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Discussion Starter · #1 ·
So.... Ive had two snap off on me in as many range visits now. KMP is great about it sending me a new one each time I send them the broken one back, but it got me to thinking, how often do you break a sear on a semi-auto 1919a4?
 

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Curious...
Where are they breaking....the ears on the bottom?

Can you tell the direction of the break/crack?

IIRC...you replaced internals or switched from ORF design..?

Dan in Oregon
 

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I have KMP sears in 4 of mine and have never had a problem. Are you sure there's not something causing them to break? Pictures would help.
 

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Yup - once is unusual - twice is out of the ordinary for sure. Unless there was a problem in a run of sears that Tom knows about. He does stand by his products - above and beyond. ;)
 

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I've had one break one ear off......after about 10K through the gun. Tom sent a replacement. Haven't had any issues with any others. I've been running 2 guns for a while now, one still has the old original (thin) design trig/sear combo and is still running strong. I would check the rest of the internals out very thoroughly and make sure something's not hitting where it's not supposed to be.

Matt
 

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The only thing I can suggest is checking to see if there is a clearance cut on the back of the barrel extension. However the cut is for clearance of the trigger and I don't know if that could possibly have any effect on the sear. The only other thing I can think of is the machined slot cut for the sear may restrict the movement of the sear and cause some kind of binding. I guess you need take the gun apart to see what that part the sear might possibly be hitting during recoil like maybe the accelerator. I have to admit I have not had one apart recently to see exactly where the parts fit in relation to each other and what might possibly cause the problem.

I am not sure if it is possible but is it possible for the sear to actually impact the back plate when firing By the way the buffer plate should extend out from the back plate about a sixteenth of an inch. This would normally keep the sear from contacting the back plate in recoil. If buffer disks are missing or compressed it might cause the problem.
 

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Discussion Starter · #7 ·
I'm sorry, I already sent the broken part to KMP, but the sear is essentially a metal "L" shaped piece right? So mine keep snapping off cleanly right where the two pieces meet. The break is clean and at 90 degrees. This is the second time. Let me know what parts you guys need pics of and I will take pics. I have already replaced the sear with a new KMP one that I bought the LASt time I sent the broken one back.
 

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Discussion Starter · #8 ·
Curious...
Where are they breaking....the ears on the bottom?

Can you tell the direction of the break/crack?

IIRC...you replaced internals or switched from ORF design..?

Dan in Oregon
My internals (I believe) are Allied Ordnance (at least that is who built the gun.) I have modified it via Troy at BarrelXchange to shoot the 54R cartridge. I use only 148 grn. light ball.

As for the sear and trigger, the "ears" broke off my last KMP trigger part so they sent me the "new" version with different ears and I (supposedly) upgraded to the "new" sear style.

here are a few snaps of the parts (the sear seen in the pic is the one before the last one that broke)




 

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Is the rear of your BBL ext. machined for the trigger to clear like the one in this pic. The area is just above the rear tang where the nose of the trigger may hit. http://shop.ironcreationsllc.com/images/parts 014.jpg

Has your accelerater been machined a bit wider between the "ears" ?...........looks like yes

Check the rear of your BBL ext . for any visible marks from the trigger hitting in that area.

You say the Sear breaks @ the L...Right in the bend or more on the long leg of L ?

IIRC the caliber conversion your useing runs a tight headspace...
.just saw your pics above and
your trigger is possibly hitting BBL ext. ( looks like yours is not clearenced in that area) If trigger is engaged in the sear when/if? it hits the rear of your BBL Ext......this may be your problem. snap
 

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Never have broken one. Top notch reports of customer service from all over forums. I wonder if there's some little thing in how the semi parts were machined that is putting stress on it?
 

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Discussion Starter · #11 ·
Is the rear of your BBL ext. machined for the trigger to clear like the one in this pic. The area is just above the rear tang where the nose of the trigger may hit. http://shop.ironcreationsllc.com/images/parts 014.jpg

Has your accelerater been machined a bit wider between the "ears" ?...........looks like yes

Check the rear of your BBL ext . for any visible marks from the trigger hitting in that area.

