Long Range Hunting Online Magazine


Go Back   Long Range Hunting Online Magazine > Rifles, Reloading, Optics, Equipment > Gunsmithing


Reply

Headspacing: Is GO gauge supposed to equate to never-fired brass?

 
LinkBack Thread Tools Display Modes
  #1  
Old 03-22-2012, 07:15 PM
Silver Member
 
Join Date: Feb 2012
Location: Remington County, PA
Posts: 383
Headspacing: Is GO gauge supposed to equate to never-fired brass?

I'm looking for the poor man's way to check for excessive headspace in a center-fire rifle. Obviously, the bolt should close without any resistance on brass that has never been fired. My question basically is: How thick of a shim can be placed between the bolt face and the fresh (I would try 5 to 10 of them, to establish an average) brass, before the bolt gets hard to close, or won't close?

If I punch out a round piece of aluminum from a can that is slightly smaller in diameter than the rear of the shell, place it behind it, and the bolt will close on it with only slightly more pressure, is that too much headspace? The aluminum is .004" (4 mils) thick. The gun (Savage 7mm rem mag) HAS had some pretty hot loads though it, one in particular that was way too hot, and roughly 500 rounds total through it.
Reply With Quote
  #2  
Old 03-22-2012, 08:47 PM
Gold Member
 
Join Date: Jan 2007
Location: Fairfax County, Va
Posts: 669
Re: Headspacing: Is GO gauge supposed to equate to never-fired brass?

NEVER use a brass case to check headspace. New brass is undersized so it should fit in any chamber, that undersizing varies from lot to lot from the same manufacturer and varies a LOT between manufacturers.
Take the gun to a gunsmith and have it checked if you are concerned, or buy a GO gage from Midway or some one else, they are about $28.00.
The GO gage can be used with a piece of scotch tape as a NO GO gage, the scotch tape adds about .0025 and the bolt should NOT close.

Dave


Search results for: go gage
__________________
"How a politician stands on the Second Amendment tells you how he or she views you as an individual... as a trustworthy and productive citizen, or as part of an unruly crowd that needs to be lorded, controlled, supervised, and taken care of."
--Rep. Suzanna Gratia Hupp (TX)
Reply With Quote
  #3  
Old 03-23-2012, 02:01 AM
Silver Member
 
Join Date: Feb 2012
Location: Remington County, PA
Posts: 383
Re: Headspacing: Is GO gauge supposed to equate to never-fired brass?

OK, new brass is undersized then. I don't want to spend on a rem mag gauge at this point because I plan on re-barreling soon anyways, and also chambering-up to RUM, while I'm at it. So I don't see the sense in also spending on a gauge for a barrel/chamber that I will be ditching soon. I was just curious if the over-charged load took it out of spec. On that shot, the chrony showed 3875fps on a Nosler 120 BT, and the bolt was definitely tight coming up (powder was RL19). Assuming a linear relationship between charge weight and energy produced in the fired round, my estimate on what the charge weight had to be in that round puts it at about 83 grains, a 9.5 grain or a 13% over-charge! I'm not really sure how it happened.

I guess it really doesn't matter if that one took the rifle's headspace out of spec, since the barrel is slated to be swapped out to the RUM barrel in about a month or so, anyways. I'll just play it safe and not fire it any more until then. But what REALLY scares me now, is that the RUM setup that I will be switching to may not be so forgiving of a mistake of that magnitude.
Reply With Quote
  #4  
Old 03-23-2012, 06:14 AM
Platinum Member
 
Join Date: Dec 2008
Location: Great Falls, MT
Posts: 4,484
Re: Headspacing: Is GO gauge supposed to equate to never-fired brass?

Quote:
Originally Posted by dirtball View Post
NEVER use a brass case to check headspace. New brass is undersized so it should fit in any chamber, that undersizing varies from lot to lot from the same manufacturer and varies a LOT between manufacturers.
Take the gun to a gunsmith and have it checked if you are concerned, or buy a GO gage from Midway or some one else, they are about $28.00.
The GO gage can be used with a piece of scotch tape as a NO GO gage, the scotch tape adds about .0025 and the bolt should NOT close.

Dave


Search results for: go gage
+1. Improper headspace could result in destruction of the rifle, injury, or even death. Don't take chances! Always check the headspace properly and with the right tools before firing.

Any other concoction is at your own risk. IMHO, there is no compromise when it comes to safety.

Good luck and happy safe hunting/shooting.
__________________

I voted for my "FREEDOM", "GUNS", and "MONEY" - keep the change - UNK.



"I am always proud of my country!"

