357 Sig and commercial lead bullets

[mortre]

I picked up a conversion kit for my son's 22lr P229 for his birthday. It's a 357 Sig, not my first choice, but what was available. I guess they stopped producing the kits a couple years back. Anyway, I was able to source brass and dies and tried my first few loads in it today. I was using commercial .358 125gr TC bullets from lasercast that I have floating around. I'm pretty sure 10 rounds left me with some minor leading. It's not bad enough to be very obvious, but there is some streaking in the grooves that I think might be the start of something. So I'm pretty sure I should make a change somewhere.

The kicker is I only have a couple hundred, and they are the last of my 9mm sized commercial bullets of any kind. I'm tempted to just toss them in the casting pot with my normal lead, and just try and start from scratch. That's probably easier than trying to chip off the dry lube and powder coat them. I could probably try reducing the load too. It's a starting load of AA7, but the chrono clocked it at 1250fps. That is almost 100fps over what the book said to expect, so I should be safe to reduce it by a bit. I could also try swapping to Universal to try and slow it down. I'd be happy with 9mm velocities to be honest, it doesn't really need to be a barn burner. I guess I could just load and shoot these as is as well. The buildup doesn't seem to be a big deal so far, so I guess I could just plow forward and start over after this first couple hundred are shot up.

That said, I already have a nice mold from Mihec that's never been cast. It was packed up and moved right after I got it and just found it the other day, 7 years or so later.... So I could easily just recast and powder coat them. That is what I am leaning towards now. I was really happy with the results I had swapping from commercial or tumble lube to dry tumble PC in 45 ACP. But I also recognize that this caliber is a bit of a different beast.

[onelight]

I have not had much luck with commercial cast bullets at magnum handgun speeds the Hi-Tek are better but will still lead in many of my pistols if shot to fast. I think they are to hard and the lube is not as efficient and you have limited choices on diameter unless you are getting what I would call premium commercial cast .
I shoot a lot of commercial cast but most at 700 to 900 FPS and some at 1000 to 1100 FPS . You make your best guess and try them . But my high speed loads get my cast where I can better tailor them to the gun. That is my experience . Experiment and see what works but the slower you shoot most of them the more likely you are to find clean shooting loads.

[Dusty Bannister]

Lightly coat with LLA and if still leading, melt and re-cast with appropriate alloy.

[justindad]

The short neck of the 357 SIG and lube groove of a cast bullet creates a challenge in getting a strong joint between the bullet & casing. I had good results using a bullet from Hunter’s Supply that had a crimp groove, which I aligned with the taper crimp to prevent bullet set-back.
*
I suspect a PC boolit without lube grooves will be best for this round. Another strategy is compressed loads, but that limits powder selection & velocity range.

[mortre]

I haven't has issues with a loose fit, but it's new brass and definitely not being sized for .358 bullets. I ended up swapping to Universal, it still came out at about 1170. Unfortunately it didn't lock the slide, so I can't really back it off further. It did clean things up a bit. At least enough to finish off the commercial cast stuff.

[44Blam]

I shoot this boolit in 357 sig:
http://accuratemolds.com/bullet_deta...ullet=35-125YG

I size to .357 and when loading I keep the barrel around and plunk each one.

With .357 sig, I use AA#9 and a full case of it. The boolit is gas check'd and pc'd and they're going in the 1400 fps range. I shoot this out of a KKM barrel in a Glock 35.