Keyholing won't stop!

[popper]

Get the correct expander for 9mm cast and size bullets 357. Use a semi-hard alloy. WD after PC.

[DougGuy]

The boolits are undersize. Most that shoot 9mm want to size to .358"

You are not doing nothing wrong by casting. It is a dance you learn as you go. Here is what works: Cast boolit .001" to .002" greater than groove diameter of the barrel. You don't need super hard alloy, you want sorta soft, like maybe BHN12.

Both of those Lee molds have the full diameter boolit sticking proud of the case mouth some to reach published COA. Most current mfgr 9mm barrels will NOT accept one of these style boolits seated to published COA because they have no freebore, and they have rifling running right down to the case mouth. You either have to seat deeper and compensate the powder charge to accommodate the shorter COA, or you have the barrels throated which will let you load a .358" seated out as long as it will cycle through the magazine.

If you can't get to .358" with those molds, try for .357" and see if that works. Depending on alloy the same mold will drop boolits of different size.

[fredj338]

Likely bullet size but could be powder choice. I have seen this phenom with TG under lead & coated lead bullets in 9mm. I size 0.357 for several 9mm including OEM glock bbls. I have yet to get a key hole bullet using several diff weights & styles, 800-1200fps.. My alloy is mostly range scrap, water dropped out of the PC oven, about 13bhn. I would give the 0.357" a try, but dont over look powders. I had a BHP that keyholed with W231. Swi6tched to Unique, it went away. I tried 0.358", no real change in accuracy but more issues in mixed brass.

[Willie T]

You sound like a fairly experienced reloader to me. Your bullet is not getting a bite in the rifling. Most likely cause is not enough diameter. Is it leaving lead in the grooves? If so that would help explain why it shot well for a bit and then started to keyhole. When loading cast, case mouth expanding and crimp are critical steps. Reduce the case mouth expansion to the minimum that will allow the base of the cast bullet to start and the bullet to seat without shaving lead. Seat and pull some. Measure before and after to know that they are not being sized while seating. If that checks out, use just enough taper crimp to remove the bell. Pull some after closing up the case mouth to see that size remains constant. SAAMI for 9mm case mouth is 3.80. If the mouth is over expanded, when you close it up the case bulges behind the mouth. Enough taper crimp to smooth out the bulge so the round will chamber can swage your cast Bullets. With jacketed Bullets it is not usually a problem. A .357 sizer and minimal expansion of the mouth then only enough crimp to close the mouth may be the ticket. With cast and 9mm wall thickness of your brass matters. With cases that are .011 you have room for .358 diameter projectiles. With a wall thickness of .012 projectiles of .356 fit. Of the cases I load, from my measurements: Federal is .011. Winchester i have is .011-.012, Starline is .012. Strarline, followed by Federal were both very consistent. Hopefully there is something useful for you in my rambling as you work it out.
Willie

Edit to add:
My apologies if I missed it but, how did you lube the bullets you did not powder coat?

[elmacgyver0]

By chance are you using a Lee factory crimp die?

Interesting, I have sized all my bullets to .356 and I use a Lee factory crimp die.
I have never experienced keyholing in in any of my firearms.

[charlie b]

...(I normally used commercial powder coated bullets of the same weight)...

...I don't normally shoot lead, so I've been obsessive in keeping the barrel clean (it's quite a mission!). I'm shooting them mostly though my Tanfoglio Stock 1 and some through my Shadow 2 to check if there is any variation from the results with the Tanfoglio

If you use commercially coated lead bullets then you have been normally shooting lead.

If the commercially coated lead bullets shoot well, then I'd measure their dia and size my coated bullets to that same dia.

[Hondolane]

I agree sounds like your bullets are undersized. Try bumping them up to 357-358. That should solve your keyholing issue.

[Seeker]

I'm going to go with....the barrel is leaded to the point that the bullets are coming out deformed. You may have corrected the problem but have you cleaned the lead out of the barrel?

[JonB_in_Glencoe]

I may have missed it, but I still did not see what type firearm you are shooting these through. If it has polygonal rifling you may be pushing the too fast for the rifling to grip.

If you think it is leading, try getting some 100% copper scrubbing pads that you use on pots and pans. Use an old cleaning brush with a patch and wrap a couple of strands from the pad around the patch and run through the bore and inspect for lead slivers.

A Tanfoglio stock 1 mostly, but I've run them through my Shadow 2 with the same results

Since the Tanfoglio is a copy of the CZ75 (same as IMI Baby Eagle), I assume it's a polygonal barrel. Both my Baby Eagles have polygonal rifling...and I had horrible lead fouling in my 40 Baby Eagle, until I got a fat mold from NOE and started sizing the boolits to .403 and dropped the charge a wee bit.

[MT Gianni]

I had a Lee 124 gr tl 9mm bullet and hated it. It was the worst for keyholing I have ever seen. I hate that design with a passion and was sure that was what I was going to read that you owned. Get the standard lube version no matter if you PC, tl or use conventional lube. I have had good luck with the 90 ge tl 32 long bullet but poor luck with a 124 9mm tl and a 175 tl 40 cal I was given. I think the shoulder gets started into the leade out of balance.

[405grain]

Earlier I didn't see where the OP stated the firearm type, but polygonal rifling is the reason that I asked. Using an undersized cast bullet with polygonal rifling means that there may be a barrel leading issue as well as the undersized bullet problem. Check the bore for leading. If it's present - use the search function on this site and look up how to remove it. I agree with others that the bullets are likely too small in diameter.

