.358 Cast Bullets for .38 Spcl

[byteheed]

Greetings,

I'm going to starting to hand load .38 Special and went to my local shop to pick up some components as most of my stuff is for .44 Special and Magnum. I like cast bullets in my .44's so got some hard cast 158gr bullets for .38.

I came home and looked more closely at the box and they're labelled .358 diameter. Will the extra .001 be a problem? I'll be shooting these mainly in my 3 inch model 60, a later model, and possibly my 442.

For what it's worth, I picked up a box of .44 240 Keith style while I was there and they're labelled .429. The old box of Missouri Bullet Co. .44 Keith's I went through when I started relaoding were sized .430, but I never really noticed.

I'm confused to say the least regarding cast bullet diameters.

 

[JohnK]

0.001" oversized, is good, not bad. (for cast lead bullets)

 

[Maximumbob54]

Lead bullets are very common to have sized at .001" or more. My Marlin has a .308" bore and I shoot either .310" or .311" lead bullets.

 

[byteheed]

Thanks guys. I won't sweat it and I'll see how they shoot.

 

[hawgleg]

FMJ are usually the caliber bore size and the lead bullets are almost always .001 larger than the caliber bore. Plated will go both ways as they are softer than the FMJ.

 

[mtgianni]

As of now you have no idea what your bore size is unless you have slugged it. If the 358 diameter doesn't shoot well slug your throats and bbl, google is your friend, and get the needed diameter.

 

[smithnframe]

I always slug the bore before I start casting bullets. And then at least 1/1000 or 2/1000 over groove diameter.

 

[byteheed]

I'll check these out and might just slug the bore and throats... Something new to me.

 

[mkk41]

Yep , my cast bullets are sized, 30cal - .309 , .38/.357mag - .358 , .41 mag - .411 , .45 ACP or Long Colt , .452

 

[358156hp]

Cast bullets for .357 mag & 38 Spl are commonly sized .358. Cast bullets should match the cylinder throat dimensions, or even be slightly larger. A simple test is to drop a bullet (not a cartridge, just a bullet) down each of your cylinders holes. If it falls through easily, they're too small. If the hang up slightly, and you can push them through with a pencil, and minimum effort, they're about right. If you have to pound them through, they're too big. Needless to say, all the cylinders chambers & throats must be absolutely clean before you do this.

 

[Cerberus62]

As of now you have no idea what your bore size is unless you have slugged it. If the 358 diameter doesn't shoot well slug your throats and bbl, google is your friend, and get the needed diameter.

Cast bullets for .357 mag & 38 Spl are commonly sized .358. Cast bullets should match the cylinder throat dimensions, or even be slightly larger. A simple test is to drop a bullet (not a cartridge, just a bullet) down each of your cylinders holes. If it falls through easily, they're too small. If the hang up slightly, and you can push them through with a pencil, and minimum effort, they're about right. If you have to pound them through, they're too big. Needless to say, all the cylinders chambers & throats must be absolutely clean before you do this.

+1 on both, these guys are right on. Cast or swaged bullets for any revolver should alway be sized to the largest of your cylinder throats. Be sure to measure all of them, each can vary a little.

One other trick if you must shoot undersized bullets is to choose a powder and charge that gives you the highest pressure for the velocity you want. The higher pressure will cause the bullet to obturate (bump up) and fill the throats and bore and will prevent leading from gas cutting.

There is a formula using Brinnell Hardness Number (BHN) x 1422 to determine the pressure at which the alloy will begin to yield. A soft swaged factory bullet like the Speer and Hornady might have a BHN of 7 x 1422= 9954 psi yield pressure. A harder commercial cast bullet at BHN 13 x 1422= 18486. about the upper limit for new published 38 +P load data. There is another formula for converting BHN to CUP (copper units pressure) found in old data. BHN = CUP / (1422 x .90) Both of these formuals have limits at the upper end but are close enough.

You probably have no way of determinig BHN of your bullets other than the manufacturers statements, but this information is useful if undersize bullets are not shooting well in lighter loads but you don't want to raise the velocity too much.

Simply choose the powder and charge with the higher safe pressure and leading from gass cutting wil go away, and accuracy should improve.

