SirLoin

If any of you are still following this thread, and in case you might find it helpful, there's a poll to collect member feedback on different aftermarket Glock barrels and how they do with regard to chamber support and feeding: http://www.brianenos.com/forums/index.php?showtopic=140159&pid=1576792&st=0entry1576792

In case you might find it helpful, there's a poll to collect member feedback on different aftermarket Glock barrels and how they do with regard to chamber support and feeding: http://www.brianenos.com/forums/index.php?showtopic=140159&pid=1576792&st=0entry1576792

Interesting, DoubleA. Looking at the input of the 15 people who have voted so far in the poll, it's interesting that KKM isn't a clear-cut winner in terms of people who've tried them - most of the threads I had read here at be.com about aftermarket barrels reference KKM, so it'll probably go up as more people vote.

Yes. That's why accuracy is not part of the poll. Better chamber support so that the brass lasts longer (and hopefully, less risks of KBs), without compromising feeding reliability. That's not my statement. Please reread the post - that was a statement by Ghost Dog / Brian Enos.

Of course, Kirk.

Thanks for the input, Biloxi23.

Folks, I decided to get an after-market fully-supported barrel for my Glock 35 .40 S&W after reading Brian’s post on how “SAAMI specs indicate that a 40 S&W chamber should have a fully supported chamber (due to the round's high pressure), but Glock chose to ignore that for their 40 caliber barrels, because it makes the gun easier to feed more reliably.” After going blind reading ~every single post on these forums on Glock after-market barrels, I haven’t seen consensus on which is the best one to get, mostly I think due to a couple of reasons: • People only have experience with only one type of after-market barrel • People pick an after-market barrel for different, personal reasons (e.g., some folks look for best for chamber support; some look for which feeds most reliably; etc.) With that in mind, I’ve started this poll, with the hope of collecting and synthesizing the combined decades of shooting expertise of the members on this site. Could you please participate in this poll? The polls are limited to three questions, so I’ve focused on the two questions – chamber support and reliability of feeding – where there isn’t consensus (accuracy seems to be a wash; cost is readily available info). The first question is what you’ve used, as opinions of folks who’ve tried more than one barrel are particularly helpful. Please feel free to post as to what your favorite barrel is, and why. While that’s a personal preference, it will help myself and others balance the different considerations: chamber support vs feeding vs cost or value vs accuracy. Thanks!

Thanks for the WWB explanation! Unfortunately here in NJ, Walmarts don't sell ammo. Good thing there's BVAC: .40s cost $11/box after shipping and taxes (you just have to buy 10K of rounds, so helps to know other folks who don't reload!).

Yeah, the charred-on-one-side-brass only happens with my Glock OEM, so I've thought that unsupported/larger chambers lead to more gas escaping to lower velocities. I haven't seen anything online that definitively says that though, but that intuitively makes sense to me.

Good to hear that. Stupid question: what does WWB mean?

Yep. Thanks for pointing that out. I do agree with you that differences in rifling affect velocities. I do think that significantly tighter barrel tolerances probably trump rifling differences, all else being equal -- as you point out. Thus, given two barrels with the same tolerances, I believe that the polygonal would spit out faster bullets. However, given: 1) a barrel with tighter tolerances AND traditional rifling, and 2) a barrel with looser tolerances AND polygonal rifling, I think 1) would spit out faster bullets. The ability to "eat" a wide range of ammo comes from a loose chamber, not barrel. The projectile itself has a fixed maximum diameter-- no need to account for anything "sloppier". IIRC, a 124 MG JHP touches the rifling in my G17 at 1.189-- meaning I could load to 1.175 and still have a huge safety margin. (The mags begin to choke around 1.165 though.) It also leaves a lot of room for the case to expand. In comparison, the M&P 9 Pro I just got maxed out at 1.145, and was definitely tighter on the case walls. Ironically, it's magazines would accomodate my "no go" Glock dummy rounds of ~1.170 without nose dive or snag. Barrel-to-barrel tolerances definitely account for the greatest variations in velocity, but I still believe the polygonal rifling of the Glock plays some role as well.

Yeah, I think that a tighter chamber trumps the rifling advantage. Thing is, I thought that the Glock OEM had the looser tolerances, as they designed it to eat any ammo, so I'm surprised that your OEM is tighter.

Biloxi123, that's pretty close to what happens to me when I shoot my rounds through a Glock 35 Gen4 OEM and when I shoot them through a Para Ordnance S16-40 Limited with its OEM barrel: it's consistently faster across different loads on the Para OEM barrel than in the Glock OEM. I chronoed 180, 165, and 155 gr plated Berrys using two different chronos (put them front-back so that each bullet would go through both chronos), and the results were consistently faster in the Para.

