Really Excessive Bullet Sizing

  • Last Post 09 November 2023
Wilderness posted this 06 November 2023

Those of us who cut our teeth on Col. Harrison’s cast bullet articles know that sizing bullets is a bad thing, but I had an accidental discovery that caused me to reconsider.

About 2012, I had cast some hard #U321297HP .32 Special bullets to try in my .32-40. Afterwards, I had some leftover bullets, lubed and gas checked. I also had a Lee .314” die I had bought to size down another bullet for paper patching in the .32-40.

Out of curiosity I ran some of the .32 Specials through the sizer. They came out at .3155” after springback, the gas check sized down OK, and they actually looked pretty good. As luck would have it, I had some older .30-30 PPU cases with very thin necks. Curiosity led me further – I loaded a dummy and all was well. Then I loaded some real loads with 28 gns 2208/Varget. and shot them to see what would happen.

The extra bullet diameter did not bother me since I still had neck clearance, and I had already been running .360” cast bullets through a .353” 9x56 MS with excellent results – I found out later that the MS throat started at .359”.

The .30-30 loads were a real surprise, with a group of about 1.25” at 50 meters.  This very quickly became my hunting bullet, now with 32 gns 2208/Varget.

After a while I got to thinking that I might be able to size them down further. I bought a .311” die. They came through that at .3125”, and still the gas checks were OK. Now they could be loaded in regular cases and still have neck clearance. To be on the safe side I outside neck turned my cases to .010” maximum thickness. This just skimmed off the high spots and caught the occasional thick neck.

Now they really shone . Overall average velocity from eight five shot groups was 2170 fps, average SD 18, and average group 1.98” (1.60” – 2.33") at 100 meters. This was with a scoped M99 Savage on a narrow range fenced on both sides against the wind. These groups encompassed three lubes – Lyman Super Moly, Lyman Orange Magic, and Alox 50:50. Composite group for the eight targets was something like 4.3”.

Last off, I tried sizing to .310” in the lubesizer, but groups were not as good. I suspect that the close fit in the neck at .3125” had been providing much needed guidance for the bullet. The abrupt throat of the .30-30, relative to say a .308 throat, is not so good at guidance unless the bullet is seated into the rifling. In this instance ammo that would feed through the magazine was still short of the rifling, so neck guidance came into play.

As the gas checks were sized, the portion on the shank elongated, and the centre dimpled inwards. If the base of the bullet was flat, achieved by scraping the sprue with a knife, the dimple was round and central. Otherwise it would be more like a half moon. Recently I tried to size some Lee 8 mm bullets in the .314” die. It was a complete mess, I think because there was not enough shank to accept the lengthening gas check.

The order in which this sizing is done is important. For me the first operation is to gas check and lube in the .323” lubesizer die, followed by sizing through the .314” Lee die, then the .311” Lee.  Filling the lube grooves first ensures they stay as lube grooves full of lube. Major sizing of an unlubed bullet will close up the lube grooves.

More recently I have also sized down some bevel based 163 gn .32-40 bullets from an old WRACo mould.  In a different .30-30 rifle these shoot quite well with 5.5 gns Unique.

I am definitely not the only one to have discovered the virtues of Lee type sizing dies. I know of others sizing 8 mm commercially cast bullets to fit errant .303s, and I am sure I have seen a reference to someone making bullets for the 8 mm Hungarian from .338 cast bullets.

The point is that these dies seem to have changed the rules about bullet sizing. It is still no doubt better if you don’t have to size your bullets, but there will be times when you really can make a silk purse out of a sow’s ear.

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JeffinNZ posted this 06 November 2023

I have been shooting in my Carcano sized .268 a bullet that casts at .281 for the .270 Win.

Sizing - How Much is Possible? | Fouling Shot Magazine| Join CBA | Cast Bullet Forum (


Cheers from New Zealand

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Aaron posted this 06 November 2023

My experience was the disappearance of the lube grooves. I never tried lubing them first to retain the groove. I learn something every day!



With rifle in hand, I confidently go forth into the darkness.

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Tom Acheson posted this 06 November 2023

My most recent experience for rhis "technique" involves a bullet for my S&W Model 25 revolver that shoots .45 ACP or .45 Auto Rim rounds. A friend made a pile of "custom" Lee bullets that surprised him how large they were out of the mold. Too large for him to use, so he gave them to me. They range in size from 0.460" to 0.468". Of course they are not totally "round", so it depends where you take your measurements.

The revolver's cylinder throats require bullets sized to 0.455" for acceptable accuracy. So they get sized down to 0,455", a whopping reduction of 0.005" to 0.013"! But they shoot just fine. The powder is WST, 3.6-grains using an RCBS Little Dandy rotor #7. No idea what the muzzle velocity is. It can be a bit of an arm exercise with the Saeco lubricator-sizer though. Not sure how well my RCBS sizer would hold up to those forces.

However, using a different bullet, I did have a "sizing down" experience that resulted is erasing the lube grooves. So to me, that experience is not totally rare.



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Eutectic posted this 09 November 2023

In high school I had a 71-84 Mauser. The original 11mm black powder loads with a 370 grain paper patched bullet were a hoot to shoot. But 0.446 bullets for reloading were scarce. The 0.458 45-70 bullets were plentiful. We turned a 0.446 sizing die, which we used in my fathers big bench vise. Problem solved, it would even size jacketed bullets!

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MP1886 posted this 09 November 2023

I just recently bought some double copper plated 250 grain .375 bullet to size down for my 9.3x57 Husky and sized them down to .366-.367.  Had no problems and they shot really well.  I've done cast bullets even further with real good results. 

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