savage chambering with nut - I know, I know....

S

savet06

Mike Suhie
So, for my first chambering job on a scrap barrel I have a 300WSM reamer from a reputable source and go and no-go gauge from same.
I did not intend to shoot this barrel, but wanted to go through the motions of crowning, threading, and chambering as though I were. I am chambering in a steady on the ol' SB 9" that I cleaned up, painted and got back to working order.
I really enjoyed the process and ended up with a pretty decent thread fit and chamber finish.

My question is relating to the headspacing of the round on this action, a large shank type. I have another barrel for this action that was chambered by a well known smith in 6br and I have the same issue which is:
With the go-gauge in the action I screw it onto the barrel until i feel a positive stop. I advance the action an 1/8th inch or so to compensate for the movement that occurs when tightening the barrel nut (next time with a shoulder, I promise!).
Tighten the nut and put the no-go gauge in which shows no resistance at all and the bolt closes. I loosen the nut and advance the action on the barrel a little more and check the no-go gauge with a barely tightened nut. It doesn't go, but the bolt won't close on an empty chamber either - i.e. the face of the lugs are contacting the barrel during the closing action.
After several attempts at trying to get it just right I find a place where, on an empty chamber, I feel the bolt face just kiss the barrel at the very end of the closing action.
I put in the no go-gauge and it shows no resistance at all. Un-fired case also feels the same way.

I put a piece of scotch tape on the back of the no-go gauge and effectively lengthen it by .002 to .006 over the go-gauge length. That length will not allow the bolt to close at all, but the bolt is still just kissing the barrel at the end of the closing action.

I have measured the front face of the lugs to the bolt face and get .120 - and then, from what I have read, I added .005 (the exact same amount of case protrusion from said smith on the 6BR) and chambered the barrel for that amount of case protrusion.

Do I need to shorten the chamber by another 1 or 2 thou or is this just something that I have to live with?
Thanks for your help.
Mike
 
Thanks, Al.
So I am essentially adding an additional .010 to the lug face to bolt face dimension for a total of .130 protrusion from the back of the barrel, and that extra .005 won't have any effect on the web of the case during firing?
I know that you like to run your chambers on the fat side at the back side anyway. As I get further into this I will be following the advice you gave me previously about the .300WSM.
Thanks again,
Mike
 
Went back and remeasured my depth and there must have been a chip or something in the chamber from my last facing cut. Long story short needed to take off that additional .005 and the length of .125 was right on the money with no bolt stick. Thanks again.
 
Yup. that is why I am taking my time and working on scrap before I go to the real thing. Even as slow and as cautious as I went such a simple thing can cause quite an issue.
I will be ordering a barrel in the near future and try it out for real.
Ron, I hope that I can run the specs by you before I screw it onto the action. From what I can tell I have about .002 TIR at the back of the chamber. I am hoping with a better fit on the bushing (the barrel was a kostyshyn and my bushings were too big for the very last part of the chamber) and going slower with my cuts to improve that, but I certainly don't expect much on my machine and experience.
Mike
 
LOL! I hate measuring stuff.....which is why I build falsies and gauges for everything.

al
 
The Savage spec. for the large shank barrel is .130" max from bolt face to barrel.

RWO
 
Mike,
I can bring over my bore scope & we can give the throat & crown an inspection. It might cost you a cup of coffee.

I would think you could strip the ejector & extractor out of the bolt head & just hold the bolt against the headspace gauge in the chamber to get the clearance. Use a feeler gauge to measure the clearance & deepen the chamber until you get the clearance you want. Go too far, you just face of the barrel a bit. The flat bolt face simplifies the job.

You might even be able to use a piece of feeler gauge between the barrel & bolt head to set the clearance when you tighten the barrel nut. It would probably take a few thousandths thicker feeler since the barrel might move with the nut a bit.

I've seen several Remingtons that had locktite on the factory barrel threads. If Savage did this then they could tighten the nut without moving the barrel. Just speculating, I've never done a savage.