You say the Sear breaks @ the L...Right in the bend or more on the long leg of L ?

IIRC the caliber conversion your useing runs a tight headspace...
.just saw your pics above and
your trigger is possibly hitting BBL ext. ( looks like yours is not clearenced in that area) If trigger is engaged in the sear when/if? it hits the rear of your BBL Ext......this may be your problem. snap

Thanks Duke. I will get pics of the bbl ext for you. As for the break, the horizontal piece of metal snaps off where it comes into contact with the vertical piece. The vertical piece remains intact and the horizontal piece simply snaps off not quite perfectly clean, but kind of like when pot metal snaps with a crunchy type end grain.
 

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Discussion Starter · #12 ·
KMP Sears

OK Gang - here are shots of my barrel extension. What do you think? Seems to me, that I might have a bit of wear right at the end of the extension. Certainly mine doesn't have the cut out milled in it like the Dukes'. Could the sear be hitting the end of the extension and getting undue stress?





 

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Bumper Technology
This is the area that may need to be taken down a bit Sounds like the trigger is touching here, I just had the same issue


Sent from my iPhone using Tapatalk
 

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Discussion Starter · #14 ·
View attachment 13298
This is the area that may need to be taken down a bit Sounds like the trigger is touching here, I just had the same issue


Sent from my iPhone using Tapatalk
Thanks Woodey, looks like that could be it! Just heard from KMP on that as well. I'm awaiting official word from them, but it sounds like the issue, and an easy one at that.
 

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Discussion Starter · #15 ·
KMP Sears

OK - finally got some more pics. Unfortunately, I can't see an obvious issue just yet. My barrel extension piece has been beveled and I don't see obvious wear patterns that would point to a cause for the sear breaking. Anyone else see something I don't?




 

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Install the trigger onto the barrel extension as if it would be in the gun. Then see how they interact


Sent from my iPhone using Tapatalk
 

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Discussion Starter · #17 ·
Install the trigger onto the barrel extension as if it would be in the gun. Then see how they interact


Sent from my iPhone using Tapatalk
Thanks Woodey. I have. Trigger goes up and down, grabs the sear and pulls it down. Not sure what else to report

 

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You still need the clearance cut for the tip of the trigger.

You can see in a couple of your pics where the trigger has hit on the back of BBL ext. ..just above the tang
.

http://1919a4.com/attachment.php?attachmentid=4594&d=1361919311

The area that says NO...is the one you should have.


More info on that here....
http://1919a4.com/showthread.php?41180-machining-1919-internals&highlight=machining

like this... My m37 bbl ext....Essentially the same as your 1919 bbl ext.
Trigger
Tire Metal Metalworking hand tool
Metal Steel Wood Floor Table

This could easily be done with a dremil if needed.
 

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It appears you have a bevel on the end of the tang of the barrel extension. I have never seen that before and it probably has a purpose but what most of the people have been referring to is the bevel on the back of the barrel extension right behind the place where the locking piece goes . Remember in recoil the barrel extension come back further than in the position shown with the barrel extension and lock frame assembled. I believe all the way back to make contact with the face of the lock frame as you can demonstrate by compressing the two together against the spring tension in the lock frame. Then you can see if there is any binding of the trigger in that area.
 

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Discussion Starter · #20 ·
You still need the clearance cut for the tip of the trigger.

You can see in a couple of your pics where the trigger has hit on the back of BBL ext. ..just above the tang
.

http://1919a4.com/attachment.php?attachmentid=4594&d=1361919311

The area that says NO...is the one you should have.


More info on that here....
http://1919a4.com/showthread.php?41180-machining-1919-internals&highlight=machining

like this... My m37 bbl ext....Essentially the same as your 1919 bbl ext.
View attachment 13354
View attachment 13355
View attachment 13356

This could easily be done with a dremil if needed.
AHH the "NO" threw me! The tech sheet you put up seems to indicate a much larger and deeper cut than you show in the pics, but I get the idea. I'll get that cut out and see

Thanks Duke
 
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