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Again, based on the failures marlinguy and I have read about, a catastrophic failure is nearly always in the breech block at the stress riser at the corner, not the pins. In cases where failure is limited to yielding, it's possible that occurs elsewhere; perhaps he's seen a few such.

What alloys Remington used in each part I can't say, and this could affect the results.

Bill
The chance of both pins failing in double sheet is theoretically possible but very unlikely
What happens in structural failures is that one member may start bending or yielding to its limit then typically the surrounding structure starts receiving the stress and spreading it over a larger area
Let’s say for conversation sake both pins sheared off at both blocks
The hammer roller kinda drops down into the receiver, the breech roller depends on the hammer roller location
If the hammer is down in the firing position, the breech roller has to go down into the receiver as well 
Not sure how these position would look at the moment the pins fail
Don’t think they would exit the receiver as both rollers are somewhat shaded from a direct exit path
I would think the breech roller pin is more likely to bend causing the breech block face to open up and potentially releas pressure at a perpendicular direction to the shooters face
Would not want either scenario 
To bust the pins in a catastrophic mode pressures would have to be well above 85 kpsi  not sure  a load can get ther

Seeing the picture of the Tipmann block, it looks more apt to fail than an original with the wide cut through it. That @1/4" wide cut removes a lot of strength in the area most prone to failure. Leaving two "ears" that the pin pivots on makes it even more likely for those ears to fail under higher pressures.