Differences between Gen 3 and Gen 4 pistols

Glock logoAs for the differences between Gen 3 and Gen 4 pistols, as a generalization:

Gen 4 pistols have the different grip texture (known technically as “RTF3”), dual spring Recoil Spring Assembly unit (with frame and slide changes to accommodate), larger & reversible mag catch (not ambidextrous as some claim), and four back straps. Gen4 guns are built on the SF frame, resulting in a shorter trigger reach and shorter heel depth than the Gen 3 guns (about 2mm). The SF frames also use a smaller trigger housing mechanism. Gen 4 guns use a “dot” connector instead of the Gen 3 unmarked connector. Gen 4 guns have an updated trigger bar. All Gen 4 guns come with 3 magazines, whereas only the blue label Gen 3 guns came with 3 – white and red label come with 2.

Some Gen 3 models are available in a factory threaded barrel version (to support compensators and silencers). Some Gen 3 and 4 models are available in a factory ported version – although not all models are available in both generations. Some Gen 4 pistols are available in a MOS (“Modular Optic System”) version to support optics. Some Gen 4 pistols are available in a few more factory colors (including Gray, and BFG) than Gen 3 pistols. Both are available in black, FDE, and OD. These are all color molded frames with black slides (the only color Glock makes), trigger, mag catch, slide lock, and slide stop lever. Gen 4 includes color molded back straps. Some Gen 4 guns are available with front slide serrations and extended controls (mag catch, slide stop lever) as well as steel sights.

From a maintenance perspective, the recommended replacement threshold for the Gen 3 recoil spring assembly (RSA) is every 2500-3000 rounds. For the Gen 4, it jumps to every 5000 rounds.

Some will point to the fact that the Gen 3 has been around for years, and thus, is proven. Well, so has the Gen 4. Production on Gen 4 guns began in 2009. I think that’s sufficient time to be considered “proven”.

Some will say the “finish” is different. Glock made a change to the metal treatment process (which is applied to the bare metal, before the finish), starting in 2007 (and that transition was completed in 2010). That original process was known as “Tenifer”. The change to the newer Melonite process caused subsequent guns to have a finish with a slightly different appearance, but a higher HRc rating, which is good. It’s not about the generation of the gun that dictates the finish, but WHEN the gun was manufactured. A Gen 3 gun and a Gen 4 gun both manufactured on the same day will have the same finish.

To see more technical data for each specific model, including both current Gen 3 and Gen 4, see https://us.glock.com/products/all.

Differences between Gen 4, Gen 5, and M pistols

Glock logoHere are the differences in the ‘M’ pistols used by agencies such as the FBI, DOS/DSS, ATF, DEA, USMS, and USMC CID, as well as the consumer Gen 5 guns vs. the Gen 4 pistols:

