out of round mould

[porthos]

i have a lee 356-147 9mm mold that cast's .001 (.3565-.3575) out of round. was wondering if sizing to .357 with lube; or just tumble lube,which is what i want to do; would make a difference in accuracy. or does the out of round make no difference at 25 yards??

[El Bibliotecario]

I'd think sizing would eliminate the problem, but since I'm a sizer rather than a tumbler that reflects my personal bias. Why not try a small batch of both for comparison? My gut feeling is that on a practical level the human error inherent in handgun shooting would make the problem irrelevant and one would see no difference between either bullet.

[Larry Gibson]

Sometimes it isn't the mould.

Out of round bullets can also be attributed to the alloy and/or casting temp. If you're using a ternary alloy with an ok amount of antimony but low on tine [such as COWWs] you might simply try adding 2% tin to the alloy or increasing the temperature of the alloy.

[jdgabbard]

Another option would be to PC the boolit, then size to your desired size. PC tends to bump up the diameter .001-002 in my experience. In this case it would give you just enough margin to be able to size accurately to your desired size.

[rintinglen]

Re out-of-round, tumble lubed boolits noticeably affecting accuracy:

Depends on the gun and the shooter. A master class shooter with a target grade pistol likely will notice some increase in group size. An average shooter with his Glock 19 likely won't.

[porthos]

don't powder coat and never will. and, larry; same mix with another mold gives round bullets.

[Forrest r]

3 ways to go:

Don't worry about it if you're shooting 25yds or less & holding +/- 2"s for your shooting needs.

Learn your mold, the alloy will tell you when you have "complete" fill out. Less shrinkage of the sprue (sink hole) ='s less shrinkage of the bullet.

While powder coating is not a "fix all" it will definitely bump up the diameter of the bullet to make it able to be sized concentric.

[Gobeyond]

Lee-menting?

[ioon44]

i have a lee 356-147 9mm mold that cast's .001 (.3565-.3575) out of round. was wondering if sizing to .357 with lube; or just tumble lube,which is what i want to do; would make a difference in accuracy. or does the out of round make no difference at 25 yards??

When you shoot a bullet, it comes out sized to your barrel, I don't worry about .001" out of round for cast bullets.
.001' out of round is really not too bad for a Lee mold.

[charlie b]

What is your forcing cone and throat diameters? As long as the bullet seals the bore you should be fine. If it does not you'll get leading.

If undersize for bore you can either toss the mold, play with alloy to get a larger dia, or lap it. I did the lap thing with a Lee .308 mold. Bullets were still a bit out of round but the sizing fixed that and they shot well.

[Joe K]

If this is a new mold Lee will exchange it.

[Larry Gibson]

don't powder coat and never will. and, larry; same mix with another mold gives round bullets.

That indicates it's not the alloy then.

[Outer Rondacker]

I bet it makes less of a difference than your skills at 25 yards. No I am not insulting your shooting skills just saying. Its a handgun and its 25 yards. Barrel will size that .001-.0005 out of roundness. As long as you are larger and not smaller.

Just get out and shoot. Heck I think most of my older lee molds are out of round.

[mehavey]

.001 (.3565-.3575)

Not going to make a hill of beans difference
once it starts through the forcing cone.
Tumble it.
Shoot it.