Factory ammo specs--just what you'd expect

[hereinaz]

So, I did the unthinkable and headspaced off of a cartridge instead of a go gauge. I'm going to get a go gauge and do it right, but I wanted to break in the barrel today. The way I did it, I made sure that it was tight and there was no excessive headspace. And, I had a no-go gauge.

I intend to reload for the gun, and just bought a couple boxes of factory ammo to break it in, and get some brass fired in my chamber.

Because of that, I ran the headspace tight. The moral of the story is that some ammo loaded in easily and the bolt could just drop down to close. Some ammo, I could feel was tight closing the bolt.

Most interesting, 1 round would not chamber at all. They were all clearly within Sammi specs. But there was quite a variation. What probably made it a little more interesting was it was a belted Magnum.

So, this just goes to show that there is a reason Factory ammo doesn't group like real loads.

[squirrel_slayer]

that is pretty suprising for a belted cartridge. I planned on doing the same thing as I figured a belt would be more constant than a shouldered.

[Zero333]

I headspaced two 300winmags with factory ammo... but I made sure I used the ammo that fit the tightest, Which was Federal Gold Medal Match 190gr. And I chose the tightest fitting cartridge out of that box of ammo.

This does however require you to set the headspace twice. First time to find what is the tightest fitting ammo, and then of course the final headspace with that ammo.

All is good and perfect. The one rifle only shoots handloads with the occasional FGMM factory ammo, and the other shoots factory hunting ammo, mainly Fed Prem 130gr TTSX for deer.

[RC20]

Well its tight and that's ok. Worse is too much, then you get primer back outs and even failure to grasp some or all of the rims..