, a hole saw, and some glue, I was 'good to go'... done in about 10 minutes (because I'm slow). ;)

It's very stable. One handed racking is simple, easy, and most importantly... safe. Two handed racking is even easier (and more controlled).

 

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Discussion Starter #4
There seems to be some confusion regarding the typical trajectories of different 9mm Luger bullets. So, let's look at the projected trajectories of some typical cartridges.

The following external ballistics graphs were generated in the current version of QuickLOAD/QuickTARGET and confirmed by the JBM Ballistics Trajectory (Simplified) calculator.

Let's assume that I have a G17 with adjustable sights and want to adjust the elevation such the the rise and fall of the bullet is equidistant relative to the line of sight (LoS) for a distance of 100 yards.

For a 147 gr Speer Gold Dot and a muzzle velocity of 950 fps, the projected trajectory is as shown here. Note that, relative to the LoS, the rise and fall of the bullet is approximately 3.5". For reference, the sights must be adjusted to elevate the muzzle approximately 17.2 MOA.

And, for a 115 gr Speer Gold Dot and a muzzle velocity of 1150 fps, the projected trajectory is as shown here. Note that, relative to the LoS, the rise and fall of the bullet is approximately 2.5" and the sights must be adjusted to elevate the muzzle approximately 12.5 MOA.

As may be noted, under these conditions, at the peak height above the LoS, the 147 gr bullet flies about 1" higher than the 115 gr bullet. However, note that the muzzle is elevated higher for the 147 gr bullet relative to the 115 gr bullet to achieve the same second zero crossover of 84 yards.

That being said, my guess is most shooters (including me) use fixed sights with standard heights, which elevate the muzzle of a G17 approximately 8 MOA... and the projected trajectories are hereand here for the 147 gr GD and 115 gr GD bullets, respectively. Also, for comparison, the projected trajectory for a 124 gr Speer Gold Dot and a muzzle velocity of 1100 fps is as shown here.

Under these conditions, at the peak heights above the LoS, the 147 gr and 115 gr bullets fly 0.4" and 0.8", respectively, above the LoS and the 147 gr bullet flies about 0.4" lower (not higher) than the 115 gr bullet. Also, note that the second zero crossovers for the 147 gr and 115 gr bullets are 35 yds and 52 yds, respectively. And, under 45 yds or so, the 147 gr bullet flies a bit 'flatter'.

With the same POA and muzzle elevation (that is, with fixed sights or with adjustable sights at the same 'setting'), given similar nose profiles, slower bullets, regardless of weight, will always fly lower than faster bullets.

Physics is physics. That won't change... and bullets will fly accordingly. ;)
 

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Discussion Starter #5
When I generated the G26, G19, G17, and G34 bullet trajectories here, I'd hoped to include the G43. But, I wanted to show the trajectories using the same sights to illustrate the different muzzle elevations as the sight radius changes.

Stock G26, G19, G17, and G34 pistols are fitted with the same sights... the standard Glock front sight and the 6.5mm rear sight. However, while the G43 is fitted with the same front sight, the stock rear sight is the 6.1mm sight.

Since I don’t yet own or have immediate access to a G43, in lieu of actual measurements, I simply adjusted my G17 rear sight height measurement by 0.4mm (0.016”) and used the following numbers to generate the G43 trajectories.

Sight radius: 5.20”
Front sight height: 0.165”
Rear sight height: 0.164”
Muzzle elevation: -0.7 MOA

Note that the muzzle is pointing very slightly below the Line of Sight (which supports the common complaint that ‘my G43 shoots low’).

The following G43 trajectories use the same bullets and speeds as the G26, G19, G17, and G34 trajectories (above) to facilitate direct comparisons. (Note: QuickTARGET seems to require a zero crossover to perform the calculations necessary to generate the trajectories. Therefore, I adjusted the sight-to-bore height to artificially elevate the -0.7 MOA curves by 1”. In reality, the elevations of the actual -0.7 MOA trajectories are 1” lower than the curves generated and presented by the software.)

G43, 115 gr GD @ 1150 fps, -0.7 MOA
G43, 124 gr GD @ 1100 fps, -0.7 MOA
G43, 147 gr GD @ 950 fps, -0.7 MOA

Additionally, the G43 trajectories with the 6.5mm rear sight, which elevates the muzzle 9.9 MOA, are as follows.