  • No finger grooves.
  • Flared mag well.
  • Ambidextrous one-piece slide stop lever – on many of the ‘M’ guns, it’s also an extended ambi slide stop. That extended ambi slide stop lever is part # 33797, and is available for sale to certified armorers. It now appears that the extended ambi slide stop lever is on the Gen 5 G34.
  • Front of the slide is rounded to match the Gen 4 subcompacts and long slide models. When first introduced, the Gen 5 and ‘M’ frame weren’t beveled to match. That has since been resolved in newer Gen 5 pistols.
  • Land and groove rifling instead of polygonal
  • Gen 5 GMB (Glock Marksman Barrel) barrel has a target match crown (FBI ‘M’ guns don’t). G17 barrels cannot be swapped with other generation guns – mainly due to the differences in locking blocks (now the same as the other 9mm pistols) and newer, longer, RSA.
  • Same style firing pin safety (angled instead of flat) as the Glock 43
  • Return to two-pin frame due to a redesign in the locking block area of the frame that removes the need for the third pin.
  • Slide lock spring similar to Glock 43 (coil vs leaf), and the slide lock is moved slightly rearward.
  • Return of cutout on bottom of front strap to assist with stripping magazine (such as due to a double feed) that were originally in Gen 1, Gen 2, and early Gen 3 full sized guns. Early prototypes did not have this cutout, which is why it’s not visible in some early pics. This cutout is on the 17, 19, and 34, but not the 26. The 26 has the extended toe similar to the MHS and 19X frames. It is also not on the Gen 5 MOS guns. Note that this was eventually removed from the Gen 5 pistols in summer 2019.
  • Tougher finish applied to the same Melonite metal treatment process. This finish is dubbed nDLC (diamond like coating) that is similar to the black nitride finish. Glock refers to it as an ion bonded finish, and will only be available on Gen 5 and M guns.
  • The upper cartouche, the flat area on the upper right grip area that show where the pistol was made, has been moved down and combined with the lower one, which contains the patent number
  • Mags have an orange mag follower
  • Mags have extended front lip to aid in reloading
  • Mags have a slightly rounded base plate (bottom front edge)
  • Initially, there were no front serrations on the regular 17 and 19, as some people claim, or as some photoshopped pictures suggest. Glock added an LCI to the guns many years ago to negate the need for press checks. Front serrations were eventually added to all Gen 5 pistols except the 19X in summer 2019.
  • ‘M’ guns come with 6 magazines. Gen 5 guns come with 3.
  • Gen 5 is available with polymer sights or several night sight variations, including factory and Ameriglo ‘Bold’ night sights. The new sights are narrower than previous models. ‘M’ guns have slightly different sights than the Bold sights. These are called the ‘Agent’ sights. Differences being FBI sights have a ‘U’ shaped notch in the read sight, whereas the Bold have a square notch. Both rear sights are serrated, and the night sights don’t have a white or colored ring around them (this is often referred to as ‘blacked out’). Both the Gen 5 Bold sights and the FBI sights are available with  a .125 orange front sight as well as a more traditional .140 width sight.
  • Glock had originally said no plans for MOS guns, but they have released the Gen 5 G17, G19, G26, G34, G45, and G47 in MOS configurations.
  • Glock said originally that the Gen5’s will only be offered in 9mm, but São Paulo Police Department (Brazil) has deployed the Gen 5 G22, which includes a manual safety like the 17S and MHS pistols. Glock has since released .40 cal Gen 5 guns 22, 23, and 27.
  • New striker, but same spring cups, spring, and sleeve
  • New extractor
  • New slide cover plate
  • New trigger mechanism housing
  • New trigger bar, but the Gen 4 dimple is removed (since the Gen 5 went to the angled trigger safety, the dimple is no longer needed)
  • Gen 5 doesn’t use the ‘S’ shaped coil trigger spring, like the previous generations, instead going to a setup like the slimlines
  • G19 and G26 come with a smooth trigger (like the 17) instead of the previous grooved trigger.
  • FBI ‘M’ guns have the nDLC finish on some internals including the trigger bar, connector, and slide stop lever,  Gen 5 guns do not. Also, ‘M’ guns that went to a select few agencies do not have the nDLC treated internals. It’s easy to spot the difference, as the nDLC finished internals are jet black. Not gray.
  • ‘M’ guns appear to have an extended and rounded mag catch as stock, vs. a normal mag catch for the Gen 5 guns
  • ‘M’ gun is also available as MOS
  • Gen 5 are currently available in black, FDE, BFG, and gray, although the FDE and gray guns were early Gen 5 with the non beveled frame, and front cutout. ‘M’ guns are available in several color molded frames.
    • Black is standard issued to all agents.
    • BFG is issued to FBI SWAT
    • FDE is issued to FBI HRT
  • Gen 5 guns have a ‘5’ rollmark on the top of the barrel. ‘M’ guns have an ‘M’ or ‘5M’.
  • Gen 5 G34 doesn’t have the cutout on the top of the slide like previous version, yet still maintains good balance due to a re-engineering of the materials used in the slide.
  • Gen 5 pistols have a rail that uses the 1913 picatinny dimensions.
  • Gen 5 G19 and G45 are available in TB versions, with factory threaded barrels and Ameriglo suppressor sights.
  • Newer production Gen 5 pistols have an enhanced breech cut that greatly improves ejection of spent casings. I’ve not seen this new breech cut on any of the ‘M’ guns.

The new mags will work in previous generation pistols, and vise versa, with the exception of the 21SF with picatinny rail & ambi mag catch, and the 19X.

Keep in mind that the ‘M’ pistols are Glock’s specific response to the FBI requirements for a new pistol. Just because any of these features exist on these guns does not mean that they will appear in any other non-‘M’ guns in the future.

The following pictures of the Gen 5 G26 and G34 are from Glock.

The Wish List

Glock logoThis is a running list of things I’m actively looking for. This is a living post and will be updated as needed. Please contact me if you have any of these items and are looking to part with them or know where I can obtain them. All firearms transactions MUST go through an FFL.

