9mm cast question

[charlie b]

My problem with the polygonal rifling in my HK is the lack of a throat. The edge of the 'rifling' is a sharp edge at the front of the chamber. Lubed lead bullets leave lead residue at the mouth of the chamber (but no leading in barrel). PC bullets the PC is scraped off and I get leading in the barrel.

I don't shoot it much so I just use jacketed bullets in it.

[Soundguy]

I'm also a fan of softer lubes especially on handgun. ww or slightly sweetened ww, sized to 356 or 7 depending on the gun..and good lube and mid high loads and a 9mm should run OK. I usually avoid Max loads anyway..they are rarely the most accurate..and that's really the only thing I load for is function and accuracy

[Kosh75287]

I haven't learned to do it yet, but I'm a major fan of PC'd bullets in 9mm and other similar high(er) velocity rounds (1000 f/s and up). Right now, I am tumble-lubing, which works very well for what I am shooting (122 gr. @ ~1075 f/s & 147 gr. @ ~900 f/s). As a "quick & dirty" way of hardening, consider dropping your cast bullets directly from the mold into a 5-gallon pail of water ("water quenching"). Between tumble-lubing and water quenching, I get essentially no leading with the 147 gr. bullets (which, in any case, may not be getting driven hard enough to worry about it), and only slight leading with the 122 gr. TCs, even when driven well over 1100 f/s.
My go-to alloy is 1:1 Lyman #2: Scrap lead from the metal yard, which gives me a Brinnell hardness of ~12-13. All the hardness calculators tell me that this alloy is too soft for 9mm/.38 Super, but the barrels on my pistols do not agree. This is what leads me to believe that water quenching is somehow contributing a worthwhile increase in bullet hardness.

[gloob]

9mm bullets don't necessarily need to be harder than WW lead to shoot right. If adding #2 or water quenching or PC'ing makes the leading go away, be sure to measure some pulled bullets. 9x19 is one of the worst offenders for case swaging.

A proper sized expander is a one-time expense/effort that might save you time and money in the long run.

Of course, time and money don't always matter. The PC crowd seems to enjoy the process so much that it's not work. It's fun. Tell me where to send them, and I'll let you's PC boolits for just the cost of return shipping!

[Soundguy]

yup..some people enjoy taking longer/waiting longer to load their bullets..I'm not one of them. lube n size n load.

[fredj338]

I don't understand what you are saying?

your alloy with Lino added...leading went away.
then you say, your harder lead grew and they leaded more?

Lube almost never has anything to do with lead fouling a pistol.

Well not true really. Run an unlubed bullet down the bore & tell me how much it doesnt lead.

[fredj338]

9mm bullets don't necessarily need to be harder than WW lead to shoot right. If adding #2 or water quenching or PC'ing makes the leading go away, be sure to measure some pulled bullets. 9x19 is one of the worst offenders for case swaging.

A proper sized expander is a one-time expense/effort that might save you time and money in the long run.

Of course, time and money don't always matter. The PC crowd seems to enjoy the process so much that it's not work. It's fun. Tell me where to send them, and I'll let you's PC boolits for just the cost of return shipping!

Not to mention over taper crimping. I've seen 0.357" bullets go in & then pulled to measure 0.354". Yes likely to lead even with PC or at least tumble.

[Pirate69]

Sometimes using a harder alloy will contribute to leading because it will inhibit the bullets ability to obdurate and seal the bore.

Good point. But if the boolit is sized 0.001" to 0.002" greater than the slugged diameter and the boolit is not reduced in diameter by seating, the bore should be sealed, I think.

Bushrat: Does your firearm have regular or polygonal rifling? Barrel leading is caused by hot, high pressure gas blowing by the bullet and vaporizing lead from it's surface. Polygonal rifling is purported to have more gas blow by with cast bullets. I agree with some of the others that you should give powder coating a try. Sometimes using a harder alloy will contribute to leading because it will inhibit the bullets ability to obdurate and seal the bore.

[trapper9260]

Did the OP slugged his barrel? Also I use that boolit and the old NRA lube with ATF in all, but my semi auto rifles . Thanks to you all on here had help me with the problem I had with cast in semi auto rifles . .

[skeet1]

I use Carnauba Red in all of my cast bullets including 9MM. No problem at all! CR is barely a hard lube and need to be heated to only around 100 degrees to make it flow.

Ken

[Pb&j]

Absolutely - never, ever, ever use the Lee FCD with cast boolits. I taper crip just enough to resist a thumb push.

