Tisas 1911 B45 Duty locking open with ammunition still in the magazine

[jjones45]

I picked up a tisas 1911 B45R with a plan to upgrade parts to customize it to my liking. I haven’t really shot 1911’s in about 17 years or so. The fact that these guns are made with forged frames, slides, and barrels for a price of around $450 intrigued me, especially with the features it offers. So before I even took it out to run some rounds through it I noticed how weak the plunger spring was and how the safety had no positive disengagement. It kind of snaps on but sponges off more or less. So I knew right then and there a plunger spring assembly with a stiffer spring was in order soon but I figured I’d shoot it first to see if it was a keeper before I start dumping money into it. Well 250 rounds later this gun shoots like a dream, but I had the slide lock open with partially loaded magazines about once every 2 mags or so. Just had to release the slide either with the slide lock/release or sling shot method and was back in business. No other failures of any kind, just this annoying premature slide lock. So I shot the gun 1 handed to make sure I wasn’t hitting the slide release during recoil and it still happened once every 2 mags or so. This happened with all the mags I had (2-wilson combat,2-sig, 1-mec-gar). Just to make sure this was a slide lock/plunger issue I held the slide stop down while firing 5 magazines and it functioned 100%, other than not locking the slide to rear obviously. So my question for you guys is can a weak plunger spring also cause premature slide lock or do I need to buy a new slide lock as well as the plunger spring assembly? Slide lock doesn’t seem to be rubbing on the inside and interfereing with rounds feeding so I eliminated that possibility. If I can eliminate this issue this wlll be the one of the Best Buy’s if every had in handguns.

 

[edwardware]

So I knew right then and there a plunger spring assembly with a stiffer spring was in order soon. . .

No, not necessarily, and this misunderstanding is related to your question.

First, buy and read Kuhnhausen's Shop Manual before you do anything else. . .

Now that you're done, I will remind you of several points you just read:
- safety detent feel is a function of the spring and the safety profile, and the profile is more likely to be the problem than the spring.
- early slide lock engagement can be caused by any combination of: shooter grip (bumping), weak spring, lock profile where the plunger rides it, lock profile where the lock intrudes into the magazine well, or bullet profile. A poorly profiled part is the most likely cause, because it's the hardest to get right.

Read Kuhnhausen, he's really good.

 

[Steve in Allentown]

@edwardware pretty much covered all the possibilities.

I recommend taking a long look at the slide stop to see if there is a copper smudge on it. Sometimes the lug is a touch too long and bullets will make enough contact with it to make it bump upward and engage the slide. If there is a copper smudge, minimally and carefully file the contact point. If you remove too much metal from the lug, it will no longer contact the follower and the slide will not lock back.



Here's a lug with a copper smear on it.
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It kind of snaps on but sponges off more or less.

As @edwardware points out the spongy feeling when you push the thumb safety down into the fire position is most likely due to the geometry of the thumb safety.

The shape of the thumb safety at "A" in the pic below is the key. The transition from the "A" surface to the vertical surface above it determines the amount of downward force required to push the thumb safety down. Careful file work will reduce the radius at the transition and increase the force. File a little then check the fit. Repeat as necessary. A little bit goes a long way.

So I shot the gun 1 handed to make sure I wasn’t hitting the slide release during recoil and it still happened once every 2 mags or so. This happened with all the mags I had . . .

. . . can a weak plunger spring also cause premature slide lock . . .

Anything is possible but double check for bullet contact with the slide stop lug first.

Remove the plunger spring assembly for inspection and cleaning of the tube.

