Cast 9MM keyholing

[ivanfern]

Hello
I am casting 124gn round nose bullets with my lee 2 cavity mold. I have only shot these rounds for fun into a berm without noticing how they were flying. Today I placed a ipsc target and used 3 9MM pistols to shoot these bullets. I am using cast lead 124gn bullets which are powder coated for 20mins. Once they are out of the oven I will resize them down to 0.356. I have verified that they are coming out to this diameter and not smaller. As for powder charge I am using Hodgdon Titegroup because I can purchase this powder for about $10 dollars a lb and I've had great luck in that past with FMJ. The load for this powder states 3.5 to 4.1 grains for 124gn fmj bullet. I cannot find a load specifically for cast lead so I chose to use the median of the charge. I chose to load them with 3.8 and they cycle perfectly. For every 10 rounds I maybe get 2 that fly straight into the paper. The rest of the magazine leave a sideways hole in the paper. I tried a glock 19, a cz P09, and a smith and Wesson shield and they all could not stabilize this bullet. I do not know if I need to push them faster or slower but I want them to fly straight. All the guns cycle them flawlessly and I load the rounds to an OAL of 1.109. My barrels do not show any signs of obvious leading. I do crimp the bullets to seal the top of the case. If anyone has any info it would be great. I will attach photos below

[Springfield]

Try more powder first, as slower rarely makes keyholing go away. And/or try larger bullets. I run relatively soft cast in my nines(BHP and Tanfoglio's) and run .358.

[John McCorkle]

Hit them with more powder and slug your barrel to see what size to size down to.

Most of my 9s take 357 and one takes 358

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[marek313]

As others pointed out .356 is small for cast and usually people have better luck with .357-.358 but that depends on your gun. If your gun wont chamber anything larger then .356 you have to either get your throat reamed or i would first try increasing charge. Sometimes that little bit of extra powder gives it a better kick and makes it obtrude properly where they wont keyhole anymore.
Also TG is ok but not the best for cast as it burns really hot. I would try other powders to. I dont find TG accurate with cast in my 9s. I like powders with little bit slower burn rate for cast 9s.

[ivanfern]

Just slugged the barrel on my glock19 and it still holding 0.356, I may bump the charge to 4. and 4.1 and see what the results are

[Driver man]

Boolits are too small. My glock cz etc need 357 or 358 . 356 keyhole just like yours. Try shooting some without sizing them.

[John McCorkle]

Just slugged the barrel on my glock19 and it still holding 0.356, I may bump the charge to 4. and 4.1 and see what the results are

So your barrel slugged at 356 or did it slug at 355?

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[upnorthwis]

I'm powder coating that same bullet and don't size at all. I also had to use a larger expander to keep the brass from sizing the bullet too small. Before the larger expander, I pulled a bullet and it was somewhere around .353.

[DougGuy]

Yep, whether the boolits aren't large enough when loaded, or the crimp die is sizing them down once in the case, bottom line is that they aren't large enough when they get in the barrel. Most folks that I throat barrels for size to .358" and this works very well for them.

[ivanfern]

Barrel slugged at 356, going to load them without resizing them down and bump the charge up, I feel like they are a little soft shooting especially threw my cz

[ivanfern]

also going to lay off some of the crimp. I was crimping a bit to hard to the point where the case was almost flush with the lead

[John McCorkle]

Barrel slugged at 356, going to load them without resizing them down and bump the charge up, I feel like they are a little soft shooting especially threw my cz

Oh yeah I think that'll help then, getting it one thou over at least....and pull a bullet from a loaded round once you lighten off the crimp too...this will help make sure you are not over crimping too.

9mm took me a minute to get right with cast. It's small case capacity, tight tolerances, higher pressure, varied barrel specs from one maker to the next and the need to cycle the action and stay under certain length for mag loading....all sort of make it more complex and any of those plus the routine factors in cast loading such as alloy, bnh, etc.

Out of all the casting I've done, 9mm took me the longest to get right

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[Buck Butcher]

Doug Guy and John McCorkle are on to it. I’d echo exactly what they say with the addition of using the Lee powder through expander in 38 S&W. It expands a little deeper and fatter.

