9mm keyholing

[nemesisenforcer]

Got a Lee 124 gr. tumble lube 6 cav mold that keyholes and leads bores out of 2 different pistols. I understand that this a common problem with this mold but wondering how to fix it.

The problem persists whether or not the boolits are swaged sized and with little or a lot of lube.

Fixes?

[Bzcraig]

Gives us more to work with: boolit size, loading data, have you slugged your bore, etc. Also go here and read this sticky: http://castboolits.gunloads.com/showthread.php?121737-Setting-up-for-boolits-in-a-new-9mm

[runfiverun]

think about this for a second.
tumbling is caused by instability.
your pushing it too slow, or it ain't gripping the rifling.


[diameter too small or your pushing it beyond the boolits ability [design] to hold on to the rifling]

[Motor]

Gives us more to work with: boolit size, loading data, have you slugged your bore, etc. Also go here and read this sticky: http://castboolits.gunloads.com/showthread.php?121737-Setting-up-for-boolits-in-a-new-9mm

Yeah. Not enough information. Also agree with last post.

Do they key hole from the start with a clean barrel or only after the rifling is completely full of lead?

I shoot the 124gr TC TL. I use the 2 cavity mould. I found that I need 15bhn hardness and I shoot them as cast, no sizing. I use 3 to 4 grains of Bullseye. I also use Unique I can't recall the data so I won't guess but it's the same velocity as the Bullseye load.

Motor

[6bg6ga]

I've never had a problem in running a bullet too slow. My experience has always been that the bullet was too small. Same load with a larger bullet always = a stable load for me. I have pushed 9mm very slow and always had a no keyholing stable condition. Its not uncommon to have a mold push out bullets that are on the small side. In addition to what has been said ....sometimes the alloy of metal being used will vary the diameter of the bullet.

[Sasquatch-1]

Are you using barrels that have polygonal rifling? Most common example a Glock.

[6bg6ga]

Are you using barrels that have polygonal rifling? Most common example a Glock.Glocks and others with polygonal rifling will shoot lead without a problem as long as the diameter is correct. The old wives tale that you cannot shoot lead in a Glock is untrue. I've done it and seen others do it without ANY problems.

[runfiverun]

it is possible but they usually also require a large enough boolit if enough bhn to matter.
I like a harder than ww alloy for my 9m's to shoot well, I also like to use 358 as the diameter for them.
and I don't have polygonal rifling, the 9's I have looked at seem to have shallow rifling.

[twc1964]

I cast my 9mm boolits at 10.5 bhn and powdercoat em. Sized to .358, i get good accuracy even when pushing em 1150-1175 fps with 125 grainers. I do tend to shy away from the tl boolits in 9mm though. Love the tl 230 rn in my 45 though. Seems fine in that caliber.

[blikseme300]

Boolit diameter too small before and/or after loading in my experience. If too small after casting no matter what kind or quantity of lube used it will keyhole and lead. Common problem with 9mmP and 40S&W is that the case can swage down the diameter of the bullet if case has been sized down small and the expander does not expand the case enough. Pull a bullet after seating and measure the diameter. This will give you a good idea what size is going down the barrel. It is amazing how low an BHN alloy will work if the size is right from the case.

[tazman]

it is possible but they usually also require a large enough boolit if enough bhn to matter.
I like a harder than ww alloy for my 9m's to shoot well, I also like to use 358 as the diameter for them.
and I don't have polygonal rifling, the 9's I have looked at seem to have shallow rifling.

That is why I switched out the barrel on my Taurus PT92. The rifling was too shallow and narrow for cast. It worked ok for jacketed.
I dropped in a Beretta 92 barrel and my groups shrunk by half.

[edctexas]

I shoot 9mm in an old luger and in an H&K poly barrel. My initial problems were solved by larger diameter and harder boolit. Both shoot a NOE 124gr RN reasonably well (well almost as accurate as J-word).

Ed C

[gloob]

Common problem with 9mmP and 40S&W is that the case can swage down the diameter of the bullet if case has been sized down small and the expander does not expand the case enough. Pull a bullet after seating and measure the diameter. This will give you a good idea what size is going down the barrel. It is amazing how low an BHN alloy will work if the size is right from the case.
+1 First thing to check.

[nemesisenforcer]

I'm using straight WW for alloy.

Weight: 125-128 gr

size: .357-359 with a few coming in at .360

Load: <.5cc Bullseye, CCI small pistol primers, "max" loads that function the actions just fine without showing overt signs of pressure.

Pistols: Zastava M70 (Tokarev pattern 9mm) and Walther P1, post war P38, both conventional cut rifling obviously.

Haven't slugged barrels, but they shoot jacketed just fine and accurately.

[runfiverun]

I have a couple of type 99 Tokarov's and shoot what I described above through them, my Hi-point carbine and my CZ-75.

a big part of your problem is the LEE T/L boolit [it really sucks]
oops,,,I said err typed that out loud.
but those tiny whatevers they got on the side don't grip rifling, you usually get leading and horrible accuracy from them in the best circumstances.

[gloob]

size: .357-359 with a few coming in at .360

Haven't slugged barrels, but they shoot jacketed just fine and accurately.
It is not that complicated. See post #10 and read it and do it. Problem solved. Unless your bore is .360+ or really screwed up.

I use the same mold. Same alloy. The little fins work fine as long as they're still there after you seat the bullet. I haven't cleaned my 9mm bores for over 2 years, and they're clean as a whistle. Cast loads just as accurate as jacketed, now.

You can slug the bore if you want. But that's like building a roof before you check the foundation. You may or may not have the problem described in post #10. But it is a common problem. And if you have multiple problems including that one, that's the one you need to fix, first. So yeah, you might need to slug your bore or buy super red frog lube or you might need to spin on your head 5 times. But maybe you could just do the first thing, first.

[merlin101]

That is why I switched out the barrel on my Taurus PT92. The rifling was too shallow and narrow for cast. It worked ok for jacketed.
I dropped in a Beretta 92 barrel and my groups shrunk by half.

That explains why my PT92 has a larger group when shooting the same lead boolits that groups just fine from my Beretta, I'll try swapping the barrels.

[tazman]

That explains why my PT92 has a larger group when shooting the same lead boolits that groups just fine from my Beretta, I'll try swapping the barrels.

It has worked twice for me. I have 2 PT92 pistols and they both wear Beretta barrels now.
Beretta PT92/M9 barrels are readily available online and were a drop in replacement in my guns.

[GooseGestapo]

I've had same problem with Lee cast in 9mm. (10mm/.40 too!)
Fix is twofold.
1. Add 95/5 lead free solder (tin,antimony). I use ~12" strip to Lee 20lb pot of wheel weights.
2. Use slower burning powders. LongShot has been the very best for me.

I also size to .357". I also have a preference for non-tumble lube molds. The TL molds don't have sufficient driving bands to work well in these three cartridges. I have gotten fair accuracy from 124gr SWC-TL mold, but nowhere as good as 120gr TC or .358" 125gr RFN. The latter will shoot under 2" at 50yds from my S&W PPC-9's over 5.2gr LongShot.
My 124gr RN-TL mold throws undersized bullets ~.354", and doesn't respond to hardening or sizing.