Cast Sizing Question

[Branspop]

I am relatively new to casting. So far I have cast some 210 gr Lee TL bullets in .41 Mag and some 250 gr RCBS Keith bullets in .44 Mag. Now the questions...

Lee claims their TL bullets don't need to be sized. I measured mine and the average .413 or so. Is this a problem? I plan on getting some more molds later and I think I like the regular lubed stuff better. Looking at Midway and a few other places I can only find size dies in .410 or .413. Do they not make one in .411?

 

[wally]

I've always been told you want +.001 over nominal (jacketed) diameter to insure a good seal in the bore, as any gas blowby will cause very bad leading of the barrel. I buy my cast bullets, but very hard cast 0.451 45ACP from Rucker (Texas local gunshow dealer) have worked very well for me for 20 years. OTOH when he's out of stock I get Northeastern 0.452 (which don't seem quite so hard to my fingernail as the Rucker) but also cause no troubles. I use the same powder charge for both (about 10% or so below the max in the Lyman manual). Felt recoil alternating factory and reloads in the mag is close enough I can't tell unless I looked to see which round was on top. POI matches most factory ammo at the target distances I shoot so I'm very happy.

If yours are soft or only surface hardened, then 0.002" over is probalby fine, like anything else you change, work up your loads carefully starting with the minmum charge weight listed.

--wally.

 

[Archie]

Lead bullets size themselves...

Branspop; when you fire that bullet, it will expand out, filling up the cylinder throat before it ever gets to the barrel. It should be a little oversize when it hits the forcing cone of the barrel.

Then it swedges down to bore diameter.

Unless the bullet is grossly oversize, you will not have any problem. And the first problem you will encounter is the round not chambering. If the bullet is grossly undersize, it will just plop down the barrel without building up much pressure except for what happens in the chamber. (That's enough to do serious damage; I do not mean to suggest you can catch the rounds as they fall from the revolver.)

Start with the beginning loads and work up. A slightly oversized lead bullet is the least of the pressure problems in a revolver.

 

[ReloaderFred]

You didn't mention how you're sizing the bullets. I have Lyman, RCBS, Saeco and Star lube sizers, and have a sizer in .411" for the Saeco. In the others, I have size dies in .410". It depends on the alloy as to which sizer I use for them.

Hope this helps.

Fred

 

[Branspop]

I have the Lyman sizer. Worked great on my .44 bullets.

 

[ReloaderFred]

Sometimes the lube also makes a difference. I've got some of my machines set up for hard lubes and some for soft lubes, again depending on the use of the bullet.

I would just shoot them and experiment with different powder charges before sizing them to a different size. If you can't get them dialed in that way, then try a different sizing die.

Lyman and RCBS don't make a size die in .411", but it would be possible to have a .410" polished out to that size. You can also measure the "as cast" bullet and see what size it measures. If it's coming out of the mold at .411", then you could try liquid Alox on the unsized bullets and see how they shoot in your gun.

It's also possible to vary the size of the bullet out of the mold by changing the alloy. The more antimony, the larger the bullet. There is a good explanation of this in the Lyman Cast Bullet Manual.

Hope this helps.

Fred

 

[Branspop]

Thanks!

 

[Bad Flynch]

What you really need to do is actually measure the cylinder throats. Your lead bullets must be as large as the the largest cylinder throat, and a little bigger does no harm as long as the ammo so loaded chambers correctly.

Most people shoot cast bullets 0.001" over the nominal jacketed diameter because they are lazy and do not want to go to the work or cost of measuring the actual throat diameter. The 0.001" number is based on the idea that a well made chamber will have a throat about that much larger than the groove diameter and it works, sometimes. Sometimes it does not work.

There is no real screaming need for you to size the Lee TL bullets; they were made to be shot as-is with lube. Use their tumble-lube and see how they work. AS LONG AS they chamber easily and shoot well, why bother with sizing? I have shot bullets 0.003" over throat diameter without any problem and that was, incidentally, 0.005" over groove diameter for that gun.

If you need, Stillwell Tool and Die, www.sizingdie.com , will make you any size you want, and he is reasonable.

 

[Pumpkinheaver]

Load a couple of rounds withthe.413 bullets, if they chamber they are fine to use as is.