Go no go Gauge mischief

[AbitNutz]

So I was checking two Savage rifles for headspace. Those of you familiar with Savages know that the barrels use a barrel nut system. That's a good thing. You can alway make your headspace right.

One rifle is a 300 WSM and the other is a 300 Ultra Mag, not puny cartridges. I plunk in the Clymer go gauge on the 300 WSM and it goes. I plunk in the no-go and it...goes...whoops. I'll have to play with that one a bit. I do the same to the 300 Ultra Mag and...it does the same thing.

Uhmm...I'm wondering what to think about this development. I can clearly adjust and fix it but it makes me wonder if someone removed the barrels on these and eye balled them back on. Neither rifle shows much use at all...

[HollowPoint]

I'd say just adjust your head-spacing on both and go from there. The reasons for them being off could be many. Perhaps whoever did it initially used two different brands of head-spacing gauges. If it was done this way from the factory, maybe they did it late on a Friday afternoon just before a major event in their lives or on a Monday morning after a major drinking binge. Maybe (just a shot in the dark) they didn't tighten the barrel nuts tight enough and they somehow backed off just enough to allow the barrel to bring the head-space out of spec. Maybe they tightened the barrel nut to tightly and it drew the face of the chamber forward a bit to much drawing the head space out of spec. Who knows?

Once you reset the head-spacing to the correct settings the reasons they were off in the first place will instantly become a mute point. You should be good to go from there.

HollowPoint

[Bent Ramrod]

Did you remove the extractor before checking the headspace? If that is not done, erroneous readings will result. Don't ask me how I know this.

[AbitNutz]

Extractor? I can see the plunger type ejector causing some grief because it is pushing against the gauge. The gauges have an extractor groove in them so I'm not sure what good removing the extractor will do...although I've heard people doing that for convenience.

[AbitNutz]

So I removed the barrel on the 300 WSM. I happened to have a Northland barrel nut and recoil lug so I might as well use them. I used the Clymer Go-No-Go gauges and confirmed that the No-Go would indeed go. I removed the barrel, it came off easily using a Northland action wrench and barrel nut wrench. I cleaned all the threads and then hit them with some nickel based anti-seize, since all parts involved were stainless steel. It all went together fine, I adjusted the barrel using the gauges and confirmed that the Go would Go but the No-Go would not. I then chambered a factory 300 WSM round and it chambered perfectly.

So it would seem that I have tightened up the chamber a smidge.

I attempted to do the same thing to a Savage 300 Ultra Mag I have but I found out it has a small shank receiver and the barrel nut I had on hand was a large. Let me repeat that. The 300 WSM has a large shank receiver and the 300 Ultra Mag has a small shank receiver.

[leadman]

I have heard of the variation in use of the different shank sizes before. Might want to check with Savage on this.
It is possible that the headspace gauges are off a bit.
Did you check the locking lug area in the receiver to see if the lugs set back in the receiver at all?

[AbitNutz]

They both look good. Like most high powered rifles, they don't appear to have been shot much. The cost is key. The cost of the ammo and the cost of the recoil on your shoulder...

The lugs on both rifles look good...

[BK7saum]

I would be curious how excessive the headspace was. Would a field gauge have passed? Scotch tape is about 0.002" If this happens again, add a piece of scotch tape to the gauge and check again. Then you may have a better idea what the measurement actually is. Was it 0.0005" or 0.005"?

[tomme boy]

Did you force the bolt down? Or feel ANY resistance when you checked the NO GO? If you feel any resistance then it was OK

[jmorris]

So it would seem that I have tightened up the chamber a smidge.

Had you put witness marks on the receiver and barrel so you could know how much you turned it it, once you calculated the angular relative movement with the threads per inch of the barrel/receiver, you would know how many thousandths a "smidge" is.

[AbitNutz]

Had you put witness marks on the receiver and barrel so you could know how much you turned it it, once you calculated the angular relative movement with the threads per inch of the barrel/receiver, you would know how many thousandths a "smidge" is.

I was going to do exactly that but it just didn't happen. I'm pretty familiar with removing the barrels on my Savages. I didn't pressure the no-go gauge. The bolt went down with the same amount of pressure it did without the gauge.

[NoAngel]

Obviously, you're a handloader. Do you own OTHER rifles in those calibers? If not and you have been shooting them already, I don't think I would mess with a gun that shoots well. Unless it's just WAY out, a bolt action ain't gonna matter a whole lot SO LONG as you are shooting fireformed brass and neck sizing. OR using a case gauge and only setting the shoulder back a couple thousandths.

Were it mine and not showing any accuracy problems, I would check the barrel nut torque to make sure it ain't loose and roll with it.
I would assume, though I have no experience with those calibers, that barrel life is limited anywho.