How come my bullet keyholes?

The only true keyholing I've witnessed is in 223s when using the wrong bullets (usually heavier) for the twist of the bbl.

Never seen it in a handgun cartridge and I have to go with the 'add a little more powder' suggestion.

Maybe not applicable

But how hard are your bullets? Pure lead? My buddy and I worked up some 8x57 rifle loads, using lead bullets(170 grn gas checked), pushed pretty fast(for cast) around 2200fps IRRC (this was from a loading manual). He purchased the bullets somewhere, didn't cast himself. And not only did they keyhole, we had difficulty hitting a 24" backer board at 25 yards! Same behaviour in severel guns, including my sporterized, scoped gun which will shoot 1" with jacketed bullets. Our only conclusion was that the bullets were too soft, and were stripping the rifling at those velocities. FWIW.

I have seen .38spec. wadcutter rounds keyhole at 7 yards. It was due to a leaded up forcing cone. I would suggest a Lewis Lead Remover ( or a clone, I think Hoppes makes one) and a good scrubbing. Quantrill

Chor Boy copper mesh wrapped around an old copper wire brush works as good as the Lewis Lead REmover and is cheaper IMHO.

What is the alloy you are casting?

What size are the barrel throats? Big throats will make for severe leading and keyholing.

What size is the bore? If the groove diameter is .430" or larger you will get keyholes with soft bullets.

Blue Dot likes more pressure to burn consistently that you are making. Switch to Unique or Power Pistol, it will be more accurate and more consistent.

I'd suspect the Bulldog first, then low bullet speed.

More linotype will harden the bullets. 25% should be good, also add about 1% tin. I get tin in the form of lead free solder, it is 95% tin.

My cast bullet gave way. Like collapsed. Big indentation in the nose. The store bought bullet seemed unaffected.

Click to expand...

You have voids in the bullet, that could be a factor.

Also some faster twist rate rifling does not like lead bullets, My Beretta 92 fs hates lead bullets no matter how hard they are, after about 15 shots they will begin to keyhole, and removing the barrel lead shavings hanging from the lands became evident.. I now only shoot jacketed or berry or ranier plated bullets from the beretta and have not had a single instance of keyholing with any of these bullets.

Keyholing

I've seen keyholing in REALLY long barrel revolvers and some military bolt action rifles. In every case the problem was eventually traced to too high a powder charge. In the case of the long barrelled revolvers, droping back 0.5 grains did the trick. In rifles I dropped back two grains at a time until I got good groups. That was reveiling. All my loads were using linotype and Unique.

What I'd try is dramatically reducing the powder charge and see what happens.

Load development

It would seem as if your 9 grain Blue Dot charge was well below the recommended minimum. If true, then what I would do is make up two batches, one using a 7 grain charge and another using an 11 grain charge. Would be instructive to see if keyholing continued in either of these.

I'm going to offer you another idea on why your bullets are key-holing.

I've had this happen with several different Lee Tumble Lube moulds. It's the design of the particular bullet and gun you're shooting it in.

I've had this happen with the .40 175gr TL, and the 124gr RN and TC in 9mm.

The bullets just won't take the rifling and "strip" the grooves, and "shoot sideways".

Two possible solutions: {actually doing both will help most}
1. Use wheel wt. alloy with about 2% (by weight) of leadfree solder added (95%tin/5% Antimony).
2. Use 5gr of Bullseye. The 9.0gr of Bluedot, though a light load, is driving the bullet faster than it will stand.

I've had this problem with most any lead bullet in the Glock .40, and by using a harder alloy, conventionally lubing with 50/50 Alox, and using 3.9gr of Bullseye has given decent accuracy with the 180gr FN-TC Lee Bullet at .401"(not the TL-SWC!).

The Charter has shallow rifling and is not real compatible with the Lee Tumble lube design. Try the 240gr SWC-GC. It will give much better accuracy with any reasonable load.

Sorry for the bad news, but I've been down that road before with the Lee TL bullets. I've had good luck with the .38spl SWC, and RN moulds as well as the DEWC. I've gotten "so-so" accuracy from the 230gr RN .452.

Always, they perform best if driven to less than 800fps. Though the .401" 175 SWC's haven't shot well in anything I've tried them in. However, my brother reports good results with them in a Beretta 99 and the 3.9gr of Bullseye load. Cleaning every 40rds or so, helps too.

(Not a slam against the Lee's, I've won a lot of matches I've shot with them in .38spl w/148gr DEWC over 2.6gr of Bullseye. I shoot about 30,000 a year of them, and have worn out two moulds, and now on my third one in 15yrs. -6-cavity moulds!)

I've never been able to get Blue Dot to combust well in light loads. It's a magnum shotshell powder and needs high pressure to burn cleanly and get any velocity. Otherwise you'll get unburnt flakes in your barrel (which you're probably not seeing with a short barreled revolver).
Switch powders first.
I'm curious about the bullet "collapsing". Was it a void, or is it really soft? Can you etch the bullet with your fingernail? That's usually pure lead. I can't etch with my fingernail using just wheelweights with nothing else added. Wheelweights should be fine for use in the .44 Special at any velocities it's capable of.
Also, you do need to check Lee bullets for diameter consistency, particularly when casting hot. When I drop .358" bullets from my Lee mold, they cool quickly in the mold and maintain proper diameter when dropped on a damp cloth out of the mold. When I drop 230gr TC TL .45's on even a soft surface, they usually exhibit just what you're seeing-a slightly oblong profile that's .001-2" out of round. You could try water dropping them from the mold. That will harden most alloyed bullets, but primarily is useful for cooling them quickly and preventing dimensional change after they're dropped from the mold.

Knock the sprue off before you open the mold blocks. I use a damp towel and a block of wood to tap the sprue plate open. Then dump the bullets into a bucket. Preferably, put a damp t-shirt over the bucket with a hole in the center to avoid splashes. You can also put a sponge or rag on the bottom of the bucket to absorb the impact (weighed down).
I don't re-add my sprues during a casting session. They go in one box, bullets in another. I pour them in at the beginning of the next session.
Dumping water and prep take more time, but you spend less time culling rejects and casting them over again. More fixed cost, less variable cost!