Daewoo pistol, seeking gunsmith advice...

Yes, I do understand this is not a S&W pistol, but this board seems more informed and educated than most of the generic firearms boards.

The gun in question: Daewoo DP 51 (which currently is being marketed as the Lionheart LH9).

The issue- light to zero primer strikes on DA, which now is occurring on SA shots too.

What I have already done:
changed the recoil and hammer springs (put new ones in).
replaced the trigger bar spring- the new one has the same tension as the old one does.

checked and cleaned the firing pin and channel- pin is good, channel is clean. The pin moves fine and smooth, does not stick.

Here's the parts photo (from Apex gunsmithing)


I am checking, by doing the "pencil test". Placing a #2 pencil eraser-end down into the barrel, pointing the gun up, pulling the trigger. Almost never gets a strike in DA; usually gets one in SA (also the same in SA+, the Daewoo "specialty").

With the grips off, when I press the trigger bar more firmly upwards (towards the slide), I get DA strikes.

When I hose the gun down with brake cleaner and completely remove any lubrication, I get DA strikes a lot more frequently.

When the gun is lubed at all, basically 0% on DA, and the pencil will barely leave the barrel on SA. And I'm beginning to get an increasing # of no-strike on SA.

What I have eyeballed thus far- the firing pin block lever appears intact and fine. It moves in SA, it doesn't seem to be getting engaged most of the time in DA. If it does, it barely moves.

I removed the Trigger Bar, and have noted that the part that fits into the Hammer Assembly looks chewed up; it's irregular and worn. Doesn't look like that in the picture above.

As far as I can tell, the Hammer Assembly parts also look ok.

So I have a new Trigger Bar on the way. The part I am concerned about on this- if you look at the parts photo, on the Trigger Bar, on the lower right part of it, that part protrudes, and is shaped basically like a pizza slice. On mine, it looks like someone has taken a couple nibbles on each side of the slice.

My reasoning is, I think the trigger bar is worn and does not securely grab onto the hammer assembly. Once cocked, there is less movement, more firm grab, but in DA it's just too worn out.
I'm guessing the better performance when bone-dry is due to the increased friction.

Here's the parts photo (from Apex gunsmithing) Where?

Rarely, when anyone posts about light strikes with a semi-auto, does anyone state that they have disassembled the slide and made sure the firing pin channel and pin were clean and gave free movement!!!! Did you? This should be first before throwing parts at the gun.

Alk8944 said:

Here's the parts photo (from Apex gunsmithing) Where?

Click to expand...

here, don't know why it didn't show

Alk8944 said:

Rarely, when anyone posts about light strikes with a semi-auto, does anyone state that they have disassembled the slide and made sure the firing pin channel and pin were clean and gave free movement!!!! Did you? This should be first before throwing parts at the gun.

Click to expand...

Yes, that was the first thing I checked out.

Channel is clean, firing pin is intact, movement is smooth and unhindered.

For good measure when I did that, I went ahead and took a small-caliber bore brush and really scrubbed out the channel, and made certain everything was good. It is. And it was when I first examined it.

After checking the pin and channel, I then looked over the firing pin block lever (without removing it), it seems to be in good shape, nothing amiss. Moves freely. Similarly, the actual hammer group and sear looks to be fine.

As I said, I then began fiddling around trying to figure out what is happening. I noted that the firing pin block lever does not "jump" in DA; it does in SA. So I pressed the trigger bar gently upwards (simulating increased spring tension on the trigger bar), and it then worked.
So I then replaced the trigger bar spring for a few bucks; I got it for a reasonable price along with the hammer spring and recoil spring. BTW better price than Wolffs for this. Figured that might be it, but the new trigger bar spring has basically the same tension.

So I then looked further at the trigger bar, and noted that the area that fits into the Hammer assembly is worn quite a bit. It is rounded off in areas, not clean and fairly sharp as the photo seems to imply.