G43, 115 gr GD @ 1150 fps, 9.9 MOA
G43, 124 gr GD @ 1100 fps, 9.9 MOA
G43, 147 gr GD @ 950 fps, 9.9 MOA

Personally, of the G43 trajectories presented so far, I much prefer the 147 gr 950 fps Gold Dot with the 6.5mm rear sight (9.9 MOA).

In my opinion, the optimal trajectories for the 115 gr 1150 fps, 124 gr 1100 fps, and 147 gr 950 fps Gold Dots require muzzle elevations of 6.9 MOA, 7.3 MOA, and 9.1 MOA, respectively... which, for a G43 fitted with the stock 6.1mm rear sight, requires (non-standard) front sight heights of 0.154”, 0.153”, and 0.150”, respectively.

Of worthy note, is that, given the G43’s short sight radius, relative to its larger siblings, the same change of sight height produces a more significant change of muzzle elevation. In other words, for the same sight picture ‘error’, a G43 will produce a much larger group than a G34.

For what it’s worth... :D
 

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Discussion Starter #6
I've used the technique described in the video below for many years. However, while recently replacing a firing pin spring, I noticed a spent .22 LR case on my workbench and wondered if that would work as well... and it does. So, I tossed it in my maintenance kit for future use. :D

 

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Discussion Starter #7
The current Polymer80 'approved' drilling and milling operations are described here...

https://www.polymer80.com/media/wys...er80-PF940_Series_Pistol_Kit-Instructions.pdf

The top rail blocks must be milled and the Locking Block Rail System and Rear Rail Module must be installed as described in the instructions to ensure that all their upper surfaces are in the same plane... or the slide may bind.

The picture below shows my G17.4 frame 'upside down' on a perfectly flat granite slab.



Note that most of the upper surface of the plastic frame is in the same plane as the top of the metal frame rails. Some of the frame is very slightly under-flush with the metal frame rails... which is fine.

If the any part of the plastic frame rail blocks extends 'above' the plane of the Locking Block Rail System and/or the Rear Rail Module, the slide may bind.

Also, if the Locking Block Rail System or Rear Rail Module is 'twisted' or 'skewed', the slide may bind.

To attempt to identify the areas where the slid is binding, 'paint' the areas to be evaluated with a marker of a different color than the 'base' materiel. For example, use a silver or gold marker on the 'dark' areas and a black or blue marker on the 'light' areas.

Any 'high areas' identified need to be corrected.

For example, once upon a time, the steel frame rails of one of my pistols exhibited some high edges. So, to remove the high spots and ensure that the top surfaces of the rails and frame were indeed 'in the same plane', I 'flattened' the edges by putting a sheet of 1200 grit emery paper between the granite block and the frame rails (refer to the picture above) and very carefully 'polished' all four rails at the same time. (Be sure to go 'slow and easy'.)

Problem resolved.

Another 'binding' cause and solution was posted by fellow member daveshea in the thread Polymer80 Glock 26 build problem...
 

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Discussion Starter #8
Please refer to the picture below.

With a G19 frame, the slide stops when the RSA cutout in the nose of the slide contacts the frame at the red arrow. And, with a G17 frame, the slide stops when the RSA cutout in the nose of the slide contacts the frame at the blue arrow.



Since the G19 slide is 1/2" shorter than the G17 slide, for the G19 to function properly, the frame stop must be moved 1/2" rearward relative to the G17 stop.

As an FYI, the G26 requires a similar 'adjustment'. Since the G26 slide is 1/2" shorter than the G19 slide, the G26 frame stop is 1/2" farther rearward than the G19 stop.

The G34 and G17L use the G17 frame, but use different slides... the longer slides are made with 'elongated' RSA cutouts of the appropriate length to properly engage the stop of the G17 frame.
 

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Discussion Starter #9
Your frame appears to be the original 'Spectre' design (below) as opposed to the newer 'V2' design (to which I referred in post #11).


In the Spectre design, the slide stop indeed appears to be the forward end of the Locking Block Rail System (blue arrows below)... not the RSA cutout/frame stop (red arrow).



How much should I trim away?
If I perceive 'things' correctly, to 'save the project', I'd consider gradually shortening the front 'tabs' (blue arrows) of the Locking Block Rail System toward the forward edge of the rails (yellow arrows) until the slide cycles properly. If necessary, I'd shorten the tabs to just a bit rearward of the RSA cutout/frame stop (red arrow)... then, if that doesn't provide enough slide travel, consider what to try next.
 

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Discussion Starter #10
It appears that the locking block can be cut back a bit farther... to the red lines shown in the picture below. However, be sure to leave enough steel in front of the mounting holes (and plastic on the frame) for the mounting screws (and frame) to adequately secure the locking block.



