Glock Unspported chamber

[wiiawiwb]

I just bought a Glock 40 MOS in 10mm. I've been reading about the "case bulge" with some 40S&W and 10mm. Does anyone know whether the G40 has a supported or unsupported chamber?

I read on another forum that if a Glock barrel has a a dot in the pentagon near the barrel serial number it is more chamber support. I don't know if there is any truth to it. For what it is worth. my G40 does have a dot inside the pentagon.

Here is a picture of the chamber and a recent 10mm handload made using Lee dies including the FCD. Does it appeaar to have that "bulge" at the bottom of the case?

Is it worth getting the Lee Bulge Buster?

 

[redbullitt]

As far as I an tell most all Glocks tend to have that style chamber for reliability. An aftermarket barrel will look noticeably different and have a fully supported chamber.

As to if you need it, thats up to you. My G20 has a stock barrel and does fine with hot loads from buffalo bore or my own made with 180 gold dots and 200 XTPs. However, Generally I only use the brass once in those loads. Then it gets recycled or marked for plinkers with cast bullets.

I have noticed that my Storm Lake barrel for the 9mm or 45 is pickier with ammo. It has a tighter chamber and less free bore, so ammo that works in the stock barrel may not function in the tighter aftermarket one.

 

[Duvel]

Does the case look fully supported? No, it doesn't.

Gen 4 barrels are reported to be better their predecessors, I don't have two to compare.

What I do have is a Gen 4 G20, and a LW 5.15". The LW chamber is tighter by 50 thousandths, but case head support is about the same.

DO NOT use a FCD / Bulge Buster to iron out smiles, as the brass has sheared.

 

[Duvel]

Mine: Stock on left, LW on right.

 

[chris in va]

That's not a bulge, it's where the sizing die 'hourglassed' the case. My CZ appears to have the same case support as your Glock, so I wouldn't worry about it.

 

[Duvel]

Is your CZ a 10MM?

Most factory loads (including DT, Underwood, etc) should be just fine. Hot handloads he'll need work towards, knowing what signs to look for.

 

[atblis]

Even though the newer Glock chambers are better, they're still too loose IMO. If you're a handloader, definitely get an aftermarket barrel.

 

[Drail]

That's not a bulge. Glock simply machines their barrels for extreme feed reliability - they couldn't care less about what happens to the fired case. They don't intend for anyone to use reloaded ammo in their guns. If I were going to reload for a Glock I would absolutely buy an aftermarket barrel - for the ability to shoot lead and to avoid messing with cases that look like that.