As I stated, the gun "functions" a lot better, when it is COMPLETELY dry of any lube. It also creaks and scrapes, and the trigger pull approaches 20 lbs. But without any oil at all, it seems that the increased friction is enough to let the trigger bar grab ahold of what it should, and trip the firing pin block lever.

To be clear about lube and oil- I am not dunking or drowning the gun. I specifically hosed it off with brake cleaner to get it completely dry. The amount of oil required to cause a slip and light/no strike:
I have 20 weight food-grade compressor oil in a syringe, with an 18 gauge needle attached. The "drop" I can produce from this is about the size of a single grain of sand or table salt (but obviously oil). This is way smaller than even a single drop of say, Ballistol from a can. My purpose was to give enough oil to keep the metal from being COMPLETELY dry, but not make anything "wet". There's probably more oil just from wiping with a rag, which I also did before.

I have little doubt that the gun is not intended to be so dry it squeaks. But anything more than that, and the Trigger Bar slips.

I always wanted a Daewoo, very interesting pistol, and since I spent 13 months in Korea near the DMZ in 1965-66 I have some interest from that perspective. I wasn't aware of the Lionheart pistol, thanks for mentioning that!

Honestly I have no idea. I have seen several guns where the firing pin lock wasn't functioning properly for various reasons and was at least partially interfering with the firing pin. These were to the extent that both the firing pin and the lock were badly burred. I am sure you would have noticed that though! If the firing pin moves freely and there is adequate hammer spring tension I can't see any reason why it wouldn't fire, at lease single-action. Lubrication should have effect except beneficial when the gun is fired single-action. I would offer to look at it for you but we are 13-1400 miles apart!

One other thing that I don't want to take the time to review in your other posts is did you replace the trigger bar, or just the spring? I see the entire "trigger assembly", which includes all trigger parts, the trigger bar and spring, is only $10 on the Lionheart web site, I would try replacing this before doing anything. Definitely do not keep playing with the gun without proper lubrication, it can do more damage than you want!

Maybe you already have this information but Lionheart's phone number is: 888-552-4743. I would call them and see if their service department has any ideas. The other option is ask if they will service your pistol originally from a different importer.

I have replaced the springs, but not yet the trigger bar. At this point I'm pretty certain that is the issue.

The firing pin is fine; everything in the slide is good. I didn't note any burrs upon removing the pin. I went ahead and cleaned it thoroughly, and everything is smooth.

Remove and clean out the firing pin block/
plunger/lever (whatever it's got). They can
accumulate a surprising amount of primer
shavings that can restrict the block's range
of motion, and drag on firing pin.

Check movement of whatever actuates the fp
block/plunger/lever, preferably with slide
mounted on frame (maybe looking up thru
grip, or leaving barrel off); looking
for bent or worn parts that fail to properly
actuate the fp block/plunger/lever.

Steve912 said:

Remove and clean out the firing pin block/
plunger/lever (whatever it's got). They can
accumulate a surprising amount of primer
shavings that can restrict the block's range
of motion, and drag on firing pin.

Check movement of whatever actuates the fp
block/plunger/lever, preferably with slide
mounted on frame (maybe looking up thru
grip, or leaving barrel off); looking
for bent or worn parts that fail to properly
actuate the fp block/plunger/lever.

Click to expand...

Yeah, I've cleaned out the firing pin, channel, block etc. Everything on the slide is good.

As far as I can tell, it's the Trigger Bar that is the culprit. It appears to slip out of engagement on DA strikes.

It really doesn't look like there's any other major issue on the internals. Kind of concerns me that this would happen, wonder how long it's expected to last (and how much this has been shot).

scoobysnacker said:

Yeah, I've cleaned out the firing pin, channel, block etc. Everything on the slide is good.

Click to expand...

I know you took firing pin out and cleaned it's channel. I
did read your first post.

You've removed the the firing pin block, spring etc from slide?

I'm not familiar with the Daewoo, but I've seen several different block designs that were remarkably good at accumulating surprising volumes of crud within interior areas--usually the area where block is expected to displace to, to allow firing pin movement. Spraying the assembled parts won't get that grunge out.