Hold off on upping the charge. It already cycles.

9 is frustrating, even more so with tight chambers and loose bores. You’ll get it if you keep after it.

B B

[Hick]

I've been working this exact same problem with my P1 and P38. 124 grain sized 0.356 loaded with 3.8 grains of Titegroup. I have been seeing keyholing also. Today I loaded a set as-cast and lubed-- 0.357, instead of 0.356. Here's the interesting part. Loaded at 0.357, I had 6 out of 50 keyhole, and all 6 were fired from military brass. The ones fired from commercial brass were all OK. By the way, I checked that 3.8 grain Titegroup load (which runs about 1000 fps in my P 38) using an on-line stability calculator and it should be waaay stable-- not even close, so I don't think velocity is the issue. Size and/or brass looks to be the problem (at least in my two guns).

[John McCorkle]

I've been working this exact same problem with my P1 and P38. 124 grain sized 0.356 loaded with 3.8 grains of Titegroup. I have been seeing keyholing also. Today I loaded a set as-cast and lubed-- 0.357, instead of 0.356. Here's the interesting part. Loaded at 0.357, I had 6 out of 50 keyhole, and all 6 were fired from military brass. The ones fired from commercial brass were all OK. By the way, I checked that 3.8 grain Titegroup load (which runs about 1000 fps in my P 38) using an on-line stability calculator and it should be waaay stable-- not even close, so I don't think velocity is the issue. Size and/or brass looks to be the problem (at least in my two guns).

I'd mic the thickness of that military brass vs your commercial...2 things could be playing into it...if the case capacity is different by alot you'll see pretty significant pressure and velocity differences especially in a small case capacity like 9mm...also I wonder if that military brass isn't thicker and sizing down that bullet with the same crimp you give your commercial brass....it may work fine for your commercial brass but if your military stuff is thicker I'll be sizing you down just enough to mess you up......and then also give you different pressure and velocity because the capacity is less....

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[JBinMN]

It has been touched on here, more than once. One thing to make sure of is that you are making the cases expand to larger than the factory size expander to deal with cast boolits.
Factory dies expander plugs are set to be used with the jacketed bullets that most use to reload instead of cast boolits & the expander plugs are sized in relation to the firearms bbl.

In the case of a 9mm Luger (9mm parabellum/9x19), that is usually .355, or sometimes .356. When we use cast boolits we prefer to go .001 or even more, over that amount to help the boolit seal the bore when fires. So, .356, .357 or even sometimes a bit more is the goal for cast boolit diameter.

Since most factory expander plugs are set to expand to .356 to aid in "bullet" seating and when the boolit is crimped it squeezes the brass to fit to the bullet.

If one uses the factory expander & plug for a cast boolit with a diameter of .356, .357 or even larger, a couple or both the following will likely happen.

1) the cast boolit will get "shaved" down smaller that its original diameter if the "bell" of the expanded case is too small,

and/or

2) the cast boolit will get "swaged" down in diameter when seated into the case, or it will get swaged when the final crimp is made if it is too much of a crimp.

The result of both is that the boolit is now undersized from the intended size of .001+ to help the boolit seal the bbl when it is fired since the lead alloy boolit is soft & the brass & subsequent crimping can further reduce the diameter.

So, instead of having a cast boolit that is still .001+ when fired, it has taken on the diameter of the brass inside dimension & is no longer that desired .001+ that was intended.

The problem can result in leading in bbl. near the chamber & streaking towards the muzzle, as well as a loss in accuracy after the cast boolit leaves the bbl.

A jacketed bullet will not usually swage down by the brass upon being seated nor by the crimping & thus does not give the same effect as the softer cast boolit will produce.

Solution is to use a larger expander plug that is bigger than the intended size of the cast boolit for the bbl of whatever firearm one is using & in this case the 9mm. As well, one needs to only use the "taper crimp" setting to the minimum "tightness" of crimp to hold the cast boolit from moving before it is fired. While there is not the same situation with a revolver where there can be "bullet/boolit setback", there is still the chance for "set back" into the case thru recoil as the round is chambered or even possibly in the magazine f the crimp is too lose to hold the cast boolit in place.

