Headspace Question

10 March 2008, 17:58

Hokie Hunter

Headspace Question

If I can easily chamber all of my once-fired brass before any sizing whatsoever, does this mean...

1) There is so little headspace in my rifle that the brass simply had no room to expand when fireforming?

2) The headspace in my rifle is so sloppy that it can accomodate the case even after expansion and before sizing?

Is it normal for once-fired brass to chamber before resizing? In other words, will I normally get a few firings before having to bump the shoulder back with P-FL or neck sizing?

10 March 2008, 18:25

Terry Blauwkamp

Were these cases fired in YOUR gun?

10 March 2008, 18:55

woods

quote:
Originally posted by Hokie Hunter:
If I can easily chamber all of my once-fired brass before any sizing whatsoever, does this mean...

1) There is so little headspace in my rifle that the brass simply had no room to expand when fireforming?

No, if you had so little headspace that the brass had no room to expand, then the cases would have been tight in the chamber before they were ever fired the first time.

2) The headspace in my rifle is so sloppy that it can accomodate the case even after expansion and before sizing?

No, cases take a 2 to 4 firings (or more) before they expand enough for a crush fit in almost all rifles.

Is it normal for once-fired brass to chamber before resizing? In other words, will I normally get a few firings before having to bump the shoulder back with P-FL or neck sizing?

Yes, it is normal for the once-fired brass to chamber before resizing. You have the option to Neck Size, PFLR or FL size as you wish.

____________________________________
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10 March 2008, 20:23

Jim C. <><

Rechambering a fired case has no meaning for headspace, the fired case simply expands to fit and no more. When pressure falls the case will slightly contract so rechambering that case is going to be easy enough.

Headspace, excessive or not, has little meaning to a knowledgeable reloader. He simply sizes his cases to fit back into the chamber correctly and goes safely along.

Only the mechanical reloader, one who insists on sizing each time according to the "instructions that came with the die" as the only way to do things will excessively resize and then excessively re-expand the case. Such cases will stretch again each time it's fired so it stretches until it ruptures.

By setting the sizer so it barely moves the shoulder, if at all, the skilled reloadeer insures that his cases fit the chamber snuggly and, volia, there is no longer any headspace or significant stretch issue to be concerned with.

11 March 2008, 04:32

El Deguello

quote:
Originally posted by Hokie Hunter:
If I can easily chamber all of my once-fired brass before any sizing whatsoever, does this mean...

1) There is so little headspace in my rifle that the brass simply had no room to expand when fireforming?

2) The headspace in my rifle is so sloppy that it can accomodate the case even after expansion and before sizing?

Is it normal for once-fired brass to chamber before resizing? In other words, will I normally get a few firings before having to bump the shoulder back with P-FL or neck sizing?

IF you are using a good strong bolt action or single-shot, and your cases DON"T go back into the chamber and let you close the bolt easily, either the firing pressures were too high or something else is wrong!

Generally after a number of shots, FL sizing will become necessary. This will vary dependng on how close to your rifle's maximum your loads are coming! But this should NOT be the case after every shot. If your fire-formed cases rechamber easily before any sizing, be happy! This will make your job easier.

11 March 2008, 07:29

Hokie Hunter

Okay guys, thanks. All this makes perfect sense. Yes, they were fired in my gun, but with all the talk of P-FL adjustments for headspace, I got to thinking that if mine chambered after firing without me having to bump the shoulder back, then something was wrong!

I've been my own worst nightmare while learning this reloading craft...every time I read about something new, I somehow think that my gear or my rifle is jacked up. Deep breath...exhale...

11 March 2008, 07:58

YUMAN

Sometimes PFL dose not work. I have had experience with two Ruger No1s The 25-06 and the 22-250 would chamber fired cases just fine, but would not accept PFL cases. Even with the size die screwed down ro touch the shellholder they would not chamber. The die had to be screwed 1/4 turn more before they would chamber. The chambers were tight on headspace but fat in diameter. Soon as the size die squeezed the body down the shoulder moved foreward,making them too long.
Lyle

11 March 2008, 08:09

ireload2

quote:
The chambers were tight on headspace but fat in diameter. Soon as the size die squeezed the body down the shoulder moved foreward,making them too long.

Typical behavior of a fired case. This is why "99% FL" resizing works best. You have to make sure the shoulder is not allowed to move forward.

11 March 2008, 08:15

woods

Hey H H

When you get the chance get some gauge to show you what is going on. I recommend the Hornady Headspace Gage

You put them on your calipers and zero them

then take a measurement

that is more or less on the datum line of the case shoulder

You keep track of the measurements from new cases through the firing where the case gets hard to chamber and develops the "crush fit". The thing about brass is that it expands and then "springs back". That is what enables you to shoot and then extract is that little bit of clearance you get from the springback. The more you fire, the more the brass gets work hardened and the less it springs back until the case and chamber are very close to the same size and the case gets tight in the chamber.

Results vary depending upon your chamber, the brass and the load but here are some measurements that I have found to be typical in my chambers:

Steyr 30-06 Nosler brass 200 gr Accubond 60 gr RL22
New brass - 2.040"
Once fired - 2.0485"
Twice fired - 2.050"
3 times fired - 2.0510" (slight crush fit)
4 times fired - 2.0515" (crush fit)

Then it is time to push the shoulder back and you can use your gauge to set the die up so that the shoulder is exactly where you want it, either Full Length Resized with no contact at the shoulder or Partial Full Length Resized with a slight crush fit.

Then you can use a Comparator set, modified case and overall length gage to set the seating depth so you can control the bullet jump.

Piece of cake, all it takes is money!

Is that enough "thingy's" for you to get upset about H C?

11 March 2008, 18:11

Hot Core

quote:
Originally posted by woods:
Is that enough "thingy's" for you to get upset about H C?

What do you mean "get upset" Pilgrim?

That sure is a herd of Thingys.
-----

I've been giving serious thought to becoming a Thingy "supporter"!

12 March 2008, 04:41

JAL

quote:
Originally posted by YUMAN:
Sometimes PFL dose not work.

You didn't do it right IMHO. You've PFLS'ed just when the case just fits in the chamber. Doesn't matter where the die happens to be.

Eg with a Hornady die my PFLS is when the die is touching the shell holder. With a Lee FLS die it's well above the shell holder, (which happenes to be a Lyman.)

The PFLS position for the case is a very small nip down of a die.

I've also had to FLS a case twice, after a 180 deg. turn to get it into a target chamber.
The point being the case IS then still PFLS'ed.