Let's play a game (from 1963) #2 w/answer

[Bocephus123]

enough play in the bolt to compress the whole base of the shell causing it to fire! not leaving a mark!

 

[gl89aw]

I agree that the recess for the rim wasn’t deep enough.

 

[Profreedomokie]

enough play in the bolt to compress the whole base of the shell causing it to fire! not leaving a mark!

That is what I'm saying in my guess. No mark because the whole rim is compressed.

 

[Catt57]

I'll post the answer and next question this evening between 8-9pm.

 

[Bocephus123]

That is what I'm saying in my guess. No mark because the whole rim is compressed.

will we get it is the question?

 

[Bocephus123]

That is what I'm saying in my guess. No mark because the whole rim is compressed.

although i didn't say the bolt was miss cut.. pretty slim chance of that on an older gun they took more care to make sure stuff was right before it left the factory.

 

[Catt57]

Here's the answer.

Scenario #3 is here:

https://www.okshooters.com/threads/lets-play-a-game-from-1963-3.344700/

 

[Profreedomokie]

although i didn't say the bolt was miss cut.. pretty slim chance of that on an older gun they took more care to make sure stuff was right before it left the factory.

Looks like even with a " pretty slim chance" I was right.

 

[dennishoddy]

That headspace issue can be caused by dirt from not cleaning, bullet shavings falling back into the chamber, operator rapidly working the bolt to close and so on.
Never had that issue, so I'm thinking it's rare.

 

[Ahall]

Semi auto
Cartridge in chamber
Bolt closes
Bang, but no finger on trigger and no mark from firing pin.

Assuming the account is accurate, we can rule out the firing group (firing pin, hammer or striker, disconnect, sear and trigger)

Priming compound in the rim is set off from percussion or heat.

Option 1 - percussion - could be an improperly cut chamber allowing part of most of the rim to be crushed by the bolt face.

Some 22 autos were made with a very small bolt face (approximately the size of the rim). If the face were not square to the chamber and a bit long it cold slam fire by crushing part of the rim.

Debris on the chamber side of the shell rim or at the edge of the chamber acting like a firing pin and crushing a small area of the rim when the bolt closed. The mark would be on the wrong side and not confused with a mark from a firing pin.

Debris on the bolt fact acting like a firing pin -
inconsistent with description of no mark from firing pin.

Stuck extractor acts as a firing pin - Inconsistent with description of no mark from firing pin

Option 2 - heat, This is a bit of a stretch given the facts presented and no description of a heat source.

Defective ammo should be on the list, but not near the top.