Glock GMB Rifling NOT Gen5 Exclusive?

[echo5charlie]

Well, I learned something a couple weekends ago. While I was explaining the product upgrades of the Gen5 line to previous generations I was asked about the rifling. I field stripped the 19.5 I was showing and grabbed a G43 from the case to highlight the differences in rifling...only to see "GMB" rifling in the 43 barrel. Thinking that *maybe* Glock was just transitioning all 43 barrels to GMB to ease 43/43X production I grabbed a 42 from the case. It also has GMB style rifling. Having no Gen3 or Gen4 9mm guns in stock I used an HK P30 barrel to highlight the traditional polygonal pattern.

So this morning I just remembered to check my 2015 vintage G43 and it also has GMB style rifling. As well as my 2014 G42. To make sure I hadn't smoked crack (and forgot about it) I compared my G43 barrel to my G43X barrel - rifling pattern is identical.

Now I feel really dumb for not noticing this in 5.5 years, the G42 I should have picked up on back in 2014. Given the real-world results in precision, I hazard that this rifling design was developed to ensure that the 42 and 43 met ATF accuracy requirements.

So is this something that was known and I was just in a different dimension?

[BigT]

42 and 43 have always had the GMB rifling, just not the target crown.

I don't recall it ever being publicly advertised.

[echo5charlie]

42 and 43 have always had the GMB rifling, just not the target crown.

I don't recall it ever being publicly advertised.

I am just astounded that with the GMB selling point that I never even read something to the effect that "it's the same rifling in the 42 and 43" with all the hoopla over the M pistols and the subsequent Gen5 release. I mean, in the three Glock Armorer classes I have attended since 2014 it was never even mentioned as an aside. Seriously, the last class the instructor was touting the NEW GMB rifling, and I stress new.

I mean I get not really pushing it as a feature before the M/Gen5 release - if it helps that much why don't all the Glock models have it now, right?

[Jim Watson]

What are ATF accuracy requirements? Do you mean a standard for arming their own agents? I never heard of any sort of government requirement for sale or even for importation.

[JTQ]

Didn't those guns introduce just about all of the Gen 5 features? They probably weren't named Gen 5 because they were new models and weren't replacing a previous Gen. Once those features were introduced on current models, they needed to give them a new Gen name.

[echo5charlie]

What are ATF accuracy requirements? Do you mean a standard for arming their own agents? I never heard of any sort of government requirement for sale or even for importation.

I may be showing my ass on this. I now believe I was wrong in recollection about handguns needing to meet some sort of accuracy requirement.

[BigT]

I am just astounded that with the GMB selling point that I never even read something to the effect that "it's the same rifling in the 42 and 43" with all the hoopla over the M pistols and the subsequent Gen5 release. I mean, in the three Glock Armorer classes I have attended since 2014 it was never even mentioned as an aside. Seriously, the last class the instructor was touting the NEW GMB rifling, and I stress new.

I mean I get not really pushing it as a feature before the M/Gen5 release - if it helps that much why don't all the Glock models have it now, right?


They also didn't mention the pretty much Gen5 internals on the slimlines when they launched them, I assume to make that part of the Gen5 launch.

They likely don't all have it as its a generational thing that differentiates Gen5 from the previous Gens.

Not all instructors have equal knowledge of the machine beyond the manual.

[JohnO]

A little birdie has told me multiple times that Glock was pressured by LE in general to adopt conventional rifling. The rational being polygonal rifling did not impart identifiable markings enough to distinguish which rounds belonged to individual guns when multiple LEOs fired. Anyone heard this? I have no clue as to the veracity of this claim.

[Jim Watson]

There was a legend some years ago that one PD, Miami, maybe, had Glock barrels made with artifacts in the bore to impart distinctive engraving.

[echo5charlie]

They also didn't mention the pretty much Gen5 internals on the slimlines when they launched them, I assume to make that part of the Gen5 launch.

They likely don't all have it as its a generational thing that differentiates Gen5 from the previous Gens.

Not all instructors have equal knowledge of the machine beyond the manual.

I kind of lost you there. The topic at hand is the rifling, not internal parts differences.

[echo5charlie]

There was a legend some years ago that one PD, Miami, maybe, had Glock barrels made with artifacts in the bore to impart distinctive engraving.

As of 2017 Glock would machine barrels with an unique forensically identifying mark for LE agencies.

[BigT]

I kind of lost you there. The topic at hand is the rifling, not internal parts differences.

My point is they changed both and brought up neither because they had other facets they focused on , in the slimline launches. So just like the internal parts being basically Gen5 , the rifling is basically Gen5. But mention of neither was part of the launch.

[echo5charlie]

In many ways, if not entirely so, the Gen5 guns are scaled up versions of the 42 and 43. :)

Mostly so.