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Discussion Starter #1
The top picture below is of a fully loaded magazine locked into the magazine well. The bottom picture shows a failure-to-feed of the first round where the nose of the bullet is jammed against the frame feed ramp. This malfunction is commonly known as a nose dive stoppage.



Many folks will suggest switching magazines, switching ammo, checking the slide stop for bullet contact, or replacing the magazine catch with an EGW Higher mag catch. While one or more of these may fix the issue none of them address the underlying problem which is most often due to geometry problems with the frame feed ramp. Specifically, the feed ramp angle and/or the ramp depth are not correct.

The image below shows the correct angle of the feed ramp as specified by John Browning. Unlike most of the dimensions for the pistol, the feed ramp angle has no +/- tolerance. It is to be exactly 31.5 degrees. In practice it is a magical number. Too steep and cartridges won't feed. Not steep enough and cartridges may escape the magazine due to inertia. The Goldilocks Principle is in play here. Not too much, not too little, just right.

In addition to the correct angle the frame feed ramp must extend far enough down into the frame to make contact with cartridges that nose dive. Ideally, the ramp should extend from the top of the frame rails downward .400" which is just about at the bottom of the frame cut out for the slide stop. The longer the ramp, the better but often a ramp that is .360" is sufficient. It all depends on other dimensions within the pistol.

The barrel bed itself must not under any circumstances measure less than .246" from the top of the ramp to the VIS. Otherwise the structural integrity of the pistol will be compromised. The longer the barrel bed, the better.



Below is a collection of pictures showing bad ramps and good ramps in terms of ramp length for .45 1911s.

#1 - bad ramp. Does not extend far enough down into the mag well.
#2 - good ramp. Extends to the bottom of the slide stop frame opening.
A - good ramp.
B - good ramp.
C - bad ramp. Does not extend far enough down into the mag well.




If you want to get a rough idea of the angle of a feed ramp you can get one of these Empire protractors from Home Depot for something less than $10. You'll have to shorten the arm enough to allow it to fit in the magazine well. While it's not a highly precise machine tool, it will let you know if the angle of a feed ramp is grossly wrong. A real machinist/1911 'smith will have the right tools (expensive) to determine the exact angle and depth of a frame feed ramp. They can also correct ramps that are bad. Correcting feed ramps is a job best left to a professional.




FYI, here's how a professional 1911 'smith fixes an out-of-spec frame ramp.







 

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It's also common from a magazine problem. There are good ones, there are bad ones. Only time I saw this with a Chip McCormick magazine was when I put the spring back in place under the follower wrong.

Some of us have been doing feed ramps and various other 1911 problems since the 70s and yes I worked at a Colt repair center. A lot of current commercial products don't normally have this problem. Oldest pistol I've seen in years I simply took a Dremel to when it wouldn't feed SMCs. Then again, some of us don't need to use a milling machine to fix things. I actually have shot this thing out to 100 yards.

DSC01108.JPG
 

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. . . when I put the spring back in place under the follower wrong.
Yup. Been there, done that, and learned from my mistake. Not uncommon among newbies.

Some of us have been doing feed ramps and various other 1911 problems since the 70s and yes I worked at a Colt repair center.
I started carrying 1911s in the early 70s courtesy of Uncle Sam. I didn't start tinkering with them until I left the Army and no longer had a unit armorer to swap springs.

. . . I simply took a Dremel to when it wouldn't feed SMCs.
I'm a .45 guy but I recently ran across a nasty 9mm full ramped barrel in my junk drawer. It was bad with deep machining marks everywhere including the feed ramp. I figured I had nothing to lose so I whipped out my trusty Dremel and in short order had recontoured the ramp to ~31 degrees without giving up too much case support and made it as smooth as a baby's behind. It actually feeds perfectly fine now.
 

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Yup. Been there, done that, and learned from my mistake. Not uncommon among newbies.
Never assume. I started shooting IPSC in the 70s. This was called cleaning magazines when I was way to tired.

