the two holes that the barrel sits between

 

There are no holes on the Moving parts group (Breech block).Do you mean the two rods portruding out the front where the ejector/extractor are that go into the two holes in the barrel group?

 

Did anyone ever get an answer to this? Page 29 of the PS90 manual says "apply 1 drop of functional lubricant to the ejector, to the extractor, and to the holes of the breech block." I've had my PS90 for a couple of months and still am not sure what holes they are talking about. There is a drawing below the sentence I quoted, but it does not point out the holes. Anyone know what they are talking about?

 

I've asked around with other ps90 owners and gun shops. No one seems to know...

 

I just kinda oil it the way I oil it....

 

I believe it is the holes/females on each side of chamber. The rods/males from the bolt fit into those. There is friction there so there needs to be some oil.

 

I thought of that but dismissed it because the guide rods and the plastic piece at the rear of the block group do not appear to move during normal operation of the weapon. They are sandwiched between the guide rod holes in the barrel group and the rear of the stock. During assembly just before the locking button engages on the barrel group the breechblock is pressed slightly back into the springs to keep the weapon securely in battery. When assembled without the rear cover in place you can press forward on the "button" that protrudes into the rear plate about 1/8 inch. The rods will bottom out in the guide holes which I take to mean that they are not intended to go all the way in when assembled correctly.

Close inspection of the guide rod holes shows no evidence of wear or movement but I only have a few hundred rounds through the weapon.

 

From the 30 November FN Q&A thread:

4. The PS90 manual states that the moving parts group should be oiled at the guide rods, ejector, extractor and "holes of the breech block". Which holes are they referring to? The side holes are the right hole that goes to the guide rod and the other side which houses the cyclical reducer or tungsten weight.

Sounds like they mean the 3/8" opening on the right side through which the guide rod is visible and the exposed area of spring in the cavity on the left side occupied by the reducer (rate of fire stabilizer).

 

Thanks everyone. After looking at the part considerably, I agree it must mean the hole on the right side and the area around the weight on the left.