Posted: 9/25/2011 4:05:42 PM EDT
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I have experienced several breech over base malfunctions with my relatively new Springfield Milspec. Each occurrence has been on the last round of the mag. The mags are CMC Power Mags and they haven't seen much use yet. The pistol has 84 rounds of FMJ and 92 rounds of Winchester Ranger through it. All the malfunctions occurred with the Ranger. One thing that is interesting to note is that all the FMJ and 42 rounds of the Ranger were fired with a buffer and only one malfunction occurred. I removed the buffer and fired 50 more rounds of Ranger and had 3 or 4 malfunctions.
Suggestions? |
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If you hadn't prior experience I could blame your magazines... and I still can. Your springs are showing sign of weakness and if I remember correctly the follower in those magazines is dimpleless, Right ? Wrong ?
Since magazine are working in other pistols I will suggest extractor is one of two things or both. 1. Too much extractor tension and/or 2. Extractor radius inside claw needs relief. Which ever to the what ever. Something is allowing or causing case rim to ride ahead of extractor. eta; also.... inevitably someone will suggest going a heavy recoil spring. Could fix issue but it's a band-aid fix at best. eta to eta... reason why you're experiencing less failure with buffer is because, buffer is taking spring space.... increasing spring tension. Makes sense, dudn"t it ? |
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Not really. If you hung out in the reloading forum from time to time you'd understand exactly why.
Cartridges have tolerance gateways they have to maneuver through in each feed system. With 1911s no two are exactly the same. Understanding ogive, case mouth od, oal and the affect each plays within feed dynamics is secret to flawless feed. That and some good tuning skills. Ammunition is either tuned to the pistol or pistol is tuned the ammunition. There is that rare occasion when you see both pistol and ammunition tuned to each other. If you'd like go to reloading forum, gateway threads, page two, scroll half way down to my thread block and read. I've devoted a lot of time to understanding feed principles. |
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If it were my pistol the first thing I'd do is ditch the magazines. Something I've already done.
Realizing that some have had success and like CMC magazines. I would change springs and followers out. I don't remember what round magazines you're using. I would replace with appropriate Wolff magazine springs. That alone could be your fix. Last round is riding forward, that's why it's getting ahead of your extractor. If, by chance this problem persists look into radius on extractor claw. I radius all before installation. This bit of tuning is important and often over looked. |
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Have you contacted SA? They have great customer service.
I have seen a Mil-Spec model that would only feed Federal Hydra-Shok, but not other HP ammo and didn't like reloads either. I have no reason to doubt that the extractor may be the primary source of your trouble. However, the barrel might contribute. A two-piece barrel was OEM for the Mil-Spec model. I believe they are made in Brazil and metric in dimensions. Scroll down about a third of the way on this page: http://www.hipowersandhandguns.com/Critical%20Look%20at%20Springfield%20Mil%20Spec.htm Some people who have had problems have sent the pistol back to SA and they replaced the barrel with Storm Lake Machine barrels - ymmv. Multi-Tool |
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Quoted:
Have you contacted SA? They have great customer service. I have seen a Mil-Spec model that would only feed Federal Hydra-Shok, but not other HP ammo and didn't like reloads either. I have no reason to doubt that the extractor may be the primary source of your trouble. However, the barrel might contribute. A two-piece barrel was OEM for the Mil-Spec model. I believe they are made in Brazil and metric in dimensions. Scroll down about a third of the way on this page: http://www.hipowersandhandguns.com/Critical%20Look%20at%20Springfield%20Mil%20Spec.htm Some people who have had problems have sent the pistol back to SA and they replaced the barrel with Storm Lake Machine barrels - ymmv. Multi-Tool My pistol has a one piece stainless barrel. If I can't pinpoint a simple fix, the next step is to send the pistol back to SA with the questionable mags to see if they can figure it out. |
