Latest Installment of Am I Going to Die

[atblis]

or perhaps lose a couple fingers.

On my Remington 700, I threaded on a new to me (take off barrel) 300 RUM Christensen Arms CF. I think the barrel came off a Christensen Arms rifle originally ( Ridgeline perhaps?).

Hand tight, on a .190" lug, the bolt closes on a GO gauge. Oddly enough, sometimes with no resistance at all, sometimes a little. Ejector and striker are removed. Makes me wonder if I should get the action trued up.

Torqued down with a vise and action wrench, barrel rotated maybe a 1/32 of a turn passed hand tight, it barely doesn't close on the GO gauge now.

However, bolt closes with zero resistance on new Norma brass.

Supposing I never intended to shoot factory ammo, is there any reason I can't just roll with?

Also wondering if some light lug lapping might get me to close on that GO gauge. Based on wear marks, I don't believe the lug engagement to be even.

Checking bolt nose clearance tonight.

Flamesuit donned.

 

[spitfire_er]

Sounds a few thou short of an "in spec" chamber. The correct answer is set the barrel back one or two thou and recheck with gauges.

Non PC answer. If you hand load for it, and form the brass, it won't matter. If you plan to ever sell it, the next guy may be stuck with excessive head space if you aren't around to disclose its measurements.

 

[atblis]

It's too tight. Doesn't quite close on a GO gauge. I think a 0.194" recoil lug would do it. Problem is I have 0.190" and 0.200".

Reading about lug lapping, it seems that it doesn't do quite what one would expect on the 700, and might be more cosmetic than anything. Interesting. I might try it with some fine grit just to see if smooths out the action.

 

[spitfire_er]

Sorry, have'nt had coffee yet today.

When you say " barely doesn't close on a Go" , meaning you can close it with some pressure?

I'd run with it if your brass fits fine. You should now have a zero headspace chamber. Factory brass "should" fit in there. Lapping isnt going to get you much, but may take a few tenths off unless you want to spend all day lapping.

 

[atblis]

No, I don't ever force them. Torqued up, It closes except for maybe the last eighth inch. Torqued hand tight, most of the time the bolt would close with zero resistance. I always do this first just to make a guess if it's even worth bothering putting in the vise/wrench as is. I say "most of the time", because if I fiddled with the gauge a bit (rotate the gauge on the bolt, etc.), some of the time you could feel resistance. My guess is that I am about 0.002" tight.

 

[atblis]

Interesting, as I read it, the GO gauge is the minimum for accepting SAAMI max for ammo.

 

[linebaugh]

That is an exellent chamber. You got lucky there. Brass will size to the chamber on the first firing so thats not an issue at all. After initial firing set the dies to set your shoulder back .002ish or as desired and enjoy.

 

[Dusty Stevens]

With a chamber that short your dies may not set it back far enough

 

[atblis]

I suspect they will. I have a another 300 RUM that won't close on the no go, and even with a +.010" shell holder, I get 0.003" of bump.

 

[INTJ]

As long as the brass fits and your dies bump the shoulder enough you are fine using that brass. I have a BR rifle like that right now--it doesn't fully close on a go gauge. It did in the lathe but when I torqued the barrel it wouldn't. (I am still refining my chambering skills.) Brass fits fine and the rifle shoots well.

Be careful on lapping the lugs to gain headspace. That can mess up primary extraction. A thousandth probably won't hurt anything.

 

[atblis]

Yeah, not going to mess with lapping at this point. Too much risk for too little reward. Honestly both my RR prefix 700s at this point have exceeded my expectations. I've been messing around with takeoff barrels. At some point a topshelf barrel will be put on by a smith.

Just took the fired brass from the previous barrel and sized it with a Redding full length S die. Worked my way down the Redding competition shell holders until the brass chambered (starting at +0.010"). The +0.004" seemed to do the trick.

We'll see. I bought this barrel knowing it was taken off because it didn't shoot well.

 

[tmwinds]

If it closes on a factory round you are good. If you need to bump the reloads a little more to fit, do it. Nobody shoots a go gauge.

 

[joshb]

I’d run with it.

 

[Nightraider]

I'd run it