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  #1  
Old 07-22-2010, 01:00 AM
koncept koncept is offline
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7-Round vs 8-Round Magazines




I was wondering if someone can explain to me why 7-round magazines are considered more reliable than the 8-rounders? I know JMB originally designed it for seven rounds, but nowadays most manufacturers are including 8-round magazines with their guns.

I've had occasional double feeds (two live rounds) with two different magazines, a CMC 8-round (new) and Kimber TacMag 8-round. It is very frustrating, because I will be able to shoot hundreds of rounds with no problem, and then a feeding malfunction will occur. It seems like an ongoing cycle. I'm considering switching back to 7-round magazines to see if the problem will stop.

Thanks in advance!

Last edited by koncept; 07-22-2010 at 01:03 AM.
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  #2  
Old 07-22-2010, 07:24 AM
Parputt Parputt is offline
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Think about it. The only way to get 8 rounds into a mag designed for 7 is to shorten/weaken the spring. Therein lies the problem.
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  #3  
Old 07-22-2010, 07:28 AM
BillD BillD is offline
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Thousands of competitors shoot hundreds of thousands of rounds each weekend from 8 rd mags without issue.
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  #4  
Old 07-22-2010, 07:33 AM
Coltdude84 Coltdude84 is offline
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I use Factory Colt 8 round mags and Wilson Combat 47D 8 Rounders in my Colt Combat Commander and fullsize Combat Elite and have zero issues with them..
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  #5  
Old 07-22-2010, 08:41 AM
pezzulli pezzulli is offline
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Some of the newer mags (e.g., Tripp, Wilson ETM) have a longer mag tube body to allow for the additional round, however, they extend slightly past the frame.

HTH,
John
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  #6  
Old 07-22-2010, 08:42 AM
earlan357 earlan357 is offline
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I've run into problems with CMC and 47D mags when I loaded them 8+1. The extra 1/4" the rounds get pushed in seemed to kill the springs. However, I've had no problem with Cobra Mags and ACT mags to full capacity, since the design extends the floor of the mag about 1/4" in. The new Wilson ETM mag seems to do this as well but I haven't tried those yet.
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Old 07-22-2010, 09:04 AM
mer mer is offline
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Some of the 8 round magazines use a modified follower in a 7 round tube. The follower is designed to collapse, allowing you to get the 8th round in. This leads to a potential weak point, causing failures.

Some 8 round magazines are specifically designed as an 8 round magazine: Wilson ETMs and Tripps are a couple that were designed from the start as 8 rounders. They do things a little bit differently, each design has it's advocates and naysayers.

Just keep in mind that for almost every magazine ever made for a 1911 (in 45 ACP) you can find someone that has had issues with it and others that have never had issues with it.
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  #8  
Old 07-22-2010, 09:33 AM
DHass DHass is offline
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Only 7 rounds fit in the magazine.
There is no room for 8 rounds unless you alter the parts. That is done by blasphemers.
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  #9  
Old 07-22-2010, 09:54 AM
mer mer is offline
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Quote:
Originally Posted by DHass View Post
Only 7 rounds fit in the magazine.
There is no room for 8 rounds unless you alter the parts. That is done by blasphemers.

If you stated "magazines made to Mil-spec" I'd likely agree, but some of the recent 8 rounders (Wilson ETM Tripp 8R-45-RG) were actually designed from the getgo as 8 rounders.

Would beavertail grip safeties also be considered blasphemy since they aren't original?
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  #10  
Old 07-22-2010, 10:39 AM
aric aric is offline
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.

Last edited by aric; 03-29-2011 at 06:08 PM.
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  #11  
Old 07-22-2010, 12:08 PM
mark2734 mark2734 is offline
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The problem your experience is caused by "inertial feed." Under recoil the top round in the mag is jumping out and going into the chamber. When the slide starts forward its stripping a new round and trying to chamber it behind the round already there.

This is commonly caused by either weak magazine springs OR oil/lube causing the rounds to slip past the feed lips.

About 7 or 8 round mags. While the original design was 7 rounds, just think about how many years have pasted. Donít you think just maybe springs are better today then 1910? People who say 8 round mags are not reliable are for the most part basing their opinion on just one or two experiences, maybe a long time ago, and are just looking for a reason NOT to use 8 rounds.

