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I have acquired a third Ruger MarkIII (this is a vile sickness) and have/had a small problem after eliminating the magazine safety. The gun shot fine in stock form but when I replaced the magazine safety parts with a Mark II hammer bushing mod, I would get the occasional stove pipe similar to the one in this thread. I assumed the malfunctions were due to the modification so I returned the gun back to stock and the problem went away. Upon further inspection I noticed that eliminating the mag safety allows the magazine to move around quite a bit inside the grip frame. This movement could be felt and seen by taking off the grips, inserting an empty magazine, and using a tool or fingertip inserted through the slot in the grip frame and moving the magazine fore and aft. I could also see this when trying to move the magazine fore and aft through the ejection port. I compared the magazine movement to a factory stock Mark II and noticed there was much more magazine movement in the modded Mark III gun than in the Mark II. In fact, unless I used considerable force, the Mark II magazine would not move around at all and was very stable inside the grip. This stability seemed to come from the Mark II style magazine release; it holds the magazine really tight inside the frame. Out of curiosity, I performed the Mark II bushing mod on my Mark III 22/45 and had no problems. It seems the design of the 22/45 grips provide more stability to the magazines. I think, at least in my case, that excess magazine movement, due to this mod, may have caused my problem.
Anyway, my question is, has anyone else had any failure/feed problems when eliminating the magazine safety feature in their Mark III and using a Mark II style hammer bushing? Hope this was clear.

Magazines in my MKIII can be moved around pretty ez and I have never gotten a stove pipe.

The only thing I can think of is that your frame was cut wrong. The tension placed on the rear of the magazine by the magazine disconnect corrected the issue by moving the magazine further from the ejector, but without the tension from the magazine disconnect the the magazine sits in the frame incorrectly.

Thats about all my experience tells me. I'm sure someone here will be able to give you a more definitive answer.

What you have observed makes sense. Without the downward pressure of the magazine disconnector hook, a Mark III magazine could flop around in the frame a little. Since there should be approximately a 1/16th inch gap between the mag lips and the ejector, any movement might create a situation were the empty case could get knocked off of the extractor prematurely. Whether that situation is amplified by a loose or weak extractor fit must yet be determined. This condition might bear more investigation.

Also, the base of a 22/45 magazine is very long compared to a regular Mark III and would tend to provide more stability to resist fore and aft movement of the magazine inside the frame.

I have not experienced this type of failure with Mark III pistols lacking the mag safety disconnector, but I always replace the extractor with a VQ Exact Edge when I do the mod.


R,
Bullseye

Bullseye wrote:... I always replace the extractor with a VQ Exact Edge when I do the mod.

I need to replace my extractor with a VQ and try the mod again. I'll post the results when I get it done.

Thanks,
T

Just to add to what has already been said, I had the same problem with extraction issues after removal of my magazine disconnect. After installation of the VQ sear, I've had NO PROBLEMS.