Attention Kimber Micro 9 owners

[tazman]

BJJ--Thanks for starting this thread and explaining what has happened. You have convinced me not ever buy one of these. I don't need this kind of problem.

[Black Jaque Janaviac]

NOPE, if Somebody at Kimber told you bullet set back is normal.

Of course they were referring to the repetative loading and unloading of an everyday carry piece. After several iterations, you can get setback. But you have plenty of opportunities to discard the ammo before you fire it.

BJJ--Thanks for starting this thread and explaining what has happened. You have convinced me not ever buy one of these. I don't need this kind of problem.

Well, that wasn't my intention, but if it saves you headache and heartache I am happy to see at least some good come from this.

[charlie b]

So, it only happens to the second round on a full mag?

The chambering of the first round causes the second to slide forward. Then when the pistol recoils the second round gets dinged by the ramp. The third round is not forced forward by the chambering of the second round so it does not get dinged. Correct?

So, I would load the pistol the way I have done with some Wilson magazines in my 1911. Load mag. Chamber round, put on safe. Remove mag and tap sharply to set all the rounds back in place. Put mag back in the pistol. Yes, you should not have to do this, but, it will solve your problem when at the range. The specific Wilson mags I had at the time would do the same thing yours is doing. The second round would slide forward enough that the recoil would ding the nose of the bullets during loading. GI mags will not do it nor will McCormick mags (which are the ones I use in my 1911s).

In the 'heat of the moment' just let the problem happen. At the ranges you will normally fire it won't hurt anything, ie, the deformed nose won't change the performance of the cartridge.

If it bothers you a lot, then sell the pistol.

[tazman]

As the OP stated, the round is getting dinged but the problem is bullet setback. The bullet is getting driven deeper into the case, causing increased chamber pressure. Possibly dangerously so.
I would normally just get rid of the gun as well but in this case it is causing a dangerous situation. I would not feel good about selling it when it causes a possibly harmful situation for someone else.
Bad deal when the manufacturer won't repair the problem.

[Black Jaque Janaviac]

The chambering of the first round causes the second to slide forward. Then when the pistol recoils the second round gets dinged by the ramp. The third round is not forced forward by the chambering of the second round so it does not get dinged. Correct?

Yep. Exactly.

So, I would load the pistol the way I have done with some Wilson magazines in my 1911. Load mag. Chamber round, put on safe. Remove mag and tap sharply to set all the rounds back in place. Put mag back in the pistol. Yes, you should not have to do this, but, it will solve your problem when at the range. The specific Wilson mags I had at the time would do the same thing yours is doing. The second round would slide forward enough that the recoil would ding the nose of the bullets during loading. GI mags will not do it nor will McCormick mags (which are the ones I use in my 1911s).

OK. Basically instead of using 7 round magazines and loading it 7+1, use the same magazine and load it 6+1. It would be like the original Micro 9 which first came with 6 round mags only with a pinky extension and no extra capacity. Maybe I'll put a plug in the magazine to prevent a 7th round from fitting - sorta like a shotgun magazine plug for waterfowl.

So with 0.03 inch setback you think pressures would rise but not to the blow-your-gun-up-with-one-shot level?

[Black Jaque Janaviac]

I would normally just get rid of the gun as well but in this case it is causing a dangerous situation. I would not feel good about selling it when it causes a possibly harmful situation for someone else.
Bad deal when the manufacturer won't repair the problem.

I know. I can't just dump the problem on the next guy down the road.

I sent that box of aluminum ammo back to Federal per your suggestion in the other thread, Taz. I then called them an explained the situation because some of the problem is the gun behaving in an unusual way. Aluminum cases are not intended for repetitive chambering and ejecting, they are intended to be chambered once and fired. Federal sent me a box of American Eagle (brass cases). I will get out soon to see whether they are able to withstand the smack of my Micro 9. Federal was astonished when I explained what happened with the Micro 9 and said there's no way they can design ammo to withstand that. Although they wouldn't tell me I was safe firing the cartridges that had been set back, they did not seem overly concerned since it was a 9mm. I got the sense that if I had a .40 that did this there would be more worry.

[tazman]

I know. I can't just dump the problem on the next guy down the road.

I sent that box of aluminum ammo back to Federal per your suggestion in the other thread, Taz. I then called them an explained the situation because some of the problem is the gun behaving in an unusual way. Aluminum cases are not intended for repetitive chambering and ejecting, they are intended to be chambered once and fired. Federal sent me a box of American Eagle (brass cases). I will get out soon to see whether they are able to withstand the smack of my Micro 9. Federal was astonished when I explained what happened with the Micro 9 and said there's no way they can design ammo to withstand that. Although they wouldn't tell me I was safe firing the cartridges that had been set back, they did not seem overly concerned since it was a 9mm. I got the sense that if I had a .40 that did this there would be more worry.

Interesting observation from Federal. Nice that they sent you a box of better ammunition.
I will be watching to see if the new ammo survives better than the aluminum cases did. I have a box or two of the aluminum cased Federal 9mm set back for storage and might need to get it shot up.
Though, I will admit that the pistols I own don't have the feeding issue the Kimber does.

[onelight]

Interesting observation from Federal. Nice that they sent you a box of better ammunition.
I will be watching to see if the new ammo survives better than the aluminum cases did. I have a box or two of the aluminum cased Federal 9mm set back for storage and might need to get it shot up.
Though, I will admit that the pistols I own don't have the feeding issue the Kimber does.

I have shot a lot of the aluminum blazer in 9 , 45 acp and 38 mainly 9 s , the 38s would jump crimp in my wife’s lcr but worked fine in heavier guns the 9 and 45 had 0 problems in CZs glocks HKs sigs and Springfield xds , xde , S&W and beretta all that said works fine for me and my shooting buddies.
But I don’t think the aluminum grips the bullet as well as brass.

