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Feed ramps


Hammerhead64
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I have read hundreds of references on proper 1911 function and they all say that, with a standard two piece ramp, add the round is stripped from the magazine it hits there frame ramp and tilts up and into the barrel.

My 1911 does not do this. With GI, CMC, and WC magazines, the rounds sit high enough so that as they are stripped off the round just barely touches the frame but mostly contacts the barrel ramp and rn bullets slide right into the barrel. Any lead bullet with a flat nose profile like a swc will jam right into the leading edge of the barrel ramp and stick there at least half the time (4 of 8 rounds). The ramps are mirror polished but since the bullets never contact the frame ramp that doesn't help. Any ideas?

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Have you eliminated the magazine springs being properly installed?

 

The feedlips are tuned and presenting rounds high enough?

 

Does the extractor have proper(no movement) fit to firing pin stop? If so, is the extractor properly tuned? I was told when brass is firmly seated on breachface there needs to be an airgap of 0.070 to .075" between extractor hook and extraction groove of case.

 

This is a parallel line on breachface to extractor hook.

 

The extractor also needs a proper chamfer so the rounds can 'tip up' beneath extractor during a 'controlled feed' type scenario. The brass slides beneath extractor, not the extractor snaps over brass.

 

A very rough breachface can also cause feeding faults. However, it seems like specific bullets are causing the issue.

 

Lastly, cartridge overall length can make a difference in feeding quality as well.

 

I would ensure the gun is 'properly specced' alongside making sure magazine springs are installed correctly first. Then, begin reducing potential causes.

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3 hours ago, Specialneeds said:

Does the extractor have proper(no movement) fit to firing pin stop? If so, is the extractor properly tuned? I was told when brass is firmly seated on breachface there needs to be an airgap of 0.070 to .075" between extractor hook and extraction groove of case.

 

Not exactly.  For a .45 the distance from the breechface to the inside edge of the extractor hook should be no less than .075".  Significantly less than that can lead to malfunctions.

 

dDptdPQ.gif

 

 

This is an example of a perfectly fit .45 extractor by one of the finest 1911 'smiths in the country, Jerry Keefer.

 

9kyW7oF.gif

 

 

Quote

The extractor also needs a proper chamfer so the rounds can 'tip up' beneath extractor during a 'controlled feed' type scenario. The brass slides beneath extractor, not the extractor snaps over brass.

 

Absolutely.

 

Details on this and much more can be found at this extractor fitting tutorial

 

Hammerhead64, what make and model 1911 do you have?

 

It sounds like the internal geometry of your pistol is out of spec somewhere.  Tough to tell without actually having it in my hands and taking some measurements.

 

Cartridges should just barely kiss the barrel ramp.  If they impact the ramp, the barrel will be forced forward and up causing it and the slide to bind and not go into battery.

 

Also, in normal operation the top most round in a full mag will impact the lowest on the frame feed ramp.  Each subsequent round will strike the ramp slightly higher than the previous one.  The last round in the mag will hit the ramp the highest, nearly at the very top.  If you inadvertently rounded the top edge of the frame feed ramp as you were polishing it, changed it's angle from 31.5 degrees, or made it anything other than perfectly straight, feeding problems could ensue.

 

Does your pistol have a gap between the lower edge of the barrel ramp and the top edge of the frame feed ramp when the barrel is fully to the rear and setting on the frame?  Can you post a clear, close-up picture of this vital area?

 

You may end up having to engage the services of a real '1911 smith to get this squared away.

 

Best of luck.

Edited by Steve in Allentown PA
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Steve, my appologies.. it seems I failed to define my statement properly. You and I are agreeing on the same thing. I used poor wording, you nailed everything I had in my mind's eye.

 

A fellow by the name of KC gave a very similar image and specification quite a while back. He does bullseye pistols. Maybe you know who he is.

 

Jerry Keefer was very reputed and equally respected.

 

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Nothing to apologize for.  I know of KC by reputation but I've never met him.

 

By the way, here are the ideal hook-to-breechface distances for a couple of other calibers:

 

9mm .060"

.40 .065"

 

You can see that as the rim diameter and length of the case increase so does the distance.  It's all about the geometry.

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