From an objective standpoint modern 8 round mags SHOULD be just as reliable as 7 rounders, provided the overall quality is the same.
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  #12  
Old 07-22-2010, 12:43 PM
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RickB RickB is offline
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If I'd ever had function problems with 8-rounders, I'm sure I'd be dogging them on this forum, but in fifteen years of use I haven't had any problems. JMB obviously designed the magazine, like everything else in the gun, with extra margins of durability and reliability built in. Enough that capacity could be expanded by one round, though as noted, not without some compromise. It's just like adding 200hp to your car; yeah, you'll go faster, but the car will require additional maintenance, and it will wear out faster. Does that mean you're satisfied going slow, or do what it takes to get the additional performance? The latest generation of "true" 8-round mags is the way to go, unless you absolutely have to have flush fit, and even then there are older generation 8-rounders that work.
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  #13  
Old 07-22-2010, 12:54 PM
dakrat dakrat is offline
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very well said RickB.
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  #14  
Old 07-22-2010, 01:13 PM
Fazer386 Fazer386 is offline
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Things improve

Seven round magazines can work forever...

Competition added the extra round. Anything can be improved upon, magazines are no different.

I have two Colt 7-rounders that have been 100% reliable. I've ran CMC and other magazines, but settled on Wilson 47D magazines cause they work and work in all my guns.

Function test. Start with good magazines. Number your magazines. Good ones to the right, bad ones left.
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  #15  
Old 07-22-2010, 01:31 PM
3baers 3baers is offline
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I've have run CMC 8 round mags for 20 years, have never had any real issues.
I've have had an occassional mag fail. They are easy to mark and spot when you are having issues, they go in the trash. In 20 years I've had 2 or 3 go bad.
However I do not plus 1 any of my mags or use that technique in any of my 1911's. If you have every done that you'll notice that an 8 round mag, loaded with 8rds inserted in the mag well takes more effort seat. When I load up I manually lock the slide back, insert and 8 round mag, hit the slide release and let the slide strip the first round and then lock the thumb safety. If I'm playing reindeer games, IE: IDPA I always load 7rounds in 8 round mags for any tactical reloads.
Also if you are having mag issues with various mags of any round count, don't rule out a defective slide stop/release as the culprit.
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  #16  
Old 07-22-2010, 01:33 PM
TeamSingleStack TeamSingleStack is offline
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Quote:
Originally Posted by BillD View Post
Thousands of competitors shoot hundreds of thousands of rounds each weekend from 8 rd mags without issue.

+1000

CMC powermag 8 rounders here.
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  #17  
Old 07-22-2010, 04:29 PM
BaldEagle323 BaldEagle323 is offline
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100 years ago, metalurgy wasn't what it is today. I'm sure that if modern CNC machines were available when JMB designed the 1911 and steel qualities of today were commonplace, the gun would differ somewhat. My 5.0 Liter Mustang I had in 88 had 225 HP and ran the 1/4 mile in 14.3 seconds. Ford now makes a 6 cyl mustang with 305 HP and is .8 seconds quicker to 60 mph than my 88 model was. JHB did the best he could with what he had then, and if he designed it today it probably would be different. Maybe (God forbid), what he'd design today would resemble a Glock. All of that said, perhaps when he tried to have an 8 round mag, the spring failed quicker or he just couldn't make it work. Without reading his notes or talking to someone that was there, all we can do is speculate.
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  #18  
Old 07-23-2010, 01:07 PM
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LW McVay LW McVay is offline
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Quote:
Originally Posted by Parputt View Post
Think about it. The only way to get 8 rounds into a mag designed for 7 is to shorten/weaken the spring. Therein lies the problem.
Wrong.
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Old 07-23-2010, 01:09 PM
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LW McVay LW McVay is offline
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Quote:
Originally Posted by RickB View Post
If I'd ever had function problems with 8-rounders, I'm sure I'd be dogging them on this forum, but in fifteen years of use I haven't had any problems. JMB obviously designed the magazine, like everything else in the gun, with extra margins of durability and reliability built in. Enough that capacity could be expanded by one round, though as noted, not without some compromise. It's just like adding 200hp to your car; yeah, you'll go faster, but the car will require additional maintenance, and it will wear out faster. Does that mean you're satisfied going slow, or do what it takes to get the additional performance? The latest generation of "true" 8-round mags is the way to go, unless you absolutely have to have flush fit, and even then there are older generation 8-rounders that work.
But Rick wait, you aren't contributing to the myth!!!
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