But that still doesn't make sense. There is still a gap between the front of the rim and the breach face on a RimX even if there is NO chamfer....example, a CX round has rim thickness of .043"...... the minimum headspace for a RimX per Zermatt print, which I don't know any tenons being cut that short is .0465" headspace. I know Keystone is cutting there .002" over min (.0485") so thats a .005" gap between the rim and the breach face (with no chamfer at all)..... just sayin.I get that. However if there isn't enough support under the rim the case the rim can either move slightly forward off the bolt face or the case can slightly deform into the chamfer at the point of firing pin contact which "absorbs" some of the force from the firing pin. It's the same concept of holding an action in your hand and trying to drive a tight trigger pin out with a punch vs having the action laying on a bench. It doesn't matter how firmly you hold the punch against the trigger pin when the hammer hits the punch the action is going to move even if it's ever so slightly and will require a harder swing of the hammer to move the pin vs if the action is prevented from moving when it is on a bench you will not have to swing the hammer as hard to move the pin.
In this design with a 6 o'clock firing pin it is even more exaggerated than if it were a conventional 12 o'clock firing pin because the case is being held on the opposite side of the firing pin.
The RimX is not like your typical 22lr....the rim is never supported by the breach face...its not possible....the tensioner would stick out too far and not allow you to close the bolt if the headspace matched rim thickness, sandwhicing the rim tight against the breach face.. By design, the fixed extractor/tensioner supports the rim 100% of the time.
I would be leaning toward a trigger issue than the chamfer for those having ignition issues. I do know Keystone just got a RimX barreled action back from a customer having ignition issues every 3-4 firings.... they put a BixN Andy on it right after opening the box and had zero ignition issues firing 3 different kinds of ammo from crap to Tenex....we are all using chamfers on our RimX barrels. Its a key part in proper feeding, I dont know of any widespread ignition issues. I think we would all be having ignition issues if the chamfer was the cause