Sizing die inaccurate?

[uglysteve]

When sizing some of my .453 200gr swc bullets down to .452, I noticed my new lyman sizing die was sizing the bullets to .4505. Did I get a defective one or am I doing something wrong?

[ffries61]

What are you using to check the diameter ? I can't think of anything that you could do to make the bullets come out undersize to the die, hope you have a 0-1 micrometer to check with, even with the best calipers it's easy to get readings off by .001" or so.

Fred

[BK7saum]

The hardness or lack of hardness of your alloy will affect the final size. But 4505 vs 452 is a bit much. Again, how are you getting your measurement?

[Skunkworks]

Are they round when they exit the sizer?
Many a Lyman has play in the top rod and thus will press the boolit a little askew into the sizing bushing.

[uglysteve]

It was my caliper. I purchased a micrometer yesterday and re-measured. It comes out at .452.

[detox]

Some harder alloys will spring back larger. I use a .451 sizer for my 45acp boolits. After sizing measurements are .4515 using Lyman #2 alloy. I once thought dial caliper was good enough to measure...WRONG. A good micrometer is a must.

[Ben]

So many people " think " that they are getting the proper diameter measurement of a cast bullet using calipers.

There is no substitute for a dependable , accurate micrometer.

[MtGun44]

As to the original question, YES - it is entirely possible that the sizer is off, but it is
much less likely than your caliper being off. If you measure a boolit with a good
micrometer and then check it with another, and it is still off - THEN you probably
have found a bad sizer. Not common at all, but it does happen.

This is why I harp on not measuring critical dimensions like boolit diam with a caliper.

A micrometer that reads to .0001" is really NECESSARY for this hobby if you want to be
in control of what you are doing. No doubt, you CAN just try stuff and see what works,
and when it works be careful to never change anything, but really knowing your dimensions
accurately give much more control.

For those that don't have a mic - GET ONE. Used on eBay you can probably afford an older
Mitutoyo, Brown & Sharp, Starrett. New, try Enco Tools online, they almost always have a
Fowler (real decent brand) 0-1 in .0001" markings for under $35, sometimes way under.

Bill

[EDG]

A very good used mike can be purchased for $15 to $20.
I have ran into people on the net with all sorts of excuses for not owning one but there really is no excuse.

[mikeym1a]

Check the jaws of your caliper for lube buildup. I've gotten as much as .0015 varience due to lube sticking to the insides of the jaws. When cleaned off, it returns to normal.