Casting oversized bullets

  • Last Post 14 November 2020
  • Topic Is Solved
steve2014 posted this 06 November 2020

I have a Colt Trooper revolver that i want to shoot cast bullets in.  Every commercial cast bullet I have tried leads the barrel from the forcing cone forward.  I have tried everything from Hornady wadcutters to Oregon Trail Semi-wadcutters which spans a large breadth of hardness.  One cylinder full will mess up accuracy.  I measured the cylinder throat and found it to be .359 in.  but molds are made at .358.  I am considering trying to cast at .360 in. but wonder,  am I constrained to order a custom mold at many $$$ or just be satisfied with copper jacketed bullets?  I don't shoot competitively so making a custom mold be financially viable is unlikely. Any advice???

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Idahocaster posted this 06 November 2020

The 38/357molds I have all cast over the listed size, usually .359 to .360. Do you have a mold that only casts at .358? Maybe try a different mold? My Lee mold casts bullets at .360, and they are inexpensive.

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Ken Campbell Iowa posted this 06 November 2020

you might consider also " powder  coating " which adds 1 or 3 thousandths.  search for discussion here, ... the technique is getting more understood for good results.   

and might consider a mold for the 9mm Makarov ... the should cast at 0.363-4-5-6 ... then need to be sized down ... and i think Lee either makes one or did make one.  i think Lee has a 0.359 and 0.360 push through sizer die.

and yes, commercial cast bullets are often too small and too hard.  i have a crate of those ...  

that is where i found oily steel wool on a brush is good for leaded throats ...  heh ...


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Boschloper posted this 06 November 2020


I agree with Ken.  Powder coating is a good way to make your bullets grow a couple thousandths, and it is really hard to get a coated bullet to lead a barrel.

The equipment is minimal, you need your own (not your wife's) toaster oven, some cheap food storage containers, and the powder.  Eastwood is a popular source, I use their Mirror Red.  My wife thinks the loaded rounds look like a tube of lipstick.


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Eutectic posted this 07 November 2020

The Hornady wadcutters should not lead with target velocity loads. It sounds like you might have a rough forcing cone. Clean out the leading and examine the forcing cone.Using a forcing cone reamer to re-cut the forcing cone will usually fix this.

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Qc Pistolero posted this 07 November 2020

I tend to agree with Eutectic.

You can also beagle your mould and cast with harder components like linotype.That should add the .001 you are looking for.But I doubt that's where your problem lies.have you tried shooting your bullets in another .357 to see if it also leads?

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Ed Harris posted this 08 November 2020

If you are shooting standard-pressure .38 Special loads almost all commercial cast bullets are too hard, and the lubes used are also too hard to flow and coat the bore to provide boundary-layer lubrication.  I have no experience with powder coating, but my experience has been that giving commercial hard-cast bullets a light coating of diluted Lee Liquid Alox, which has been cut with equal parts by liquid volume with mineral spirits or LSStuff 45-45-10, to put a light film coating of lube over the entire bullet, prevents leading and improves accuracy.

For standard-pressure .38 Special loads you would be better served with softer bullets of 8-10 BHN, such as 10 tin-lead or 96-2-2 instead of the more common 15-16 BHN of most commercial bullets using 92-6-2 Pb-Sb-Sn alloy. 

While linotype will cast larger in diameter, it will make the leading worse if the bullets do not fit your cylinder throats.


73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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BigMan54 posted this 08 November 2020

I've learned in loading for S&W M&P of WW2 vintage made in .38S&W that I need a bullet that drops at .361 or a double Powder Coat. 

PC works very well to increase the diameter of a bullet.

On the other hand I've loaded many swaged wadcutters in .38Spl for my old K38, never had a leading problem. But those are HBWC's over a light charge of Bullseye.

All three of our USA based Custom Mold makers will cut a hold to suit the diameter you need. Just tell them the alloy you will be using and what diameter you want to drop from your mold. 

I think if you get Tumble-Lube design and use a good Alox based lube such as WLL 45-45-10 you will be able to load with an absolute minimum of leading.

Good Luck,

N.O.E. Molds

Accurate Molds 

Arsenal Molds

Long time Caster/Reloader, Getting back into it after almost 10yrs. Life Member NRA 40+yrs, Life S.A.S.S. #375. Does this mean a description of me as a fumble-fingered knuckle-draggin' baboon. I also drool in my sleep. I firmly believe that true happiness is a warm gun. Did I mention how much I HATE auto-correct on this blasted tablet.

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steve2014 posted this 10 November 2020

Thanks all for the advice. All of the cylinder holes were ball gauge tested and all were consistent in size.  The ball was measured with calipers.  As for the forcing cone, I suppose it could be rough.  I don't know what a smooth cone should look like so I haven't considered a visit to Brownells yet.

My lead supply is somewhat limited.  I got several hundred pounds of unknown lead mix through a friend and two-week old ingots cast from it measure 17 BHN with a Lee hardness tester.  I have some pure lead that I can cut it with to get closer to the 8-10 BHN that Ed recommends.  (Love Ed's Red, W7JAA)

I don't currently have any mold for this firearm.  I don't have the funds to do a buy-n-try so wanted to try one-n-done.  I want to load a Keith style SWC bullet at about 158 gr.  and am debating about looking for a bullet that takes a gas check.  I use a Lee Factory Crimp die which may also be causing an issue by swaging the cast bullets I have loaded to jacketed diameter with its sizing ring.  Lots of stuff to sort out and your suggestions are really helpful.  Thanks.

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ALYMAN#1 posted this 14 November 2020

Several items I have experienced with oversize throats on an OMBH:

you did not specify if trooper is 38 or 357 - could not use 38 brass in my BH.

most of my Colts have smaller bore/groove dimensions.

I have been able to see/polish slightly the forcing cone using the screen and then crocus cloth on a Lewis lead remover taper fixture by hand for appropriate caliber - don't change size!

Have gone up to .360 diameter bullets and have had to go to 38 S&W cowboy roll crimp and expander plug to load.  This will get you to a point somewhere that cartridge will be difficult or impossible to chamber.  Using profile die will probably set you back some.

Check barrel cylinder gap follow Mr Harris's writeups on forcing cone dimensions especially entrance diameter - Kuhnhausen says max for D frame is 0.383 and E frame is 0.378";  E frame is Officer's model and I think D frame is smaller.

Just recently I have been able to get respectable groups from the BH.


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