Note: Items that are strike-through are items I’ve purchased but have not yet received.


These are publicly released pistols that I’m actively looking for. Many are fairly hard to find. I prefer those pistols with the original case, including the matching case label, and all case contents (loader, brush, rod, lock, correct manual/packet, spent casing, etc.). But I’m willing to discuss any opportunity.

Gen 1

  1. Glock 17 Gen 1 chambered in 9×21 IMI
  2. Glock 17 Gen 1 chambered in 9×21 IMI with “CAT. 5180” roll mark on the slide

Gen 2

  1. Glock P9M Gen 2
  2. Glock 17 Gen 2 chambered in 9×21 IMI with “CAT. 5180” roll mark on the slide
  3. Glock 17L Gen 2 ported
  4. Glock 19 Gen 2 training pistol (basically 19P but roll marked “19”)
  5. Glock 20C Gen 2
  6. Glock 20CC Gen 2 – must include the original case with a matching label
  7. Glock 21C Gen 2
  8. Glock 21CC Gen 2 – must include the original case with a matching label
  9. Glock 22CC Gen 2 – must include the original case with a matching label
  10. Glock 23CC Gen 2 – must include the original case with a matching label
  11. Glock 29 Gen 2
  12. Glock 30 Gen 2
  13. Glock 31 Gen 2
  14. Glock 31CC Gen 2 – must include the original case with a matching label
  15. Glock 32CC Gen 2 – must include the original case with a matching label
  16. Glock 34 Gen 2

Gen 2.5

  1. Glock 20CC Gen 2.5 – must include the original case with a matching label
  2. Glock 21C Gen 2.5

Gen 3

  1. Glock P9M Gen 3 used by Germany’s GSG9
  2. Glock 17 Gen 3 chambered in 9×21 IMI with “CAT. 5180” roll mark on the slide
  3. Glock 17 Gen 3 chambered in 9×21 IMI without “CAT. 5180” roll mark on the slide (just caliber)
  4. Glock 17AO – Australian Gen 3 G17 with threaded barrel, in Olive Drab (GLOCK17AO)
  5. Glock 19 Gen 3 chambered in 9×21 IMI
  6. Glock 26 Gen 3 chambered in 9×21 IMI
  7. Glock 29 Gen 3
  8. Glock 34SC (“Sport Competition”) Gen 3 chambered in 9×21 with “CAT 10861” roll mark on the slide – sold in Italy
  9. Glock 35C Gen 3 – even though there were only 2 of these made, and they’re both owned by a collector I know, I can always wish, right?
  10. Glock 17MB/19MB – Gen 3 ambidextrous mag release pistols from Europe. The 17MB is also available in OD.


  1. Glock 30 RTF2 FDE – yes, I know only 1 was made
  2. Glock 30SF RTF2 FDE – only one exists
  3. Glock 32 RTF2 (no gills)

Gen 4

  1. Glock 17 Gen 4 chambered in 9×21 IMI with “CAT. 5180” roll mark on the slide
  2. Glock 17C Gen 4 chambered in 9×21 IMI
  3. Glock 17 FTO Gen 4 chambered in 9×21 IMI (120mm-long threaded barrel)
  4. Glock 17 LCS Gen 4 chambered in 9×21 IMI (milled slide cuts)
  5. Glock 19 Gen 4 chambered in 9×21 IMI
  6. Glock 19 Gen 4 MOS chambered in 9×21 IMI
  7. Glock 19 FTO Gen 4 chambered in 9×21 IMI (threaded barrel)
  8. Glock 21C Gen 4 (European only)
  9. Glock 26 Gen 4 chambered in 9×21 IMI


  1. Glock 19X chambered in 9×21 IMI
  2. Glock 19X MOS (PX1950703MOS) – I don’t believe any of these have been built yet, but the SKU exists.
  3. Glock 19X MOS TB (PX1950S03MOSTB)