I have been loading for several calibers for a bit now and I have not had any issues with the fcd from Lee and cast boolits. Could you please explain what I am missing with this part of the process that you have experienced? Thanks

[steve urquell]

I have been loading for several calibers for a bit now and I have not had any issues with the fcd from Lee and cast boolits. Could you please explain what I am missing with this part of the process that you have experienced? Thanks

The FCD has a ring that squeezes all brass to the same size. It has been shown to squeeze some softer alloy boolits undersized. The brass springs away from the boolit and now the boolit is undersized and has decreased neck tension.

I just went thru this with my FIL. He was having leading and inaccurate loads. We ran a .357 boolit thru it, immediately pulled it and measured it at .354". Pulling the boolit took 1/4 the force to pull one of mine where I use only the boolit seater die set to only remove the flare.

Different brands of brass have different thickness so the undersizing will vary by brass mfg as well as boolit alloy.

[Pb&j]

Thank You for the clear explanation. I haven't had any issues that I am aware of and will go through and pull some boolits to see what I find out of curiosity. One never stops learning from this site and its fine members.

[steve urquell]

Thank You for the clear explanation. I haven't had any issues that I am aware of and will go through and pull some boolits to see what I find out of curiosity. One never stops learning from this site and its fine members.

No problem. About 9/10 threads on here where someone is having leading with 9mm turns out to be from overcrimping and undersizing the boolits.

[gloob]

I'd say what makes the 9mm so especially dysfunctional with cast bullets versus other straight wall cartridges is the thickness of the cases combined with the original taper of the case leading to case-swaging.

9mm cases are slightly tapered, because the theory at the time was that this would increase feed reliability. This is one of the only "straight walled" calibers we have that isn't actually straight. (This is why 9mm MP5 mags are curved like a banana, and 40/10mm versions are not). But modern sizing dies are 99% carbide, which don't recreate the original taper. They just squeeze the entire brass into a cylinder that is slightly smaller than it should be where the base of the bullet sits. And 9mm cases are THICK and strong at that point.

Beefing up the hardness of the alloy will obviously help the bullet to push the case back out, rather than the case making the bullet smaller.

But hard alloys tend to foul the barrel in a new way. I've heard it called antimony wash. Aside from potentially not obturating to plug the barrel back up (which is more commonly an issue in revolvers, which often have a tight point where the barrel has been pounded into the frame), the harder alloy tends to leave very fine residual buildup over time.

"My problem with the polygonal rifling in my HK is the lack of a throat."
This obviously has nothing to do with polygonal versus button cut rifling. Older glock barrels had the opposite problem. The throat is super long in older glocks, which allows more time and space for gas to blowby the bullet before it can plug the barrel. So the bullet suffers this additional abuse and has a smaller margin from there before it starts to melt and erode. Combine this with Glocks being highly popular in 9mm and being one of the first affordable pistols to use polygonal rifling, and we have the myth that polygonal barrels are not good with lead.

[Half Dog]

I see many good suggestions in the previous posts.
I slugged my barrel and sized the bullet to accommodate the coating. Then I found out the rounds wouldn’t chamber unless I crimped them too tight, which defeated the sizing step. I had the chamber opened up and now everything works smoothly.
I hope this helps.

[gloob]

Yep. If you need to crimp to get the cartridge to fully chamber, the crimp has nowhere to open out when you fire it. So your perfectly sized bullet gets sized down a step when you shoot it! I have one barrel like that, but I can sort out the cases with thicker case mouths.

[fredj338]

My problem with the polygonal rifling in my HK is the lack of a throat. The edge of the 'rifling' is a sharp edge at the front of the chamber. Lubed lead bullets leave lead residue at the mouth of the chamber (but no leading in barrel). PC bullets the PC is scraped off and I get leading in the barrel.

I don't shoot it much so I just use jacketed bullets in it.

Load to a shorter OAL?? CZ shooters have to deal with short throats too.

[Pb&j]

OAL has been the only issue I had at the beginning as I went by the hornady oal and it just wouldn't go into battery by a tiny amount. But tiny is huge if it doesn't work properly. Played with powder and bullet seating with chrono info and life has been good for several years. For 2 different pistols to boot. Still going to pull some boolits to see how they are. The information has me curious.

[Divil]

Make sure you are using 9mm cases that are not swaging the .358 bullets to a smaller diameter. Winchester 9x19 brass in my experience is guilty of this trait. I only load j-word bullets in Winchester 9x19 brass.
Remington brass is great at not swaging down “chubby” .358 boolits in 9x19. I have had success using .358 sized boolits, in Remington 9x19’brass, lubed with hard lubes, specifically Thompson Red Angel and Lyman Orange magic. Browning HP, Beretta and second and third generation Smith & Wesson 9mm all shot that combination without leading.