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Police Sergeant Pontificates on .40 vs 9mm "cartridge ignition pressures"
Gun Watch ^ | 9 September, 2018 | Dean Weingarten

Posted on 09/09/2018 5:05:27 AM PDT by marktwain


Two police departments in Michigan are trading in police guns for new ones.

The Valparaiso police department is trading in .40 caliber Glocks that are a few years old for 9mm Glocks that are new. The trades should happen this year, in 2018.

The public often look to police for firearms expertise. Unfortunately, some police feel the need to demonstrate their lack of knowledge.  When asked about a trade-in of Glocks, Sergeant Michael Grennes is reported as giving this response. From nwitimes.com:
The difference between the 9mm and the .40-caliber guns, he explained, is one of cartridge ignition pressures. The 9mm has a long, low, smooth ignition impulse, while the .40 has a short, sharp, abrupt ignition impulse.

That recoil caused cracking of the frame in the .40-caliber guns, especially ones that had been used often over four to five years, he said.
There is no significant difference in pressure levels in Glock .40 caliber and Glock 9mm pistols.

SAMMI pressure limits for the 9mm = 35,000.   For the .40 cal = 35,000.

Given the abysmal ignorance of most reporters about firearms, it is possible the Sergeant was misinterpreted.

The Sergeant's information carries a bit of truth. Early Glock .40s used the same recoil spring as the 9mm, which allowed the .40 to recoil more sharply. The .40 caliber has more energy, so there is more energy in the recoil impulse. With high round counts, a small number of frames suffered hairline cracks.

The Sergeant may have confused internal pressures with external mechanics.

In the early generation 3 Glocks, starting about 1998, the frames were reinforced with an  extra pin in the frame, that also offered a stress relief hole to stop the rare cracking of the Glock .40 calibers. As the pistols the Sergeant is referring to are only 4-5 years old, they are not subject to the cracking problem.

It appears there is a current trend to go from .40 caliber Glocks to 9mm Glocks. It may offer the opportunity to pick up some inexpensive, but excellent Glock .40 calibers as police trade ins.

Reinforced frames have 2 pins instead of 1 pin above the trigger, so they are easily noted.  The Generation 5 Glocks have gone back to 1 pin, but are only offered in 9mm.

©2018 by Dean Weingarten: Permission to share is granted when this notice and link are included.

Gun Watch



TOPICS: Business/Economy; Government; Society
KEYWORDS: 40; 9mm; banglist; glock
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Expectations of police firearms expertise often exceed reality.
1 posted on 09/09/2018 5:05:27 AM PDT by marktwain
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To: marktwain

Never cared for Glocks myself. They have the ergonomics of two 2”x2”s nailed together, at least in my hand. I far prefer the feel of a Beretta or CZ75 which seem to point themselves.


2 posted on 09/09/2018 5:14:33 AM PDT by Hugin
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To: marktwain

Or, as the author posits, perhaps the reporter just switched from covering the Ladies Auxiliary Potluck Supper to firearms expert.


3 posted on 09/09/2018 5:17:02 AM PDT by ProtectOurFreedom
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To: marktwain
My Smith & Wesson MP .40c has replaced my Ruger .357 Police Service Six as my favorite carry piece. Several more rounds, Crimson Trace laser sighting, and similarly devastating impact with smoother recoil. Then there's the reload factor.

A vastly superior personal carry piece. IMHO.

4 posted on 09/09/2018 5:17:21 AM PDT by Gargantua (The wheel is spinnin' and it can't slow down... ;^)
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To: Hugin

>>Never cared for Glocks myself. They have the ergonomics of two 2”x2”s nailed together, at least in my hand. I far prefer the feel of a Beretta or CZ75 which seem to point themselves.

Glocks are something you have to force yourself to love for the first few months. Then, you wonder why you even bother with all the other guns out there.