"Leadership Rule #2: Don't be an @zzhole." - Maj Gen Burton Field.
Reply With Quote
  #5  
Old 03-23-2012, 04:35 PM
Platinum Member
 
Join Date: Jul 2004
Location: Texas
Posts: 5,410
Re: Headspacing: Is GO gauge supposed to equate to never-fired brass?

Quote:
Originally Posted by Max Heat View Post
I'm looking for the poor man's way to check for excessive headspace in a center-fire rifle. Obviously, the bolt should close without any resistance on brass that has never been fired. My question basically is: How thick of a shim can be placed between the bolt face and the fresh (I would try 5 to 10 of them, to establish an average) brass, before the bolt gets hard to close, or won't close?

If I punch out a round piece of aluminum from a can that is slightly smaller in diameter than the rear of the shell, place it behind it, and the bolt will close on it with only slightly more pressure, is that too much head space? The aluminum is .004" (4 mils) thick. The gun (Savage 7mm rem mag) HAS had some pretty hot loads though it, one in particular that was way too hot, and roughly 500 rounds total through it.
A head space gauge is based on SAAMI specks and all ammo is sized smaller in order to fit
any chamber. The use of ammo to head space a chamber is not recomended because is is
difficult to know what there size is compared to SAMMI is There can be .003 to .005 Thousandths
difference between brands.

It is common however to check factory ammo for for fit after the chamber has been head spaced.

If the ammo is new .004 worth of shims should be tight/snug but if it is fired in that chamber it
should not go at all. (Note: if you force the bolt closed on a fired case with a shim behind it of
any thickness it will set the shoulder back on the case and will not tell you anything) That
is why you must use a head space gauge that will not compress.

J E CUSTOM
__________________
"PRESS ON"
Reply With Quote
  #6  
Old 03-24-2012, 11:22 AM
Silver Member
 
Join Date: Feb 2012
Location: Remington County, PA
Posts: 383
Re: Headspacing: Is GO gauge supposed to equate to never-fired brass?

Ok, I forgot to mention, that right now I don't even posses any un-fired brass. It WAS fired (maybe 4-5 times) Winchester brass that I could close the bolt on with minimal resistance with the 4 mil aluminum shim behind the cartridge.

Here is the other thing that concerns me: On several of the shells that were fired in the rifle after the over-charged shot, and then were reloaded, the primers fell out, indicating that the primer pockets are streched! Is this an issue with the brass itself, or is it a more serious issue? I am NOT firing the gun right now, and don't plan on firing it again until AFTER my new heavy stainless 7RUM barrel goes in.

Who makes or sells a GO gauge for 7RUM? I'm having trouble finding one.
Reply With Quote
  #7  
Old 03-24-2012, 03:04 PM
Platinum Member
 
Join Date: Dec 2008
Location: Great Falls, MT
Posts: 4,484
Re: Headspacing: Is GO gauge supposed to equate to never-fired brass?

Quote:
Originally Posted by Max Heat View Post
Who makes or sells a GO gauge for 7RUM? I'm having trouble finding one.
Gauges - Pacific Tool and Gauge Inc.
__________________

I voted for my "FREEDOM", "GUNS", and "MONEY" - keep the change - UNK.



"I am always proud of my country!"

"Leadership Rule #2: Don't be an @zzhole." - Maj Gen Burton Field.
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes


Similar Threads for: Headspacing: Is GO gauge supposed to equate to never-fired brass?
Thread Thread Starter Forum Replies Last Post
Once fired brass sticking (that was fired from the same rifle?) Wookie316 Reloading 10 05-13-2012 07:02 AM
WTB: savage barrel wrench and .308 headspacing gauge upjeeper Trade, Freebie and Loan 0 11-06-2010 03:20 PM
What are these Infa red screens supposed to do? Iron Worker Equipment Discussions 6 03-24-2010 01:03 AM
This Wasnt Even Supposed to Be A Hunt!!! 7mmRemMag Long Range Hunting & Shooting 13 12-30-2008 12:26 PM
WTB- 300RUM brass. once fired, twice fired, three times.... Mountain Man Guns For Sale 5 07-31-2003 07:03 PM

Current Poll
Are you on Facebook?
Yes - 46.38%
1,113 Vote
No - 19.54%
469 Votes
No, but I may join - 1.75%
42 Votes
No way, are you kidding? - 36.08%
866 Votes
Total Votes: 2,400
You may not vote on this poll.

All times are GMT -5. The time now is 01:38 PM.


Powered by vBulletin ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Management Powered by vBadvanced CMPS
All content ©2010-2014 Long Range Hunting, LLC