Model 41 - Range Report, Last Round Misfeed

[StandardVelocity]

I was finally able to take the Model 41 (with the short conversion) out to the range last night. Very nice, with one issue apparently related to magazine tuning. An internet search turned up the suggestion that the front of the magazine lips must touch the round to allow proper positioning. On my single, very old 41-1 mag, the dimensions appear incorrect, leading only the last round in a mag to misfeed and be eaten by the returning slide. The angle is too great.

So I am looking for adjustment tips. I do have the capability of obtaining a long magazine, and transferring the short parts - some minor machining is needed, but no big deal,if the lips cannot be adjusted. Before breaking out the tools, I am looking for some feedback.

Any hints, actual dimensions, etc are welcome. This was the same result using 1970's era shorts or modern production - no difference, always only the last round. Flawless otherwise. Oh, the 1970's target rounds would occasionally fail to lock the slide back when empty - must be really low power, or just very old. It cycled fine, just no lock back.

Here are the pics - yes the magazine is dirty, but I wanted to get the pics fast:

That is the result - crushed round

Bad Angle - these are shorts, so the round is in the proper position, even though it looks too far forward. Touching lips.

Correct angle - not touching lips.

Front showing gap.

What happens to the last round - bad angle - jams.

The gap from above.

 

[BE Mike]

Have you considered a weak magazine spring and/ or too heavy of a recoil spring?

 

[StandardVelocity]

Yes, but the interesting thing is that when only one round is loaded into the magazine, and it is inserted, you can see the round pop up at the wrong angle. Sometimes. Magazine inserted gently, the round stays at the proper angle.

It appears that the root cause is the magazine lips not contacting the case, allowing the angle to be incorrect. I may be completely wrong. Here is a round, one in magazine, inserted, showing the too-steep angle because the case may not be gripped properly:

I'm going to adjust the magazine lips a bit - I think that may fix it. I have an ammo shipment arriving today (shorts are hard to find), so I'll adjust and test.

 

[StandardVelocity]

Better pics - used a damaged round just for demonstration:

They way it should be:

 

[Barrie]

I would suggest cleaning the mag you are going to use as well. Any dirt at all may possibly be some of the cause for the last round going wonkey on you. Stranger things have happened on occasion.

 

[StandardVelocity]

Fixed. A gentle squeeze at the very front of the lip with a machinist's vise altered the geometry just a bit. Actually a large number of very tiny squeezes, just to be careful. Squeeze - test fit in the gun, see what happens, repeat. There is still about a thousandths play on the one side, but I am leaving that for now. The metal stamping seems to be a bit irregular as it is, and maybe that is normal for this stamped part. The recommended pliers seemed brutal and risky, and the small vise was safe, including tiny brass jaws. In the end, a very small adjustment - maybe a good drop could alter that geometry and throw it off. Seems critical, and I tried to not ruin it because I get one attempt with this part.

Additional adjustment will be more difficult, so it stays here for now. I would like to re-shape one side, but since it works, it stays, and I would have to make a jig, a form, and who knows what else. Here is the fixed magazine - it has a constant feed angle right to the last round now, and no longer crushes anything or misfeeds:

It turns out that the internet article I found here was correct - the very front of the magazine lips must just touch the case. The non-functional feed mode had the lips parallel, now you can see a slight angle. It looks like a round may have been levered out of the magazine, maybe many times over the years, and that spread the gap just enough. I have no way to compare it with another magazine under magnification, so I do not have a reference for normal. At least the physics works out on that.

Anyway, I learned how things feed, and that was worth it - you only learn when something breaks. It works well now.

Once again, I want to thank everyone for the pointers and for patience with someone learning how this works. That is rare these days.

Now to clean it all up and make it pretty - the first outing was just a test, and I was way too anxious to just use it.