Reloading and Tuning my 16" AR-10
- By FLIGHT762
- Reloading Depot
- 8 Replies
Just measure you fired cases from each of you rifles (I would measure 5+cases or an average) and make notes for each rifle.
My first year production SR-25 fired cases measure 1.631"(tight chamber) and my 2013 era GAP 10 fired cases measure about 1.634". Your Rifles should be in about the same neighborhood. These measurements are calculated from the comparator number length and converted to the SAMMI minimum go gauge length.
Don't be surprised if you get some higher datum length numbers on a Rifle that could be over gassed. I have a buddy that has a Les Bayer AR-10 that shoves the fired cases shoulders forward to 1.640". There's no way I'd believe that Les Bayer cut that chamber that long. The cases were from Factory Federal GMM. He gives me the cases to reload.
M1-A's & M-14's are notorious for shoving case shoulders forward on extraction. On the two M1-A's I own, I turn the gas spindle off and fire 5 rounds without the gas and then measure those cases to get a more accurate fired datum length.
My first year production SR-25 fired cases measure 1.631"(tight chamber) and my 2013 era GAP 10 fired cases measure about 1.634". Your Rifles should be in about the same neighborhood. These measurements are calculated from the comparator number length and converted to the SAMMI minimum go gauge length.
Don't be surprised if you get some higher datum length numbers on a Rifle that could be over gassed. I have a buddy that has a Les Bayer AR-10 that shoves the fired cases shoulders forward to 1.640". There's no way I'd believe that Les Bayer cut that chamber that long. The cases were from Factory Federal GMM. He gives me the cases to reload.
M1-A's & M-14's are notorious for shoving case shoulders forward on extraction. On the two M1-A's I own, I turn the gas spindle off and fire 5 rounds without the gas and then measure those cases to get a more accurate fired datum length.