Thumb safety question

[Firehand]

Was helping clean/oil a new Sistema, and ran into something interesting.

When reassembling, had the frame back together and checked the safety, and found that with the grip safety depressed, if you pulled the trigger the hammer would slip off the sear and the safety slide down to off. Figured something had to be out of place so pulled everything back apart, checked assembly, spring, etc., still happened. Finally, just to see, completely assembled it and with the slide/barrel installed, the safety worked perfectly. :confused:

I understand that there's something in the slide/frame being assembled that made the difference, but I don't understand what. Explanation, anyone?

[1911Tuner]

The thumb safety lug isn't blocking the sear. Get a new one.

[Firehand]

Ok.

Still wonder, what in the slide being on would make the difference?

[pistoldoctor]

I'll wager a guess.

The thumb safety notch in the slide stops the thumb safety from going up (sometimes!). When you had the slide off, the thumb safety was able to be pushed up higher than it normally would, and the part of the safety that stops the sear, overshot its optimal position, allowing the sear to move, thus appearing to not be fit properly.

If the thumb safety works properly with the slide on, I'd say you are fine, but a properly fit thumb safety shouldn't have this problem. It sounds like your thumb safety is BARELY getting by.

[Ten_Ring]

I'll wager a guess.

When you had the slide off, the thumb safety was able to be pushed up higher than it normally would, and the part of the safety that stops the sear, overshot its optimal position, allowing the sear to move, thus appearing to not be fit properly.

Tried it with my RIA.... same thing... If I moved the safety to where it would be with the slide in place it worked perfect, but move it up a bit futher and it would travel past the contact point allowing the trigger to move enough to disengage the sear.

[Firehand]

I think I'll look for a new safety. With the slide on it works perfectly through numerous tests, but this is something I'd prefer not to take chances on.

Now to look for 'how to fit'.

[1911Tuner]

With the slide on it works perfectly through numerous tests

Then it's okay. With the slide off isn't a definitive test for the reasons stated above.

[Firehand]

Thank you, gentlemen, one and all.

[Pappy]

I'll jump in with:

http://www.m1911.org/technic_forum.htm

And click on:

How to function-check an M-1911 (courtesy of D. Camm) (javascript:redirectWin4('technic25.htm'))

Pappy

[Karnaaj]

Hmm. With the slide off on my RIA 1911A2, the safety at max up, the hammer will come off full cock... but only slightly. Won't even make it to half-cock. (Looks to be a little less than the distance from hammer-down to half-cock.)

I guess I'll just have to be extra-careful, when the slide is off, to make sure the chamber is clear, for safety.






<heheheh>

[pdoppenheim]

Actually, all you have to do, when the slide is off and you're manipulating the gun, is to make sure the slide is pointed in a safe direction. :)