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Have you contacted SA? They have great customer service. I have seen a Mil-Spec model that would only feed Federal Hydra-Shok, but not other HP ammo and didn't like reloads either. I have no reason to doubt that the extractor may be the primary source of your trouble. However, the barrel might contribute. A two-piece barrel was OEM for the Mil-Spec model. I believe they are made in Brazil and metric in dimensions. Scroll down about a third of the way on this page: http://www.hipowersandhandguns.com/Critical%20Look%20at%20Springfield%20Mil%20Spec.htm Some people who have had problems have sent the pistol back to SA and they replaced the barrel with Storm Lake Machine barrels - ymmv. Multi-Tool My pistol has a one piece stainless barrel. If I can't pinpoint a simple fix, the next step is to send the pistol back to SA with the questionable mags to see if they can figure it out. I sent a SA back for warranty once and mistakenly put a CMC mag in the box. They blamed my non-mag related problem on the mag not being a factory SA item, adjusted extractor and sent it back. Still has same problem with any mag I use. |
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Have you contacted SA? They have great customer service. I have seen a Mil-Spec model that would only feed Federal Hydra-Shok, but not other HP ammo and didn't like reloads either. I have no reason to doubt that the extractor may be the primary source of your trouble. However, the barrel might contribute. A two-piece barrel was OEM for the Mil-Spec model. I believe they are made in Brazil and metric in dimensions. Scroll down about a third of the way on this page: http://www.hipowersandhandguns.com/Critical%20Look%20at%20Springfield%20Mil%20Spec.htm Some people who have had problems have sent the pistol back to SA and they replaced the barrel with Storm Lake Machine barrels - ymmv. Multi-Tool My pistol has a one piece stainless barrel. If I can't pinpoint a simple fix, the next step is to send the pistol back to SA with the questionable mags to see if they can figure it out. I sent a SA back for warranty once and mistakenly put a CMC mag in the box. They blamed my non-mag related problem on the mag not being a factory SA item, adjusted extractor and sent it back. Still has same problem with any mag I use. That's why I'm hesitant to send it back. |
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Weak mag springs. |
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Here's what I believe is going on.
The Springfields use a heavy 28# main (hammer) spring. To balance this for reliability, they tend to use a lighter recoil spring. The Rangers are causing the problem because they are throwing the slide back faster, resulting in a stronger impact as the slide goes back to full travel. This is causing the last round of the magazine to pop forward in the mag, ultimately getting ahead of the extractor as the slide returns to battery. You didn't have as many problems with the shock buff installed, because it cushioned the blow somewhat as the slide went back, and the last round tended to stay in place better. It sounds as if your CMC mags are pretty new, and while they could probably benefit from upgraded springs, you really shouldn't need them. The Powermags don't have the dimple on the follower, while I believe the Springfields do... which is why the CMC mags allow the last round to jump forward. My troubleshooting approach would include installing a 16 pound recoil spring, and if that didn't help, I'd go to a 17# or 18#. I'd also ditch the ILS mainspring parts and install a 19# or 23# mainspring and a standard non ILS mainspring cap. That will help the trigger a bit, as well. ETA: feedramp gap looks OK. |
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Quoted:
Here's what I believe is going on. The Springfields use a heavy 28# main (hammer) spring. To balance this for reliability, they tend to use a lighter recoil spring. The Rangers are causing the problem because they are throwing the slide back faster, resulting in a stronger impact as the slide goes back to full travel. This is causing the last round of the magazine to pop forward in the mag, ultimately getting ahead of the extractor as the slide returns to battery. You didn't have as many problems with the shock buff installed, because it cushioned the blow somewhat as the slide went back, and the last round tended to stay in place better. It sounds as if your CMC mags are pretty new, and while they could probably benefit from upgraded springs, you really shouldn't need them. The Powermags don't have the dimple on the follower, while I believe the Springfields do... which is why the CMC mags allow the last round to jump forward. My troubleshooting approach would include installing a 16 pound recoil spring, and if that didn't help, I'd go to a 17# or 18#. I'd also ditch the ILS mainspring parts and install a 19# or 23# mainspring and a standard non ILS mainspring cap. That will help the trigger a bit, as well. ETA: feedramp gap looks OK. I didn't realize that SA used a lighter recoil spring. That's good to know. What you're saying makes alot of sense. |
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