If that doesn't provide sufficient slide travel, then it seems 'you're done'.

(Note: In all honesty, as you are doing, I'd try to 'make it work'... mostly for the education and just to see if I could do it. BUT, personally, after it's done, I'd 'bite the bullet' and buy the newer PF940C 80% Compact Pistol Frame Kit for the G19 slide... and I strongly recommend that you do the same.)
 

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Discussion Starter #11
Glock Doubling:

Basically, look at any part that may affect the proper interface of the firing pin lug and the rear of the trigger bar cruciform (sear).

The firing pin lug and the sear should be perfectly flat (no rounded edges). And, when the trigger bar is 'reset', the firing pin lug should overlap the sear about 0.040".

If the edges are rounded and/or the overlap is too small, when the slide 'slams' into battery, the firing pin lug may 'jump' the sear... firing another round.

Other 'things' that could cause the 'jump' may be that ...

- the trigger bar is catching on trigger mechanism housing and it doesn't fully reset (causing a 'thin' overlap)
- a weak trigger spring is not fully 'pulling up' (resetting) the trigger bar (again, causing a 'thin' overlap)
- the trigger connector reset tab is bent so that the trigger connector catches the trigger bar and the trigger bar doesn't fully reset (again, causing a 'thin' overlap)

Said another way... by my perception, the list of suspect parts that could be worn or defective include the...

- trigger bar assembly
- firing pin
- firing pin channel liner
- trigger mechanism housing
- trigger spring
- trigger connector

Yeah... I know. Some of these things sound a bit far fetched... and maybe they are... but stranger things have happened.
 

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Discussion Starter #12
I can push slide off with trigger in forward position:

... as shown below, the slide can be moved rearward about 1/4" (red arrow) before the firing pin lug engages sear (the rear of the cruciform).



With the slide in the same position as in the picture above, the picture below shows the position of the firing pin lug... the lug is 'sitting on top' of the rear of the cruciform...any further rearward movement would cause the lug to reengage the sear (red arrow).



Under the conditions you describe, the reason that it takes 'a small amount of force with the trigger fully forward' to remove the slide is that, with the NY triggers, 'things' tend to 'bind up' a bit.

Also, if the slide is moved rearward just a tad more than the 1/4", the lug and sear will reengage and the slide won't come off.
 

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G30SF Slide will not lock:

The slide stop lever is but one of many pistol components that affect the slide locking to the rear after the last round.

Other components include the...
- magazine
- magazine catch
- slide
- RSA

Let's check some things.

Remove the slide and install an empty magazine in the magazine well. Then, confirm the magazine is properly seated and 'captured' by trying to remove it without pressing the magazine release. If you can remove it, the magazine and/or magazine catch is defective and should be replaced.

With the magazine installed, the slide stop lever should engage the magazine follower as shown below (red arrow)...



And, the slide stop lever should be pushed 'up' as shown below (red arrow)...



Push the slide stop lever (as shown in the above picture) 'down'... then release it. The lever should immediately 'pop up'.

The rear face of the slide stop lever should be 'flat and square', as shown below (red arrow)...



The notch in the slide should also be 'flat and square', as shown below (red arrows)...




The slide stop lever should fit the slide stop notch as shown below (red arrow)...



A 'good' RSA (red arrow below) pushes the slide forward with about 14 lbs of force and 'binds' the slide stop lever in the slide stop notch (blue arrow)...



Please check 'all the above' and let us know what you find.

Simply replacing the slide stop lever may or may not correct the problem.
 

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Discussion Starter #14
G19 Gen 5 feels heavier then G17 Gen 4:

The Gen 5 trigger group is a bit different, so, to some, it may feel 'different' as well... in your case... 'more responsive'. (Quite honestly, I can't feel any significant difference.)

And, while you may perceive that the G17.4 is lighter than the G19.5, it isn't...

https://us.glock.com/products/compare?g1=g19gen5&g2=g17&g3=&g4=

 

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Discussion Starter #15
Glock 26 Gen 5 slide issues:

It appears you may be correct.

In the picture below, the spring on the left is my original G17.5 slide stop spring and the spring on the right is my original G17.5 slide lock spring.

The spring in the center, which looks like my original G17.5 slide lock spring, is the spring from Glock's 'new' extended slide stop lever...

https://www.midwestgunworks.com/page/mgwi/prod/47249)

Glock's 'new' extended slide stop lever is indeed 'stiffer', but operates smoothly in my G17.5 and passed all 'dummy round' and 'empty' functional testing with absolutely no issues.
 

