.....or lack thereof. I have a Glock 20SF and have seen many comments about lack of support in Glock 10mm chambers. In looking at the barrel the chamber surrounds the casing except at the lower area where the ramp blends into the chamber. Or, is the criticism of the chamber sizing? Using pin gages the chamber tapers 0.436" down to 0.425" with the depth being 1.260. Hey, I promised dumb questions when I joined. :)
Serious Glock guys will chime in I am sure.
But in general in more recent generations of Glock (Gen 3 on I think) have better chamber support for high pressure rounds.
Quote from: EdMc on July 20 2012 10:35:08 AM MDT
.....or lack thereof. I have a Glock 20SF and have seen many comments about lack of support in Glock 10mm chambers. In looking at the barrel the chamber surrounds the casing except at the lower area where the ramp blends into the chamber. Or, is the criticism of the chamber sizing? Using pin gages the chamber tapers 0.436" down to 0.425" with the depth being 1.260. Hey, I promised dumb questions when I joined. :)
[bold]
That's the key area we most often refer to when discussing "chamber support". This is the part of the case that will blow out, if it does in almost every case. Most aftermarket barrels will support more of this area, and some will enclose the entire case web area. The trade-off is a tighter feed area, which can result in less than ideal feed characteristics, although FTF's due to this are extremely rare in normal situations.
OEM Glock barrel chambers are very generous (loose), in comparison to most AM barrels. This "feature" lends to Glock's remarkable reliability, in almost any condition a shooter may encounter. The trade-offs for the generous chamber are brass condition after firing (may be excessively expanded, bulged, or "smiled" with extreme pressures), less consistent firing/pressure characteristics, and perhaps less consistent accuracy. YMMV
Yep. What DM1906 said.
That 6 o'clock position of the Glock barrel chamber where case head (and just above) is relatively poor. Colt Delt Elites are even worse. But it is true the Glock 10mms have gotten better. Not much, but better.
Quote from: REDLINE on July 20 2012 01:51:38 PM MDT
Colt Delt Elites are even worse.
This really brings it to the source question. Underwood, who runs as hot as anyone really should, does NOT call out the Glock as lacking enough head support for max loads.
" Underwood, who runs as hot as anyone really should, does NOT call out the Glock"
I've noticed this too, in addition to a photo of a S&W barrel seen online that leaves the same area above the ramp 'unsupported'. Never seen any criticism of the Smith.
As an aside I'm a little old for the 'fanboy' term....if anything, I'm more inclined towards Colts, the 20SF is the first Glock product I've owned.
Here are the various barrels for my G-29...
(https://s20.postimg.org/rvcl647m5/IMG_0333-1.jpg)
Two Storm Lake barrels - Factory 10mm - Two Lone Wolf Dist.
Here are some of my S&W barrels...
(https://s20.postimg.org/8dhxq6ie5/2354283_SWBarrels.jpg)
The amount of exposed area is not the only thing involved, lock up and timing play a big roll in the situation as well.
I use the Wolff Gun Springs, non-captive two piece recoil rod with the 21 lb spring set in the G29 and the Wolff 22 recoil spring in the S&W 1006/1026/1046 and Wolff 21 lb spring in the 1066/1076/1086. I handload my own to simular levels as Underwood and haven't had any "SMILED" brass yet!
Here are some pictures of a Delta Elite barrel from a form\um member on another forum in my area...
(http://i38.photobucket.com/albums/e104/Sigarmed1/10mmPressurepics001.jpg)
(http://i38.photobucket.com/albums/e104/Sigarmed1/10mmPressurepics005.jpg)
Colt Double Eagle barrel
(http://upload.bayoushooter.com/images/116umx01v87ux310jdl.jpg)
(http://upload.bayoushooter.com/images/njrg57g3h1st88tr0fa.jpg)
Thanks gentlemen, ya'll never disappoint. ;D Quite obvious from the photos that Colt does have the least support. Be interesting to see a Kimber 10mm barrel for comparison.
Shadow, with the changes in rod and springs on your G29 are you still using the stock 10mm barrel?
Yes I carry it with the factory barrel! The others are just for play and range work or hunting.
The 21 lb spring I feel helps with the dwell time and lock up.
Thanks. I did find a photo of a Kimber 10 barrel with an internet search. I'm not sure how to post photos here, but it looks to be very well supported.
Quote from: sqlbullet on July 20 2012 02:01:31 PM MDT
Quote from: REDLINE on July 20 2012 01:51:38 PM MDT
Colt Delt Elites are even worse.
This really brings it to the source question. Underwood, who runs as hot as anyone really should, does NOT call out the Glock as lacking enough head support for max loads.
That's absolutely true, but still doesn't change that fact that the Glock barrel does leave a portion of the case completely unsupported, which to me is the main point that folks should be aware of, as it is a limitation in some respects whether we as individuals deem it "okay" or not.
Informative thread. Might be considered for a sticky.
I'd forgotten ...........here's the photo of Kimber and Colt barrels. Colt on the right.
(http://i167.photobucket.com/albums/u142/tayninh1969/Firearms/KimbervsColt10mmbarrels-small.jpg)
Now the $64 question? Is the Kimber barrel considered a Nowlin ramp cut? or Clark Ramp Cut? ???
