Long time lurker. First time posting here.
I have an issue with a 1903 that has me scratching my head.
Allow me to give some background, then the issue.

Background:
I have headspace gauges from PTG for .30-06. (Let's assume they are correct)
I also own a RCBS Precision Mic for .30-06.
The Go gauge I have measures perfect in the precision mic; it measures zero. (2.0487)
The No-Go gauge I have measures +.004 (2.0527) and the Field gauge measures +.009 (2.0577) in the precision mic.
This Springfield can close the bolt on the No-Go gauge but can't close the bolt on the Field gauge. Fine I think, it's a bit long but within SAAMI specs. It's between 2.0527 and 2.057

Issue:
I wanted to find out what the headspace was so I loaded 5 LC cases (FL sized) with Fed 210 primers and Hornady 3037 150gr. FMJ-BT bullets over 49.5 grs of IMR 4064.
Here's the perplexing part; I measured those 5 cases with my precision mic and get the following:
-.005
-.006
-.008
-.010
-.012


How in the hell does a chamber that measures at least 2.0527 put out fire-formed cases that are as short as 2.0367?
And why are they all over the place like that?
I have never seen this before.

Another thing, the primers were backed out significantly. The primer pockets on these case were not loose when I seated those primers, yet these things backed out at least .020 or more.

I am thinking I should throw this thing in the car and take it to Chuck Moline and let him look at it but I am curious if anyone here has any ideas as to WTH is going on.
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