K40 troubleshooting, fixed, runs great now thanks

[AFCop]

Recently bought a new to me black k40 SN: DL04XX. Cleaned and lubricated it and it appeared to be practically unfired. I love the fit and feel of this little gun and need help to make it work dependably.

I shot 50 rounds of Federal 180 grain HST JHP using both 6 round magazines. Several fail to feed with the round nose diving slightly with the tip of the round in the mag well and the brass head on the breech face. Also a few fail to feed where the gun went into battery without a chambering a round.

I cleaned and lubed and put another 100 rounds of the same ammo through it with similar results.

I read the Kahr prep posts and tested the magazines as directed, they were hanging up, so I polished the right side of the magazine followers, cleaned and lubricated the weapon as indicated and put another 50 rounds down range. Only one FTF with the round hanging up on the feed ramp. However there were numerous failure to feed where the gun cycles and goes into battery without stripping or chambering a round. Click.

I carry an HK P2000 on duty and have shot semi autos for 30 years. I don’t think I am limp wristing. In fact I have intentionally tried to limp wrist during the first 100 rounds and it cycled fine, the FTF were when I maintained a good grip. Also, I am not engaging the slide lock with my off hand, although the nose of the round comes close to the slide lock it isnt touching. Mag springs are in properly, with the coil angled up toward the front of the magazine.

Any other suggestions on what could be the issue. I don’t want to try another brand of ammo. I have access to the 180 grain Federal which is why I bought the .40 in the first place.

Thanks for your help, appreciate this forum.

[RRP]

Cleaned and lubricated it and it appeared to be practically unfired.

If it was mine, I would polish the feed ramp and see if it feeds FMJ. Maybe this gun just needs to be broken in before it will feed JHP reliably.

If that didn't resolve the problem, I would replace the recoil spring. This should resolve failure to return to battery.

I would also inspect the magazines to ensure the springs are installed correctly. You might try stretching the springs a bit to see if that resolves failure to strip the next round. New springs may be in order.

I would also check if the mag follower, or spring coil, is hanging up on the magazine catch. This could contribute to your feeding problem, as well.

[Bawanna]

With it occasionally not picking up a round I'd check the pick up rail and see if it's got a bevel on the front.

For awhile some had no bevel and the round in the magazine would pop up under the rail instead of in front of it.

Just lock the slide back and insert a loaded magazine and see if the case slides up in front of the breech face.

[AFCop]

If it was mine, I would polish the feed ramp and see if it feeds FMJ. Maybe this gun just needs to be broken in before it will feed JHP reliably.

If that didn't resolve the problem, I would replace the recoil spring. This should resolve failure to return to battery.

I would also inspect the magazines to ensure the springs are installed correctly. You might try stretching the springs a bit to see if that resolves failure to strip the next round. New springs may be in order.

I would also check if the mag follower is hanging up on the magazine catch. This could contribute to your feeding problem, as well.

It returns to battery, just doesnt always bring a round with it.

Mag follower was hanging on the mag catch, I believe I fixed that, as now the primary FTF issue is with it going into battery without a round.

[AFCop]

With it occasionally not picking up a round I'd check the pick up rail and see if it's got a bevel on the front.

For awhile some had no bevel and the round in the magazine would pop up under the rail instead of in front of it.

Just lock the slide back and insert a loaded magazine and see if the case slides up in front of the breech face.

Thanks you both for your replies.

The rail does not appear to be beveled, however the rounds sit well forward of the rail/breech face.

[RRP]

...now the primary FTF issue is with it going into battery without a round.

My thought was that if the travel of the mag follower is impeded by the magazine catch, or if a coil of the spring hung up on the mag catch, the next round may not be pushed tightly into the feed lips, where it needs to be to be stripped by the cycle of the slide.

[AFCop]

My thought was that if the travel of the mag follower is impeded by the magazine catch, or if a coil of the spring hung up on the mag catch, the next round may not be pushed tightly into the feed lips, where it needs to be to be stripped by the cycle of the slide.

Oh, I see.

I 600 grit sanded/polished the mag follower until the nose dives in the magazine stopped. It still hangs when the follower is inserted in a disassembled mag in the well, just not as bad. I thought it was enough for the spring to overcome.

I was worried about taking too much material off the mag follower, I could take more off and see if that helps the fail to strip.

[RRP]

Oh, I see.

I 600 grit sanded/polished the mag follower until the nose dives in the magazine stopped. It still hangs when the follower is inserted in a disassembled mag in the well, just not as bad. I thought it was enough for the spring to overcome.

I was worried about taking too much material off the mag follower, I could take more off and see if that helps the fail to strip.

One of my Kahrs had a burr on the tip of the magazine catch. I first noticed it because the mag was difficult to drop. I had to push the mag release with more force than normal. I corrected it in minutes with a few strokes of a file.

If your mag catch has a similar burr, it may be impeding the travel of the magazine follower.

[sas PM9]

If it was mine, I would polish the feed ramp and see if it feeds FMJ. Maybe this gun just needs to be broken in before it will feed JHP reliably.

