Home Forums Reloading Big Game Rifles Good little article on partial FL sizing

I found this article, and wanted to share it with those reloaders torn between NK sizing, FL sizing and partial FL sizing. I have made it my goal to resize my brass so it mimics 1x fired cases as far as the headspace is concerned (i.e. shoulder location, shoulder bump). The case body obviously will be resized too, but will still be "larger" than virgin brass.

I would appreciate all positive and negative comments concerning this article.

http://yarchive.net/gun/ammo/precision_resizing.html

bartbobs results were exactly the same as mine have been for years.

Good article and interesting. I don't know why but it DRIVES ME CRAZY when people call a properly set up die as "partial sizing". You are just a couple thousands of an inch away from touching the shellholder yet it's called "partial". It could rather be called "99.9999% sizing"...or we could call touching the shellholder....simply...oversizing. I vote we all call bumping the shoulder back .001-.002 "PROPER SIZING". Oh well...I'll try and get over my hangup.
I've been trying to set my ammo up like this for years. I DO NOT like it when I have tension when the bolt closes and have noticed pretty good point of impact shift when doing so.
My favorite set up for the last year has been a lee collet die followed by a redding body die to bump the shoulder......simply wonderful.

kraky +1. Partial FL sizing is a very dubious term to a new reloader. Hell, if you are using a FL sizing die, then it's FL resizing, with some minor adjustments.

+2 Kraky.
A body die and a lee collet die makes things about as simple and good as it gets.

Take the bushing out of a FL die, and you have a body die.

That depends on the bushing die. Redding has two types, FL with the neck bushing or neck only.

mathman, yep. Type S Match FL has the bushing. I stand corrected.

It's "partial"--darnit!--It's too late to be changing the nomenclature now

I've been using PFLR for 20+ years--it works for me in all my hunting rigs. Most of the time, NS gets me worse accuracy.

But I'm a bit confused what the author is sayin here:

The smallest test groups came from cases full-length sized
such as the shoulder was not set back from it fired
position. Sized-case headspace was the same as, or not more
than .001-inch shorter than fired-case headspace. Test
groups were about 1/2 MOA. And cases could be reloaded
20 to 30 times.

This well explains why most folks get better accuracy with
partial-sized cases using full-length sizing dies than by
following press/die instructions for full-length sizing. It
also explains why they get better accuracy with neck-only
sized cases compared to conventional full-length sizing with
the die set according to supplied instructions.

So did his smallest groups come from full length sized or partial sized? Or is he trying to say he partial sized in a FL die? (I mean, with conventional dies, how the heck are you going to partial resize except with a FL die?)

John Barsness's article is one of the most straight forward I've read:
http://www.24hourcampfire.com/reloading.html


Casey

alpine- I think he is saying that the best groups came from brass that was PFL sized using a FL die, to duplicate fired brass shoulder location. In other words, the shoulder was kept in the same place or bumped .001 after PFL sizing.

A part of the confusion lies with thinking the common admonition for FL sizing requires that the case be pushed as far into the size die as possible. Unfortunately, that almost always over sizes the brass and creates a small amount of excessive headspace which in turn causes unnecessary case stretching/lengthening.

What the writer of the article is addressing, IMHO, is how to correctly FL size without overdoing it. Adjusting the size die until it just touches the shoulder enough to allow it to chamber snuggly is not "partial", it is fully sizing the case properly. A 1/16th turn of the die changes the headspace about .008" and that's far to much change in headspace difference but I usually see suggestions to change the sizer a quarter or half turn to get "proper" sizing. WRONG! Once we get close we should limit die turns to no more than 1/32 of a turn or we will over shoot the ideal point for sure.

Striving for only .001" set back is a good goal but is almost impossible to attain in the real world. The die threads are too coarse for that and brass spring-back in different cases will cause that much or more variation, and the type of lube will also come into play with that tiny tolerance! But, striving to size the minimum amount neccessary is what we should all seek; it aids accuracy AND extends case life significantly!

As Ronald Reagan put it, "The problem ain't that folks don't know, it's that so much of what they know is wrong!"

I have come to really like using Redding's Competition Shellholders to make those fine adjustments.

Good, I was hoping that's what I was reading

That is what I do with all my "serious" big game loads......


Casey