Gen 5

  1. Glock 17 Gen 5 chambered in 9×21 IMI
  2. Glock 17 Gen 5 built for special forces, milled specifically for the Delta Point Pro optic (PA175A202MOS3)
  3. Glock 17 Gen 5 TB (factory threaded barrel and suppressor sights)
  4. Glock 17 Gen 5 TB MOS
  5. Glock 19 Gen 5 TB MOS
  6. Glock 19 Gen 5 chambered in 9×21 IMI
  7. Glock 22 Gen 5 with manual safety (Brazil only)
  8. Glock 26 Gen 5 chambered in 9×21 IMI
  9. Glock 26NZ Gen 5 – made for New Zealand with a longer barrel
  10. Glock 45 Gen 5 MOS in gray (PA455S203MOSGF) – I don’t think any have been built yet, but the SKU exists.
  11. Glock 45 Gen 5 MOS TB (apparently European only)
  12. Glock 45 Gen 5 TB in FDE (PA455S203TBDE) – I don’t think any have been built yet, but the SKU exists.
  13. Glock 45 Gen 5 TB in gray (PA455S203TBGF) – I don’t think any have been built yet, but the SKU exists.
  14. Glock 45 Gen 5 MOS5 with Trijicon RMR (PA455S202MOS5)
  15. Glock 45 Gen 5 MOS6 with Holosun (PA455S202MOS6)

M pistols

  1. Glock 17M FDE – issued to FBI HRT
  2. Glock 17M OD – issued to FBI regional SWAT
  3. Glock 19M OD – issued to FBI Regional SWAT
  4. Glock 19M MOS

Slimline pistols

  1. Glock 43 chambered in 9×21 IMI
  2. Glock 43X chambered in 9×21 IMI (black slide version)
  3. Glock 43X Rail (non-MOS version – Europe only)
  4. Glock 43X Rail chambered in 9×21 IMI
  5. Glock 48 chambered in 9×21 IMI
  6. Glock 48 Rail (non-MOS version – Europe only)
  7. Glock 48 Rail chambered in 9×21 IMI
  8. Glock 48 MOS with Shield RMSc (see GLOCK Perfection | G48 MOS with RMSc Shield)

Misc Pistols including imports

  1. Glock original P80 pistol
  2. Glock original P82 pistol
  3. P9A1 used by the Kampfschwimmers of the Bundeswehr (See this link)
  4. Glock 44DK for Denmark with muzzle device (See this link)
  5. Glock 19 made for Canadians with an extended barrel and maple leaf on the slide (See this link)
  6. Glock 19 Tactical (‘Tactical’ written on the right side of the frame. I believe these were marketed for the Philippines) – 4.5lb connector
  7. Glock 17DK/19DK – Danish pistols with an extended barrel
  8. Glock 17S – G17 with manual safety used in Tanzania, New Zealand, Israel, Pakistan, South America, and Royal Thailand Police
  9. Glock 22S – G22 with manual safety
  10. Glock Gen 2 19S with manual safety
  11. Glock 17 Pro – produced for Finland, with threaded barrel, maritime spring cups, extended slide stop lever, 4.5lb connector, night sights, +2 mag extensions, and redesigned mag release.
  12. Glock 23 Mariner – ‘Mariner’ marked slide, 4.5lb connector, maritime spring cups, + floor plates (I believe marketed solely for the Philippines) (See this link) This is not the recent release by Glock.
  13. Glock 25TB
  14. Glock 26 Mariner
  15. Glock 46 – rotating barrel in G19 size frame

Special Purpose / Training / Cutaway Pistols

  1. Glock 17 Gen 5 Cutaway
  2. Glock 17T UTM Gen 4
  3. Glock 17T Gen 5 MOS UTM
  4. Glock 17T Gen 5 MOS FX/FOF
  5. Glock 17P Gen 4
  6. Glock 19T Gen 5 MOS FX/FOF
  7. Glock 19T Gen 5 MOS UTM
  8. Glock 19T Gen 2
  9. Glock 19P Gen 3
  10. Glock 19P Gen 5 (full red)
  11. Glock 19R Gen 3
  12. Glock 19 Gen 5 Cutaway
  13. Glock 20 Gen 2 Cutaway
  14. Glock 20 Gen 3 Cutaway
  15. Glock 23 Gen 2 Cutaway
  16. Glock 23P Gen 3
  17. Glock 26P
  18. Glock 45P Gen 5 (full red)
  19. Glock 47P (full red)
  20. Glock 45T MOS UTM

