Headspace conundrum

[timo308]

Agreed. Only reason I asked was a quarter turn of a typical threaded Savage barrel (20tpi) would represent about 0.025 inch. That seems excessive. Am I incorrect in thinking the gage headspaces off the belt?

One complete turn equals 0.050 thousands, so a quarter turn will be off 0.0125 thousands.

 

[Barrelnut]

This is just what you will have with savage. If the lettering always lined up, you would be able to buy shouldered prefit barrels for the actions. You are only seeing the difference in tolerance of the parts made. I would bet that if you had 100 actions made at all differnet times over 30+ years that you would see more different places of the stampings. And I would guess that newer actions are more consistant than older actions for where the stampings line up.

^^^^ This ^^^^

 

[Rflshootr]

The bolt heads and the start of the lead of the threads vary from rifle to rifle so it will head space in a different orientation.

 

[cdherman]

Very interesting! Makes total sense. So, using brass fired at least once in a particular rifle, and head spacing off the shoulder, is the best way to build accurate hunting loads in my 300 Winmags? And, for new brass, it should be fireformed before building hunting loads? And…(for barrel nut users) headspace to the belt should always be set very tight to prevent any base stretch?

I would say yes, your most accurate loads, with the longest case life ( on average) will come with neck sizing (not a viable option in a hunting rifle, or PRS etc) or just bumping the shoulder back 1-2 thou.

Now there are lots of people that do otherwise. FL resize everytime. Win matches too. Pretty sure their case life is not what a more careful judicious bump of the shoulder will yield.

I have gotten some of the best accuracy through the years in a hunting rifle with once fired virgin brass (usually Lapua or similar) on the second loading. No tumble, just basic clean and reload. But you cannot have "second fired" brass forever.

I've been playing with pin tumbling, mandrel neck resizing, bushing dies, graphite lube of internal neck (to approximate the "natural lube" of the carbon from the burned powder). Its all a pursuit......

As for a Savage and a belt. Have not done one. Guess I would indeed thread it tight. But you really don't want to over-do things, lest you render your gun incapable with other ammo. Basic concept is that long term, the belt is not where you headspace. Some case length growth initially is not a problem. Its the long term effects of repeat FL resizing. Belted or otherwise.

 

[Highbrass]

Some great responses. This was just one of those second guessing exercises. You know how that happens, someone showed / taught you how it was supposed to be and you trusted it was "The way". Then you see something that makes you think wha?? Both my 300s shoot better than average so I'm not going to fret over it.
I have noticed the generous spacing on the shoulder for my 300s. Once fired i bump the shoulder .002 and call it good and load em up.