Author Topic: Reforming 243 from 308 (Read 528 times)

aulrich · « **on:** February 22, 2005, 12:23:07 PM »

I am not sure if I should post this here or to handloading but it is for my Handi, So I'll start here first.

On FredM's site he talks about using GI 30-06 brass to make 25-06 cases. He sited the thicker neck helped with accuracy I guess filling up the empty space of the "loose" handi chambers. So I thought I would give it a try with my 243, besides I can get once fired 308 from an indoor range near my house for almost nothing.

The first attempt was straight into the 243 die. It sort of worked but not quite, it took way too much effort. The next try was to first resize the cases with a 308 die with out the de-capping pin and expander ball, (I thought there was no sense to expand it just to pull it down again) and then run it through the 243 die. This seemed to work well even though it took two trips into the press it was a relatively quick process

But the one thing I am not sure of is do I have to turn the outside of the necks. I am thinking no, this is because I had made up a dummy case by seating a bullet, and it chambers fine. Now it does "feel" tighter than a true 243 case but other than that odd feeling, it seems to operate fine.

RugerNo3 · « **Reply #1 on:** February 23, 2005, 01:19:52 AM »

As regards to neck turning brass, the neck area needs .001" clearance to expand and release the bullet at firing. This should keep pressures in the normal operating range. Your " tighter " feel can be caused by many things, so you have to be the judge in that regards. The handi is a mass produced firearm with wider tolerances then a custom chambered rifle.

dave375hh · « **Reply #2 on:** February 23, 2005, 03:13:12 AM »

Aulrich,
If your seeking accuracy why would you use mixed brass used in someone elses rifle? You need to use new brass of the same lot # or your wasting your time.

As to the neck thickness, measure an unsized case (.243) that was fired in your chamber. Then measure one of your .308 neck downs with a bullet seated. If the .308 case isn't smaller than the neck on the fired case then you need to turn them. If the tightness you feel is from the neck your flirting with disaster. The neck needs room to expand to release the bullet. If it has nowhere to go the pressures will go through the roof! The .001 Ruger#3 mentioned is actually .002 ie; .001 on each side or .002 total.
Short sizing your present cases to leave a centering ring at the base of the neck will do what you need without risking a KABOOM!!! :eek:

aulrich · « **Reply #3 on:** February 23, 2005, 04:43:42 AM »

Thanks dave375hh about the using the fired case as a comparison. I was thinking that short of a chamber cast there was no way to know before pulling the trigger (An option I did not like, potential kaboom and all).

As for the the cases it was easy to get all of the same brand. You see this part of this range's business is "rentals", pay an entrance fee and for the price of ammo you can shoot their guns. I just asked what the headstamp of their range ammo was and picked only that.

handirifle · « **Reply #4 on:** February 23, 2005, 05:26:12 AM »

I have done it before with nothing other than reforming in the 243 die. I wasn't dissapointed but not overly impressed either.

safetysheriff · « **Reply #5 on:** February 24, 2005, 03:44:38 PM »

saami spec's show a maximum neck diameter for a loaded .243 round as being .276 inch. if you load a round assembled from the .308 brass and use a dial caliper (properly zeroed) to check the neck diameter of that loaded brass you should come in at that .276 inch at the max'. any more and you'll be in trouble.

I'D turn the loaded round in the dial caliper to see if the diameter varies somewhat -- to see if you've got a different thickness of brass in some area of that neck. it'll also allow you to see if one area of that brass exceeds the .276" spec.

some argue the point, but the outside turning of a neck generally produces more accurate ammunition.....since it is peeling away excess brass equally (where needed) all the way around the neck. inside reaming can produce a neck that has variations in thickness of brass holding onto the bullet........for various reasons.

see also www.redding.com -- i believe -- for some hints about resizing cases and avoiding problems with 'donuts' in some conversions. it should not be a problem with the .308 to .243 conversion; but it could be with others.

take care.