BTW I'm impressed with the Kimber's chamber support! I wonder how it compares to the Fusion design? ::)
That is a Nowlin/Wilson cut. Clark/Para is rounded on the rear of the lug where the barrel hits the frame.
(http://fellingfamily.net/images/clarkParaCut.jpg)
Thanks sqlbullet, when it comes to 1911's I'm not totally up to speed :(...still learning though! :D
Quote from: The_Shadow on September 02 2012 11:17:19 AM MDT
Now the $64 question? Is the Kimber barrel considered a Nowlin ramp cut? or Clark Ramp Cut? ???
BTW I'm impressed with the Kimber's chamber support! I wonder how it compares to the Fusion design? ::)
Shadow I'll try to remember to post a pic of the support in my CCO when I get to a desktop. I can say this, though. The ramped STII I had was completely supported while the unramped barrel in my Fusion CCO is not. However, based on the pics of the DE, I'd say my CCO has better support than the DE.
By the way, I believe most of Fusion's barrels are Storm Lake.
It really is about how the barrel is throated. The pic I posted above if from the original barrel from my P12-45. It was out and convenient to take a picture of as such.
The barrel in my P16-40 is the same Clark/Para ramp but it support isn't great. Previous owner had the barrel throat enlarged during the guns life as an IPSC gun. As a result it get the occasional smile on brass when the "perfect" convergence of factors occurs.
A standard 1911 barrel, non-ramped can be cut to provide really good support, but you have to start with a completely un-throated barrel and cut the throat as a part of the fit to the gun. That is probably what Fusion does.
Having the frame cut is only about $50. Fitting a new barrel is the spendy part. You are probaby still looking at $500 by the time you buy the barrel ($200), have the frame cut ($50) and pay to have the barrel fit to the gun ($200). Not a cheap game.
Quote from: sqlbullet on September 03 2012 06:18:56 AM MDT
It really is about how the barrel is throated.
sqlbullet, something's getting lost in translation in that last post. The
throat is the transition area between the chamber and rifling; it's at the front of the chamber and has nothing to do with case support or barrel fit. The throat is the same thing whether we're talking about a pistol, revolver, rifle, or shotgun, although in a shotgun it's usually called the "forcing cone".
I think you mean the feed ramp? Even unramped 1911 barrels still have a feed ramp, although it is small.
Yondering, you bring up an excellent point.
I have always thought though, when it came to 1911s, and other semi-autos, throating referred to "slicking" up the feed ramp for reliability.
Althought what you say is true.
When used correctly, the term "throating", as in a long-throated competition gun, involves lengthening the throat so the rounds can be loaded long. A good example of this is the long-throated P16-40 I had, where the 40 S&W rounds could be loaded long, to the same length and velocity specs as 10mm.
Of course, the term does get used incorrectly, like the post above, which does add to the confusion about what it really means.
I ain't going to say who is wrong and who is right, or even if there is one.
But, when referring to the back of a 1911 chamber where the feed ramps are I have always heard it referred to as the throat. American Rifleman seems to use the term like I do in the context of a 1911 barrel.
http://www.americanrifleman.org/GalleryItem.aspx?cid=22&gid=118&id=1027
Asking google about a 1911 throat seems to predominately bring up information about modifying 1911 barrels at the breech. And calling this area a ramp can be confusing too since when you order a 1911 barrel you order no-ramp/un-ramped, Clark/Para ramp, or Wilson/Nowlin ramp.
I agree the term is used to refer to the front of the chamber immediately before the leade.
In computer programming we call this function/method overloading, when you use one term for multiple items and the meaning has to be inferred by context. Less than ideal all the way around.
Function method overloading- what a mouthful :o
I just learned something and it makes sense. I wish they had less complex verbage. Leave it to the computer geeks to make it harder than what it is. ;D
side by side of conventional barrel (Fusion CCO) and ramped barrel (Kimber STII)
(http://img804.imageshack.us/img804/9118/img3851n.jpg)
(http://img706.imageshack.us/img706/7536/kimberbarrel.jpg)
and here is a barrel that has not been throated. From a 1975 Colt LWT Commander
(http://img253.imageshack.us/img253/9361/clw7.jpg)
The Fusion barrel looks quite like a Colt Delta barrel. The Commander barrel has what I call a feed ramp machined @ 6 o'clock. Thanks for posting the photos.
Quote from: EdMc on September 05 2012 06:47:18 AM MDT
The Fusion barrel looks quite like a Colt Delta barrel. The Commander barrel has what I call a feed ramp machined @ 6 o'clock. Thanks for posting the photos.
Indeed. After looking at the DE and the CCO barrels together, they are all but identical in support. I have had no problems with the Underwood DE loads WRT case bulges, etc.
Wow, I was under the impression that the Fusion barrel would have more support. Just looking at the pick it looks worse than Glock 10mm barrels, and more/less like Colt DE barrels as has been mentioned.
Quote from: REDLINE on September 05 2012 06:45:20 PM MDT
Wow, I was under the impression that the Fusion barrel would have more support. Just looking at the pick it looks worse than Glock 10mm barrels, and more/less like Colt DE barrels as has been mentioned.
I also would like to know if any of the 5" conventional barrels used in Fusion builds have similar support. Could be that the commander length 10mm barrels are done this way for more reliable feeding.