Hammer goes halfcock for top IPSC shooter. Shooting too fast?

[Jediwarrior]

Hello, a customer of mine has a unique problem. When he shoots a fast double tap, sometimes the hammer goes halfcock.

I checked the hammer/sear engagement. 0.020 in hammer hook height, 2/3 sear engagement. Neutral contact. 2 lb. trigger pull. Mainspring is ISMI 17 lb. There is enough slack and a little overtravel.

Hammer/sear/disco set is Extreme Engineering Round style. EGW sear spring. SVI trigger.

Gun is STI single stack Cal. 40 with tungsten sleeved bull barrel. 12 lb. recoil spring.

He could replicate it happening in my shop. He rests lightly, NOT PRESS, his finger on the trigger and releases the slide from the locked open position. It goes halfcock sometimes.

If I do not touch the trigger, or if I fully press the trigger and release the slide, the hammer would NOT halfcock. I fired his gun slow and fast, but I could not duplicate his halfcock. On other words, his gun and trigger work is sound for us ordinary shooters.

I then got other pistols in my shop, a single stack 40 and an STI hi-cap 40 with 2.5 lb. trigger pulls, and we were able to replicate it using his static test of resting finger on trigger and releasing slide.

I then thought that his static test would cause "normal" guns (unless the trigger pull is really heavy) to go halfcock.

Has anyone experienced this, and if so, what did you do to prevent this halfcocking from happening?

I have been thinking about this for 2 days now, and I just can't figure out how to help him.

[JaeOne3345]

Peen the sides of the sear spring or wrap tape around the bottom portion of it.

The sear spring could be moving in the grip.

[CAB33]

Check to see if the disconnector is dragging in the frame or if the sear spring leg does not have good pressure against it.

[Powder Finger]

how much spring pressure on the middle leg?

[wanttolearn]

also, consider the overtravel screw position, it might have moved.

[Jediwarrior]

Not too light on the middle leg.

This is a single stack gun.

Please note that he only goes halfcock on really close targets (hoses it) and it happens only a few times.

[Rob Tompkins]

I am NOT a gunsmith but just a shooter so...

It sounds like he might be releasing pressure on the trigger ahead of the hammer / sear reengagment?

[Powder Finger]

it really sounds like the disconnector is not going back up quick enough.

if it were me I would put a different leaf in it trying to match the left leg

as much as possible and start upping the middle leg to boost the disconnector some.

that way your not messing with his spring.

if that fixes it then I would find out why his spring isn't getting the disco up.

the best fix is to turn him into a trigger slapper, that way he ain't float'n the trigger

[Chuckie45]

Is it tied to the slides interaction with the disconnecter? Can you duplicate it by holding the slide just out of battery and pulling the trigger?

[Jediwarrior]

Is it tied to the slides interaction with the disconnecter? Can you duplicate it by holding the slide just out of battery and pulling the trigger?

No, it is not. When slide is just out of battery, sear is fully disconnected.

Powder Finger, you may be on to something here. Will give it a try.

[bonglee0507]

A tough one

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[Jediwarrior]

Update: We changed H/S/D set to a new Extreme Engineering set. We bent the middle finger for more tension. We also tried to increase the slack by readjusting the front tab. We even tried a new sear spring.

He can still do it, both statically and actual firing. Once going full auto.

This has led me to conclude that it's the shooter, not the gun.

What Powder Finger said about floating the trigger is similar to bump firing: the forward impact of the slide causes the finger to tap the sear, causing either a halfcock or full auto.

Remember, he can replicate this on other guns with his static test.

Also, when the slide is moving forward, the disconnector is down and not connected to the sear. So when the slide slams forward, the disco moves up instantly, allowing the trigger to contact the sear. That is the only time his finger can tap the sear.

So, his shooting technique needs to be changed.

[latech15]

Get a different customer.

[outerlimits]

Get a different customer.

Nah...just give him a revolver.

[Jediwarrior]

Haha!

Oh well, there is always a limit on the equipment.

[Jediwarrior]

I heard this is becoming more common as a shooter reaches a certain level of speed.

Just like trigger freezing on a shotgun or rifle, You can release and pull the trigger faster than the cycling of the bolt.