[popper]

Jacketed case sizing/expanding die will NOT size/expand the case properly. I use a 38p in a lyman sizer. Squishes the base down and keyhole is result.

[243winxb]

Has the Lee Factory Crimp Die struck again?


https://www.thehighroad.org/index.ph...9mm-luger.317/

Photos & tips on loading the 9mm Luger @ link

[Texas by God]

I had the same experience with the Lee TL TC bullet in a Ruger P89 as MtGianni did.
Leading(visible strands of lead) and keyholes in the target.
Back then 9mm ammo was cheap, so I didn’t mess with cast in the 9mm again until a few years ago.


Sent from my iPhone using Tapatalk

[gloob]

I thought Popper's answer should be higher up.

9mm cases are tapered, and carbide sizing dies are not tapered. So the case gets squished in a bit extra, towards the base of the brass. Brass isn't playdoh. So when the base of the case gets this extra squish, it brings in the brass above it, too. And your bullet gets squished when you seat it.

To boil it down to one term, you can call it "case swaging."

If you doubt a case is hard enough to swage your bullets, I suggest you pull some bullets out of your assembled cartridges and put your calipers on the base.

Going up in size and making bullets harder will help alleviate it. And if your guns chamber a bigger bullet, I would advise you do so. But one of the most elegant solutions is a proper expander. I use 358 bullets in 9mm with an expander plug that measures 358 with a 362 flare. Also important, the length of the expander reaches all the way to where the base of the bullets ends up.

I shoot soft bullet in 9mm, no problem. I don't like to water quench my bullets, because I don't want to have wet bullets, and I don't know when I'm going to shoot them. Water quenched bullets get harder and then softer over time.

Same way the sizing die squishes the brass above it, the proper diameter and length expander will open up the case a bit beyond the end of the plug. This brings the case back closer to its original tapered shape. So this also removes the coke-bottle effect of loading 358 bullets into a 9mm case. You could also set your sizing die to partial size cases, but then its on you to ensure you don't get setback.

BTDT, myself, with my first attempts at reloading cast in 9mm. If you shoot outdoors, you don't even need paper to tell if your bullets are keyholing. All you need to do is shoot at a backstop 100 yards or more, away, and look for where the dirt kicks up. The circle where they land opens up super quick once you get past 30-40 yards, so make sure it's a good backstop.

[Bigslug]

I never had keyholing, but did have leading from brass sizing the bullets down below ideal diameter. What's working for me:

Using a Lee .38 S&W sizing die to get a little more expansion.

Tumble lube bullets out of the mold at .357" (all of the bores I've checked have been mostly .356" with one .355"" so this seems to work)

Alloy in the wheel weight hardness range of 12-14 BHN.

Finish will Dillon taper crimp die.

Groups very well to 75 yards and well enough for social purposes at 100 out of a Ruger carbine.

[bruce381]

First check for leading of the barrel.

If that is not the issue, then size to .357". IIRC those barrels are .355" and .002" over should work.

Just a pet peeve of mine...plus do not call bullets "heads". Calling them bullets will not solve your keyholing problem, but you will at sound a bit more professional. BTW "pills" is just as bad.

Good luck.

100% agree on the vanacular

[GhostHawk]

Of all the calibers I have loaded and shot I have had only 2 guns that consistently keyholed, both 9mm. One a single shot H&R handi rifle stub job, and a Hipoint C9.

In both cases switching from .356 or .357 cast to .359 the keyholing stopped instantly. Groups shrank from 6" or bigger to coke can or smaller.
I took the handles off my lee .356 124 grain 6 cavity and put them on a .38 special/.357 125 gr and got cast boolits that dropped at .359 to .3595.

Lubed with BLL, loaded as cast and keyholing instantly gone, and gone for good.

You do need to make sure they will chamber in your gun.

Cast boolits do have to be BIG enough. In most cases 1-2 thousandths bigger is enough. In some cases you may need more.
It is also possible for cast to be squeezed smaller in the loading process.

[Plate plinker]

Interesting, I have sized all my bullets to .356 and I use a Lee factory crimp die.
I have never experienced keyholing in in any of my firearms.

You’re just lucky. I have a springfield 1911 in 9 mm that requires larger boolits.

For the OP.
BTW if your sizer says .***. Check some boolits after sizing and make sure it’s correct. Variables can cause differences in finished product.

[Kosh75287]

Just a couple thoughts;
Clean barrel.
I would slug the barrel and size bullets .002" over groove diameter.
I would soften up the alloy to no harder than 15 or so BHN.
Just un-flare, do not crimp (if possible use a standard taper crimp die to just unflare enough to pass plunk test).
Do another load work up starting with manual starting loads...
Go slow. Double check everything. Most important, have fun.

ALL of the above!
When removing the flare, measure the diameter at the case mouth. It should be .380" + .002", or thereabout.
You also mentioned that your chronograph gave you a velocity of ~900 f/s, I did not see the bullet weight specified. If you are getting 900 f/s with 125 gr. bullets, you have room to go faster, which may increase their stability in flight, and solve or somewhat reduce your tumbling problems. If you are getting 900 f/s with the 147 gr. projectiles, you are getting most of the performance you are likely to get with them, and pushing them faster would likely gain you nothing.
The above may seem counter-intuitive to others following this thread. I don't disagree with them. I have nonetheless noted, in my own attempts to get MY cast bullets to fly straight (without resorting to casting them with FINS), that sometimes, more velocity is an indirect solution to stability problems.

MDI, thanks for using the correct spelling of the word "flare"! I don't know for how many years I've used the wrong word!