Headspace?

[M-61]

Would like some clarification:
Too little head space would cause the bolt to be very difficult to close and if it were really insufficient you would not be able to close the bolt.
Too much (excessive) head space allows improper support of the brass which could result in damage to the weapon and/or the shooter.

Therefore excessive head space presents a danger to the shooter whereas insufficient head space would cause an inability (possibly) to even fire the weapon.

I know proper head space is what you want....but is what I said on the right track or am I lost?

Thanks for the clarification...I know it was a general question....my may concern was bolt action but the knowledge that a semi-auto differs gave me a better understanding.

My project is a switch barrel Savage 12 Bench Rest currently in 6.5x.284...my goal to have a 30BR. Having never done this before I have read what I can, bought the required tools ( barrel vise, action wrench, go gauges, etc.) Because of Savages jam nut type assembly I see it as do-able. Concerns involving head space which got me confused although I now see that a semi-auto is what may have confused me. Now my concern is to successfully (without marring) breaking the jam nut loose and unscrewing the barrel from the action.
My idea is stamp a register mark on the action-jam nut-barrel in its current 6.5x.284 position...install the new 30BR barrel recoil lug and jam nut--mark them also when head space is set. I then think (?) I should be able to swap barrels quickly and safely by lining up the register marks. Does this seem like a workable idea? What pitfalls? Is it possible to secure the jam nut (JB-Weld) and then the register marks become merely a double check?
Anyone have experience with this project?

 

[clowdis]

Pretty much on the right track.

 

[kendog]

Would like some clarification:
Too little head space would cause the bolt to be very difficult to close and if it were really insufficient you would not be able to close the bolt.
Too much (excessive) head space allows improper support of the brass which could result in damage to the weapon and/or the shooter.

Therefore excessive head space presents a danger to the shooter whereas insufficient head space would cause an inability (possibly) to even fire the weapon.

I know proper head space is what you want....but is what I said on the right track or am I lost?

Thanks

Too little headspace on a gas gun (AR, Garand, M14 etc) could be far more dangerous than excessive headspace. You can fire a rifle that closes on a field gauge all day long and just suffer from trashed brass and lousy accuracy. An out-of-battery fire or a partial battery fire from a tight chamber in these guns can result in catastrophic failure.

 

[rayjay]

Improper resizing of the brass can create excessive headspace even if the chamber is within spec.

 

[M-61]

additions....

 

[NorCalMikie]

Since you're talking Savage, set the headspace where "you" want it. Mine are tight and I never plan to shoot factory made ammo. All are set on "full length resized brass". I have gauges but don't bother to use them anymore.
I shoulder bump, neck size and try every case that gets sized in the chamber to make sure there's no problems closing the bolt.
Lots of folks "full length resize" every time. I prefer my way and it works for me. (good thing we don't all think the same)
My brass lasts a LONG TIME and still is going strong after 20+ firings.
Once your brass is fireformed to "your" chamber, make sure you only size it enough to fit back in "your" chamber. Body size if it starts getting snug and you're good to go.
Resize however you choose and what works best for you.
As far as marking you barrel and action to go back to the same place for switching barrels, if you don't change anything else, it should work but, it's just as easy to reckeck the headspace to be on the safe side. YMMV, Mike.