9mm mold for my Beretta M9A1

[Seth_AZ]

Hi all. I have the Lyman #356402 2-cavity 120gr TC mold. I want to cast for my Beretta M9A1, so I slugged my barrel and it came in around .357" or a hair under.

The Lyman mold dropped bullets right at around .356 or so. Also, the mold was cut very poorly, and the front driving band is slightly narrower than the rear driving band, and is fairly rough (tooling marks and whatnot). In other words, the bullets aren't nearly as crisp and even as I'd like.

I made the decision that I would size the bullets right at .357". I know people recommend .001" over, but I have two reasons: the mold is dropping bullets at .356" and it's taking some work to lap it out. I don't want to try to lap this all the way out to .358. Additionally, I don't want to have feeding problems with a wider bullet than the 9mm expects. As long as I'm not actually undersize, I shouldn't have the gas cutting problem, so my theory is that .357" ought to be sufficient.

I've never lapped a bullet mold before now, but I've been working on it for a day or so. At first I was hand-turning the nut and using polishing compound (turtle wax brand, for car paintjobs) and it just shined up the cavity but wasn't cutting much. Then I went to rubbing compound and it was a little better, but still slow. So I went to the auto parts store and bought some Fine and Coarse valve lapping compound.

I've also now been turning the lap using a hand drill with a nut driver bit, on a slow setting.

When I stopped for the night last night I had the cavities to where the rear driving band showed about 80% good sizing wear, but the front driving bands were only at like 20-30%. The diameter has increased enough that I no longer have patches of the front driving band where lube will squirt out toward the front of the bullet while pushing them through the Star sizer.

Has anyone got any comments on this progress? If it seems I'm going slowly with this lapping it's because I've never done it before, and I'm scared I'll ruin the mold.

Is it likely that I'll see good success with bullets sized to .357 in a bore that slugs out to around .357"?

I'm really disappointed with the quality of this mold, in terms of the cut of the cavities. My other Lyman molds have nice crisp bullet profiles without excessive tool marks, but this particular mold just plain sucks. I wish my lapping would smooth out the tool marks and even the bullets up, but I haven't seen that very much so far.

[Wally]

You sure are brave---seems to me that it will be just fine doing what you are doing.

I have a 356402 and it casts out at .358"....I just bought a new Lee 120 TC 9mm mold and it is casting out at .358"+...

Good luck on the project.

[9.3X62AL]

Any idea what the barrel's throat diameter might be? I set my 9mm boolit diameters to match the throat diameter, just like in a rifle barrel. Luckily, .357" works in all three barrels quite well (2 SIG-Sauers, 1 Ruger).

Making haste s-l-o-w-l-y while lapping is a good thing. Rome wasn't built in a day. :)

If chamber clearances cause issues, brass makes vary in case mouth thickness. R-P is thinner than W-W IME. I've not messed with an M-9 per se, but Beretta 92SB-F barrels have had pretty generous radial clearances IME.

All of the 120-125 grain TC designs work well for me. They have more drive band width to engage the rifling in the quick-twist barrels found in most 9mm barrels (1-10" or 4 turns/meter) than do most RN designs, and feed just as well as the RNs.

[ChuckS1]

I had similar issues with my T-series BHP. Wjat ended up working for me was finding a Lyman 358242 125 grain mold and sizing to .357.

[Seth_AZ]

Thanks for the comments so far guys. I didn't slug just the throat. I don't have any pure lead, so for the two slugs I did this time I had to melt down some pulled .22 LR bullets in a handheld ladle and pour them that way. And since my mold was dropping .356" bullets I tapped them a couple times with a hammer to widen them out enough to get a good bore fillout.

I'll remelt these two and cast some more and slug just the throat and see.

I guess I'll cast a couple new laps this evening and keep working on the mold. I should set the goal of continuing until I get 95-100% good sizer wear on both fore and aft driving bands, I think.

Also, apparently brake cleaner isn't a good enough degreaser. Cleaning the mold with brake cleaner and Q-tips between lapping runs so I could do some more test casts, apparently enough of the lapping compound grease was left in the mold that I constantly got wrinkles, even if I did 15-20 casts to make sure the mold was up to temperature. Is there a chance that the wrinkles are from air vent lines filled with grit instead of residual grease? I've tried swiping the vent lines with Q-tips very thoroughly, but there still may be grit stuck in there that I can't see with my naked eyes.

[sgabel1]

I have a Beretta 92 that almost everything I cast leaded . I ended with .358-.359 and used a Lyman M-die. That gun slugged .357+

I had a Lyman 358212 147 gr mold that was out of round. With some work I was able to true the mold which varied almost .002" and made it work pretty decent. There is a link to an article that was mentioned here in the past. Note you need to polish and recast new bullets often and repeat to get anywhere with the process.

http://www.lasc.us/Brennan_4-0_ModifyCastBullets.htm

[GREENCOUNTYPETE]

I like the Lee 356-120-TC but mine drops at .360

[LUCKYDAWG13]

my Bretta 92FS loves the 358-242 sized to .357 & Bullseye

[Wally]

I have a Beretta 92 that almost everything I cast leaded . I ended with .358-.359 and used a Lyman M-die. That gun slugged .357+

I had a Lyman 358212 147 gr mold that was out of round. With some work I was able to true the mold which varied almost .002" and made it work pretty decent. There is a link to an article that was mentioned here in the past. Note you need to polish and recast new bullets often and repeat to get anywhere with the process.

http://www.lasc.us/Brennan_4-0_ModifyCastBullets.htm

My Taurus 99AF does the same but the leading comes out very easily and so I clean it after so many shots. I've tried different bullets, sizer dies, powders...the barrel is smooth and I even tried a different barrel. Seems that cast bullets in the 9mm Luger is a bit challenging. However even with a badly leade barrel, it still shoots accurately enough for plinking.

