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Old February 2, 2011, 09:20 PM   #1
colospgsAVID
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Fully supported chamber?

Hello All,
I have some confusion as to what a "fully supported chamber" is. I have a couple Sig pistols and a Glock pistol. I have a Glock 20 chambered, of course, in 10mm. I have heard a lot of things said about Glock barrels not being "fully supported". I want to use some "Buffalo Bore" type ammo, but have read I need an aftermarket barrel that is "fully supported". From what I understand, Sig barrels are "fully supported". The only difference I see comparing the barrels themselves is, the lock up on the hood of the barrel is symmetrical on my Sig barrels, and on the Glock barrel it is asymmetrical. It looks to me, that feature on Glock pistols is for ejection purposes. Is the difference in the barrel lug? Having different lock up types, that comparison is worthless to me. I just don't know the difference or how to identify the differences. I've searched a bit out there and also in here, came up with nothing helpful. Any guidance will be truly appreciated!
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Old February 2, 2011, 09:34 PM   #2
mete
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Chamber means the area in the back of the barrel that surrounds the cartridge. With barrel removed from the gun put a round in the chamber and see how much of the case you can see at the lower rear part of the chamber .Usually the camber in this area is relieved to assist in chambering the rounds. The early Glock .40s had the least amount of chamber support though this was changed in later versions.
The Glock [and others ] had problems with the .40 but that involved more than just chamber support .Reloaded cases , cartridge LOA also were factors.
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Old February 2, 2011, 10:41 PM   #3
FoxtrotRomeo
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Yup. I have a Glock 27 generation 4. The support looks pretty decent in comparison to my XD-40 which has full support and tighter chamber measurements. There is some slop in the Glock 27 chamber as you can wiggle the round around in there but this aids in the feeding an extraction process. This is the same reasoning behind looser tollerances in an AK rifle, reliability. So when they tell you the Glock is designed to be a combat/service/self defense pistol first and foremost, they're not lying. However, it will put the lead on the target and if it's not pin point, it's close.

Just don't load the Glock with reloaded ammo. If you do (and some still do) inspect the geometry of the casing. If it looks questionable, you're better off not shooting that round in a Glock. I've seen some reloaded rounds and looked them over and though I trust the reloader, I do not trust the casing it's self so I will save that round for my XD which can handle that. The casing wall on the outside was not straight it had a slight curve to it and I do not need to know what will happen when that casing expands in the looser chamber of my Glock so that one is XD only.

Just be careful what you shoot in your Glock and you should be ok. As to Buff Bore? Maybe one of the other Glock owners here can help.
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Old February 23, 2011, 07:30 PM   #4
colospgsAVID
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Thank you gentlemen,
Looking at the Glock Vs Sig barrels it is clear the Sig has more support, however not by much at all. By my measurement .015 inch. Not bad at all compared to my LCP barrel that has the feed ramp relieved to past the case head! Scary. I no longer have concerns with shooting Buffalo Bore ammo in my G20. No more max loads for the LCP though!
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Old February 23, 2011, 08:05 PM   #5
balance
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I always had that "Glock smiley" bulge on the empty cases out of my Glock 20. I don't think it is just visible chamber support around the feed ramp (even though Glock chambers have less of that as well), I think the actual chamber an Glock pistols are larger than others which is probably better for reliability, but not as good for "nuclear" loaded 10mm ammo like Buffalo Bore or Double Tap. They gave that warning for a reason, and I can't think of another 10mm pistol with a chamber with less support.
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Old February 24, 2011, 12:00 AM   #6
NWCP
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HK has a fully supported chamber for the 40 as well as all other of our favorite flavors. I wish they made a 10mm, or .45 Super on their .45 Tactical platform.
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Old February 24, 2011, 06:05 PM   #7
laytonj1
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Quote:
They gave that warning for a reason, and I can't think of another 10mm pistol with a chamber with less support.
Buffalo Bores warning is for the 40S&W.
BB tested their 10mm ammo in a Glock 20 with the only recomendation being the use of a stronger recoil spring.

Jim
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Old February 24, 2011, 06:17 PM   #8
balance
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laytonj1, I stand corrected. My brother has a Glock 20 now with a 20lb recoil spring that supposedly functions perfectly with a .40cal conversion, so I guess Glock undersprung the model 20 for reliability with weaker loaded 10mm ammo.

NWCP, I've heard of people shooting 45 super out of a .45 model H&K pistol with just a spring change, but I can't remember if it was the Mark 23, or the USP. Both are built like tanks.
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Old March 12, 2011, 07:22 PM   #9
colospgsAVID
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@ Balance, I shot a couple mags of 180 grain BB, loaded with golden saber bullets, last weekend. All of the cases were bulged and all of the primers cratered. Curiously the cratered primers show the location of the case as the striker hole to the breech face is rectangular. The bulges did not coincide with the 6 o'clock position, the unsupported part. They varied from case to case. I believe you are correct, just a bit looser chamber, wherever the case wants to bulge it does. The cases resized just fine so I think for range loads they will be safe enough to reload. I also tested all three weights of Hornady ammo with no bulges or cratered primers. 10mm is an impressive round and I love the G20!
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Old March 12, 2011, 08:03 PM   #10
balance
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That's great colospgsAVID, the Glock 20 was a fun pistol while I had it, and it always made people look when it went off with Double Tap at the range , but I never got into reloading, and that is good help with the 10mm. I still remember a lot about the pistol and the round since I spent a lot of time reading over on the "ten ring" on Glocktalk.com. There is a lot of information about the 10mm and all of the pistols chambered in it on that site and you should check it out.
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Old March 12, 2011, 08:16 PM   #11
Daryl
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The "loose chamber" on a glock has nothing to do with how "hot" the ammo can be. Chamber support does, but later Glocks are much better that the earlier models. I had a G20 that scared me a bit with the lack of chamber support; my current G23? Not so much, since it's much better.

When a cartridge is fired, the brass WILL form to the chamber wall as long as it's not an extremely light load. If the load is too light, the empty case will show black on the outside.

But normal loads will cause the casing to form to the chamber wall. That's the job of the case, in order to seal the chamber to prevent gasses from blowing backwards from the gun. Whether the chamber is loose or tight, the case is going to form to the wall of the chamber. No matter whether the cartridge is loaded "normal" or "hot", the same reaction will occur.

The loosness or tightness of the chamber has nothing to do with what level of loads the gun will handle.

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Old March 12, 2011, 08:54 PM   #12
alabama
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I have a 3rd gen glock 20 and yes you can shoot buffalo bore or any other factory ammo. The gun is fine with the factory recoil spring to. Glocks chambers are fine the way they are they are made loose for reliability. The glock .40s are the most unsupported of any but even they are fine with any factory ammo. I shoot the most powerful factory made ammo made in my stock g20. I have swaped recoil springs and the gun jammed so i went back to all stock parts and it works great. Glock knew what they were doing when they made it. The best thing to do is not change anything but the sights. Be carefull what u read on the internet its not always good advice. I fell for it before and started changing parts then my gun started jamming.
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