Need help with Headspace and/or barrel swap

Yes, I know I need to get a Go/No go gauges but they won't arrive for awhile.

Got a new model 10 fcp in 300 wsm. First thing was to get a brake for it. Being the goof that I am I took off the barrel without taking the front scope base off and flattened the barrel threads a tiny bit, not really an issue but ...
Just got the barreled action back from the smith and he did an awesome job with the brake. He said he didn't have the gauges or a cartridge to set the head space and left the nut loose.
Using a cartridge I got it to where the round chambers freely and with 1 piece of scotch tape its VERY tough, and with 2 pieces theres no way to close it.
My issue is this.... I did use a cartridge (rifle has never been fired so couldn't use once fired) and now the rifles cartridge designation " savage mod 10 300wsm ..... " is now hidden in the stock in the 12o clock position.
Can this be right? Safe?
Whats your take on this?

Sounds to me like you have set the space tighter than it was originally. This is not necessarily a bad thing, I tend to sent my chambers about as tight as I can get them and still function properly. It helps with my case life and case stretch.

New brass tend to be a bit smaller than a Go-gage and cheap scotch tape tends to be .002" thick, so this will result in a slightly tighter headspace over the gages that are normally designed for a .004"-.005" difference between Go and No-Go.

Now figuring the distance you are smaller. Barrel threads are 20 Threads Per Inch (TPI). So 1 full revolution will move the barrel .050". From your description it sounds like your barrel is rotated roughly 1/4 turn from its original position, so that would be .012" tighter. If Savage set the headspace closer to the No-Go then your barrel may have been factory set +.005" and then if your brass is say -.005" on the small side (some may be even more under) then from factory spacing you could be .010" tighter, give or take under the very loosest your headspace was originally set.

So basically you just went from being on the loose end of the tolerence to the very tightest end of the tolerence.

No matter what, its your rifle and your face behind it when you shoot it, so if you have any doubts, wait for the gages.

I am assuming he used a brake that did not need timing.
Put you rifle on half safety and try to make it fire. If it will not, then pointing the rifle in a safe direction like in the dirt chamber every round you have. If all go then be done with it and know that you set the headspace for the cases you are using. Like Boots, I like chambers set on the minimum. sounds like you have the tools to change it if you need to down the road.

Remember this...

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No matter what, its your rifle and your face behind it when you shoot it, so if you have any doubts, wait for the gages.

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+1 Good advise from both.

hmmm

Thanks for the advise gents.... after the first post and before the rest I already had loosened it back. There's just something about making a man imagine a rifle blowing up in his face that makes him stop and say "whoa.... wait a second".

Though it would have cycled every round without flaw the fact is not every manufacturer have the same tolerances. Minimum is probably the better way to go.

If anything loosening it will cause the gun to blow up. Guns do not blow up from having tight headspace, they blow up when the case isn't supported when the headspace is too loose. The problem comes from too loose of headspace, not too tight.

How do you know that when the writing is lined up you are not .050" too loose? If you tried to fired it, and if it went off, you would have some serious issues. Are you more worried about the writing on the barrel lining up or about your health?

I would do like you originally did using tape and call it good for now. I suspect when you get the headspace gauges the writing will not line up like before either.

I think he was concerned cause it lined up from the factory, before the brake was installed. Valid concern, considering NO gauges were used to set it by him.

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Originally Posted by handirifle

I think he was concerned cause it lined up from the factory, before the brake was installed. Valid concern, considering NO gauges were used to set it by him.

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i agree handi, The issue I see with all of this is that the headspace may have been excessive from the factory. As boots suggested it is probably over .012" longer with the factory setting. Lets hope that 1) the factory ammo does not vary that much and 2) he caught a factory screw up before he had, albiet an outside chance with new brass, a head seperation. It is probable or at least possible that the ammunition he bought was sized on the minimum and the factory set the chamber at the maximum accounting for some of that difference.

Anyhow I still contend that the closer setting is preferable to the wider demesion.

Tagged for when my new barrel gets here, thanks for the info gents, I will be doing a 300 win mag, I plan to make sure its tight as it can be against the belt, correct? I have 4 different gauges but none in 300 wsm or I would send you one to use Steven.

I have started setting headspace like this. I measured a ton of different kinds of paper for thickness until I found the one I wanted. I took a hole punch and punched out a few hundred and keep them in a small bag with the gun I use most often. Yes I swap often. I will take a piece of confetti and drop it inside the bolt head, insert a piece of sized brass or the ammo I plan on shooting into the bolt, hold it in place until I snug the barrel down then I tighten the nut down. I have another bag of confetti that is my "no go" guages. I repeat the process except the bolt should not close.

I either set headspace without the paper on my sized brass or I will use the confetti to give me a little leeway. The piece of paper I use to set is .0015" thick. The one I use as a "no go" to check is .006".

I have talked to friends, but never personally seen it, where factory ammo is pretty far out of spec. It wasn't that it was too big but too small.