centershot
I have had brand new cases that were .009 shorter than a GO gauge. Your problem is you bought cases fired in other rifles with different headspace settings and different chamber reamers.
Using the primer method mentioned here will let you know how much head clearance your shorter cases have. Meaning using the bolt face to seat a fired spent primer will tell you how much head clearance or air space you have between the rear of the case and the bolt face
Measure a case from its base to the case mouth and write the measurement down.
Now using your fingers start a primer into the primer pocket and then use the bolt face to finish seating the primer as you close the bolt.
Now measure the case again from the base of the primer to the case mouth and write it down.
Now subtract the first case measurement from the second measurement and this will be your head clearance.
If you have a Hornady cartridge case headspace gauge and any headspace gauge you can compare the seated primer measurement with the headspace gauge to get your chamber length.
Below a Colt 5.56 Field gauge at 1.4736
Below a Hornady cartridge case headspace gauge that has been adjusted to read the actual headspace. This vernier caliper is accurate to .0005 so the most it will be off is 1/2 a thousandths or .0005.
Below measuring a fired Lake City case from my AR15 rifle and a close approximate of my chambers length minus brass spring back. And my die was then set to bump the shoulder back .002 to .003.