 

[jjones45]

Thanks you guys. I looked closely at the slide stop lug and seen a little copper. I field stripped the pistol and inserted the slide stop back in without the slide and with the thumb safety up to take tension off the plunger spring and slide stop. Then I inserted a magazine with a round in it slowly and noticed it was definitely making contact with the slide stop and pushing it up. So I took my wet stone to it so slightly until that contact was no longer happening but was careful not to take off too much and didn’t hit the bottom of the lug at all really. Test fired another 100 rounds and what do you know, no premature slide locks and locks back on empty. It seems the problem has been fixed and this gun shoots like a dream. Now I just need another 150 trouble free rounds and I’ll have total confidence in said gun. I’ve been using walthers, glocks, hk’s, sigs, and m&p’s over the better part of the last two decades and kind of forgot about the little 1911 teething issues. On a side note, there was a fellow shooter next to me shooting who had two nighthawk 1911’s and he was impressed by the tisas b45r, especially for the price.
Here’s the groups I was pulling with this thing at about 21 feet (I know, not really a real testament of accuracy but pretty decent non the less for a $450 1911). Two of the groups are 8 shot and the other two are 10 shot. I think this thing is a keeper and will be getting upgraded parts in the future if all stays well.

 

[Steve in Allentown]

Very nice.

That is one seriously dead target

 

[ontarget]

OP, I feel your pain.
I just recently acquired a Colt Commander and had a mushy thumb safety. I had to do some filing, but now it's great.
Nothing better than a smoothly functioning 1911.
BTW the shop manual mentioned above by @edwardware is worth every penny.
My wonderful wife ordered me one for Christmas. An absolute must have for a 1911 enthusiast.

 

[3Crows]

Sorry to butt in on this thread @Steve in Allentown but in the photo you posted what was being shown to be done by the "B" arrow please?

In what book or manual is that photo from? The manual in the link?

3C

 

[Steve in Allentown]

. . . what was being shown to be done by the "B" arrow please?

The "B" surface is what contacts the sear when the safety is in the up or on-safe position. Note that the surface is coated with blue Sharpie and that there is a spot where the blue has been worn away from repeated contact with the sear during the fittng process.

In what book or manual is that photo from? The manual in the link?

I don't remember linking to a manual. I took that photo while fitting the thumb safety. I originally posted it in a thread posted HERE.

Here's a good video showing Jason Burton fitting a thumb safety:

 

[ontarget]

The "B" surface is what contacts the sear when the safety is in the up or on-safe position. Note that the surface is coated with blue Sharpie and that there is a spot where the blue has been worn away from repeated contact with the sear during the fittng process.

I don't remember linking to a manual. I took that photo while fitting the thumb safety. I originally posted it in a thread posted HERE.

Here's a good video showing Jason Burton fitting a thumb safety:

That write up in your link above is what helped me through the refitting of my factory TS on my Colt Commander. Thanks for posting. Great info.

 

[3Crows]

Thank you @Steve in Allentown. The reason I asked is that I have had an issue with my RIA 1911 FS GI. I bought a WC drop-in beavertail and a lightweight hammer. I changed nothing else but the safety would not engage. So I bought a WC sear. I removed my OE hammer, sear and beavertail and set them aside in event I want to return the pistol to original condition. The reason to change out the parts is that my large hands would not engage the grip safety and the spur would bite my hand.

I used wet dry paper to take the new sear contact surface down to equal the OE sear but still the safety would not move into the lock position. I removed additional material from the sear contact surface and the safety would now almost rotate into position to lock the slide and engage correctly the sear surface. I then, reluctantly, used a jeweler file to remove a small amount of material and polish the safety at the "B" location.

The slide safety now properly engages. It may still be just a little tight but I figure best to let it work in some and see if it loosens up.



I hope I did right, everything seems to work correctly but I hate removing metal from anything, sear surface or slide safety.


Thanks,
3C

 

[jjones45]

Threw a Wilson Combat plunger spring assembly in and the safety snaps very nicely now. The mushiness is completely gone. I figured I’d try a $6 part before I started removing material from the thumb safety. The spring is noticeably longer and stronger. Definitely worth the upgrade in my opinion.

 

[Steve in Allentown]

Well done.

 

[halfmoonclip]

Unwanted slide stop engagements happen pretty often in the Officers-size Colt Defenders in 9mm; the advice on the Colt forum was to examine the slide stop, and see where the plunger rests when the stop is in its low, unlocked position.
Then, strike that spot with a center punch, and make a slight dimple there with a drill. Emphasis on slight.
Of course, you'll have to jig up the stop, to punch it and drill it.
It solved the problem on my Defender.
Moon