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Key-holing 9mm lead bullets
max2005
Member Posts: 96 ✭✭
Gents:
So, tired of spending almost as much for 9mm jacketed bullets as loaded rounds, so acquired a Lee 124 gr tumble-lube mold and cast some of my own - straight wheel weight metal - tumble lubed and sized to .356" (all Lee equipment), loaded up 300 rounds with various charge weights of Bullseye, Unique, Titegroup & HP-38 (same as Winchester 231), and got nothing but key-holing with ALL powders at ALL charge weights! Needless to say, at 10 meters grouping was little better than a scatter-gun - I was using a Browning Hi-Power that shoots everything else well - what am I doing wrong???
Thanks for your input.
So, tired of spending almost as much for 9mm jacketed bullets as loaded rounds, so acquired a Lee 124 gr tumble-lube mold and cast some of my own - straight wheel weight metal - tumble lubed and sized to .356" (all Lee equipment), loaded up 300 rounds with various charge weights of Bullseye, Unique, Titegroup & HP-38 (same as Winchester 231), and got nothing but key-holing with ALL powders at ALL charge weights! Needless to say, at 10 meters grouping was little better than a scatter-gun - I was using a Browning Hi-Power that shoots everything else well - what am I doing wrong???
Thanks for your input.
Comments
I thought the tumble lube bullets were supposed to be shot as cast.
If a round loaded with one unsized won't chamber, don't size it any more than necessary to get it in the gun.
So, the mystery thickens.... my bore was perfectly clean when I started my shooting session, and I know my bore is .355 (Hi-Powers are very standard here, all I've slugged were the same). I drove 3 of the offending Lee TL bullets through my bore this morning, and miked them on the lands and groves - consistent .348 & .355, and the bullets were about .3555 to begin with (these cast small enough that the .356 sizing die barely engages them; really just makes sure they are "true" and round). Plenty of rifling evidence on the slugged bullets - I'm still baffled! I know lead in 9mm is a finicky business to start with, but the key-holing is truly amazing to behold; almost every shot!
HELP!
Hi Guys,
So, the mystery thickens.... my bore was perfectly clean when I started my shooting session, and I know my bore is .355 (Hi-Powers are very standard here, all I've slugged were the same). I drove 3 of the offending Lee TL bullets through my bore this morning, and miked them on the lands and groves - consistent .348 & .355, and the bullets were about .3555 to begin with (these cast small enough that the .356 sizing die barely engages them; really just makes sure they are "true" and round). Plenty of rifling evidence on the slugged bullets - I'm still baffled! I know lead in 9mm is a finicky business to start with, but the key-holing is truly amazing to behold; almost every shot!
HELP!
Sizing to .358 completely solved the exact same issue with my 9mm 124 grain Lee six cavity RN bullets. The theory of .001 over bore size is a great start, it is not written in stone. I was shocked to see the difference by going bigger.
3.9 grs. of Bullseye gives me a little over 1050 fps in my Browning Hi-Power with no keyholing.
If your bullets are keyholing then the obvious problem is that they do not have enough spin to stabilize them.
The question is why ?
You say you have driven them through the barrel and checked the dimensions so it appears that undersize bullets are not the problem.
As v35 pointed out, cast bullets that are loaded too hot may strip and tumble.
You didn't say what load you are using or what kind of velocities you are getting. It is possible that your bullets are too soft for the loads you are using.
You mentioned that the bullets were cast from wheel weights. I believe most wheel weights are not pure lead but are alloyed with some tin and/or antimony to make them harder (I recently bought a bucket of wheel weights but I have not yet used any to make bullets). Possibly you need to add some additional tin or antimony to make your bullets harder.
On the other hand, if you are using light loads it could be that you are simply not getting enough velocity to put enough spin on the bullets.
I suggest you post whatever additional information you can (load, velocity, etc.). There are a lot of experienced reloaders here. I'm sure someone will come up with a solution if they have enough details to work with.
OK, I did cast with straight wheel weights, and maybe I need to put a little Linotype in the mix to harden more? I'll try that, and not sizing the "as-cast" bullets, which come from the mold at about .356 to begin with. Also, here are the loadings I tried:
Bullseye - 3.8 / 4.0 / 4.2
Unique - 5.0 / 5.2 / 5.4
HP-38 - 4.0 / 4.2 / 4.4
Titegroup - 3.6 / 3.8 / 4.0
I don't think these are too hot to strip, and I don't think the bullets are too small (no way to go to .358 with this mold as they cast smaller to begin with). The only thing I can think of right now is to harden the alloy with Linotype; maybe 5 lbs wheel weights to 1 - 2 lbs Lino? Your thoughts?
Thanks!
I have best luck in the 9 with cast if I use just enough powder to reliably cycle the action.