Regards,
Ron
 
Wanted to post an update on the 300wsm project.
Went to the range today and shot the green mountain 1.2" straight taper 1:10 barrel for the first time. I was able to achieve <.001 runout at the back end of the chamber FWIW, and the crown came out great if I do say so myself.

Did a pressure test of one shot each of 65-69gr H4831 in 0.5gr increments and the shots with 66, 66.5, and 67gr all went into 0.25 ctc!! From there the rounds strung vertically into 0.75'ish with no signs of pressure.
And, more importantly, it didn't blow up! (I did stand back from the gun and might have closed my eyes when the first shot went off)
I do shoot competitively for short range score and I know that 3 shots does not an agg make, but I am PUMPED! For $150 barrel blank and my first chamber job I couldn't be happier. Multiple 3 shot groups under 1/2" and the gun is a pleasure to shoot - at close to 20lbs it should be.

I was shooting 168gr Berger Hybrids 0.005 off the lands ahead of 65gr H4831 for the initial load testing. Also tried some 125 nosler BT's and Berger 115's (I ran out of H4831 and had to try Varget - results were OK - 1:10 twist for the barrel and a powder charge that might need some boosting to get it to ideal, but still had some decent results.)

I have some 178gr Hornady's to try next and to try to zone in on what the 168's like now that I have more H4831. The throat is a bit short for anything longer than the 178's, but a buddy of mine (RJM) has a uni-throater and maybe we can stretch this round out a bit.

Thanks for all the advice!
Mike
 
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Congrats

Mike,

Congratulations on the WSM build, sounds sounds as though you have a shooter. With a WSM you may have to come out Williamsport and try it at 1,000 yds.

Regards,

Dave Burkart

savet06 said:
Wanted to post an update on the 300wsm project.
Went to the range today and shot the green mountain 1.2" straight taper 1:10 barrel for the first time. I was able to achieve <.001 runout at the back end of the chamber FWIW, and the crown came out great if I do say so myself.

Did a pressure test of one shot each of 65-69gr H4831 in 0.5gr increments and the shots with 66, 66.5, and 67gr all went into 0.25 ctc!! From there the rounds strung vertically into 0.75'ish with no signs of pressure.
And, more importantly, it didn't blow up! (I did stand back from the gun and might have closed my eyes when the first shot went off)
I do shoot competitively for short range score and I know that 3 shots does not an agg make, but I am PUMPED! For $150 barrel blank and my first chamber job I couldn't be happier. Multiple 3 shot groups under 1/2" and the gun is a pleasure to shoot - at close to 20lbs it should be.

I was shooting 168gr Berger Hybrids 0.005 off the lands ahead of 65gr H4831 for the initial load testing. Also tried some 125 nosler BT's and Berger 115's (I ran out of H4831 and had to try Varget - results were OK - 1:10 twist for the barrel and a powder charge that might need some boosting to get it to ideal, but still had some decent results.)

I have some 178gr Hornady's to try next and to try to zone in on what the 168's like now that I have more H4831. The throat is a bit short for anything longer than the 178's, but a buddy of mine (RJM) has a uni-throater and maybe we can stretch this round out a bit.

Thanks for all the advice!
Mike
Click to expand...
 
Mike deserves a lot of credit. A newbie, he rebuilt a WWII vintage south bend lathe so that it's very nice, learned to grind his tools, and cuts nice threads. We inspected his 300 wsm chamber, throat, & crown with my bore scope - they looked up to snuff as well. The green mountain looked quite good for a production barrel, better that the usual factory barrel. Not surprising that it shoots well.

Also, he just got this lathe a year ago & did all of this in a year! So watch out, he's an up'n comer!

Regards,
Ron
 
Thanks for the kind words, guys. I couldn't have done what I did without the help of this board and a lot of youtube videos!
I am looking forward to many years of learning more and opening my benchrest passion up to a whole new dimension.

Dave,
I don't know if she would cut it in true competition, but I wouldn't mind stretching it out to a 1,000yds and give it a go. I am not one to brag/claim about the "1/4 minute all day long capability" of any of my guns, but I felt like a kid on Christmas when I shot it for the first time.

Thanks again,
Mike
 
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