Had a Couple of 9mm Key Holes Today

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CQB45ACP

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115RN plated, 1.135" 4.6gr Sport Pistol. Beretta 92FS.

At least two out of 140. Others perhaps but target was pretty beat up by the time I saw the two.

Haven't had a keyhole before. I'm guessing either too light a load or cracked cases I didn't catch. Latter seems unlikely to miss at least two cracked cases. BTW, these were 36th/37th firing of those cases.

If too light a load, how light do you guess it would have to be while not causing a squib instead? 4.8 is Alliant's max. Light is 4.2.

If too light, here's what could have happened--

Been shooting this load for eons and up until very recently all hand dipped. But very recently broke out my Lee drum for old times sake and apparently didn't double check loads frequently enough. Every ten or so after first several. Once I did check because a case didn't look full enough and it ended up being only 3.6gr. Wonder if that would've caused a keyhole but not a squib?

Thoughts?

Sorry no pictures.
 
I have a Lyman #402 mold that I have been casting and shooting since the late 80's in several 9mm pistols I, (and my kids) have, I size them .356. For Christmas a few years ago, I cast a coffee can full for my brother in law, he has a S&W M&P he's been shooting. Last summer he gave the bullets back to me, said "they keyhole", I loaded a box with my usual load, and had him shoot those, no problems, I told him not to be cheap on the powder! (This year I loaded some jacketed 115gr that I had, no replies yet!)
 
CQB45ACP said:
115RN plated, 1.135" 4.6gr Sport Pistol. Beretta 92FS.

At least two out of 140. Others perhaps but target was pretty beat up by the time I saw the two.

Haven't had a keyhole before. I'm guessing either too light a load or cracked cases I didn't catch. Latter seems unlikely to miss at least two cracked cases. BTW, these were 36th/37th firing of those cases.

If too light a load, how light do you guess it would have to be while not causing a squib instead? 4.8 is Alliant's max. Light is 4.2.

If too light, here's what could have happened--

Been shooting this load for eons and up until very recently all hand dipped. But very recently broke out my Lee drum for old times sake and apparently didn't double check loads frequently enough. Every ten or so after first several. Once I did check because a case didn't look full enough and it ended up being only 3.6gr. Wonder if that would've caused a keyhole but not a squib?

Thoughts?

Sorry no pictures.
Click to expand...
Did you fire all 140 at the same sheet of paper?
My initial thoughts are fmj 9mm don't put clean holes in paper for one and for 2, the bullets aren't much longer then wider so proper diagnosis could be hard especially with a beat up piece of paper.
Free hanging targets or stapled to a board?
However, the majority of keyholing ive ever had have been with plated bullets and was likely due to the plating coming off in my cases.
None of this is of major concern, unless these are for winning matches.
Annoying, yes.
As long as you're shooting published data, belling/expanding enough as to not damage the plating, and light taper crimping then you're doing your part.
 
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I would say, since it is a Beretta, it was likely NOT a cracked case. I say from experience, because I have had 3 in my Beretta, and, due to the open-top design, I ate burning powder all 3 times. i.e. a cracked case in a Beretta is fairly unmistakable. OTOH, the only time I have had a keyhole is the first time my son helped load by dipping the powder, and he must have put a light charge in one, or the flash hole was plugged, because the wife was shooting, BANG, BANG, BANG, *pop*. I yelled "Stop! Stop!", all was clear, then my brain replayed it, and I had actually watched the bullet fly the 7 yards to the target 😯
 
My two Beretta Pistols (M9 and 92 FS) slugged .357"+, my BHP slugged .357"+ and my Walther P1 slugged nearly .358". I sized my cast bullets @ .358" and .359", and used Hornady .357" JHPs with great results. Might mic those bullets and see where they are, and even if at the defacto .355" you might consider slugging or going to a 'fatter' bullet. Good luck.

From my M9:

index.php


Lee 125 grain 2R bullets sized .358"

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And how they shot:

DSC_5379.JPG
 
Do slug your barrels I went through the same thing with my S&W 929 PC revolver I couldn’t hit the broad side of a barn and the key holing was bad . I slugged the barrel and it was .357 and the cylinder throats pin gauged at .357 I called S&W and they told me the barrel and cylinder are within 9mm specs . I went with a .357 diameter 135 grain LRN problem solved. And as one other poster pointed out measure your bullets I bought some Armscor 125 grain .355 FMJ they were .354 ….
 
