1903Collector
NES Member
There is always a lot of discussion on AR15 headspace so I thought it would be interesting to look at my own rifles and see what I actually have. Since I have rifles that will close on a no-go gauge and some that won’t I wanted to see what the differences in fired cases would be between the two.
The first step was to check headspace on the rifles and see where they stood.
I was trying to figure a way to measure the fired cases with the tools I have on hand. What I decided to do was to measure my Wilson case gauge from the base to the top step and record that number (see below). Then I would insert a fired case and measure from the base of the gauge to the bottom of the fired case and note the difference.
Remember I am only trying to see the difference in fired cases from rifles that will close on no-go gauge as compared to ones that will not. Also keep in mind the numbers below are the difference from the empty case gauge measurement compared to the gauge with a fired case in it. I actually have three more rifles to check, just didn’t have time today, I will add those later if there is any interest.
Hope this makes sense! LOL
Ammo used: Australian Defense Ind. 62gr FMJBT
Forster headspace gauges.
Wilson .223 case gauge measured from base to top step = 1.759”
BCGs: I'm not sure which one is in which rifle, but it's one of the ones listed as those are the only ones I have used.
Rifle #1 XXXXX65
Barrel – BCM 1/7 5.56 chamber
BCG – BCM/LMT/CMT
Headspace check:
Go/1.4636” – Bolt closes
No Go/1.4666” – Bolt will not close with light finger pressure but will close with firm finger pressure.
Field/1.4696” – Bolt will not close
Fired case measurement:
1.1.763” diff +.004
2.1.763”
3.1.762” diff +.003
4.1.762”
5.1.763”
Rifle #2 XXXXX48
Barrel – BCM 1/7 5.56 chamber
BCG – BCM/LMT/CMT
Headspace check:
Go/1.4636” – Bolt closes
No Go/1.4666” – Bolt does not close
Field/1.4696” – Not checked
Fired case measurement:
1.1.762” diff +.003
2.1.762”
3.1.762”
4.1.762”
5.1.762”
Rifle #3 XXXX76
Barrel – Windham 1/9 5.56 chamber
BCG – BCM/LMT/CMT
Headspace check:
Go/1.4636” – Bolt closes
No Go/ 1.4666” – Bolt closes
Field/1.1696” – Bolt does not close
*Rechecked with a new BCM bolt, had same results.
Fired case measurement:
1.1.764” diff +.005
2.1.765” diff +.006
3.1.764”
4.1.765”
5.1.764”
Disclaimer: I am not a gunsmith, armorer or any kind of expert!!
The first step was to check headspace on the rifles and see where they stood.
I was trying to figure a way to measure the fired cases with the tools I have on hand. What I decided to do was to measure my Wilson case gauge from the base to the top step and record that number (see below). Then I would insert a fired case and measure from the base of the gauge to the bottom of the fired case and note the difference.
Remember I am only trying to see the difference in fired cases from rifles that will close on no-go gauge as compared to ones that will not. Also keep in mind the numbers below are the difference from the empty case gauge measurement compared to the gauge with a fired case in it. I actually have three more rifles to check, just didn’t have time today, I will add those later if there is any interest.
Hope this makes sense! LOL
Ammo used: Australian Defense Ind. 62gr FMJBT
Forster headspace gauges.
Wilson .223 case gauge measured from base to top step = 1.759”
BCGs: I'm not sure which one is in which rifle, but it's one of the ones listed as those are the only ones I have used.
Rifle #1 XXXXX65
Barrel – BCM 1/7 5.56 chamber
BCG – BCM/LMT/CMT
Headspace check:
Go/1.4636” – Bolt closes
No Go/1.4666” – Bolt will not close with light finger pressure but will close with firm finger pressure.
Field/1.4696” – Bolt will not close
Fired case measurement:
1.1.763” diff +.004
2.1.763”
3.1.762” diff +.003
4.1.762”
5.1.763”
Rifle #2 XXXXX48
Barrel – BCM 1/7 5.56 chamber
BCG – BCM/LMT/CMT
Headspace check:
Go/1.4636” – Bolt closes
No Go/1.4666” – Bolt does not close
Field/1.4696” – Not checked
Fired case measurement:
1.1.762” diff +.003
2.1.762”
3.1.762”
4.1.762”
5.1.762”
Rifle #3 XXXX76
Barrel – Windham 1/9 5.56 chamber
BCG – BCM/LMT/CMT
Headspace check:
Go/1.4636” – Bolt closes
No Go/ 1.4666” – Bolt closes
Field/1.1696” – Bolt does not close
*Rechecked with a new BCM bolt, had same results.
Fired case measurement:
1.1.764” diff +.005
2.1.765” diff +.006
3.1.764”
4.1.765”
5.1.764”
Disclaimer: I am not a gunsmith, armorer or any kind of expert!!
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