Case gage help please.

[TH3180]

Long story short I ened up with two case gages for 9mm. I have a L.E. Wilson and a Dillon. I know my length is fine because I check with a caliper. I just filled a 50 count box of rounds that went throught the L.E. Wilson just fine. To do that I ended up with 18 rounds that didn't pass the test. Now I took those 18 failed rounds and ran them through my Dillon case gauge and only one failed. So what one is correct? I am running these rounds through my case gage because I plan on shooting them in a match. Any advice would be great.
Extra info. 147g Montana Gold Bullet, Federal once fired brass (I fired it out of a G17), all passed in the L.E. Wilson after resizing before belling.

 

[1SOW]

I know my length is fine because I check with a caliper.

Your pistol chamber is the true gage for your bullet. Test them with the barrel out. Drop in and hear/feel the seat on the case mouth, then drop out easily and they should feed fine.

 

[TH3180]

The bullet is CMJ F/N on the front. I did the drop test on my barrel and I came up with 1.789" I am setting at 1.150".

 

[rfwobbly]

Your question: Case gauge help please.

A case gauge is concerned with the dimensional shape of the cartridge case, not the OAL. What my learned colleague is telling you is that your gun's barrel is the ultimate arbitrator between good and bad cartridges, since it is your barrel they ultimately have to fit in to fire. Follow? In other words your "bad" cartridge might be sized perfectly for my pistol. And vice versa.

The chamber drop test he is suggesting checks your OAL, but it also checks the shape of your case. Gun chambers vary from gun to gun. There is no one, single universal chamber shape. So "chamber shape" is the underlying answer to your question.

Therefore, if the same 18 fail your chamber drop test, then the Wilson is the better gauge for YOUR gun. If the same 3 fail your chamber drop test, then the Dillon is the better gauge for YOUR gun.

It's all relative, my friend.


Additionally
Often times, new case and cartridge gauges come with grit left over from the machining process. These gauges detect changes of as little as .001" (about 1/3 of a human hair), so it's important that they be absolutely clean with zero rust or dust.

Hope this helps!