Lead bullet users ?

[Don P]

Dare I say it...use a FCD.

I concur and have an extra piece of raisin pie

[dardascastbullets]

Brigond,

Your cast bullets should not have any mould halve fins on them. They should look like they have come from a CNC machine. The fins are 'adding' to the diameter of the bullet(s) and are causing the brass to bulge (according to what you have described). You are also attempting to correct a problem that will not go away with the use of the Lee Factory Crimp Die. This die is not intended to be used with cast bullets. You are swaging the cartridge (and the cast bullet) down to a lesser diameter. Fix the cast bullet problem first, stop using the FCD for cast bullets, and get the Lyman 2 Step M Expander Die to properly prepare your case mouths for cast bullets. You will be back in the ballgame once you have achieved this.

[Beans]

I used to have that problem. To determine where my problem was I took a flared and de primed case with no powder and adjusted my seating die until that case would fit into and come out of my barrel easily, then took bullet and placed it into a un primed case that had been flared but had no powder and started with the recommended COAL and slowly shortened it until the case would pass the plunk test as you call it. It all had to do with the ogive of the bullet I was using.

I have had that problem also is several of my handguns. I also found that the ogive of my selected bullet was the problem. and I also corrected that by playing with the OAL.

[Unclenick]

Brigbond,

Take a look at the SAAMI drawing for 9 mm Luger. It likely answers a lot of your issues.

Note that the diameter of the case mouth of a loaded round is 0.3800" -0.007", or 0.3730" to 0.3800". Set your crimp die so the case mouth diameter falls into that range.

Note that the COL is 1.000"-1.169", and not 1.100" minimum. I don't know where you got that.

Keep in mind that SAAMI specs are for manufacturers to follow so their ammunition is compatible with all brands of guns and magazines. If something else works better in one of your particular guns, you can use it. It just won't necessarily work in some other gun. The main thing is that you work your load up in your gun with your seating depth, while watching for pressure signs.

Also note that while commercial jacketed round nose bullets tend to have elliptical noses, many makers of molds for cast bullets seem to have found that harder to cut than just a simple hemisphere on top of a conical section (Lee molds, for example). That shape is shorter and fatter than an elliptical nose profile is for a given weight. It is also often fatter at the ogive forward of the bullet bearing surface (the cylindrical portion). This forces you to seat deeper for the same feed reliability.

You may already be at your best seating depth. The "plunk" test works when a cartridge headspaces on the case mouth, as is the design for this cartridge. However, with lead bullets it often improves accuracy and reduces leading if you headspace on the bullet instead. This means the bullet sticks out just enough to come to a rest in the throat of the barrel just before the case mouth makes it all the way to the end of the chamber. This is because it is easier to distort a lead bullet on its way into the throat, so it's important that it start out straight. Jacketed bullets are tough enough to tend to align themselves on the way into the throat without distorting. Below is how this looks in the .45 1911 (third from left) but it applies to the 9 by analogy. It won't make so pronounced a "plunk", but it shoots well.



I don't know where the guys calling for .358" bullets are getting that idea. It is standard practice to make commercial lead bullets 0.001" wider than bore groove diameter. While the .38 Special, .357 Magnum, and .357 Maximum cartridges all have .357 groove diameter barrels and therefore get .358" cast bullets as standard, the .380 ACP, 9 mm Luger, .38 Auto, and misleadingly named .357 SIG all have .355" groove diameters and therefore will want .356" lead bullets standard. Unless slugging your barrel has shown you to have an oversize groove diameter, .356" is what you want.

[reloader28]

Because every 9mm I have slugged is .357. I know its not always the case, but almost everyone I've talked to in person and on castboolits forum say the same thing for 9mm and for .380.

I cast and load for seven .380's and four 9mm's, and they all have .357 bore's and get .358 bullets

The .357's and .38spl get .358-.360.

[Unclenick]

Interesting observation and a surprise to me. Certainly the .357" and .451" bores are not made that much over their nominal dimensions. It should tend to cause terrible leading issues with all the .356" commercial cast bullets out there. It should also tend to cause some underperformance of 9 mm ammo, as the SAAMI test barrel spec is 0.3550" +0.0005" groove diameter, so you know ammunition pressure and velocity testing isn't being done with the loose bores. The only 9 mm I have is European-made .380 and it slugs 0.3553".

I see the complaints about 9 mm bore diameter variability on Castboolits.com. So this leads me to fall back on the standard casting advice to slug your bore before choosing a final sizing diameter.