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W.E.G.
September 22, 2001, 20:09
Here are some comparative numbers I got by measuring several headspace tools and loaded rounds of factory ammo. The tool used to determine the comparative nubers is an RCBS "Precision Mic" for .308 Winchester.
http://www.rcbs.com/images/precisionmic.jpg

For purposes of this discussion we will say that the nominal reading on the dial of the tool when measuring a Forster 1.630 "Go" gage is "zero."

The numbers which follow are the amount in thousandths of an inch that the cartridge/tool specimen measured above or below 1.630 "zero."

Forster No-Go gage: +.004"
Clymer Go gage: +.001"
Clymer No-Go gage: +.007"
Clymer Field gage: +010"
Malyaysian cartridges: +.002" to +.006"
Chilean cartridges: -.001" to .000"
Radway Green cartridges: +.002" to +.004"
Lake City M852 cartridge: -.003" to -.002"

Bullet
September 22, 2001, 20:47
Thats very intresting. Even within the same manufactures, there can be a wide range. Thanks.

Upside Down @ 100 MPH
September 22, 2001, 21:07
Here's what I got from my stuff. This is why 1.632" works so good for me. I'm gonna list it like Gary did.

Forster 1.632" = 0.0"
Radway Green -.001" to -.0015"
New IMI brass -.005"
Factory Rem 150 -.005"
My handloads -.002"(target) to -.004"


1.632" doesn't give me too much headspace on commercial stuff yet will let the gun chamber the Radway Green.

[ September 22, 2001: Message edited by: Upside Down @ 100 MPH ]

NZ L1A1 Collector
September 22, 2001, 21:47
Here are the military limits for headspacing for "inch" rifles

Australia (L1A1)
1.6325 in. "ACCEPT" (GO)
1.638 in. "REJECT" (NO GO)
1.640 in. "CONDEMNING"

British (L1A1)
1.6325 in. "ACCEPT" (GO)
1.638 in. "REJECT" (NO GO)
1.643 in. "CONDEMNING"

Canadian (C1 & C1A1)
Barrels with 0.400 inch diameter on the cone
Min: 1.6315 in. "GO"
Max: 1.640 in. "NO GO"

With new barrel or locking shoulder
Min: 1.6315 in. "GO"
Max: 1.6378 in. "NO GO"

Hope this helps :)

W.E.G.
September 22, 2001, 21:59
Kevin, what does "Barrels with 0.400 inch diameter on the cone" mean?

Radio
September 22, 2001, 23:33
As a modern American, I like things spoon-fed to me, so for the mind-numbed out there like me, here's the converted numbers.

gary.jeter's figures:
Forster NO-GO: 1.634" (published figure: 1.634")
Clymer GO: 1.631" (published figure: 1.632")
Clymer NO-GO: 1.637" (published figure: 1.636")
Clymer FIELD: 1.640" (published figure: 1.640")
Malyaysian cartridges: 1.632" to 1.636" (Hey! These suckers are LONG!)
Chilean cartridges: 1.629" to 1.630"
Radway Green cartridges: 1.632" to 1.634"
Lake City M852 cartridge: 1.627" to 1.628" (*sigh* sure miss that LC)

Upside Down @ 100 MPH's figures:
Radway Green: 1.631" to 1.6305" (THIS is more what I would have expected from RG)
New IMI brass: 1.627"
Factory Rem 150: 1.627"
My handloads: 1.630" (target) to 1.628"


--Radio

[ September 23, 2001: Message edited by: Radio ]