anybody have any ideas why my 9mm is keyholing 115 gr LRN bullets, I shoot 115gr FMJs just fine. The loads were stepping up from 4.3 to 4.7 gr of W231

One way or another, your lead bullets are not being stabalized. I'm too lazy to walk out to the shop and check my loading manuals for how heavy your load is but, going from a jacketed to a soft lead bullet and increasing the charge may have you stripping the rifling. Or, perhaps the bullets are undersized and stripping. Either way....stripping.

I got my data from the hodgdon/winchester website, 4.3 is the min load and 4.8 is Max, the keyholing seemed to be more severe with the lighter charges

Your barrel isnt leaded up too badly is it?

Most common reason for keyholing in a 9mm is that the bore isn't 9mm. Know it's listed that way, but will often find .356 -.357" bores on 9mm's. Given that some maker's lead bullets are really .354", that missing .003" might be the problem.

A jackeed bullet doesn't care as much...tough jacket will spin with a lite rifling "bite". Lead bullets really want to fill to the bottom of the grooves to do their best work.

Most common reason for keyholing in a 9mm is that the bore isn't 9mm. Know it's listed that way, but will often find .356 -.357" bores on 9mm's. Given that some maker's lead bullets are really .354", that missing .003" might be the problem...
Yes, I've got one of these. I got a cast bullet and slugged the barrel. The OD of the bullet is just barely toching on the groove walls, and not all the way around. I measured the barrel grooves at .357 at the muzzle. The 9mm-labeled bullets are cast and sized & lubed to .357. Yes, they're keyholing.

I suspect the problem is maybe a little worse because my dies size the cases so the bullets are pretty tight going into the case. I wonder if the bullets get sized down a little in the crimping process.

:mad:

You found the second "secret" of 9mm's. Many have generous sized chambers to go with their over-diameter bores. Seating a lead bullet into a real tight case can reduce the bullet's diameter (can load some...inertia pull them..and measure)...so can a strong taper crimp. Longer bullets, seated deep, often come back out looking a bit like mini-boat tails from reaching down to the thick part of the case.

For the 9mm's that showed big-bores (and some of the WWII guns ran larger than ,357") would use a .357" expander, run the expander in shallow (run in a bit short of where the bullet base would end up), seat a .358" bullet so it was firmly a bit past the expanded case neck, and taper crimp lightly. Getting real .357"-.358" 9mm bullets required home casting (lots of the older Lyman molds tend to cast large) and sizing. "Stumpy" bullets (short with a shorter nose/longer bearing area) let you work with the front of the 9mm case, wherre it's a bit thinner.

The little Lee 105gr. SWC actually works great for oversized 9mm's if your gun will feed them.

ALL of those things contribute. Oversize chambers, undersized expanders, heavy crimp, oversize bore, shallow rifling, too-hard bullets, too-small bullets, and light charges can add up to a bullet being blown out the barrel with little or no spin at all.

The 9 Parabellum can be the very dickens to shoot lead bullets from.

9's tend to have shallow rifling. Another factor is that to make the action cycle, you have to push the bullets at a velocity around 1000 fps or over, depending on the bullet weight.
Loading for the 9 gave me fits until I realized that the wheelweight alloy I used for wadcutter 38's and other light pistol loads wouldn't work. When I hardened my alloy, the 9 suddenly became accurate.

The gun has just over 200 rounds through it, so its not leaded, and the 25 leads I shot yesterday were the first lead through it. I'll slug the barrel and see what I come up with

anybody have any ideas why my 9mm is keyholing 115 gr LRN bullets, I shoot 115gr FMJs just fine. The loads were stepping up from 4.3 to 4.7 gr of W231

I've tried a couple of different 115's in my Kahr, and found that if they were going fast enough for reliable cycling, the barrel leaded up pretty quick. The suppliers assured me they used a harder alloy for that reason, but they weren't hard enough for my 9.

125's are enough heavier to get around that.

For what it's worth, I've had better luck with the faster powders in my 9's, including a Marlin Camp Carbine, that shoots way better than you might think. Red Dot and Green Dot are my favorites to date.

I slugged the barrel tonight, didn't have a soft lead slug, so used a little light grease on a bullet and drove it through, but I don't think I got a very good slug, the grooves don't appear to be as deep on the slug as they are in the barrel, which would be the case with an udersized bullet?

Yep.

Undersize bullets allow gas cutting and that causes stripping. Leading too.

I slugged the barrel tonight, didn't have a soft lead slug, so used a little light grease on a bullet and drove it through, but I don't think I got a very good slug, the grooves don't appear to be as deep on the slug as they are in the barrel, which would be the case with an udersized bullet?
Jb, stop in and get a hand full of the LeeTL356-124-2R I don't know if they would work for you but I bought the mold thinking it would work for my 380 which it didn't. Wouldn't take long to cast up a bunch.
Mike

I slugged the barrel and it is 355 on the groves and 348 on the lands. I'll stop in next time I'm down that way and pick some up Mike.

I had this problem with W231 and a light 115 gn bullet. Try reducing the charge and increasing the bullet weight...or go with a slower powder option....I get best results with heavier bullets and a light charge.

I slugged the barrel and it is 355 on the groves and 348 on the lands. I'll stop in next time I'm down that way and pick some up Mike.

Maybe someone out there has some experience with the Lee bullet (TL356-124-2R) and the 9mm??? I'm guessing a fairly hard cast (#2) might be better but don't really know I have no expericence with the 9mm.

what type of firearm are you shooting?

some of these have polygonal rifling, and will not stabilize lead. I had an HK that shot plated almost thru the same hole, but feed it lead and it was a better shotgun than pistol.

Its a beretta/stoeger, so I don't think it has polygonal rifling.

I had the same problem finding a good cast bullet load for practice. Looking at the 9mm cast bullets, they all have a short bearing surface. Decided to try a heavy bullet. Picked up some 160 gr cast for the 38 Super. Couldnt find much loading data but an old Lyman cast manual had some loads. You can get up to 1000 fps if you want to. Also found data at Accurate Arms for a 158 gr fmj. Tried starting out a 3.0 gr AA#2 and worked up .1 gr at a time until I had 100 per cent function. I havent chronoed this load but it about 800 fps and very light recoil. Gave 3 inch groups at 25 yards, good enough for cheap practice. This load has worked in Glocks, S&Ws, Uzis, Marlin Camp Carbines and other guns 100 per cent with good accuracy. Even works in FA guns. There is one problem. You have to use the Lee factory crimp die. Some cases will bulge a little at the bottom of the bullet. The Lee FC die will iron this out. Also you want to use the longest OAL that will fit in the chamber and magazine. An advantage to this load is that you can get 2000 or more loads from a pound of powder. Also the brass almost falls out of the gun, right at your feet. If you want more loads and powders, Ill see if I can dig up that old manual.

Looking at my press, I noticed some lead shavings around the seater die, any chance I could get away with using a 357 expander to keep the bullets from shaving?