Chamber length dimension

[MUP]

Well I made my MUP chamber length gage today. I chose 7075 AL for this application, as it's soft enough to not scratch the chamber in any way, yet has the tensile strength of mild steel. Didn't get a chance to assemble into a case yet tho, as Mama needed a new mattress and box spring picked up, delivered and set up after work. So, now Mama's happy, and I'll accrue some much needed honeydo points after losing many by spending a lot of time at the range lately.

 

[243winxb]

How did you find that out?

Had a misfire/bad CCI 400 primer in 223. Tried it the 2nd time, no fire.

Knowing the head to datum measurement before firing, i measured everything before pulling the bullet.
Shoulder set back was .013" for 2 firing pin strikes.

Tested using 3 brass with known head to datum & used primers. Each 1 have shoulder set back of 5 0r 6 thousandths.

Brass not annealed.

Savage Axis rifle. The extractor will let the case move forward from the pin strike. A Remington extractor may not??