[MtGun44]

Lee 356-120-TC drops at .358-359 works well in all my 9mms, highly recommend it.
Not the TL version.

Bill

[9.3X62AL]

Verify ALL measurements with a micrometer--just because a sizer says "XXX" diameter doesn't mean that YOUR castings from YOUR mould are getting sized to the given diameter. Measure measure measure.

The 9mm is much more a rifle caliber than a handgun chambering, owing to its high operating pressures and relatively fast twist rates. I use fairly hard alloys (92/6/2), soft lubes, and a PROPERLY DIMENSIONED expander spud to process brass with. If your spud is the standard item from most die sets, its diameter is likely .352"-.353".......and a spud that small will size down even a hard-alloy boolit. A .355" diameter expander spud will firmly hold a .357" boolit during feedramp contact and cycling. And DO NOT go nuts with taper crimping......just straighten the flare out, and NO MORE.

[Seth_AZ]

Here's a before-and-after progress photo. The bullet on the left was cast prior to any lapping. You can see the rough tooling marks on the driving bands are essentially unsized, and there is a spot on the side where enough of a gap existed that the warm Carnauba Red lube was able to squish up the side of the bullet. The bullet on the right is what the mold would cast right now, after some lapping. The lower driving band is mostly sized now, with some sizing on the upper driving band. Nowhere on the bullets is there enough gap to allow for lube bypass.

I'm going to work on it some more tonight, and hopefully get it done. When both driving bands are nearly completely sized in the .357" die I'll stop, polish it up, cast a bunch of bullets, and test them on Saturday morning. I've never shot cast in this Beretta before so I'm pretty excited to see if it works out well.

One bummer is before I'd slugged the bore and seen the difference between the bore and what the mold was casting, I'd spent a good evening and cast up several hundred of these bullets. They're all have to go back into the furnace to be recast. Oh well. The journey is the reward. ;-)

By the way, I'm new to posting on this board. I've lurked here on and off over the years, mostly off, since I have been on a reloading/shooting hiatus mostly for the last 7 years or so since I moved.

http://leigh.org/seth/pre_and_%20post_lapping_9mm_photos_web_0008.jpg

[MtGun44]

Don't cast too many, I think there's a good chance you will still be too small at .357, but
it may work.

Are you measuring with a micrometer that reads to 0.0001" or with a caliper. If with a
caliper, this is not accurate enough to really do this sort of work properly.

Bill

[Seth_AZ]

Here's a before and after followup pic after I finished one of the cavities. It took a considerable amount of work with the fine valve lapping compound. I did a final polish of it with JB Bore paste. Both driving bands show pretty complete contact with the .357" sizing die.

I notice that all the pre-lapping bullets I cast have a flat spot on one side that you can see in this photo. I'm not sure why that's there, but it is. Whether it was a flat spot in the cavity that I've lapped out, or just the mold wasn't filling out properly for whatever reason I don't know.

I'll return and report back in this thread after I fire a bunch of these on Saturday.

By the way, the purpose for these bullets in this gun is for shooting practical pistol on Tuesday nights at my gun club. The longest shots are taken at 15-20 meters or so. I'm not looking for hair-splitting accuracy, just good enough, reliable functioning of the weapon, and reasonably low bore leading.

I still have more work, since I only consider one of the cavities finished. I'll bring the 2nd one up to the same state.

There are still some wrinkles on the bullets I'm casting, even after a good cleaning with mineral spirits and casting 20-30 times with hot metal. I checked the air vent lines with the point of a needle and most of them seemed to have some kind of obstruction where they meet up with the edge of the cavities. Whether it's grit particles, or metal burrs from the grinding, I don't know. Tomorrow after I'm done lapping the second cavity I'll chase the lines with an X-acto knife blade, perform a really good degreasing, and hopefully cast up a couple hundred good, wrinkle-free bullets to load up for Saturday.

http://www.leigh.org/seth/post_lapping_9mm_0018.jpg

[MBuechle]

I'm casting for a PT-92. I started with a Lee 124TL, it is a no-go. I lapped it to .359 - .360 as my bore slugs at .3573. Then I got a Mihec 124HP mold. What a difference! Virtually no leading with L-Alox, even on 15-1 alloy bullets at 1050 fps. I'm trying White Label's BAC next. I size to .358 with a Lee push thru although the Mihec drops just about this size. My first cast was for the .40 and I had success in pretty short order, the 9 has been more of a challenge. I lapped my Lee mold with 400 grit Clover compound, press the grit into the bullet lap by rolling between 2 pieces of glass to in-bed it into the bullet, then turn slowly with a cordless drill. Change the lap frequently. Your cast iron mold will take a lot longer than my aluminum one did, even with six cavities. The bottom line though; same alloy, same gun, same powder, same day, the Lee TL leads like crazy full length, the Mihec, just traces of foil at the muzzle. Good luck.

P.S. I'm envious of your Star.