So you go beyond the limit of the equipment.

[ltdmstr]

Update: We changed H/S/D set to a new Extreme Engineering set. We bent the middle finger for more tension. We also tried to increase the slack by readjusting the front tab. We even tried a new sear spring.

He can still do it, both statically and actual firing. Once going full auto.

This has led me to conclude that it's the shooter, not the gun.

What Powder Finger said about floating the trigger is similar to bump firing: the forward impact of the slide causes the finger to tap the sear, causing either a halfcock or full auto.

Remember, he can replicate this on other guns with his static test.

Also, when the slide is moving forward, the disconnector is down and not connected to the sear. So when the slide slams forward, the disco moves up instantly, allowing the trigger to contact the sear. That is the only time his finger can tap the sear.

So, his shooting technique needs to be changed.

There's a big difference between operator trigger speed vs. full auto. Even for the top shooters. If it's an operator issue, that doesn't explain why it falls to half cock. It should either disconnect, or reset. And if it resets, it shouldn't fall to half cock. If it really is going full auto, obviously you have a different problem.

[Mat Price]

I have had this happen. The combination was a really good trigger very crisp break at 2lbs. The gun was a sti trubore 38 super and a fat heavy slide. Basically I was on the trigger before the slide was in back in full battery. I guess I was exerting force on the trigger enough that it would drop to half cock occasionally. I could not be purposely replicate. It gave me fits because it didn't happen all the time but when I shot targets very close 3 or more it tended to be more prevalent. I had the slide lightened and reduced the recoil spring weight. And become much more than conscious of my trigger going through the motion. Touch prep press fire return and it went away without losing time off my close (2 - 3 yards) targets fwiw

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[Mat Price]

Oh also. My Gunsmith also increased the reset a small bit. I haven't had issues since. But I think it's more about being very aware of the firing cycle touch prep press release even when shooting very fast splits

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[tulsashooter45]

+1 on Matt said, this makes more sense

[Jediwarrior]

Thanks for sharing Mat, this does make more sense.

I suggested the following:

1. Use a very light trigger such as STI carbon fiber with titanium bow.

2. Fit it a little on the tight side. No up and down play. This increases friction between frame and trigger.

3. Bend middle finger forward to increase trigger tension. This will increase overall trigger pull..

4. Increase trigger slack by not bending the front tab too much.

Ltdmstr, remember, I cannot reproduce his feat no matter how fast I double tap his gun. His shooting style is unconventional.

[Mat Price]

Thanks for sharing Mat, this does make more sense.

I suggested the following:

1. Use a very light trigger such as STI carbon fiber with titanium bow.

2. Fit it a little on the tight side. No up and down play. This increases friction between frame and trigger.

3. Bend middle finger forward to increase trigger tension. This will increase overall trigger pull..

4. Increase trigger slack by not bending the front tab too much.

Ltdmstr, remember, I cannot reproduce his feat no matter how fast I double tap his gun. His shooting style is unconventional.

For me it was more of the crossroads between trying to shoot fast and shooting fast. It seemed the faster the slide would cycle the better it got. When I finally started to focus on the firing cycle the hammer follow problem stopped. Also as a byproduct of the better trigger control my hits all around got better and the little bit I did loose between splits I gained in transmission time. Shooting splits between. 09-. 15 does no good if you can't track the dot that fast and are dropping a point for a charlie at that close range.

I'm just a lowly A class open shooter but I can squeeze the trigger with the best of them.

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[jrbet83]

He's riding reset. Increase over travel, put more tension on the sear and less on the disconnector. For a 2-2 1/2 trigger, put 6-7 oz on the disconnector, and an additional 17-18 oz on the sear (24-25 oz total)

Decreasing disconnector tension, will lighten reset pressure, forcing him to get off the trigger, plus the added tension on the sear will aid in cases he does ride rest.

Edited November 24, 2013 by jrbet83

[latech15]

Who is this Jedi master with the lightening fingers?

[Jediwarrior]

He's been all over the world in World Shoots.

What is not surprising at is that this problem has been encountered by a lot of top shooters worldwide,

So we gunsmiths can only do so much to the equipment, and ultimately the shooter has to do some adjustments.