I was reloading some 45 ACP rounds today when I decided to check the cylinder throat tightness compared to the cast bullets I had sized to .452. I was surprised when they dropped straight through with no resistance. I measured the throat with a caliper and I get .456 to .457. I've read that can adversely affect accuracy, but when I took it to the range for the first time this weekend, the accuracy was really good.

The cast bullets I shoot are powder coated, and typically measure .455-.456 after powder coating. My question is, would there be any harm in loading those powder coated bullets without sizing them down to .452? I'm wondering if the accuracy could be even better. Any potential harm doing this?

Thanks in advance for any advice on this.

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What could possibly go wrong?

Accuracy should be better if you don't size them down. You might also want to try some plated bullets.

Larger throats can cause deformation as the softer lead bullet wants to bump up to the throat size. Then size down in the bbl. Try the oversize bullets, only way to know.

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NRA Cert. Inst. IDPA CSO

Thanks fellas. I definitely will give it a try.

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What could possibly go wrong?

I shot a bunch of 230 gr. FMJ RN bullets and they were very accurate.

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What could possibly go wrong?

The 1917s and the 25-2 were built with 230 ball as the ammo of choice. Cylinder throat size isn't as critical with jacketed bullets.

I've had one of the 25-5s with the oversize throats for about forty years. It does well with a wheelweight alloy (moderately soft) .456" bullet (Lyman #454424) run through a .461" size die so that the bullet is lubed only, not sized. Also, a .454" bullet works reasonably well; perhaps it obturates for a better fit. You don't want to shoot a .452" bullet in these guns.

My 25-2 has .456 throats +/- a couple .0001".
It shot 185 grain jacketed semi wadcutters OK; I was able able to keep them all in the black at one-handed 25 yd bullseye matches, but .452 lead in any weight converted it to a shotgun. The doggone thing also has .0012 thread choke as well, so I haven't fired it in years, as the jacketed bullets have become too expensive.

Another project in waiting. Sigh..... So much to do.

Fortunately I've got a stockpile of 230 grain jacketed round nose. I'll be shooting those for awhile until I have a pile of 45 brass to reload with some .456 lead SWC's.

Thanks for all the good information. This forum is pretty awesome.

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What could possibly go wrong?

You'll get better accuracy if you size to throats . ACWW / Range lead will work for target loads , straight WW if you want to lean on them .

Thanks. I've got tons of range scrap that tends to produce bullets with a BHN of around 12. I've got some hardening alloys too. Already ordered a Lee .457 sizer. Will be interesting to see how it works out.

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What could possibly go wrong?

I determine the size of my cast bullets by matching the bullet diameter to the throat diameter. I would say if your coated bullets are .456" and the throats are .456" you already have a good fit. Bullets .004" smaller may/probably lead to leading and inaccuracy.

BTW; measuring a small ID with calipers won't give an accurate measurement due to the shape of the jaws. For a good measurement the jaws would have to be a knife edge, with no flat face. I have used pin/plug gauges and expanding ball gauges and even slugged throats the same way as I slug barrels. Works for me...

Deplorabusunum,

Before I even knew about things like throat measurements, etc. I blindly sized my bullets to . 452 because thats what the manual said. I went on to achieve stellar accuracy from my .. 25-2. Years later I got a set of pin gauges and discovered my throats were all . 456-.457. I just didn't bother to tell the gun it was screwed up and to this day it shoots amazing groups because it doesn't know any better

The undersize bullets will work fine if they're soft enough to obturate; of course this is dependent on the powder charge being about optimum for the pressure needed to make the bullet bases "swell up" when fired. Some handloaders stop short of this phase of experimentation. Maybe others get it just right the first time. That's never happened to me.

Sounds as if my gun might be like yours??????? I was pretty happy with the accuracy of the 230 FMJ's. Only shot two moon clips full of LSWC's. Accuracy was less.

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What could possibly go wrong?

Jacketed are very forgiving of diameter.