Just a Little Leading in the throat.

[Colorado4wheel]

Bullets are .356 using a .357 Magma Star Die. Seems every die I use sizes things on the small side (I checked my calipers). I have not slugged the barrel but before getting the Star I was able to get my Lee .357 die to give me decent results with this barrel (also .356 on my calipers). Now with my Star sizer I have ZERO leading past the throat and some leading in the throat. These are water dropped 155gr (Lyman 147 gr 9mm mold). About 18bhn using my Lee test kit. Running about 850 fps. Barrel is perfect after the throat. Only fired 30 rds today over the chrono. Batch’s of 10 rds. First rds were very light. Heaviest rounds are what I am sticking with as far as velocity. So I don’t know if things will change when I only shoot the 850fps stuff vs the 800 fps stuff. Any suggestions? Is it possible my lead is too hard or maybe my bullets too large? Every time I ran anything in the past that was .3555 or smaller I got horrible leading. So that does not seem likely.

[RobS]

Bullet fit is your best way to accuracy and to combatting leading which actually go hand in hand. Considering your past results which showed promise with a .357" bullet then I would say that a .356" bullet is too small for the groove diameter of your barrel. You may be able to use a softer bullet though and as the pressures rise it will allow the bullet to obturate and seal the barrel. If it were me though, I would slug the barrel and then size .001 to .002 over groove diameter.

[leadman]

You don't say what you are shooting but I assume it is a 9x19. I had a Ruger P89 that had a .3575" bore.
If they are larger than .357" you might lube a few by hand and see what happens. You don't really need 18bhn for the velocities you are shooting but if the bullet fits the bore it should not matter.

Have you slugged your barrel??

[Colorado4wheel]

I have not slugged the barrel. I am not shooting .357. I am using a die marked .357 and they come out @ .356. In all my past experiments any bullet sized .3555 or smaller leaded horrible. Anything I did not size leaded horrible. The only thing that came close to working were size @ .356 using a .357 die. Don't ask me why but thats just been my luck I guess. This is for a Glock 9mm with a KKM barrel. I have checked my dial calipers. They are accuarate. I have not slugged the barrel I think .356 is as big as I can get these things sized to. They don't touch every part of the sizer already. Just about 90% or better.

[runfiverun]

it's not your sizer then.

[Colorado4wheel]

I was kind thinking maybe the lead was too hard. I heard they get harder with age if you water drop them. I did water drop them and they were frosty hot and went into really cold water. I think I will try a batch that is not water dropped. Only issue is my seating die marks the nose of the bullet pretty good. I may flare a little more to see if that helps at all.

[Edubya]

It is necessary to log evry action in your casting and loading of the 9mm boolits. This is probably the most difficult handgun to load for.
I struggled with this for a year or so. I finally started writing down each step in each procedure and have found that I was crimping too much. I pulled several boolits and measured them, they were .001 under sized! With target loads, they were not obturating.
Measure the thickness of the brass walls and add that to the diameter of boolit, i.e., .0125+.0125+.356=.381. You would not want your finished cartridge to measure .380 or less. This is one reason that it is very important that you load by headstamp (different brass has different wall thickness).
EW

[fecmech]

I would also see how much you are taper crimping the case, all you want to do is get rid of the bell you put in for bullet seating, any more will start to size the bullet down. I would also continue to water drop your bullets but not because of the velocity you are running. The 9 mm cases are tapered inside and the 147 is a long bullet. You do not want the case sizing your bullet down when you seat it, a hard bullet would be less susceptible to that happening. Also if you add a little tin to the mix you might get some larger bullets out of the mold. Good luck.

[243winxb]

Try a different lube?
Cast bullet leading

A clue to what is causing the leading is where the leading first begins to appear. If it appears near the chamber, chances are that bullet diameter or hardness are the cause.

A diameter too small and/or too hard an alloy will allow high pressure gas to leak past the bullet, which erodes the bullet and leaves leading near the chamber.

If the leading first appears on the leading edge of the rifling (if you imagine the bullet being pushed through the barrel, you will note that one edge of the rifling does most of the work of imparting a spin to the bullet. This is the edge you see when you look through the barrel from the breech end) the bullet might be too soft, and/or the velocity too high.