Your .358 bullets are fine, but if your throats are larger you can use the info above to get better results.

 

[Titegroups]

+1 on both, these guys are right on. Cast or swaged bullets for any revolver should alway be sized to the largest of your cylinder throats. Be sure to measure all of them, each can vary a little.

One other trick if you must shoot undersized bullets is to choose a powder and charge that gives you the highest pressure for the velocity you want. The higher pressure will cause the bullet to obturate (bump up) and fill the throats and bore and will prevent leading from gas cutting.

There is a formula using Brinnell Hardness Number (BHN) x 1422 to determine the pressure at which the alloy will begin to yield. A soft swaged factory bullet like the Speer and Hornady might have a BHN of 7 x 1422= 9954 psi yield pressure. A harder commercial cast bullet at BHN 13 x 1422= 18486. about the upper limit for new published 38 +P load data. There is another formula for converting BHN to CUP (copper units pressure) found in old data. BHN = CUP / (1422 x .90) Both of these formuals have limits at the upper end but are close enough.

You probably have no way of determinig BHN of your bullets other than the manufacturers statements, but this information is useful if undersize bullets are not shooting well in lighter loads but you don't want to raise the velocity too much.

Simply choose the powder and charge with the higher safe pressure and leading from gass cutting wil go away, and accuracy should improve.

Your .358 bullets are fine, but if your throats are larger you can use the info above to get better results.

Just started casting myself and asked the guys over on the cast bullet forum about using lees BHN tester and thoughts on loading to just under bullet compressive strength and they said it was a nice theory but it doesn't work out for handgun loads in the real world. Some pretty long threads over there concerning this subject. I plan on picking one up myself and doing some testing first hand.

 

[Titegroups]

Put 20,000 PSI behind a piece of lead and it will extrude .001.

 

[Cerberus62]

Just started casting myself and asked the guys over on the cast bullet forum about using lees BHN tester and thoughts on loading to just under bullet compressive strength and they said it was a nice theory but it doesn't work out for handgun loads in the real world. Some pretty long threads over there concerning this subject. I plan on picking one up myself and doing some testing first hand.

I use an LBT tester which is very fast and gives a direct readout.

You can make yourself a little crazy sweating details. I know those guys on the CB forums cuz I am one, been casting for 25 years, rifle, pistol & shotgun.

The 1422 formula works well enough but there are so many other variables it will only really get you close. I can't say if it is precise enought to get to to just under or over a specific point, but it's a lot better than just guessing.

Be very careful entering the world of casting and make sure it's where you want to go, it can be very addicting.

I have over 70 molds for every caliber I load, from 22 to 45, and I'm not sure where it will stop. There are still so many designs I haven't tried yet...

 

[mtgianni]

Just started casting myself and asked the guys over on the cast bullet forum about using lees BHN tester and thoughts on loading to just under bullet compressive strength and they said it was a nice theory but it doesn't work out for handgun loads in the real world. Some pretty long threads over there concerning this subject. I plan on picking one up myself and doing some testing first hand.

I have a cabintree that runs circles around the Lee. IMO, get some alloy mix a lot of it and ask someone to test a few bullets if you mail them to 'em. Base your load development off of that.

 

[mikld]

I cast bullets for my handguns for mebbe 12 years before I "learned" about BHN. I cast/shot for my Specials and Magnums and worked out all my leading issues without much regard for "BHN" numbers. I didn't shoot any pure lead swaged bullets nor any linotype hard bullets, but 95% wheel weight alloy. Fit is king regarding shooting lead in handguns, for clean shooting and accuracy. Sizing bullets to the same size as the cylinder throats will normally give bullets a few thousandth over groove diameter and works best for accurate non-leading shooting (My Ruger SBH has .431" throats with a .429" bore so I size the bullets for this gun to .431". With my Dan Wesson it's .430" and .428", and shoot .430").

I looked at the pressure/BHN formuls a few times but could not put it into real life use (the data I got/used from the formuls didn't have the same results as listed.). I'm sure this will work under some circumstances, but haven't for me.

My suggestion for now would be settle on an alloy (wheel weights, or #2) and size the bullets to fit your gun, and do the BHN formula later, or not...