Glock Demystification--Step 1

[9.3X62AL]

Last week, I had the great joy of running 175 rounds of factory R-P hardball through the new Glock M-21 in 45 ACP. During this shooting bit, I collected samples of fired brass from it and from an ancient S&W 645, as well as a recently-made Kimber match-grade 1911A1. All rounds were R-P 230 grain FMJ from the same lot number. 10 samples of fired brass from each pistol were compared, all of which were collected after each pistol had fired 50 rounds to get "service-gritty".....and to loosen up the Glock a little, which had stuttered a bit at first. The idea here was to pursue the question of wide chamber diameters in the Glock pistols in this example, to answer the question of need for an aftermarket barrel to promote/extend brass life. This is apart from the cast boolit question, which will follow later.

Rather than belabor the process further, the findings were as follows--at the mid-point of the case wall (the area of widest expansion) the Glock cases' mean was .4780", E/S .003". The well-worn S&W's mean was .4758", E/S .001". The allegedly tight-chambered Kimber target model's mean was .4765", E/S .001".

So, YES--the Glock's chamber appears to run wider than the other examples tested, by .0015" and .0022". Is this significant in terms of brass life? Maybe.

More significantly, this wider chamber may work in my favor when it comes to cast boolit usage. The bore dimensions of about .453" at its widest point and .4535" in the throat indicate a .454" boolit might pay dividends. Gaining roughly .002" of chamber clearance might be just what the doctor ordered.

Prior to firing, I mic'd the R-P loads and found the mid-point of the cartridge cases to average about .470", the case mouth about .471". Winchester Ranger duty loads run .001" smaller at both points. With this in mind, I ran fired cases through the RCBS T/C sizer dies of both 45 ACP and 45 Colt. Sized diameters ran .467" and .469" respectively. There's that fortuitous .002" differential again.

The 45 ACP brass is tumbling as this is written. More to follow.

[AnthonyB]

Al, will an unsized case fired in the Glock drop into the chamber of the Smith and the Kimber? All the 45 ACPs I have tested will digest unsized brass from my M30s with no problem, so I quit worrying about the supposedly oversized chamber issue. Now all you need to do is run a few hundred cast loads through the Glock as fast as you can load the magazines and fire them; I'm willing to bet there will be no significant leading and that the pistol will be equally accurate with cast. In my admittedly limited experience with two M30s, the Glock 45s are very cast reload friendly. Tony

[9.3X62AL]

Tony--

The caliber itself is cast-friendly, so it stands to reason that a Glock would be less likely to go sideways in 45 ACP than in the more lead-hostile chamberings like 9mm or 40 S&W. I'll try the .454" boolits first in that weird bore form, then if they act right--I'll try .452". It would be VERY nice if I could load one boolit diameter (.452") in all my 45's, like in the 9mm's (.357").

I have satisfied myself that the Glock reputation for excessive chamber diameter is--at least in my pistol--another urban legend. How much more of the Glock's supposed rep for poor performance and unsafe operation with reloads and cast boolits remains to be examined for validity.

No one ever speaks of having slugged the Glock barrels' throats or bore form to get the same measurements that are de rigeur for most cast boolit load development. I have--the throat is .4535" or so, the widest barrel diameter is .453", and the shallowest is .449". Not being deeply steeped in physics, I don't know how a cast boolit will respond to being re-formed into that polygonal environment. The surfaces appear to me to be about equal in cross-section, so perhaps we can estimate an "average" bore/groove/WHATEVER dimension of .451", and that the boolit's plasticity will swage up to fully fit the barrel form under the influence of firing pressure. Or--should we go with the throat predication model that serves us so well in conventional bore forms and revolvers? THAT is what I'm after, sort of a "Mythbusters" exploration.

[AnthonyB]

Al, I'm looking forward to reading your results on different diameters. Boolits from my .452 sizer die actually measure .453, and I have been able to use the same diameter in all the ACPs. I've never tested for bench type accuracy though. I am very curious about what you learn. Tony

[versifier]

Al,
I know several people that reload for their Glock 45's (cast & jacketed, factory barrels) plus those that have commented here. I have not seen upon examination the bulged case heads in .45ACP's that are so obvious in Glock-fired .40's. You can clearly see and feel them without even needing to put the caliper to them. If it happens to the .45's it is not obvious to me, nor serious in my estimation. The chamber in my G23 is definitely oversized when its fired brass is compared to other non-Glocked range brass I have collected at our club. I have been debating if I should get a more cast friendly barrel for the G23, or if I should just sell it and buy a .45. I'm leaning toward the .45 as I feel like shooting the G23 is a waste of good brass. I am sold on the reliability and ease of use of Glock pistols, though, and can't see not having one, especially one that would get shot more often.
I don't shoot 9mm often, but I load for an old S&W m59 sometimes. Glocked 9mm brass does not appear to suffer from the bulges like the .40's do, either, but I have not done more than casual measurements in the 9mm, so that may not hold true with a larger sample and more careful measuring.

