Headspace question, 22-250 and brass life.

[Texas10]

Well, I set the headspace with the gage, but set it a bit tight. Bolt closes about half way on the gage and get tight. It closes easily on the unfired, Lapua case, and closes with a little effort on the case with one layer of scotch tape. So I am just under SAMMI spec by about half a thou, maybe a full thousandth.

If I read it correctly (m12lrs) , it comes down to FL sizing die adjustment, and I think I've got that down pretty good now. Thanks for the responses, guys.

Gonna take it out Thursday and see how it shoots the 80 grain A-Max.

[darkker]

Nature of shallow shoulder angle, tapered body, high pressure cartridges. They all do this, the brass flows. Going AI reduces this.

+1 Yes indeed.


Case head separation is caused by the case being undersized in the head space dimension, or from base to shoulder. When the case base to shoulder dimension is shorter than the chambers bolt face to shoulder dimension the case grows just above the web area.

Brass flow, where the neck gets longer does not cause case head separation. as Scott said sharper neck angles reduce or practically eliminate the flow.

I would add, although may not apply to this particular loader. Federal is well known to have dangerously soft case heads. They like very soft brass for case obturation and accuracy. While that does work, it is at the price of very short case life.

[FW Conch]

^ Does this mean that a fire formed case, neck sized and reloaded, is a good thing? ^

[m12lrs]

^ Does this mean that a fire formed case, neck sized and reloaded, is a good thing? ^

you can neck size only until the cartridge will not chamber. That depends a lot on the cartridge and how hot you load it. Then you will have to at least bump the shoulder if not full length resize.

[darkker]

^ Does this mean that a fire formed case, neck sized and reloaded, is a good thing? ^

I agree with M12lrs above. But in the case of extra soft Federal heads; yes.
I'm not saying that they ALL are bad/dangerous/etc, but have found many more than I care for. We've had them seperate while testing with the Pressure Trace too.
Personally I took a hammer to any remaining that I found. Assuming a decent rifle and not over-loaded, head-seperations aren't typically a terrible event. So use them, don't, whatever makes your day. Just be aware that a seperation with one isn't inherently from pressure.

[FW Conch]

Obturation is the subject for another thread. Don't want to hijack this one.

I avoid Federal brass also.

[Iowa Fox]

I measure the base to datm on brass before firing and them after firing to establish a baseline before doing anything, well unless I use a gage which I measure also. I quit using an expander ball in resizing dies years ago, all they do is stretch necks and make them crooked no matter how well the ball and inside of the neck are lubed. Before headspacing I also try a piece of fired in the gun brass to see what the dies are capable of.

[Texas10]

Range report:

I shot the new barrel using a load work up with 80 gr. A-Max and H-4350, and I have to say that setting the headspace close was a good move. All of the shot brass measured exactly what it did before shooting.

I was able to re-chamber the ejected brass easily so this may just do the trick and extend my brass life.

The 4350 shot very well, right up to max book load. No primer, or other signs of excessive pressure, and although the Magnetospeed said I was about 100 fps over book velocity, my barrel is also 4 inches longer than book.

Interestingly, I took my bore scope camera with me and performed a before and after view of the chamber/throat at the first shot. It's amazing how much the first bullet knocks down the lands in the leade. I noticed this on my new Criterion barrel too. Big changes occur during that first shot.

[FW Conch]

^ That's what I'm talkin about! ^

[bootsmcguire]

^ I like the way You roll "boots" :-) ^

Thanks, for me I just found it was a lot less work to set the barrel once to match the dies rather than try to set the dies to the barrel. If I had a Remmy then by all means setting the dies to the barrel makes complete sense to me because of the inability to adjust headspace, but with Savage its adjustable so might as well utilize it. I know that doing it the way I suggested is not everyone's preference, but for me its simpler, makes the handloading process faster and accuracy seems to be comparable if not identical in my experience.

OP, glad to hear your results thus far.

[darkker]

Range report:
The 4350 shot very well, right up to max book load. No primer, or other signs of excessive pressure, and although the Magnetospeed said I was about 100 fps over book velocity, my barrel is also 4 inches longer than book.

Just remember that you also don't have a SAAMI minimum spec: Bore, Groove, Chamber, as was used in the universal receiver used to determine pressure either. Perhaps the barrel length would add something, but don't expect a miracle from it.
If you are happy, fantastic!! Just remember "signs" aren't accurate, but your chronograph is.

[Scott Evans]

Wouldn't get too concerned with 100 fps difference, Magnetospeed is like 4" from end of barrel at first timer, chronos used in lab load dev are going to be further away and I have no clue if they use a conversion to MV or what, I suppose its all spelled out in the SAAMI spec, anybody know? You can easily lose 100-150 fps from actual muzzle to 6 to 10 ft away.

[darkker]

I think it's everything, but at least on pistols SAAMI uses 15' from the muzzle.
Unless you are shooting a pie plate, there isn't any match bullet fired from a 22-250 that is going to lose 100-150 fps in 10 feet. Don't think any bullet anywhere would lose that much velocity, but don't have my ballistic calc on this phone.