Guidelines for sizing cast bullets?

[PennsyPlinker]

I did a search on this, and got sucked into the Laidhaidthraid. I did learn some things that will be useful to reloading through that, but I am still on a quest here.

I have three boxes of lead bullets in my possession. Two are "factory made" and one was homemade by someone other than me. They are in three separate calibers to boot - .45, 9mm, and .44 magnum. The .45 bullets are lubed and advertised as sized to .452. Actual size is .451.

The 9mm are also lubed and advertised at .356, Actual size is .354.

The .44 mag bullets are not lubed, and measure .430.

I would like to see some general discussion on the necessity of sizing lead bullets, and contrasting factory made with home cast. Specifically, do I need to be concerned about sizing bullets that are already marked as sized and lubed? What about ones that are NOT sized and lubed? Is lubed enough, or is sizing them critical to performance/safety?

I am sure I will come up with some more questions before all this is said and done.

[mongo]

The .45 look to be on the money for 45ACP or use in a newer 45 Colt.
The 9mm's look a "little" small. 9mm's are usually .355" for jacketed and .356" for lead. The 44's with no lube look a little large at .430" Most bullets for 44 mag are .429". Also if they are to be loaded up to 44 mag specs they should have a gas check installed and this will require that the be run through a sizer unit and lubed.

[PennsyPlinker]

The .45 look to be on the money for 45ACP or use in a newer 45 Colt.
The 9mm's look a "little" small. 9mm's are usually .355" for jacketed and .356" for lead. The 44's with no lube look a little large at .430" Most bullets for 44 mag are .429". Also if they are to be loaded up to 44 mag specs they should have a gas check installed and this will require that the be run through a sizer unit and lubed.

Thanks. I forgot to mention that I had gas checks for the .44 mag bullets. But that answers my question.

[Tim Ault]

As others have said the 45 cal are probably good as is The 9mm will probably be too small that depends on your barrel and most aren't .355. The 44's may work as is if you don't have overly large cylinder throats you'll have to measure then for what you actually need

[PennsyPlinker]

As others have said the 45 cal are probably good as is The 9mm will probably be too small that depends on your barrel and most aren't .355. The 44's may work as is if you don't have overly large cylinder throats you'll have to measure then for what you actually need

Here's a twist to the whole thing. I have a couple of different calipers. The ones I used to measure these bullets before I made my first post are Wixey electronic digital calipers. The others are a manual, old fashioned dial type with no name, but convey an impression of very good quality, and have been reliable for other things I have used them for in the past. So I dragged them out. They give a measurement across the board of 0.002" larger. So now I am like the guy with two watches. What time is it really?

[Brick]

Here's a source that I hope will help you:

http://www.saami.org/specifications_...wnload/205.pdf

The only down side of it is it is a pdf and you have to browse through it to find what you want.

If we use .44 Magnum as a sample you'll see they cite a 0.432" bullet with a tolerance of -0.006" so bullets sized 0.426" to 0.432" are within spec. But, that being said in general for a semi-auto it is best to slug the bore and size the bullets to match the groove diameter. And for revolvers it is sometimes neccessary to size the bullets to just shy of the diameter of the chamber mouth (the part of the chamber closest to the forcing cone). This seems to be especially true for S&W Model 25 (and 25-2) revolvers with mouths that can run as large as .455", but still have .452 bores.

[streaker69]

Here's a twist to the whole thing. I have a couple of different calipers. The ones I used to measure these bullets before I made my first post are Wixey electronic digital calipers. The others are a manual, old fashioned dial type with no name, but convey an impression of very good quality, and have been reliable for other things I have used them for in the past. So I dragged them out. They give a measurement across the board of 0.002" larger. So now I am like the guy with two watches. What time is it really?

Time to buy a better and calibrated caliper, I'd say.

[PennsyPlinker]

Here's a source that I hope will help you:

http://www.saami.org/specifications_...wnload/205.pdf

The only down side of it is it is a pdf and you have to browse through it to find what you want.

If we use .44 Magnum as a sample you'll see they cite a 0.432" bullet with a tolerance of -0.006" so bullets sized 0.426" to 0.432" are within spec. But, that being said in general for a semi-auto it is best to slug the bore and size the bullets to match the groove diameter. And for revolvers it is sometimes neccessary to size the bullets to just shy of the diameter of the chamber mouth (the part of the chamber closest to the forcing cone). This seems to be especially true for S&W Model 25 (and 25-2) revolvers with mouths that can run as large as .455", but still have .452 bores.

Thanks for the PDF! According to some quick preliminary study, the 9mm bullets I have are also in spec, as the tolerances allow a -0.003". But according to what you are saying about slugging the barrel to achieve optimum fit, it sounds like loading lead bullets for a number of .45 ACP guns could be problematic, unless they all happen to be exactly the same size. How critical is that? I am thinking of leading here. I am not concerned with match grade bullets, just good enough for COM hits at the range.

[PennsyPlinker]

Time to buy a better and calibrated caliper, I'd say.

Well one would think so. But which one is not accurate, and how does one calibrate them? Both zero out just fine, and both are consistent across their range - i.e. they give the same reading in both directions. Neither was particularly cheap either, and the older design has served me well for as accurate as one needs to be with metal involved in working wood.

[streaker69]

Well one would think so. But which one is not accurate, and how does one calibrate them? Both zero out just fine, and both are consistent across their range - i.e. they give the same reading in both directions. Neither was particularly cheap either, and the older design has served me well for as accurate as one needs to be with metal involved in working wood.

You'd have to find a Metrology place that can calibrate them. There's one not too far from me, I'm sure there's somewhere around you could take them to for calibration.

http://www.garberscale.com/