[9.3X62AL]

Tony--

The brass from the S&W and the Kimber will fit in the chamber of the Glock--not a slip-fit, but it goes in with a little assistance (fingertip push). I'm hoping for service-grade accuracy from the pistol with the castings, safe operation, sustained firing capability, and lack of leading.

Versifier--

There is NONE of that distended case wall that is seen in brass fired in Glock 40's on the cases fired in my M-21. Supposedly--the "3rd Generation" Glock 40's have addressed this issue in some fashion chamber-wise, but I can't confirm that either way. The "expansion" I speak of on the brass is apparent on cases fired in all three pistols, looks identical in character between the 3 sample groups, and requires a mic to discern differences. In other words, the expansion on Glock-fired brass is just like the expansion characteristics seen on every other piece of 45 ACP brass I've fired in a slew of pistols over the years.

More to follow.

[Wayne Dobbs]

Deputy Al,

I am looking forward to your results. I've been a Glock fan for many years, but I've abandoned the .40s entirely and just shoot the 9mm guns. I recently acquired a G21 (used for a great price) and think I'd like to return to my cast bullet .45 ACP days. Keep us updated on the project...

[9.3X62AL]

Will do, folks. I wanted to fire off some more factory rounds on Tuesday at the Burrito Shoot, but between the cold windy conditions and some eyesight difficulties I called the game early. I do like shooting that critter, for sure. One smooth ride!

[mooman76]

I also am looking forward to your results. Right now I am shooting the Glock 22C with lead bullets with extra caution watching for leading, shooting light loads, looking the brass over extra good and shooting no more than one box at a time between cleanings! No problems so far except a small amount of leading that easily cleans out.

[mike in co]

deputy al,

not sure what you are looking for.
there was an actual problem with early glocks in 40sw.
it left a significant section of the case unsupported.
its unlikely any of these guns are on the market, as glock fixed the problem.
if one searches back far enough in pamphlet reloading guides, several were published that specifically excluded thier data for use in glock 40's.
there were some case failures, the problem identified and fixed.
a variation has let some to claim brass fired in all glocks MAY fail if reused due to
constant resizing of brass from oversized chambers.....as you have seen it is actually very similar to other guns.
mike

[9.3X62AL]

Mike--

I'm trying to de-bunk claims about the non-suitability of Glock barrels for reloaded ammo and cast boolits. This partial review above is to note my satisfaction that reloaded ammuntion sensibly assembled will pose no problems in my stock Glock 45 ACP. The "second chapter" will deal with cast boolits and "old standard" cast boolit loads that we have used for years--and I'm leaning toward Lymans #452374 and #452460, sized at .454" and at .452", with WW-231 and Unique. This might require a casting session with Beagled mold to get boolits fat enough to clean up at .454", gotta check that. Might also need a little fatter expander spud--both for this project and for the 45 Colt loads I'm using with .454 boolits. The spuds in my 45 Colt and 45 ACP die sets both mic @ .447" IIRC. So--I might need to acquire some tooling to do this right.

I went into this venture with the idea that the urban legends about Glocks and reloads were pretty weak factually, excepting the 40 S&W in 1st Generation pistols. Seen that sort of brass you mention A LOT, and recognize it readily.

[Bubba w/a 45/70]

I had a 36 in .45ACp, and the majority of loads it digested were lead boolits. Nary a problem with anything in that little joy. I traded it off for a XD45, and now regret that trade.

I was putting mostly 185 SWC's down the tube, with a couple of 230gr RN, and there were never any leading, feeding, or pressure problems in mine. The .45 Glock barrels are good for lead boolit shooting, the other calibers you might get lucky with (I'm making NO comment on this, as it is not something I would like to be held to the wall for). Glock does a more "standard" type of rifling on the .45 barrels for whatever reason, and it makes them more friendly for us.

Just for the record, I would put everything and anything down that tube, have no complaints, and just made sure that I cleaned the barrel out after the range session. The cleaning was only to make sure that nothing built up too much in the barrel, and it went boomy in my hand the next time. Even though I never had any more leading problems than my Colt 1991A1 (nothing to complaint about, just making the comparison), I still cleaned the barrel on the Glock.


I money wasn't an issue, I'd have another 36 right now. No reservations.