I think polygonal is just the general heading, referring to multiple sides, and hexagons, octagons, etc. are specific types of polygons (hexagons = six sides; octagon = eight sides). I believe Glock barrels have hexagonal rifling in general, vs the octagonal rifling in the 45 ACP (http://en.wikipedia.org/wiki/Polygonal_rifling; http://en.wikipedia.org/wiki/Glock)

I set up this poll to get some first-hand data from other shooters on whether their bullets go slower out of a Glock OEM unsupported barrel than out of a supported, traditional rifling barrel: http://www.brianenos.com/forums/index.php?showtopic=139536&pid=1569715&st=0entry1569715 If bullets shoot slower out of a Glock, then that could potentially explain why you experience cycling issues with your weak loads.

Folks, Do you experience higher velocities / power factors when you shoot bullets out of a Glock OEM barrel or a traditionally rifled barrel? Please vote as follows: Higher velocities out of a Glock OEM barrel Higher velocities out of a traditionally rifled barrel It has been commonly stated that the polygonal rifling of Glock barrels leads to higher velocities. However, others have reported experiencing actually LOWER velocities when shooting out of a Glock OEM barrel. For example, “Mike Orrick (GlockTalk's "BrokenArrows") has pointed out that his chronographed results of identical loads in conventionally-rifled barrels versus same-length polygonal barrels yielded higher velocities in some of the conventionally-rifled barrels” (from http://www.glockfaq.com/content.aspx?ckey=glock_faq_reloading. (Perhaps the unsupported nature of a Glock OEM barrel leads to there being a looser seal, resulting in lower gas pressures, and thus pushing the bullet out at a lower overall velocity despite the advantages of polygonal rifling?) My experience has been 2. higher velocities out of a traditionally rifled barrel, i.e., like that of Mike Orrick’s: my bullets shoot faster out of non-Glock / non-polygonal barrels. I’m hoping to get people’s opinions to see if my experience is typical. Thanks!

Yeah, makes sense that it shouldn't be caused by a Glock barrel -- whether Gen 3 or Gen 4 -- being different from another Glock barrel. From what I understand, Gen3 and Gen4 barrels are the same. The difference might be with how Glock barrels differ from other manufacturer's barrels. Have folks seen a difference in power factors when switching from an OEM Glock barrel to an aftermarket (KKM, Lone Wolf) barrel?

I too had read that the Glock's polygonal rifling led to higher pressures and faster bullets. However, my own experience using Berrys plated bullets, as well as the experience of some other folks who've posted load data here at brianenos.com, have been that the bullets actually come out slower in a Glock. The polygonal rifling typically makes them faster, actually. Death grip and locked elbows does not directly transfer to/mimic strong wrists. However, if (after the Jager rod) the gun is still having feed issues for other shooters, it may indeed be a mechanical problem. Are you seeing any odd/accelerated wear spots on the frame rails? What lube are you using-- and how much? Does anything feel "off" during hand cycling of the weapon? How many rounds have you got through this thing? Keep in mind that the ISMI springs do experience some significant break in within the first 500-1k rounds. When switching from a worn 15 to a new 13#, I thought for sure they'd sent me the wrong weight. After some shooting, it was quite obvious that they had not. You are running a reduced power striker spring, I take it? 13# (worn) and lower can result in some unlocking issues as the gun slips out of battery with the factory weight spring. My guess is that this particular G34 wouldn't have that problem, but it's something to be aware of as you go lower and lower.

...unless I misread his post...

fastarget says that the same thing happened when he shot it, so I think it's probably not due to any limp-wristing / grip issue on his wife's part...

I was having the same problems on my G35 Gen 4 just a few weeks ago. Loads that were chronoed at 125-135 PF in other guns, and which cycled fine in other guns/barrels, wouldn't cycle the slide back on my G35. When I chronoed the ammo in my G35, I was getting PF readings a lot lower. I tried an 11# spring, but I'd still get cycling issues ~50% of the time. I've jacked up my loads to ~150 PF in other guns / ~135 PF in my G35, and that has fixed the problem. I've read other folks with Gen 4s have similar problems, so I've started to wonder if there's something with the Gen 4 barrels (larger chamber perhaps?) that results in lower pressures / power factor readings.

Wow. How much did you guys pay total (e.g., shipping, additional charges) to send everything to Dillon and to get whatever other items you needed to get replaced?

Counterbored means you need a longer guide rod.

Ah ok. Wasn't aware of that. Good luck.

Here's an article about the recall: http://www.ammoland.com/2011/09/07/glock-gen4-recoil-spring-assemblies-recall/ The stock rsa won't reliably cycle 130 pf loads. Actually, there have been quite some posts about how the Glocks shoot best at 135 PF, and even then, most folks drop to a 13# spring.