One of the best ways to check for this prevention of set back, but not so tight a crimp as to deform the diameter of the cast boolit is to set the crimp to the lightest one can use, then testing the boolits "hold" by measuring the OAL of the round first to make sure it is correct, then pushing the boolit into the edge of the reloading bench & then re-checking the OAL to see if the boolit moved into the case at all( "set back").

If it moved then the crimp needs to be tightened up a bit more until the cast boolit will not move when pushed against the bench & the OAL remains the same as what it was set at after removal from the crimp die.


So, in order to prevent the shaving or swaging issue, one needs to use a die & larger expander plug that will allow for the cast lead boolit to be seated & crimped to the .001+ larger size.

The crimping can still effect the cast boolit even if the expander plug is larger than a factory one if the crimp is set too tight, but the first step is to make sure that the cast boolit is not being shaved or swaged when it is seated after expanding the case.

Then the crimping check as described previously can be used to set the crimp.

I suggest setting the larger exp die first, then seat a cast boolit & then pull it & chack for any swaging or shaving and that the boolit is the same size diameter as it was before seating.

Then if it passed that test, then the next step is to work on setting the crimp as described previously & do the testing for "set back" to make sure that the round stays seated & crimped without swaging it smaller in diameter.

If the round is expanded properly to maintain the diameter of the cast boolit as intended & the crimping is not swagin the cast boolit, then the problem should be resolved.

If one still has a "fit" issue as shown by key holing, & leading by the chamber, then one may want to enlarge the cast boolit diameter even more as the bbl may be bigger in diameter than the .001+ that was used. Another factor can be the alloy BHN( hardness) where the boolit is too hard & is not obturating(<sealing the bbl) to the grooves of the bbl completely & that too will make for leading near the chamber & streaking down the bbl, as well as poorer accuracy.

Now, I realize that some who read this already know what I am trying to share, but I am posting this even though it has been explained by others before this & many times IIRC.

Sometimes it takes going back to some of the basics to get a handle on what one issue is being caused by.

Sometimes it is more than one step causing the issue, so it is best to just work oneself thru the steps, one step at a time & eliminate the variables that can cause the issue(s).

So, if someone reads this & already knows. So be it.

If not, then please give it some thought to try the suggestions & se if it helps you with the issues you are having.

There is more that can be addressed, but I think I typed enough now.


G'Luck!

P.S. - I had to work thru this with several of my pistols ( .380 & 9mm) and finally got it figured out. I hope that everyone else has the same success I did in solving the issues as they happened.

[GhostHawk]

You got a lot of great advice above, I don't disagree with any of it.

Many of us have been down this road, I had it happen on both a 9mm pistol and a barrel for a H&R Handi Rifle.

Your in good company, enjoy the journey!

[Sig556r]

Kinda tricky when you got no obvious barrel leading (sign of good bullet fit) & cycles the action (enough powder charge). Try a slower-burning powder first (see link below) before changing your sizing/seating methods. TG can be finicky fast at times, it leads my suppressor but not my barrels in subsonic applications. Good luck.
http://castpics.net/dpl/index.php/re...et-data-lookup

[Conditor22]

slug the barrels. mine range from .355 to .3585 and go 1 to 2 thou over that diameter

neck expanders help especially with softer alloy I use NOE and had a member make some custom size expanders. IF you use 15 BHN a Lee powder through die should work.

pull a boolit with a hammer type puller and measure the diameter

I use a Lee FCD and crimp only to the point that when the loaded boolit is pushed against my bench the boolit doesn't move.

remember the 9MM is a tapered case.

[mdi]

When trouble shooting a gun problem, change one thing at a time. I'd suggest larger diameter bullet first. If your barrel slugs at .356" I'd suggest a .358" bullet. I cast for 3, 9mm pistols and two slug out to .356". With these two a .358" bullet, either nekkid lead or PCed, works great. For the other pistol, a Tokerev, the barrel runs about .357"-.358" and if I cast some bullets that run .359" or so I'll use them, otherwise this gun just gets jacketed bullets. Higher pressure may bump up the bullets and help, but for my guns I often use light loads with good fitting bullets and get excellent results...