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Posted: 7/7/2014 2:49:46 PM EDT
| With a new barel and a new bolt, but form different manufactures, do i need to check the headspace? do i buy a go and a no go gauge or what? |
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With a new barrel and/or bolt, yes, it's a good idea to check headspace. It can't hurt, and might just identify something that's could hurt you.
A GO gage is made to the specs of a minimum chamber headspace dimension; if you CANNOT close the bolt on a GO gage, the chamber is too shallow and WILL cause excessive pressure. A NO-GO gage is made to just past [/i]maximum[/i] chamber headspace dimensions; if you CAN close the bolt on a NO-GO gage, the chamber is too deep and will not support the case enough to prevent head separation or other bad things. Yes, get both. |
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I check to make sure my builds will pass Go and No-go headspace specs.
Check before installing the barrel … better return options. In my experience a barrel/bolt combination that fails will fail the Go gage. A 5.56 NATO chamber might fail the SAAMI 223 REM No-go 1.4666” gage, but will likely pass the US mil-spec No-go 1.4706” gage. Bolts have tolerances also so different bolts may get different headspace readings. My 18” DD 5.56 NATO barrel came in at 1.4656” – 1.4666” with my worst case loose bolt. With the tightest bolt 1.4636” – 1.4646”. The No-go spec is not a safety point, but it is a reject point for a new barrel. As the locking lugs wear headspace increases. A barrel that passes the No-go gage should have a reasonable service life headspace wise. |
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