I’ve shot Glocks for 30 years and love them, but I recently picked up a full-size S&W M&P 2.0 in 9mm and I think that Glock has finally met its match.

But, I heard a rumor from a guy who had to sign an NDA at an invitation-only Glock event that there is an entirely NEW Glock coming out. Not a Gen 6, but something altogether different.


5 posted on 09/09/2018 5:27:22 AM PDT by Bryanw92
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To: marktwain
I have a bunch of glucks (sic). They are super reliable, ugly as everything but a Hi Point...., but I love them. They are everywhere, reliable, accurate and easy to find parts for.

For that reason, I LOVE it when police depts decide they need to change models. I have picked up a bunch of cheap 22s and some 17s because some bureaucrat thought they needed to change. I mean, under 300 dollars cheap. I treat em like gold and silver, in that I never sell them. Just put them in the can with the ammo and keep them till the zombie apocalypse, I guess. I will admit I DO sometimes use them in a swap out for another weapon (usually a glock 19, or my favorite carry, a sig 228), but mostly they stay clean, oiled and stored away.
6 posted on 09/09/2018 5:44:21 AM PDT by mostly_lies
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To: Hugin

“Never cared for Glocks myself.”

I’m just the opposite. I have several Glock platforms.


7 posted on 09/09/2018 5:46:56 AM PDT by ought-six (Multiculturalism is national suicide, and political correctness is the cyanide capsule.)
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To: marktwain
I noticed only a bit more felt recoil in most .40 S&W versions of 9x19mm pistols I was familiar with, but was not tempted to buy one when the .40 was still ascending, as they didn't seem to do much that a 9mm wouldn't do as well (and do it more cheaply). Now that the .40 has lost some of its luster in LE, I am no longer pestered by well-meaning people to get on the .40 bandwagon.

I have, however, given up on striker-fired guns and returned to hammer-fired DA/SA pistols (albeit with decockers rather than safeties). I remain a contrarian even in my golden years.

Mr. niteowl77

8 posted on 09/09/2018 5:50:02 AM PDT by niteowl77
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To: ought-six

Do NOT start with an automatic, folks.

Think : REVOLVER!

Simple, simple, simple.
Change later, iffen you want—months and a few THOUSAND rounds later, perhaps.


9 posted on 09/09/2018 5:57:42 AM PDT by Flintlock (The ballot box STOLEN, our soapbox taken away--the BULLET BOX is left to us.)
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To: ought-six

Do NOT start with an automatic, folks.

Think : REVOLVER!

Simple, simple, simple.
Change later, iffen you want—months and a few THOUSAND rounds later, perhaps.


10 posted on 09/09/2018 5:58:03 AM PDT by Flintlock (The ballot box STOLEN, our soapbox taken away--the BULLET BOX is left to us.)
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To: Hugin

2x2? My Glock 30 feels like a 2x4! But it just runs and runs and runs. The CZ75 is nice - just picked up a j frame 38 - what a revelation- wheel guns are so fun to shoot.


11 posted on 09/09/2018 6:03:01 AM PDT by model B (attitude is a little thing that makes a big difference -- Sir Winston Churchill)
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To: marktwain
The public often look to police for firearms expertise.

Well, I ain't all of the public, but I assure you, the police is the very last place I go to for firearms expertise and/or advice.

Most of the PO's I know can't hit the side of a barn from two feet and have no real knowledge of what makes their gun go bang.

The majority of firearms training for PO's is abysmal.

Sometimes I wonder if any of them actually ever receive any training at all, beyond 50 or so rounds every 3-6 months.

There are exceptions, but most medium and small departments simply cannot afford the time and expenditure for good, realistic firearms training.

12 posted on 09/09/2018 6:17:18 AM PDT by OldSmaj
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To: Hugin

Not all Glock models are created equal. For sub-compacts with double stack mags, I would generally agree with you. But I love my G19s and 43.