If that didn't resolve the problem, I would replace the recoil spring. This should resolve failure to return to battery.

I would also inspect the magazines to ensure the springs are installed correctly. You might try stretching the springs a bit to see if that resolves failure to strip the next round. New springs may be in order.

I would also check if the mag follower, or spring coil, is hanging up on the magazine catch. This could contribute to your feeding problem, as well.


AFC:

/\ /\ /\ this!

I would only add that magazine springs are available from wolff gunsprings and due to it being a used weapon replacing them might not hurt.

Be sure that the inside of the feed lips are nice and smooth.

HTH.

-steve

[AFCop]

One of my Kahrs had a burr on the tip of the magazine catch. I first noticed it because the mag was difficult to drop. I had to push the mag release with more force than normal. I corrected it in minutes with a few strokes of a file.

If your mag catch has a similar burr, it may be impeding the travel of the magazine follower.

I pulled the grips and there is no burr. With a disassembled mag in the well the follower does hang a little but the spring passes through smooth. I will tune the followers and see if that helps though the fail to feed is happening consistently not only on the 2nd or 3rd rounds.

[kahrnut1]

with these small guns timing is critical. make sure ur recoil spring is installed with open end to front of gun. a sleight bevel on front of rail is a must. there are pics of bevel on this site.

[AFCop]

with these small guns timing is critical. make sure ur recoil spring is installed with open end to front of gun. a sleight bevel on front of rail is a must. there are pics of bevel on this site.

The recoil spring was/is intalled with open coils toward the muzzle.

My feed rail may be slightly beveled, is it supposed to be an obvious bevel?
I cant find any pictures and dont have a straight edge.

[AFCop]

I appreciate all of your input. I traded my black K40 for a stainless K40 and it shoots great. My first one had a very long, uneven trigger pull with a definate hitch at the end right before breaking. This newer gun has the smooth crisp trigger that I have been reading about. It makes for an accurate shooter since the trigger break is so smooth and unexpected. This new gun doesnt have any of the Fail To Feed issues of the original. I really love this pistol.

The only issue now is the 180 grain Federal rounds are hitting the slide lock as they move up in the magazine causing the slide to lock back. I will contact Jay at Kahr and see about getting a new slide lock.

[rjt123]

Mmmmm, K40 (bad Homer Simpson impression).

After getting my K9 and finding out that the metal Kahrs are, IMHO, just *better*, the K40 is definitely on my want list.

NRA Life Member

[Barth]

Mmmmm, K40 (bad Homer Simpson impression).

After getting my K9 and finding out that the metal Kahrs are, IMHO, just *better*, the K40 is definitely on my want list.

NRA Life Member

My MK40 Elite took 200 rounds just to start to loosen up.
And a second 200 before it became 100% reliable.
But after that the all stainless micro has been nothing short of amazing.
I'm a big fan of the all stainless Kahr autos.

[b4uqzme]

[QUOTE=Barth;280761]
I'm a big fan of the all stainless Kahr autos.[/QUOTE

Ditto ^^^^^

... Sorry you had to trade pistols but I'm glad you found a solution.

[AFCop]

I'm happy with the trade as it shoots much more reliably and I don't think the sticky trigger on the old one would have smoothed out with age.
I also wanted to go stainless because I want to take a stone to the sharp edges on the beaver tail that are cutting into my dominant thumb. Anyone else have that problem? It drew blood after 50 rounds.

[Barth]

I'm happy with the trade as it shoots much more reliably and I don't think the sticky trigger on the old one would have smoothed out with age.
I also wanted to go stainless because I want to take a stone to the sharp edges on the beaver tail that are cutting into my dominant thumb. Anyone else have that problem? It drew blood after 50 rounds.

My MK40 Elite I believe came with the melted treatment from the factory.
The Kahr Elite treatment I think has a smoothed and polished exterior,
beveled magazine well and polished feed ramp.
The trigger feels like the internals may have been polished as well.
It's like the gun went to the Kahr custom shop after it left the factory.
I asked my gunsmith what else could be done to the gun? And he said nothing...

Got my Elite complete with the factory NS.
I highly recommend those options.

[b4uqzme]

I also wanted to go stainless because I want to take a stone to the sharp edges on the beaver tail that are cutting into my dominant thumb. Anyone else have that problem? It drew blood after 50 rounds.

Hmmm. I'm not sure I'm clear on what you mean. I remember the slide lever rubbing my RH thumb at first and I resolved that by adjusting my grip. When I added the thicker wood grips that also helped as the lever didn't stick out as much. I believe many also dehorn the slide lever and that's a good idea.

Everything in the backstrap/bearvertail area is really smooth. Are you talking about the bottom edge of the slide? Those are the only sharp surfaces I can see back there. If so, I think the best cure for "slide bite" is to shore up your grip.

Not sure if that helped but....:o

[AFCop]

Hmmm. I'm not sure I'm clear on what you mean. I remember the slide lever rubbing my RH thumb at first and I resolved that by adjusting my grip. When I added the thicker wood grips that also helped as the lever didn't stick out as much. I believe many also dehorn the slide lever and that's a good idea.

