headspace

[1967spud]

Right after much talking to Col48 i have invested in a body die for my .243 ai. The brass has had a lot of use and is getting tight to chamber, thus i had a word with Col. Any way i got the body die and a Hornady headspace guage comparater. I have got 5 readings foe five different cases all lapua:

 

Case 1 before 1.7030 after 1.0990

Case 2 before 1.7025 afetr 1.6995

Case 3 before 1.7025 after 1.7010

Case 4 before 1.7030 after 1.7000

Case 5 before 1.7025 after 1.6990

 

After pushing the shoulder back by that difference it chambered like new brass.

 

Q1: Does that headspace seem right? as i have looked on the net and found conflicting measurements.

 

Q2: Will neck thickness now be an issue?

 

Q3: Do i use the body die before or after neck sizing?

 

And lastly:

 

Q5: I have about 150 rounds already made prior to buying the body die, can i just run loaded rounds through it?

 

Thanks mark.

[Vermincinerator]

Hi Mark,

Maximum headspace should be no more then .004" any more then this would be considered as excessive.

Ideally you want to be somewhere mid way.

Using a body/bump die correctly is not easy as you should only be looking to set the shoulder back .001"

 

Personally i would have dumped the cases and fireformed a new batch, to be totally honest body/bump dies are really the domain of target/BR shooters who have minimum spec, tight necked chambers and who's cases are subjected to minimal expansion.

However, Jam your bullets hard into the lands when you fire the loaded bumped cases otherwise you will probably find strtching in the case web area, which with already brittle brass is not good.

 

You should not find any thickening of the necks but check anyway because the brass has to flow somewhere.

On no account put loaded ammunition through a sizing die of any kind thats a big NoNo, even though you think you might get away with it, one day you wont.

 

Ian.

[col48]

hi spud

 

i was under the impression that they where new cases.and you had just shot them.

 

as for the head space all i have done in the past and now is just keep knocking the cases back till they chamber nice.this is normally under the 1 thou of bump.

i have not had any problems with a factory rifle but i do get a few with my custom rifles.

and i make a point of bumping them back every time. i just make this a part of my reloading procedure.

i have had no bad results and i find the hole process quit simple.

 

ATB

Colin