13 posted on 09/09/2018 6:22:35 AM PDT by Magnum44 (My comprehensive terrorism plan: Hunt them down and kill them)
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To: Flintlock

After decades of shooting, I’ve never had a failure in an automatic that I couldn’t fix in a few minutes. With the exception of my issued M9 which broke most times I shot it.

I’ve owned 4 revolvers and had many lockups with prolonged shooting sessions. Several that I had to solve by hiring a gunsmith.

If you can regularly clean your weapon, the revolver may be more reliable but if you plan on ever being in a situation we’re you must keep shooting a dirty weapon, the auto is more reliable in my experience.


14 posted on 09/09/2018 6:24:49 AM PDT by dangerdoc
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Glocks get the job done just fine. And they’re very serviceable for the armchair smithy.

I also think that now as 9 mm ammunition has been thoroughly enhanced and has had a number of years to mature so to speak... That the loads available are effective and probably just as effective as a 40. Personally I wouldn’t carry either but I have shot and trained with both the 9 and the 40... and the .451911A1. The 92F was a piece of junk as far as I’m concerned, and I thought it was a poor replacement for the 1911, however I am not a big fan of the 1911... I like the 1911, but I don’t think I would carry one routinely because I would like to have something lighter.


15 posted on 09/09/2018 6:30:34 AM PDT by Clutch Martin (The trouble ain't that there is too many fools, but that the lightning ain't distributed right.)
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Wasn’t Smith & Wesson sued by Glock for the M&P for copyright or trademark infringement? I think originally they were design identical. and I believe, that Smith & Wesson now pays Glock royalties for each sale. I don’t think there was a settlement I think the agreement was royalties and some back payment. So Glock by proxy license Smith & Wesson to produce Glocks design with Smith & Wesson stamp


16 posted on 09/09/2018 6:35:17 AM PDT by Clutch Martin (The trouble ain't that there is too many fools, but that the lightning ain't distributed right.)
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To: dangerdoc

Thank you for your post. Your experience is so foreign to mine that I would very much appreciate more details from your experience if you would please.

I use S&W and Dan Wesson revolvers, and in my mind compare them with colt 45’s. Thank you!


17 posted on 09/09/2018 6:37:24 AM PDT by BDParrish (One representative for every 30,000 persons!)
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To: niteowl77

I’ve only owned 1 40 cal and to this day I’ve yet to shoot it as a 40. I wanted to build a Browning Hi-Power in 357 Sig and I had to get a 40 Hi-Power to do it. I sent it to NOVAC for the conversion and now it’s convertible from 40 to 357 SIG. I’ve never shot it with the 40 set up. hell I don’t even have any 40 cal ammo.

Striker fired pistols I have no use for nor do I have a use for plastic framed anything. They’re some good solid and reliable plastic frames out there but I just can’t make the change. I even recommend them for others!

As far as calibers go I’ll stick with the 9 mm it’s proven to be a reliable and user friendly round in most hands. While I like my 45’s in both 1911 and 220 SIG configurations they’re just not as user friendly. When I say user friendly I mean putting accurate rounds down range quickly. Time and time again the lowly little 9 mm out performs in that area.


18 posted on 09/09/2018 6:42:47 AM PDT by Dusty Road (")
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To: marktwain; mylife; Joe Brower; MaxMax; Randy Larsen; waterhill; Envisioning; AZ .44 MAG; umgud; ...

RKBA Ping List


This Ping List is for all things pertaining to the 2nd Amendment.

FReepmail me if you want to be added to or deleted from the list.

More 2nd Amendment related articles on FR's Bang List.

19 posted on 09/09/2018 6:53:21 AM PDT by PROCON ('Progressive' is a Euphemism for Totalitarian)
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To: marktwain

The LEOs want new guns. Who on the city council is going to challenge the explanation of the ‘expert’ and deny them the new toys?


20 posted on 09/09/2018 7:06:19 AM PDT by Bitman
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