Commemorative Pistols

  1. Glock 19 & 26 “Defense Set” w/ presentation case or just the presentation case
  2. Glock 17 “Homeland Defender” w/ GTL-10 light (although I can provide the GTL-10 if needed)
  3. Glock 23 Apache Instructor Pilot Model
  4. Glock 23 Gen 2 “Kiowa Warrior Commemorative” (only 26 made – with USAxxx serial) (See this link)
  5. Glock 19C Gen 3 Operation Enduring Freedom (“OEF-XV11 2011-2012” on the slide)(See this link)
  6. Any of the pistols from the ELP program. I already have one of them, but looking for more. See Hand Engraved And Gold Inlaid Factory Glocks for more info.
  7. Any of the 30th-anniversary pistols. See A Year of Perfection. (See this link)
  8. Detroit PD marked Glock 23. I have a matching G22 and G27 and would like to complete the set.
  9. Glock 19 made for the Vatican (See this link)
  10. Glock 23 Gen 2 “50th Anniversary of Bell Helicopter”/ 100th Atlanta Olympics with display case (See this link)
  11. Glock 27 Gen 3 “Ducks Unlimited/Great Outdoors” (only 1 made)
  12. Glock 27 Gen 3 “40 years of Alaska Statehood 1959–1999” (only 100 made)
  13. Glock 17 Gen 3 “2 millionth Glock” (either the single Austria pistol or the single USA pistol) (See this link)
  14. Glock 17 Gen 4 “The Evolution Of A Revolution 1982-2012” 30th Anniversary Edition
  15. Glock 23 225th Anniversary US Marshal (See this link)


Here are the various non-pistol items that I’m looking for.

Glock Tactical Lights

  1. Glock Tactical Light GTL-11 (light w/ dimmer)
  2. Glock Tactical Light GTL-51 (IR light & IR laser)
  3. Glock Tactical Light GTL-52 (IR light & IR laser w/ dimmer)

Glock Knives

  1. Glock 78 ‘Perfection Desert Storm’ knife used in some of the Desert Storm display cases. See these photos. I’m not convinced this was a Glock-produced item. Might be a one-off custom job.
  2. Glock 78 gray with the current logo
  3. Glock 81 desert tan with circle logo
  4. Glock 81 from Malaysian military with VAT 69 Komando logo on blade and sheath
  5. Glock 81 with “Noricum” roll mark on the sheath
  6. Bayonet adapter for the Steyr Aug rifle that works with the Glock knives


  1. Orange Glock 17 and 20 training mags. I currently have the orange training mags for the 19, 21, 22, and 23. So I’m open to orange training mags in other models not listed here.
  2. Glock warranty card, Form US 003 – 04/88, without any writing in the serial number boxes
  3. Glock mag loaders marked ‘4832‘. I need 6 of them. See this picture.
  4. Glock-staked front sights in excellent condition. I need 4-6 of them. See this picture.
  5. Some of the original plastic thread protectors for the TB pistols. I bought a couple of used TB guns and they didn’t come with them.
  6. Glock disassembly tool (olive)
  7. Laser filters (all of them)
  8. Dummy barrels (all of them)

Printed Materials

Glock Autopistols magazine. I have extras of 1995, 2012, and 2013 to trade/sell. I need the following issues:

  1. 1996
  2. 1997
  3. 1998
  4. 1999
  5. 2000
  6. 2002
  7. 2005
  8. 2006
  9. 2007
  10. 2008
  11. 2009
  12. 2011
  13. 2014
  14. 2015
  15. 2017
  16. 2018

Bullet In magazine – this was a magazine sent only to stocking dealers. I’ll take any issues.

Glock Armorer’s manuals. Not the aftermarket ones. I need the following ORIGINAL (although I’ll also gladly accept quality scanned PDF versions):

  1. 1985 – not sure this even exists
  2. 1986 – not sure this even exists
  3. 1987 – not sure this even exists
  4. 1990
  5. 1993
  6. 1994
  7. 1995
  8. 1996
  9. 1998
  10. 1999
  11. 2001
  12. 2003
  13. 2004
  14. 2005
  15. 2006
  16. 2007
  17. 2008
  18. 2010
  19. 2011

Glock Annual magazine. I have every issue, so I don’t need any. But I have extras of the following issues to trade/sell.

  1. 1995
  2. 1996
  3. 1997
  4. 1998
  5. 2001

Glock Report magazine. I need all issues before 2011 issue 1, with the exception of 2007 issue 2, which I have. I have extras of the following to trade/sell:

  1. 2012-2
  2. 2013-1
  3. 2013-2
  4. 2014-1
  5. 2014-2
  6. 2015-1
  7. 2015-2
  8. 2016-2
  9. 2017-1