I started carrying 1911s in the early 70s courtesy of Uncle Sam. I didn't start tinkering with them until I left the Army and no longer had a unit armorer to swap springs.
Early 70s to 76 preference with the Browning High Power. Mike Harries talked me into trading it for a Series 70 that had most of the "tuning" done on it. I can roughly tell you how many rounds it had through it before it cracked, got welded and sold to a novice ( he was well aware of what he was buying at a very good price). First serious work in a 1911 (Yes a WWI Navy Colt) was to weld the frame back together, mill it back to spec and for the heck of it, checker it etc. Collector value wasn't there, so I have fun with it.

My preference for firearms are rifles, SMGs, LMGs and rarely MaDuece. I did spend years bouncing back and forth between a Colt repair center and Sherwood's International about 4 blocks away. In front was a small gun store, in back was a huge warehouse with nothing but military small arms. We refurbed a lot of Military small arms.

Single most eccentric weapon I've worked on was Sid's original Minigun, and then setting the actors up for it in: Predator, T2 (on location) and Soldier. Funny stories.

I'm a .45 guy but I recently ran across a nasty 9mm full ramped barrel in my junk drawer. It was bad with deep machining marks everywhere including the feed ramp. I figured I had nothing to lose so I whipped out my trusty Dremel and in short order had recontoured the ramp to ~31 degrees without giving up too much case support and made it as smooth as a baby's behind. It actually feeds perfectly fine now.
I bought an RO Champion in 9mm about 4-5 months ago to see if I'd like it without spending a lot of money. Having a ball with it, overcome shooting with a curved trigger. I did swap out the ignition system since I hate MIM. Love it, having a ball with it and anytime my arthritis kicks in, I simply grab the ROC. I'm getting downright wicked with it.

This is a rare bird since it'll stay fairly stock. It works, it's fun and I'm still more accurate that most average shooters with it. Next it'll be a Ronin and then send that one to a friend for the mods I want on it. I'm to old to screw around with checkering and I have a problem justifying the cost a Grobet for one or two pistols.
 

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Never assume. I started shooting IPSC in the 70s. This was called cleaning magazines when I was way tto tired.



Early 70s to 76 my preference was the Browning High Power. Mike Harries talked me into trading it for a Series 70 that had most of the "tuning" done on it. I can roughly tell you how many rounds it had through it before it cracked, got welded and sold to a novice ( he was well aware of what he was buying at a very good price). First serious work in a 1911 (Yes a WWI Navy Colt) was to weld the frame back together, mill it back to spec and for the heck of it, checker it etc. Collector value wasn't there, so I have fun with it.

My preference for firearms are rifles, SMGs, LMGs and rarely MaDuece. I did spend years bouncing back and forth between a Colt repair center and Sherwood's International about 4 blocks away. In front was a small gun store, in back was a huge warehouse with nothing but military small arms. We refurbed a lot of Military small arms.

Single most eccentric weapon I've worked on was Sid's original Minigun, and then setting the actors up for it in: Predator, T2 (on location) and Soldier. Funny stories.

I'm a .45 guy but I recently ran across a nasty 9mm full ramped barrel in my junk drawer. It was bad with deep machining marks everywhere including the feed ramp. I figured I had nothing to lose so I whipped out my trusty Dremel and in short order had recontoured the ramp to ~31 degrees without giving up too much case support and made it as smooth as a baby's behind. It actually feeds perfectly fine now.
Bought a Ranger Officer Champion in 9mm about 4 or so months ago. I'm having a ball with it. When my arthritis kicks up, I just shoot the 9mm. Looking for a Ronin 5" in 9mm. The Champion is light, fact and I simply had to overcome using a curved trigger. I'm just wicked with it now. I still pull reserve duty now and again, even at my age. Since the dept is 9mm, I simply carry the ROC until I get a Ronin. I do swap out the ignition parts, I do not believe in MIM for any reason.
 

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Great info...for anyone who likes the sweet science of the 45.. I...like rojkoh was an IPSC guy in the late 70's, early 80's for about 12 years.

I owned a couple of pure custom jobs, but always fell back to either my GC that I had done myself, or even a military frankenpistol.

Thanks for this thread.
 

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Discussion Starter #7
. . . for anyone who likes the sweet science of the 45 . . .
I've never heard it described this way and it made me smile. Among the uninitiated it's more common to hear muttered cussing accompanied by head scratching when malfunctions occur. :)
 
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