[9.3X62AL]

Bubba--

Thanks for the info, sir. The Glock 45 caliber barrels are 8-sided/octagonal, while the other calibers are all 6-sided/hexagonal. The 45 bore LOOKS conventionally rifled, but when slugged the high and low spots are discernable.

I can speculate until the cows come home about how this rifling form works, and why it is or isn't amenable to cast boolits--but such musing would be no more valuable than the urban legends now present concerning the matter. A lot of casters (like Bubba) report good, safe, unleaded results from shooting castings in the Glock stopsign bores.

I re-checked the dimensions of the RCBS expander spuds in the 45 ACP and 45 Colt die sets--those are .449", NOT .447" as previously posted. Memory as I get older is less and less reliable.

[9.3X62AL]

I'm assembling ammo for the Glock M-21 now, and the RCBS .452" sizer die I use for 45 ACP boolits sizes this lot of 92/6/2 #452374's to .453"--a perfect match to the barrel's widest dimension. As-cast, they run about .455", so they may "clean up" when sized at .454".

Nope--didn't put this project on a shelf someplace.

[9.3X62AL]

Last week at the range, Pistolero 451 gave me some swaged 230 grain boolit handloads to run through the Glock 21. If a load was prone to and motivated toward leading--I think these would have obliged. I cleaned the pistol today to prep it for shooting tomorrow--zero/zilch/nada leading.

Tomorrow's test loads will include BD-45's, #452460's, and #452374's atop WW-231, Bullseye, and Unique. All boolits are sized to .453" in the much-used RCBS .452" sizer die, all are Taracorp/92-6-2. I wonder just how many boolits that die has processed.....many thousands over the past 20+ years.

[Bubba w/a 45/70]

....told ya!!!

[9.3X62AL]

Bubba et al--

Oh, I hear ya sir. One of those ideas that keeps rattling around in my head on the Glock/lead boolit subject is the large number of people like yourself that have obtained good service from the humble castings (or swagings) in these pistols.

Also interesting is how--like in Anthony B's case--my sizer die of long service (nominally a .452") actually produces boolits at the possible proper .453" diameter for the barrel's dimensions. I imagine it did indeed produce "spot-on" boolits when it was new, but 20+ years of service.....maybe closer to 25 years have prepped it for this project.

I should also note that I'm running the 45 ACP cases through the 45 Colt T/C sizer to reduce brass working a bit. The Colt sizer produces .469" case diameter, while the 45 ACP sizer (also 25+ years old) produces .467" case diameter. The Colt die-sized loads feed admirably when dry-cycled through the Glock. The #452460 SWC's also seem to feed error-free when seated with about .035" of front drive band protruding from the case. The loads with the front drive band seated flush caused the previously-mentioned cycling issues, with extracted case rims tying up against case mouths of a cartridge in the magazine. Cartridges in the Glock 21 magazine "ride high" compared to 1911A1's or S&W's.

Lots to do this morning before hitting the range--I hope to get some shooting done after making my way through all that crapola. I would miss the burrito for lunch, and my week is not complete without having Glen and/or Rick whup me soundly.

[NVcurmudgeon]

Deputy Al,

"I imagine it did indeed produce "spot-on" boolits when it was new, but 20+ years of service.....maybe closer to 25 years have prepped it for this project."

Now that's interesting. I keep a homemade chart on the wall of the shop comparing nominal vs. actual diameters produced by my Lyman H&I dies. Some were bought new, some used. Some are recently aquired, some ancient. I can use this chart because I use one alloy almost exclusively. But your post makes me think I better check what diameter these things are turning out in 2007.

[carpetman]

Dep Al---Maybe it's just a rumor that persists that Glocks cant use cast bullets. In Dear Abby just today another old rumor was debunked. It was said that "Circumcision of African Men can cut HIV risk by half."

[9.3X62AL]

Thanks for that last, Uncle Ray.

After having Glen and Rick whup me but good yet again yesterday, I ran some #452460, #452374, and some of the BD Original castings through the Glock--60 all told. All were cases processed through the 45 Colt sizer, and all were sized at .453" as detailed previously. Not a bit of leading was visible--anywhere. I will do some more firing with the pistol to attempt accumulation of whatever fouling will appear--but the barrel looks no different than the many Colt, S&W, SIG-Sauer, and parts gun 45 ACP barrels I've run castings through since my first 45 ACP in 1979. NO leading--at all. Size matters. Alloy and lube might--in this case, 92/6/2 and Javelina alox, but the 45 ACP isn't one of the more demanding calibers for cast boolits, compared to the 9mm or 40 S&W. That may be an advantage the Glock 45's possess that the more stressful-to-castings chamberings don't have.

We'll see how it progesses.