Trigger bar is stamped/bent sheet steel. It might be just a bit off on a bend or two, for whatever reason. If you can watch the bar's interaction with the firing pin block as you work the
trigger, you may see in one of the modes (DA/SA) that the bar
has different movement on the firing pin block mechanism.

Something's doing it, you'll find it if you keep looking.

I know you took firing pin out and cleaned it's channel. I
did read your first post.

You've removed the the firing pin block, spring etc from slide?

Click to expand...

Yes... on this pistol, you have to remove the block to remove the firing pin. Had to remove that to get it out.
Drive out a roll pin running across the slide, in the slide serrations. This lets the block (and spring) come down and out of the slide; the firing pin will not come out until this is removed.

another Apex image, showing how it looks.

Drive out the firing pin retainer roll pin. Direction doesn't really matter here but I like to be consistent and go left to right. You can start this pin with an AR-15 3/32" bolt catch roll pin punch, and it shouldn't be overly tight. This is the larger perpendicular pin in the middle of the slide serrations.
Remove the firing pin and spring. Pressing the firing pin block plunger in will free up the firing pin. The spring may try to hide in the firing pin channel, so fish that out.
The firing pin and block plunger.
The firing pin and block plunger.

Remove the firing pin block and spring. These fall right out, and you may notice the spring is surprisingly light so not to add weight to the trigger pull.


When I did, I checked everything out best I could. Smooth, no burrs or gouges, and I cleaned everything. Sprayed, then used a bore brush, then really scrubbed with patches/cloth. Going the length of the channel, and also going in from below (where the block goes in).

I had replaced firing pins on a couple of pistols before, so when this issue started that was the first area I looked. Was hoping that was it.

Trigger bar is stamped/bent sheet steel. It might be just a bit off on a bend or two, for whatever reason. If you can watch the bar's interaction with the firing pin block as you work the
trigger, you may see in one of the modes (DA/SA) that the bar
has different movement on the firing pin block mechanism.

Click to expand...

Yeah, that's where I am now. I've looked, pushed, pressed and everything else, and for the life of me, it seems like the trigger bar just floats in the general area of the hammer group and firing pin block lever.


It is held in place by inserting a post into the trigger, and the spring is the only thing that provides the tension forcing it into the hammer assembly.

When I pull the trigger in DA, the bar seems to "slip" downwards, instead of being grabbed and caught up in the movements the rest of the internals. I've been able to confirm that by pressing it gently upwards at the rear, I again get correct function.
I replaced the spring, hoping that increased tension on that area would fix it; but it doesn't appear to be changing anthing.

On SA (when it's cocked), the trigger bar does get 'captured" by the hammer etc, and it functions as it should.

So, I have a trigger bar on the way.

The guy on ebay that sells the parts has a storefront, Bama Gun Parts, and he lists 43 different parts for this pistol. A bunch are springs and roll pins, detentes, etc. He has basically everything but the frame, slide, barrel and grips.
I have those , and a reasonable certainty of what ISN'T at fault.
So, removing that from the equation, that leaves me with:

1. trigger bar (which is coming)
2. firing pin block lever- he lists for $6
3. Hammer assembly-I really don't think this is at issue, but he has the components for $24

I know my trigger assembly, hammer spring and strut, mag safety catch etc are good, and won't replace them. So at worst case scenario, if the trigger bar isn't the issue, I will be $30 worth of parts to complete the rebuild of the pistol.

Based on the price I paid and how much I've since put in, that would still leave me with a gun less than $400.

Wasn't my plan at the time, but it's been kind of fun fiddling around with it. I just want it to work afterwards.

Might be worthwhile checking to see if any aftermarket "improved
performance upgrade" parts have been installed, too.

Pm enroute.

I am sure no expert 'smith, but I have never seen a spring like that used to hold something sideways. Does the trigger bar have a groove or slot on the bottom that the wire spring will engage and hold th trigger bar up? This is in reference to the 2nd and 3rd pic in post 9.