2 out of 140 this outing. How many cartridges have previously been fired from this lot of bullets?

How many total batches using the same load?

If the only change is the powder drop, then it’s a good suspect. The case age is probably a red herring given how punctilious the OP tends to be about case handling.
 
LV Gun said:
Do slug your barrels I went through the same thing with my S&W 929 PC revolver I couldn’t hit the broad side of a barn and the key holing was bad . I slugged the barrel and it was .357 and the cylinder throats pin gauged at .357 I called S&W and they told me the barrel and cylinder are within 9mm specs . I went with a .357 diameter 135 grain LRN problem solved. And as one other poster pointed out measure your bullets I bought some Armscor 125 grain .355 FMJ they were .354 ….
Click to expand...
No, I wouldn't know where/how to begin. Been using the pistols since before I was reloading.

I need to get to range with my 9mm 1911s and try the remainder of this batch of bullets. That could help figure out where the issue lies.

I'm going to measure the bullets.
 
CQB45ACP said:
I'm guessing either too light a load or cracked cases I didn't catch.
Click to expand...
You weren’t shooting your Son’s reloads, were you?
I haven’t slugged my 92 but it hasn’t keyholed any of my reloads, but I shoot a heavier bullet which may help powder ignition. Blues coated are .355 unless you order their special profile .356 and I’ve shot both without issue.
Sport Pistol data for the 115 Speer TMJ is 1.135 and max 4.8 - I’m presuming that’s what you’re using? I’d measure the bullets but suspect they’re .355, it‘s more likely a light 115 with a light charge and perhaps less neck tension and you’re almost in squib range. Did you notice any difference in reports?
 
GeoDudeFlorida said:
2 out of 140 this outing. How many cartridges have previously been fired from this lot of bullets?

How many total batches using the same load?

If the only change is the powder drop, then it’s a good suspect. The case age is probably a red herring given how punctilious the OP tends to be about case handling.
Click to expand...
Bullets--Maybe 150-300? Not a lot.

Powder/load--over 1/2 pound of SP with this exact load.

My eyes are bad enough that at 10-15 yds until I retrieve target, I cannot see much detail and thus the shoot n see stickons.
 
lordpaxman said:
You weren’t shooting your Son’s reloads, were you?
I haven’t slugged my 92 but it hasn’t keyholed any of my reloads, but I shoot a heavier bullet which may help powder ignition. Blues coated are .355 unless you order their special profile .356 and I’ve shot both without issue.
Sport Pistol data for the 115 Speer TMJ is 1.135 and max 4.8 - I’m presuming that’s what you’re using? I’d measure the bullets but suspect they’re .355, it‘s more likely a light 115 with a light charge and perhaps less neck tension and you’re almost in squib range. Did you notice any difference in reports?
Click to expand...
Wise guy:)

Yes, that's the load. Esp since all my pistols (berettas & 1911s) will feed 1.135"

Yep, going to measure bullets.

As for reports, maybe I did now that you mention it, but that's really hard to remember now that I'm chasing a boogeyman:)
 
The only time I have had keyholing is with a severely leaded bore after a few shots with undersized lead bullets.
 
CQB45ACP said:
Bullets--Maybe 150-300? Not a lot.

Powder/load--over 1/2 pound of SP with this exact load.

My eyes are bad enough that at 10-15 yds until I retrieve target, I cannot see much detail and thus the shoot n see stickons.
Click to expand...
2 out of 300 is within the realm of random chance. Shoot the rest of the lot and see how many more keyholes per hundred you get. If it reaches more than 3%, 3 per 100, consider the lot a bad investment and try a new one.
 
CQB45ACP said:
Never shot lead 9mm but also have never done more than a little hoppes on a swab either. I'll take a look.
Click to expand...
It was a .38 S&W (not special) with spl .358 bullets. Never had anything but light leading in 9MM, with no issues. You shouldn't be getting leading with plated. I have
no idea why you got some key holes, unless, like suggested, there were some undersized bullets in there, which might have done it.
 
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