If the leading appears in the second half of the barrel, the bullet is running out of lube. You should see a star shaped pattern of lube accumulate on the muzzle. This is an indication that there is a little excess lube. http://www.leeprecision.com/cgi/faq/index.cgi

[runfiverun]

dude, your boolit ain't big enough to be sized by your sizer.
sizers make them smaller not bigger.
change your alloy somewhat to make the boolit large enough to fit your sizer then start over.
you might need to lap your mold a bit to make them bigger,or beagle it, then size them to round.
you might just need a half a thou.

[warf73]

Running about 850 fps. Barrel is perfect after the throat

Use this load and air cool your boolits and give it another try DON"T change anything else. I bet your leading at the throat goes away with the air cooled boolits.

Warf

[243winxb]

your boolit ain't big enough to be sized by your sizer. Good point, but his bullets are water dropped, he might be using the large die so it does not size the bullets a lot, making them softer?? Lyman tells us to use an oversized die for this reason when lubing heat treated water dropped bullets.

[runfiverun]

if he gets after the sizing the same day as casting the final hardness won't be affected by scraping the sides or even a thousandth of an inch.
waterdropped takes about 2 weeks for final hardness and they will usually grow about a thou during this time.
for 850 fps you should be able to use straight lead or a 40-1 mix and do fine.
the original winchester mix for their 45 colts was 40-1 and it certainly did 850 fps.
he either has too small of boolits or a tight spot in the bbl.
the only other thing it could be is his hard boolits are trying to swell up some and not quite making it the powder pressure is dropping off at this point and he is getting lube and lead smearing at the pressure drop off point.
i'd maybe try bumping the load up even [for 10 rounds] and see if that has any effect on where or if there is any leading at that point.

[RobS]

if he gets after the sizing the same day as casting the final hardness won't be affected by scraping the sides or even a thousandth of an inch.
waterdropped takes about 2 weeks for final hardness and they will usually grow about a thou during this time.


This is my experience as well when sizing directly after casting.

[Colorado4wheel]

I didn't change a thing. Just did some non-water dropped bullets. Shot 60 just to see. I had worse leading by far then with the water dropped bullets. It went about 1/2 way down the barrel. It came out with a chore boy fairly easy. I have had leading that was much harder to remove. I am going to try a larger batch of my water dropped bullets. I have about 200 of those left, unsized. To be clear. My sizer is sizing to .356 despite being marked as a .357. Trust me, it's sizing the bullets. It's obvious that they are getting sized.

[fecmech]

To be clear. My sizer is sizing to .356 despite being marked as a .357. Trust me, it's sizing the bullets. It's obvious that they are getting sized.

In that case I would try some unsized. If you have some of the lee mule snot just coat them and load. If you are using a hard lube heat the bullets to 200 deg in the oven on some aluminum foil and rub the stick of lube over the hot bullets to coat them and then load them. I have never had any luck with .356 lead bullets in any 9 MM I loaded for( I owned 3).

[runfiverun]

all mine have done much better at 358.

[Colorado4wheel]

Tried it again. Bullets sized to .356". Same bullets as before that I water dropped. This time I tried a bigger batch (over 100). Very minimal leading. Came out with a wet patch and two swipes of a chore boy/old copper brush. No significant leading at the throat. I couple streaks in the barrel in the first inch. Clean beyond that. I am happy. Only changes were.

1) Water dropped bullets sat a extra couple days before sizing.
2) Slightly better fill out of the lube grooves with a hotter sizer. It wasn't bad before but this was better.
3) Deeper bigger flare on case. I didn't need a bigger flare but I wanted the expanding plug on my 550 to size deeper in the case to eliminate the possibility that my cases are sizing the bullets while being inserted. This is the thing I think may have helped more then anything.
4) All of these were full power loads. No light loads in the batch. Previous batch was only 30 and was a chron build up batch.

I'm happy and I think I am done for now with my plan.

[454PB]

For what it's worth, you can open that Star sizer .001" relatively easily.