So.

Threw my PS90 in the mud.



Observations:

The gun was removed from the dunk with a round chambered. Gun on safe.

Gun fired and chambered rounds. Immediate issue was that it required the trigger to be pulled forward to reset. This told me that the gunk had caused excessive friction on the trigger bar and trigger making the sear spring (which is responsible for resetting the trigger and trigger bar to the fwd position) unable to return the assembly to the fwd position.

Then I field stripped and cleaned the gun with a canteen full of water. Issue number two: the magazine stopped feeding with the last 10 or so rounds. The gun fired and was reliable until those last ten rounds were up. The spring simply didn't have enough oomph to get the round to rotate down to the feedlips.


The magazine stopped on this round and removing it revealed the rest of the rounds simply wouldn't feed up the ramp to the lips.

Recommendations: do not buy a weaker sear spring. These may enhance trigger pull by reducing weight, but in bad conditions the friction can make the trigger stick to the rear.

Buy extra power magazine springs. Elite Ammo sells "HD" springs which I may try to evaluate and see if they have enough oomph to let the gun feed those last rounds.

Cool to post. I’m looking to try one out.

Seems a stamped SBR would be really cool.

Thanks for posting this. Buying one for an SBR project is on my bucket list.

Are you using ManCave rollers?

No they come in on Monday.

What happened to the pics?

Here is the full test. You can skip forward to 5 min for the mud.