To Size or not to size

[JWJarrett]

All, I am relatively new to this forum and to reloading. I have been reloading .40 S&W for my range consumption and began casting boolits this past fall, starting with Lee and jumping to a beautiful MP that casts 160 to 175 grain flat or HP at .402 inches. I shoot an S&W Shield that, as near as I can measure with the offset rifling, slugs to a width of ~.400 (I have gotten .399 to .400 but I can't get a good angle with standard calipers). I have a Lee push through sizer that consistently sizes to .401. I was casting 175 grain using a Lee mold and Lyman #2 that was casting on the smallish side at .400 or .401. Some didn't seem to even brush the sides of the sizer. I was shooting either PC coated or lubed but was getting some keyholing which I think was a combo of Lyman #2 and undersized bullets.

Fast forward to the MP Mould which casts a perfect .402. I have the option of sizing these to .401 and then applying PC for an end result of about .402 to .4025 or not resizing for and .402 w/o PC and about .4035 after PC. I am casting using 20 to 1 lead. The bullet weighs in at 165 gr and I am probably going with a light to mid load of 231.
276294

[mehavey]

PC, then size....

[Targa]

I am with Mehavey.

[tinsnips]

Same here

[JWJarrett]

So, sizing after PC produces a perfect .401. Combined with the softer lead, that should lubricate, obturate and alleviate my keyhole problem?

Would it be problem to try some w/o resizing? I'm more curious than anything. I certainly don't want to cause a kaboom.

My end goal is perfection, of course. Short of that, I want a consistently accurate loaded that can be used as a SD load, if I choose.

[Wheelguns 1961]

An added benefit to sizing is that it makes your bullet more round than the mold does. Does that make sense? I wasn’t sure how to word it.

[JWJarrett]

An added benefit to sizing is that it makes your bullet more round than the mold does. Does that make sense? I wasn’t sure how to word it.

Makes perfect sense to me. I love the consistency of a sized bullet. It helps my OCD ��

[GregLaROCHE]

An added benefit to sizing is that it makes your bullet more round than the mold does. Does that make sense? I wasn’t sure how to word it.

The boolit will become round automatically when it enters the bore. As long as you have enough diameter the boolit will size itself when it enters the bore when being shot. Only when the boolit diameter is more than you ideally want should you have to size it down. I always PC before sizing. That way I know that all Boolits will be the same diameter.

[dverna]

I would never size a bullet if it will feed and shoot well. Lube it or PC it and try it. Why waste the time?

[MrWolf]

I would never size a bullet if it will feed and shoot well. Lube it or PC it and try it. Why waste the time?

This. You said you had a keyhole problem. See if just pc works, you may just need a slightly larger bullet.

[JWJarrett]

There's a lot of experience represented here. I'm going to load a few w/o sizing and a few with sizing after PC. Then I'll go to the range and play. I never need much encouragement for that.

Thanks everyone for the input!

[Mk42gunner]

I don't powder coat, yet. I may in the future, and I do think it is a viable way of not needing an expensive lubrisizer.

With that said, I think running boolits, coated or not, through at least a Lee type sizing die is a good insurance step. Case in point, I have been loading some 148 grain WC in .38 Special, cast from a Lee six cavity mold and tumble lubed with BLL. A few took just a bit more effort on the press handle to size. My thoughts were those were the ones that I had inadvertently held the mold open on. Probably by touching the sprue cutter while filling the mold.

The point is, those were over sized, and a visual inspection didn't catch them. Now they are .358" like they are supposed to be.

Robert

[firewhenready7]

Powder coat then size

[mdi]

If a round with .4035" chambers OK, plunks, I'd probably try it. If groove diameter is .400" then you are only having .0017" engagement.

[44magLeo]

If your powder coated boolit when loaded in a case plunks in your gun then shoot it. If it won't plink then size it.
But size it no more than you have to top get the plunk.
The better the boolit fits the throat the better it shoots.
Leo

[Soundguy]

An added benefit to sizing is that it makes your bullet more round than the mold does. Does that make sense? I wasn’t sure how to word it.

Agreed. I size everything just because I like shooting round bullets.

[JWJarrett]

I have several loads I want to try so I produced 10 sized and 10 un-sized for each powder and charge. I'm hoping to get some range time this weekend. I wish I had a chron, but I don't.

[JWJarrett]

I had some good range time today and tested 6 different load/powder combinations firing 165 gr hollow points cast with 20-1 and Powder coated. I made one set of sized and a set of unsized in each combination for a total of 120 rounds. I used 231 and CFE Pistol. All performed acceptably. After I sorted through the targets, there was an interesting pattern. The unsized outperformed the sized in every instance. Another thing I found was the CFE Pistol produced the most consistent groups and produced 7 of the top ten groups.

I was shooting a S&W Shield with a 3in barrel. With my twitchy hands and that short barrel, the best I can get from bench is 7 rounds in a 5in circle from 20 yards. I won't win any contests but I can cause a lot of leaks in center mass.

[robg]

well done now you can save time by not sizing .its the only way to know is by trying things.

[toallmy]

You might have discovered you have been shooting undersized boollits when sizing at .401 , just a thought .

[fredj338]

I size everything after coating. Slight changes in alloy & casting temps affects final dia so sizing makes reloading more uniform; OAL & crimp. A fat bullet & thick piece of brass may be a failure to chamber.

[JWFilips]

Me...I size before and after PC coating Win Win!

[Soundguy]

If nothing else, you know you have round bullets.