Everything in the backstrap/bearvertail area is really smooth. Are you talking about the bottom edge of the slide? Those are the only sharp surfaces I can see back there. If so, I think the best cure for "slide bite" is to shore up your grip.

Not sure if that helped but....:o

I would post a picture but I apparently need to have 30 posts under my belt first. There are pictures on the site showing the area I am talking about but I will try to describe it better.

The top of the grip where a beaver tail would be if this were a 1911. I grip high, pressing the web of my thumb into this area. On the all steel K40 there is a sharp angled edge where the back of the grip transitions to the side of the grip. On my first black carbon K40 this edge was sharp and cut into my thumb. This newer stainless guns has a "slightly" more rounded edge.

I would like to round it off a little more. Wondering if a stone is the best way to do this. Not sure if sandpaper will do much to stainless.

[b4uqzme]

I think I got it. I never even noticed that area before as it never presented a problem. Sure - I think you could soften those edges a little but I'd start with the sandpaper first and maybe some emery cloth? It really shouldn't take much. You probably want to protect the integrity of those curves so a stone with a straight edge might be a problem. But I think I see what you mean. I think mine is just softened with 15 years of wear ;)

[AFCop]

Yes, that is the culprit, that edge rests right on my thumb knuckle.

I was going to borrow a round machinists stone, if you say sandpaper will work I will start with that. I assumed the stainless was too hard to sand.

Thanks for the input.

[b4uqzme]

Give the sandpaper a try. You can always upgrade to the stone. Whatever you think will take the least material is what I'd start with.

Some here who've done "melt" jobs may have some good input.

[FLBri]

Sandpaper will be more controllable on an irregular shape like that. Depending on the amount you want to remove, I would start with 220 and progress to 400 with one or to steps between. Try to keep your removal to the very edges, because if/when you hit the back flatter area you will change the sheen.

I would put some masking tape, or electricians tape on the flats that you don't want to change. Finish the edges off with a gray scotch brite pad and you should be pretty happy with the result.

[AFCop]

Sandpaper will be more controllable on an irregular shape like that. Depending on the amount you want to remove, I would start with 220 and progress to 400 with one or to steps between. Try to keep your removal to the very edges, because if/when you hit the back flatter area you will change the sheen.

I would put some masking tape, or electricians tape on the flats that you don't want to change. Finish the edges off with a gray scotch brite pad and you should be pretty happy with the result.


Great advice, Thank you.

[AFCop]

The stainless K40 performance has improved. I have been tuning and polishing parts in an attempt to resolve a coulple of issues.

During the last 50 round test fire:

One jam, the round became wedged between the feed ramp and the breech face with the rear of the case tilted upward.

(I have polished the feed ramp)

Three or four return to battery without stripping a round.

(Removed the magazine catch and polished the bevel, sanded and polished the magazine followers so they pass the mag catch smooth when a disassembled mag is inserted in the mag well.)

Three or four premature slide lock.

(Sanded and polished the slide stop lever so rounds rising in the magazine are less likely to bump it and engage the lock.)

New springs are on order. I will let you know how the next fifty rounds goes. I wont give up on this Kahr as I love it so. I am commited to seeing it through until it is dependable. Thank you all for your advice and input.

[AFCop]

Shot another 50 rounds after sanding and polishing feed ramp, mag followers and internal slide stop lever. Experienced less malfunctions. I am starting to think the gun doesnt like the shape of the bullet on my duty ammo.

Had one slide lock with rounds in the magazine.

Two rounds wedged between feed ramp and breech face.

One round jammed between the top of the barrel and the breech face.

One incident of going full into battery without stripping a round.
(Not sure what is causing this or how to fix it)

One fail to lock back on empty magazine. (probably because of my slide stop modification) Will attempt to post pictures from photobucket.

I will try to find some ammo with a bullet that is not as blunt as this Federal 180 JHP and see how it performs. Sure would like to shoot this round as I have better access to it.

This is the ammo I am breaking the pistol in with and the ammo I would like to use for every day carry.
http://i688.photobucket.com/albums/vv249/APBROWN70/Kahr%20K40/th_Federal180grain.jpg (http://s688.photobucket.com/user/APBROWN70/media/Kahr%20K40/Federal180grain.jpg.html)

[AFCop]

It running good now.

Replaced the slide stop with a free factory provided new slide stop.

Replaced the recoil spring and the magazine springs.

No jams, no premature slide lock, no failure to strip a round.

All of the problems were solved with new springs. The new magazine springs were about three times as long as the old (set) mag springs. I broke a sweat trying to cram all that coiled steel into those little mags.

I think the weak mag springs were allowing the rounds inside the mag to ride forward and engage the slide lock lever on thier way up.

Thanks for all your help.

So all is well, I have been meaning to ask you other K40 owners. Does your slide stop hole have a notch cut in the top near the slide stop spring inside the frame like this?

http://i688.photobucket.com/albums/vv249/APBROWN70/Kahr%20K40/K40slidestophole.jpg (http://s688.photobucket.com/user/APBROWN70/media/Kahr%20K40/K40slidestophole.jpg.html)