I wonder if headspace changes over time with use of a rifle. Or if I get a gun with too much headspace, does that mean it was not put together correctly the first time?

500 grains---

Yes, it does change but the amount of change depends VERY much on how good it was put together to begin with, if it's shooting factory or fireformed cases, lube, pressures, and a hundred other things.

The BIG reason is--

How much running head start impacts the bolt??

Cases that fit the chamber seldom increase headspace. Those that have room to run can increase it rapidly.

Very interesting.

Then I would guess that high pressures combined with a running start would increase headspace even more.

500 grains---

When considering lug set-back think of the base of the case as a hammer and the powder colum as another hammer. The "powder hammer" has energy just like you'd swing one hammer and hit another hammer with it. The bolt face is *another* hammer. The lug seats are the anvil.

IF the the stack of three hammers are in firm contact with the anvil, the top, swinging "powder hammer", can have a LOT of energy before the anvil is dented. The more space there is between hammers the more denting, dinging, and set back will occur.

BTW-- that analogy works with the pressure curve too. A steep, sharp pressure spike is like a swinging hammer but the shove of a more moderate load will reduce the wear and tear on the action.

Question for Jack or ?? Is there a particular action/actions that are more suceptable to set back lugs than others?

Wstrnhuntr--

It's fairly rare in anything but the split lug actions......or at least it's rare to *notice* it.

With split lug actions the "one O'clock" lug (as sighting the rifle) has to over-ride the lump cast up in the ejector slot. It's very noticable at the very start of the bolt lift.

M-70 type actions still set back but it shows up as an increase in headspace that you have to find by gauge, or smoke signal. You can't feel it.

500 grains, just keep in mind that a perfectly fitting chamber in Salt Lake might give you a problem chambering when a cape is running at you in Africa. Remember the 1911 has to have one of the loosest chambers feeds and fires just about anything.

Jack, darn good word picture as per usual... I'm tellin you man, you ought to compile all your posts and arrange/rewrite them into a book... you could call it "Riles For Dummies." I'll be the first in line to buy one