^^^^
I agree, that spring looks like it should be pushing up on the bar. It even looks like there is a groove in the bottom of the bar for the spring to ride in.

If the photo shows how the spring is to be installed, you would think that it needs a bend in order for it lay flat on the bar.

To the OP, I have no idea how to solve your problem, but your accurate description of what you done and your very good pictures make your post stand out from the usual vague narrative and fuzzy cell phone shots.

I agree with Arquebus357 and cahotshoe that it appears the spring should be in the groove on the bottom of the trigger bar.

There is a narrow slot in trigger bar, that the spring should track in/stay in.

almost like the beretta 92fs, the spring goes into the groove on the bottom of the trigger bar like the previous post says

Inusuit said:

To the OP, I have no idea how to solve your problem, but your accurate description of what you done and your very good pictures make your post stand out from the usual vague narrative and fuzzy cell phone shots.

I agree with Arquebus357 and cahotshoe that it appears the spring should be in the groove on the bottom of the trigger bar.

Click to expand...

Thanks, I can't take credit for the photos, I merely found and posted them from a site that did a very thorough and detailed job of explaining the gun.

Regarding the trigger bar- there is a slot on the underside of the bar, the spring fits into that. This keeps the bar basically free-floating. The safety (which is set up facing backwards, instead of rotating at the rear) serves to keep the rear of the bar engaged in the hammer assembly. The grip will keep the bar flush and even with the frame, otherwise it can ride outwards.

It appears very similar to the Beretta design.

The bar will be engaged by the hammer, and then as it travels forward, it will engage the firing pin block lever. Remove the bar, and the hammer will travel, but the firing pin block lever will not, and the firing pin is not free to move.

What is happening in my case- coming from straight DA (hammer uncocked), the trigger bar is 'slipping'. It is not catching the firing pin block safety lever. It appears to move downwards, out of engagement, prior to engaging the firing pin safety lever.
I have tested that, by gently appling more upward pressure, and the pin is then freely moving.

My initial thought was that the spring itself was too weak, but the replacement spring maintains the same tension and yields the same results.

To me, this disqualifies the hammer spring (which I replaced anyway), and disqualifies anything in the slide assembly (firing pin etc). When the firing pin block lever is engaged, the firing pin will knock a pencil - dropped into the barrel so the eraser sits where a primer would- knocks the pencil about 4 ft into the air, when pointed up. This definitely should give me a good strike.

I suppose my verbal error is "light strike", the actual issue is "no strike" in DA. The hammer itself does work... if there were no firing pin block, the gun would definitely work.

So, the slide parts are fine. The springs are fine.
To me, that leaves the hammer, the trigger bar, and the firing pin block lever.

Have not totally removed things (only removed the trigger bar), but the hammer and FPB lever look "like they should"; and the trigger bar looks chewed up pretty seriously in the spot that it is supposed to engage the other parts.

Trigger bar arrives tomorrow. Will know then, if I have solved this, or if it's on to the next part!

It's nice to know that you are not stupid enough not to realize the proper orientation of that spring.

Hope the new parts will solve the problem. Keep us posted as I feel invested in your saga.

I hope this gets it

Most guns, you can find a whole forum (like this for example) dedicated to it, and usually the top 5 or so problems are going to be listed with fixes detailed. If not already listed, you usually get a post soon with someone saying "oh, it's ____, you will have to do this".

I've returned next to nothing on the Daewoo, and even searching Lionheart (they currently import an 'upgraded' Daewoo), I get little. I was very fortunate to find the Apex site detailing the Lionheart; they completely take the pistol down and reassemble it. It's where I got the photos, and the parts lists. Then, when I checked auctions for parts, again very fortunate to find a seller that seems to have large supplies of every Daewoo part for sale.

daewoo

BTW , S&W mags will work-69 series or 59 series -cant recall which but # of shots will determine.
Larry

YAY! New trigger bar did the trick!

I now have good strike (tosses the pencil 4 ft in the air) on every trigger pull, whether DA, SA or SA+ (the proprietary Daewoo thing).