what is the correct pin diameter to hold a Timney trigger solid on a mark X receiver?

All of the Timneys I have installed on Mausers and Rem 700's had loose pins. Had to send a few back and turned some to fit. Was told they had QC issues at some point. We don't install Timneys anymore. The true answer is the pin size that fits snug.

A MKX is a Mauser and all those use 3mm pins. All.
You can buy hardened precision ground 3x10mm pins by the hundred.
If you try to use a pin that fits an enlarged trigger, then it will no longer fit the receiver and I do not recommend drilling them out.
I do still use Timneys. Have not had one with big holes yet.

I use 3 mm x 12 mm long dowel pins
The 10 mm pins will work fine but most military pins are 12 mm long
I see on MSC Industrial they can cost $ 24 a hundred

James Wisner