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Discussion Starter #16
Striker isn't getting released by cruciform:

Given what you've described and that it's the least costly to remedy if a 'mistake' happens, filing the rear of the cruciform seems to be the best option.

Carefully file the cruciform as shown below (red line)...


Do not 'disturb' the sear face angle shown below (red lines)...


When finished, the sear should conform to the red lines shown below...



I looked into the firing pin safety being the issue but doesn't seem to be it. I tried holding the trigger down and manually pushing up the firing pin safety to no avail. However, I'm not quite sure what the OP did when he was messing with the firing pin safety, I couldn't understand his words very well.
In rare instances, the firing pin safety and the vertical extension of the trigger bar 'don't like each other' and they may tend to 'bind up'. In some cases, instead of traveling 'straight back' (green arrow below), the vertical extension is pushed to the side (red arrow) and binds against the slide... which can stop the trigger bar from traveling sufficiently rearward to release the firing pin (and is what was happening in the referenced thread).



G19NC corrected the issue by filing the angle and deburring the edges of the vertical extension so that it moved smoothly over the firing pin safety


In addition, my firing pin safety does not bottom out when the trigger is fully rearward, I can push it in a tiny bit
 

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Discussion Starter #17
Glock 17 ejector questions:

The LWD ejectors should look similar to the Glock parts pictured below.



 

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Discussion Starter #18
Glock 43 racking slide is not smooth:

I had intended to post this (more detailed) response a bit sooner, but I've been busy with other issues. Sorry!

That said, here we go...

The following pictures illustrate the relative slide-to-frame positions of my G17.4 when typical 'sticking points' occur during slide installation and cycling.

When installing the slide, if the RSA isn't properly seated in the barrel cutout, the rear disk of the RSA may 'stick' on the frame slide stop (red line below)...



As the slide is pushed further rearward, it may feel 'sticky' or 'gritty'...

... as the barrel locking lug strikes and depresses the slide lock (red line below)...


... then, as the vertical extension on the trigger bar strikes and depresses the firing pin safety (red line below)...


... then again, as the slide trigger connector reset rail strikes and depresses the trigger connector reset tab (red line below)...



Also, from 'fully rearward', as the slide moves forward, the slide may feel 'sticky' or 'gritty'...

... as the slide trigger connector reset rail (again) strikes and depresses the trigger connector reset tab (red line below)...


... then again, as the rear barrel lug strikes and 'rides up' the locking block (red line below)...


With the exception of the 'not properly seated' RSA, the above 'sticking points' are normal.

And, while I've illustrated a G17.4, the 'sticking points' presented above are common to all Glocks.
 

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Discussion Starter #19
NY Triggers:

If a NY trigger spring is indeed installed in your pistol, you may wish to change it to a stock trigger spring, which is Glock part #350 and may be purchased from one of many sources. (Personally, I prefer Midwest Gun Works and MidwayUSA).

https://www.midwestgunworks.com/page/mgwi/prod/350

https://www.midwayusa.com/product/1...-25-26-27-28-29-30-31-32-33-34-35-36-37-38-39

If you want to swap the springs, the following video and pictures may be helpful...



NY1 and NY2 trigger springs


The NY1 trigger spring (red arrow below) is installed, but the trigger bar assembly is not installed.


Remove the trigger group from the lower receiver and remove the trigger bar assembly from the trigger mechanism housing.

Push the NY trigger spring tab (red arrow below) to remove it from the housing.


Then install the stock 'coil spring' trigger spring as shown starting at 3:18 in the above video and reassemble the lower receiver.

Stock trigger spring in the trigger group assembly (red arrow below)


Stock trigger group assembly installed in the pistol (red arrow below)
 

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Discussion Starter #20
RMR Adjustment is confusing:

Simply stated, even though the RMR is mounted at the rear of the pistol, given the design of the optics, the red dot is effectively the front sight... and the front sight is moved in the opposite direction of the desired POI to POA change.

Assuming a proper sight picture, moving the front sight (the red dot) to the left pushes the muzzle to the right... and moving the front sight (the red dot) to the right pushes the muzzle to the left.

Similarly, a shorter front sight (moving the red dot down) pulls the muzzle up... and a taller front sight (moving the red dot up) pushes the muzzle down.

Iron sights work the same way.

Some simple explanations of how red dot optics actually work may be found here...

https://www.quora.com/How-do-red-do...e-the-light-if-its-turned-on-and-aimed-at-you
 
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