I just joined this forum, but I have been around guns my whole life. I just recently purchased a Savage 11VT from Dick's in .243. I purchased it with the intent to change the barrel to an aftermarket 7mm-08 barrel. I removed the old barrel and started taking some numbers off the receiver to figure out what I want for go gauge protrusion once the barrel if fully chambered. Well, with the go gauge in the factory barrel, I get .1249" of protrusion. If I take my measurements, I get .109" of go gauge protrusion. Here is how I calculated it, maybe I'm doing something wrong. From the face of the receiver to the the bolt face I got a dimension of .797". From the face of the receiver to the front of the bolt I got a dimension of .688". If I minus .688" from .797" I get .109". I'm tempted to just go with the factory dimension of .1249", but would like to know what you guys think and If I'm doing something wrong to figure out go gauge protrusion.
Thanks,
Frank
I am not a gunsmith so i am just going by what i read. But i believe a .01 clearance from the breach face to end of bolt face is the norm. So .016 for a factory barrel is probably within the acceptable tolerance. You have not mentioned anything about a clearance so i think that is you discrepancy.
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I haven't mentioned anything about clearance due to the fact of the numbers being so far off. I don't see .001"-.002" clearance making that much of a difference in this situation.Originally Posted by MI223
I am saying that at 109 there is no clearance between the breech face and the face of the bolt. I believe the standard is .01 clearance. That would mean. 119 protruding. the .006 variation is probably do to factory tolerance.
Hope this makes sense
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I got what you're saying, standard clearance is .001-.002". so let's say I add .002" to my .109" number, I get .111". So .1249" (let's call it .125" to make it less confusing) .125" -.111" = .014" not .006" difference. Am I adding and subtracting my numbers correct LOL! I've always been bad with thousands. I really appreciate all your help so far.
Maybe I am too simplistic.
Get barrel, get GO 7mm-08 gauge, put tape (scotch for tight, freezer for loose) in gun, screw in barrel until it touches the gauge, set nut, check, if full bolt close, add a piece of tape (scotch) if still loose undo nut, repeat until the GO gauge closes almost all the way or all the way, tight on the no go tape.
Add ammo, got shoot.
LOL!, that would be the way to do it if the barrel I have was already threaded and chambered. I have a 7mm barrel blank which needs to be threaded and chambered. I need to know the correct go gauge protrusion so I know how deep to finish ream the chamber. Thanks for the reply though, greatly appreciated.
MI223 is giving good data but I feel like something is missing at the same time i feel like it is a known. What is the depth of your bolt head? It should wrestle around at .120 +or-. this is important becase of the nose clearance of wht MI223 mentioned and the ability to make head-space. So if your bolt head depth is .120 and your gauge protrusion is .130 you will have < .010 - nose clearance at correct head-space
The Dunning-Kruger effect is alive and well.
Unless you are looking to shoulder up the barrel like a Remington you're greatly over thinking this. The beauty of the Savage barrel nut is that the headspace is adjustable. As such the only measurement you need to worry about with your barrel is how much the go-gauge protrudes from the breech, which should be 0.120 to 0.125" according to factory specs. Most pre-fit barrels I have received were made closer to the 0.125" mark to allow for some wiggle room. Again, the nut allows you to adjust it to match your bolt head depth so it's not as critical as your making it out to be.
So as MI223 pointed out, your zero clearance 0.109" measurement + the standard 0.1" minimum clearance = 0.119". Likely your bolt head or receiver face is short 0.001" (again, within a tolerance range) which would get us back to the 0.120" reference I gave above. The 0.006 he referred to is adding that missing 0.001" to the factory allowed 0.005" tolerance which gives us the 0.120-0.125" range previously mentioned.
Robinhood, let's clean the slate and start over. If I have an action on my bench and a barrel blank, how do I go about finding the go gauge protrusion? Once I know that dimension, I'll know how deep to finish ream the chamber.
Thanks,
Frank
70oldsracer, if you have your bolt assembled and action cocked you will get a short measurement from the action face to bolt face. Sorry in advance if you know that already.
Edited to say I would establish GGP just like you are.
a ha. My bolt was cocked. I'll take some new measurements when I get home.
Thanks
This!
That all makes sense to me, because the go gauge protrusion on my take off barrel is .1249. I'll just cut the chamber on the new barrel to have a GG protrusoin between ,120 and .125" and call it good. Thanks guys, I guess I was over thinking it. It looks like I actually misread MI223's measurement of 0.1 as .001. That's why the numbers didn't jive. Oh well, my bad. Thanks again.
Got it, new one to me but then I don't do chambers or threads.
Definitely what you would call build it yourself.
Get a Button rifling machine and .......
Very simple answer.
Yes. You were way over thinking it.
With the Go Gauge sticking out the back of a finished Savage barrel chamber, it should measure.125" to .130". No less than .125", no more than .130". Like the barrel that You now have. .1249" is close enough ;-)).
None of the rest of Your measurements mean anything. :-))
Edit: My bad:-((. I didn't read all of Mr. Furious' post. I have 16 Savage barrels...stock, custom, and drop in. All of them have Go Gauge protrusion of at least .125". Some plus .001" or .002". All of them work just fine. If I were to thread and chamber a barrel, I would shoot for .125"...:-))
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