[Greg S]

It may be a compound problem, i.e. spring weights (recoil and mag) along with faster slide speed due to smaller mass.

Being it only affects the second and not subsequent rounds in mag maybe mag spring pressure is too much for a 7+1 and as previously mentioned run it as a 6+1. Reducing mag spring pressure could work for a short while until spring set/weakening occurs causing feed problems due to the higher slide speed and the next round not rising fast enough and causing the dreaded classic feedway jam (nose in feedramp).

It sounds as if the pistol was originally designed as a 6 round mag and later 'Mimber' tried to improve marketability by increasing capacity to 7 but didn't fully engineer the design or as I understand it it is a hit and miss and might be a production part (s) tolerance stack that would have to be diagnosed and either hand fitted or problem parts critical dimensions re-specified.

It would be an interesting project to examine as a hobbyist kitchen table smiff of 1911s examining a couple of problem and non problem examples to determine the exact tolerance stack and solution. The problem is as a non-FFL and not knowing folk(s) with examples of problem and functioning examples, I won't tackle Mimbers problem at my expense.

[charlie b]

OK. Basically instead of using 7 round magazines and loading it 7+1, use the same magazine and load it 6+1. It would be like the original Micro 9 which first came with 6 round mags only with a pinky extension and no extra capacity. Maybe I'll put a plug in the magazine to prevent a 7th round from fitting - sorta like a shotgun magazine plug for waterfowl.

So with 0.03 inch setback you think pressures would rise but not to the blow-your-gun-up-with-one-shot level?

No, go ahead and use a full mag. After chambering the first round, remove mag, load the next and tap it to make sure the round is to the rear.

And, no I don't think .03 (less than 1/32") setback will cause a dangerous situation unless you are loading max +P loads. Even then you are probably within the safety margins.

[Black Jaque Janaviac]

No, go ahead and use a full mag. After chambering the first round, remove mag, load the next and tap it to make sure the round...

That doesn't work. For purposes of explaining this, lets say that the first cartridge places in an empty mag is round #1, the second is round #2, and so forth. So that if I fill the magazine the first round chambered would be round #7 or #8 (if I load +1).

So fill the mag, slingshot slide, #8 goes in the chamber, drop mag, reposition cartridges and place another round in mag which becomes round #7. Right now all round in mag are against the back. Fire gun, slide operates, round 7 is chambered, now round 6 is pushed forward and will get smacked. Fire round 7, round 6 is now chambered, and 5 is next in line. However by now the spring has relaxed such that the problem goes away.

If I were to doe the same procedure only after slingshotting the round I dropped the mag and DIDN'T top it off, just repositioned the cartridges it should work. But I wouldn't get the full benefit of the 7 round capacity.

I can live with that but... I got Hi-point quality at Kimber prices.

[FergusonTO35]

To me, an extended mag defeats the purpose of a gun whose main attribute is small size. I stick with 6 round flush fit mags in my Micro 380 and they work great.

[charlie b]

That doesn't work. For purposes of explaining this, lets say that the first cartridge places in an empty mag is round #1, the second is round #2, and so forth. So that if I fill the magazine the first round chambered would be round #7 or #8 (if I load +1).

So fill the mag, slingshot slide, #8 goes in the chamber, drop mag, reposition cartridges and place another round in mag which becomes round #7. Right now all round in mag are against the back. Fire gun, slide operates, round 7 is chambered, now round 6 is pushed forward and will get smacked. Fire round 7, round 6 is now chambered, and 5 is next in line. However by now the spring has relaxed such that the problem goes away.

If I were to doe the same procedure only after slingshotting the round I dropped the mag and DIDN'T top it off, just repositioned the cartridges it should work. But I wouldn't get the full benefit of the 7 round capacity.

I can live with that but... I got Hi-point quality at Kimber prices.

Ok I misunderstood.

[onelight]

I have a friend with one and am trying to understand. Do they just have the problem when fired with a full mag and one in the chamber ?

[Black Jaque Janaviac]

I have a friend with one and am trying to understand. Do they just have the problem when fired with a full mag and one in the chamber ?

to test is simple. Fill the mag with 7 rounds, place mag in gun, slingshot the slide, fire first round. Eject the next round by slingshotting the slide again. Examine that round.

That is the best way I can distill the test into written word. Do not load 7+1, it will goof up the test.
I can answer other questions in separate posts.

[Black Jaque Janaviac]

To me, an extended mag defeats the purpose of a gun whose main attribute is small size. I stick with 6 round flush fit mags in my Micro 380 and they work great.

responses like this confuse me. Does this mean you've done the test and found no flaw? Or does this mean you've been shooting it and it just doesn't jam?

As one guy on the Kimber forum astutely noted, the problem is probably a lot more common, it is just that most people practice by loading a full magazine and shooting until it is empty. So the typical shooter never ejects t hat second round unless there is a jam.

[Black Jaque Janaviac]

For those following:
I tested the American Eagle ammo and found that the setback was only 0.006". However that was with a heavier recoil spring and a weakened magazine spring. The nose damage appears less too. I will have to test this again with everything back to factory spec.

[onelight]

to test is simple. Fill the mag with 7 rounds, place mag in gun, slingshot the slide, fire first round. Eject the next round by slingshotting the slide again. Examine that round.

That is the best way I can distill the test into written word. Do not load 7+1, it will goof up the test.
I can answer other questions in separate posts.

Thanks a lot, other than testing , at the range we normally just load 5 rounds at a time.
It’s a shame some of the little Kimbers are having this problem.