I'm still new to reloading and I have a question about my headspace (on my rifle). I fired off a primed but otherwise empty cartridge and noticed that the primer had moved out of its seat a small amount. Can that amount be a rough measurement of excess headspace?
I'm shooting a rolling block rifle with a rimmed and bottlenecked case. Would the best/easiest way to correct excess headspace be to leave the shoulder forward during re-sizing and only neck re-size? That way I figure I can avoid nearly all case stretching. I would end up controlling headspace off the shoulder even though its a rimmed case.
You may be new to reloading, but you understand the concept of headspace much better than many veterans.
Yes, the backed-out primer fired by itself represents, though not perfectly, the headspace with that particular case.
Yes, it doesn't matter if the case is rimmed, rimless, rebated, or belted, you can still set your dies to headspace on the shoulder of a bottlenecked cartridge. This is ALWAYS better than headspacing on the rim or belt. With a full length die, simply turn the die down in the press progressively and resize to the point that the fired case reenters the chamber with reasonable ease. There you have it -- perfect headspace.
Posts: 13236 | Location: Henly, TX, USA | Registered: 04 April 2001
That always happens on an empty case and that amounts to the exceptable headspace in the caliber......
When setting the shoulder be sure to bump the shoulder enough that feeding is more than easy, if you intend to hunt dangerous game, in fact thats the time to headspace on the belt, feeding is a prime factor under these circumstances and balistic retterick goes out the door....Run every loaded round through the gun before hunting...
Ray: How can feeding be "more than easy"? And although "exceptable" headspace might also be "exceptional" headspace, the only "acceptable" headspace is that which is tight enough that the case does not stretch in the web area, thus promoting head separation at an early and unpredictable firing.
As I said before, only resize to the point that case re-entry into the chamber is reasonably easy.
It IS a good idea to trial chamber all of your ammunition used for serious hunting of any type (not just for those man-eating bullaphants that Ray hunts). But still, I'd rather risk a slighly hard bolt closure rather than a head separation -- the head separation putting your gun out of commission until remediated, as well as possibly squirting your shooting eye full of 50,000 PSI cutting torch-hot gases.
[This message has been edited by Stonecreek (edited 10-18-2001).]
[This message has been edited by Stonecreek (edited 10-18-2001).]
Posts: 13236 | Location: Henly, TX, USA | Registered: 04 April 2001
Since I'm shooting a rolling block rifle, good feeding to me means being able to close the breechblock far enough for the hammer to fall freely.
The only dangerous game situation I've ever encountered so far was when I was charged by a groundhog who was trying to get to his hole behind me. It was a tense moment to be sure...
But seriously, thanks to all for the advice which is well taken.
Let me try to help you here. It sounds like you are shooting a 40-65 or such. Rimmed cases and rolling block rifles are very much different beasts than bolt actions. Most of us who shoot these things in competition have learned some important facts. You want these guns to be set-up with about .002 inches of headspace, measured against a cartridge in the chamber and the block just closed against the cartridge. The type of brass you use may influence this measurement slightly. I use Federal in my guns. YOU should see the primer backed out a little if you fire such a gun without a charge and bullet behind it. NOT TO WORRY unless you see this on a fired round. THEN WORRY.You need to remove the firing pin to make this measurement properly. A feeler gauge is fine, but you must know how to completely take one of these things apart and put it back together. The cartridge is DESIGNED to headspace off the Rim forget about the shoulder! If you size your cartridges to snugly hit the shoulder I will guarantee that it will shoot poorly. You want the cartridge to easily chamber(literally drop in the chamber and the rolling block MUST close easily( NO force required) and just touch the shoulder or be bumped back .001. A tight chamber in these guns is literally the worst thing you can have.I'd talk to DAVE at Buffalo ARMS about loads and headspace. He's a world champion shooting Rolling blocks and Sharps at shilohets in 45-90. He knows these guns better than anyone else.-Rob
Posts: 6314 | Location: Las Vegas,NV | Registered: 10 January 2001
Robgunbuilder, The cartridge is the 8X58R Danish Krag. It looks like the recess in the chamber for the rim was cut extra deep, maybe because this was a military rifle and some extra room for dirt etc. was cut in. Without actually measuring, I'd guess the headspace is maybe .010. I will measure using a gage. But as long as the fit is no tighter than what you said, say .001 or .002, would it matter if I headspace off the shoulder vs. the rim?
I forgot to say, from what I've read so far on this forum, if you headspace off the shoulder, you are guaranteed the least case stretch. So as far as case stretch is concerned, headspacing off the rim can be made as good as off the shoulder, but never better?
[This message has been edited by gunboat (edited 10-20-2001).]
YES, bolt actions are a different breed because of their powerful chambering and extracting action. Single shots w/ rolling block or break actions etc. and lever actions and semi-autos need [relatively] easy chambering rounds. However, you can probably find a 'happy median' in partially resizing your brass where it's still headspacing on the rim BUT not pushing the shoulder back far enough to cause much case stretching [you might experiment a bit- for a start try putting a nickel on your shellholder and then adjust your full-length sizer die down to where it just touches it when the handle cams over then see how the brass chambers in your rifle. With trial and error you can probably come up with cartridges that chamber easily and stretch little enough to give you decent brass life].
