What are headspace specifications for 300WSM? how many thous' to lap lugs?

01 August 2005, 19:06

Question on headspacing:

I have an action that can close (tightly)after I place three layers of birchwood casy shoot-n-see stickers on the base of the cartridge. Decided I needed to check, after a misfire with shallow firing pin indent. There is a miced .018 behind the cartridge base, which I am pretty sure is too much. maybe way too much?

I did lap the lugs just until the second lug had >50% "shine". Suppose I could have taken off enough to make rechambering needed?

Was it a major mistake to lap lugs before shooting the rifle enough times to "Hot seat" the lugs?

thanks for info.

01 August 2005, 19:39

tsturm

I lap the lugs BEFORE chambering

01 August 2005, 20:29

Jameister

Too soon old too late smart.

01 August 2005, 20:47

tsturm

quote:
Originally posted by Jameister:
Too soon old too late smart.

In a nut shell that sums up my life

Good luck with your project!!

02 August 2005, 00:36

Rick 0311

quote:
Originally posted by Jameister:
Question on headspacing:

I have an action that can close (tightly)after I place three layers of birchwood casy shoot-n-see stickers on the base of the cartridge. Decided I needed to check, after a misfire with shallow firing pin indent. There is a miced .018 behind the cartridge base, which I am pretty sure is too much. maybe way too much?

I did lap the lugs just until the second lug had >50% "shine". Suppose I could have taken off enough to make rechambering needed?

Was it a major mistake to lap lugs before shooting the rifle enough times to "Hot seat" the lugs?

thanks for info.

Jameister,

Like tsturm said, you should lap the lugs before you finish chamber...and I also have to ask, what in the world is â€œhot seatingâ€ the lugs?

02 August 2005, 08:16

Jameister

Hot seating the lugs would be the difference between an unfired action and a fired action. I am just guessing, but I would think that a few firings of bullets with 50,000+ PSI chamber pressure would have some influence on lug-to-action seating. same as a few shots with a barreled action in a stock settles it in and requires a bit of screw tightening. Course if I knew what that was, I would be smarter than to have lapped lugs after a barrel was headspaced.

Still, what is the adequate headspace for a 300WSM?

02 August 2005, 08:47

Rick 0311

quote:
Originally posted by Jameister:
Hot seating the lugs would be the difference between an unfired action and a fired action. I am just guessing, but I would think that a few firings of bullets with 50,000+ PSI chamber pressure would have some influence on lug-to-action seating. same as a few shots with a barreled action in a stock settles it in and requires a bit of screw tightening. Course if I knew what that was, I would be smarter than to have lapped lugs after a barrel was headspaced.

Still, what is the adequate headspace for a 300WSM?

Jameister,

On a stock your theory is sound... but your stock isnâ€™t made of hardened steel like the locking lugs and receiver lugs are.

Just a stab in the dark...but I would think that your head space sounds a bit excessive if you can put three layers of tape on the case head and still close the bolt.

If you are asking for suggestions, I would recommend you take your rifle to a smith and have the headspace checked with the proper gauges, and adjusted if necessasry, before you fire it again. As you noted...thatâ€™s 50,000 plus pounds of pressure less than a foot in front of your face.

02 August 2005, 09:46

JustC

have the smith take a thread off the barrel lenght and it should be back to tight. If you have that much paper in the chamber behind the casehead, it sounds like too much headspace. Have you measured a fired and unfired case at the datum line? That will tell you how much your cases have to grow to blow the shoulder out to meet the chamber shoulder.

02 August 2005, 11:37

Grandpasez

If you reload you can back sizing die
off to make headspace tight for the case and your particular chamber.Ed.

02 August 2005, 11:52

Old Elk Hunter

If he has excess headspace and does as you suggest then all he is going to get is cases that are stretched too far and may have potential problems with case failure such as head separation. The wise way is to have the rifle checked for excess headspace and have the smith set the barrel back and chamber properly.

If he has normal headspace then what you suggest will adjust the die to the rifle rather than blindly adjust the case to hit the shell holder like the reloading books advise.

03 August 2005, 05:18

Jameister

I have talked to the company, described my concerns, and they asked me to send the actions back, for repair and consideration as "warranty repair" if it appears they were reamed long, or I will pay if they find that my lapping took off more than 1-3 thou'.

Jamie