1911 feeding question

[Steve in Allentown]

I've not mis read my actual experience with a 9mm 1911. 26lb hammer spring made it push feed city. Replacing the stock hammer spring and no push feeds in 400 rounds since the return to normal -- I don't run enough recoil spring to snap the extractor over the rim, so every push feed is a stoppage.

Well, I guess we can chalk this up to black magic and gremlins.

I wonder if the better way to tune 1911 funtioning is to start with the lightest recoil spring that will strip and chamber rounds reliably then find the hammer spring weight that will allow the slide to travel fully to the rear.

So, instead of starting with a 23lb hammer spring and swapping recoil springs until you find the one that works best, you proceed from the opposite end. Just wondering out loud.

 

[wally]

Well, I guess we can chalk this up to black magic and gremlins.

I don't believe in such.

The 9mm 1911 is much more prone to push feeds because the rounds are so much shorter in OAL than .45ACP. The fact that just about everyone puts the spacers in the magazine at the rear of the follower in an attempt to compensate for the shorter OAL makes less feed lip available to hold the top round under recoil.

Basically the top round can move forward enough under recoil, before the slide has decoupled from the barrel that less than half the feed lips are left trying to hold the round, then it doesn't take all that much of a frame impact to have it about jump out and result in a push feed when the slide moves forward.

Its all a matter of timing and balanced forces. I'd wager that if the "spacers" were in front of the follower (like Tanfogilo has done with their large frame 9mm & .40S&W mags) that the issue would greatly reduced and the 9mm 1911 would have a better reputation.

I love mine but they can be finicky and take a bit of playing around to get running right.

So, instead of starting with a 23lb hammer spring and swapping recoil springs until you find the one that works best, you proceed from the opposite end. Just wondering out loud.

That is basically what I did, I went to the lightest recoil spring I had and one step above stock for the hammer spring. It just didn't work for me, in an attempt to stop the push feeds with some very short OAL, 20+ yo reloads the ammo shortage has had me dig out to shoot up. I wasn't expecting it to be worse with normal OAL rounds, but it clearly was.

 

[Steve in Allentown]

The 9mm 1911 is much more prone to push feeds because the rounds are so much shorter in OAL than .45ACP. The fact that just about everyone puts the spacers in the magazine at the rear of the follower in an attempt to compensate for the shorter OAL makes less feed lip available to hold the top round under recoil.

I fully understand.

That is basically what I did, I went to the lightest recoil spring I had and one step above stock for the hammer spring. It just didn't work for me . . .

This is the thing that has me confused. Everything worked until you substituted in a heavier hammer spring. Then things didn't work as well. If the amount of force imparted to the frame by the slide impacting the recoil spring guide rod is the root cause of the inertia feed then reducing that force would seem to be the key to solving the problem.

I thought that a heavier hammer spring would reduce that force and thus reduce the tendency for inertia feeds.

But just the opposite happened.

I guess I'm just too dull to grasp what's happening or I missed something important in an earlier post.

 

[wally]

If the amount of force imparted to the frame by the slide impacting the recoil spring guide rod is the root cause of the inertia feed

Its part of it, the other part is how much the frame/magazine jerks back before the slide/barrel decouple. The net resultant of these two effects is what ends up happening. The first effect is minor for .45ACP as they don't have much space in which to move forward until the slide/barrel decouple and they don't give up ~1/8" of feed lip to a "spacer" from the git go.
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