AW93 - premature lockback

[orionshooter]

Gang;

I just picked up a very nice AW93 with one annoying problem – the slide locks back while there’s still one round left in the mag. The problem occurs about once in every 50 rounds with all four mags. Changing ammo does not resolve the problem. Ammo is all standard velocity. Gun and mags have been thoroughly/painstakingly cleaned.

For those familiar with the gun, the slide stop is activated by a lock bolt which protrudes from and rides up a slot on the side of the magazine as the ammo is depleted. When functioning properly and when the last round is stripped, the lock bolt moves to its uppermost position, makes contact with and maintains upward pressure on the slide stop which then slide into the slide stop recess holding the slide it in place.

When the slide locks back prematurely on my gun, I take the grips off and notice that there is one round left in the mag. The one round prevents the bolt from reaching its uppermost position and contacting the slide stop - exactly the way the gun is designed. However, the slide stop is nonetheless just barely engaged in the slide recess - even though the locking bolt is in its proper position (with plenty of space between it and the slide stop). This premature lock back only happens after the fourth round is fired.

I’m losing my hair trying to figure this one out. Any ideas?

Thanks in advance everyone.

[Gwhite]

I'm not familiar with the AW93, but is there any way the mechanism could overshoot or bounce internally? I'm guessing a stiffer spring on the side stop might help. If the pistol is old & it was stored with the slide close, the slide stop spring may have taken a tiny "set" and could be a little weak. The slide will cycle a tiny bit more vigorously with only one round in the magazine, and that might be enough to make something bounce internally.

[orionshooter]

I never considered the mags as the source of the problem since it's happening with all of them but.....you must be right because it simply does not appear possible that the slide stop could move up into the slide recess without getting hit by the bolt. Maybe it is getting that slight bump you spoke of and what I need is a stronger mag spring. The gun had, in fact, been laying around for a long time before I got it - thanks for picking up on that as a clue.

[Gwhite]

I was assuming there is spring that keeps the slide stop down until it is overcome by the upward force of the magazine mechanism. I was thinking that spring might be weak, not the ones in the magazines. If it's like other pistols I've worked with, there is always a spring that keeps it from popping up until forced to.

[orionshooter]

Yup. I just looked at the configuration again and realized it can't be the mag spring because it provides tension in the wrong direction. Then I noticed a spring (just a piece of wire not a coiled spring) that puts downward (just asp you described) pressure on the slide stop. I removed and tweaked it a bit but the darn thing is so tiny that it's impossible to discern any increase in pressure.

Guess I'll just have to keep range testing it. Thanks for the advice.....for someone unfamiliar with an AW93, you were sure able to walk me through some tricky stuff. IOU !

[Gwhite]

I've worked on a wide range of pistols over the years. The only thing that stays generally consistent is the laws of physics. If you can figure out how it's supposed to work, you are usually 90% of the the way to a fix. Of course, there are always cases that defy logic, either of the "what were they thinking!?" design issue sort, or a pistol that just refuses to behave, laws of physics or not...

[rigwhanson]

I have a AW-93 and had a problem a little different than yours but the cause was very subtle. If you look at the housing on the top of the breech area of the gun that the bolt slides back into when it cycles on each side of that top piece there is a short pin that holds that housing down on the frame. On my gun those pins had loosened just a little and let the housing pop up slightly not enough that you will notice it unless you look real close. Make sure these are in and seated and the top housing over the bolt has not popped up. This caused my pistol to not reset the trigger. Probably would not affect the lock back mechanism I don't know but it is not a easy problem to notice. The pins had not fallen out of the holes they had just backed out enough that they no longer were into the frame and holding that housing in place tightly.

[orionshooter]

rigwhanson thanks for the valuable tip. Do you by any chance have a part number for these pins which might help me locate them? I think the manual if you have one, has a schematic.

[rigwhanson]

Yes the pin is 6.6325.035 2.5mmx6.0mm. I had a parts diagram that I think I downloaded from FWB.

My Manual and Parts listing was stolen when I had a pistol bag stolen. They didn't get the pistol but they did get 2 magazines and a Marvel conversion along with several thousand dollars worth of files, jigs and other gun smithing tools. Gun box, scope etc. This was in a motel parking lot daylight at 6:15 in the morning. Don't leave anything in your vehicle until your ready to leave.

[Dipnet]

It is possible that the grips have been screwed to the frame too tight, pinching magazine? My two cents. dipnet