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Discussion Starter #1
What is the purpose of the plastic trap door in the inside front of the ejection port? It has a spring loaded hinge and sliding inner part. Does it reciprocate during the firing cycle? It seems to stay in the forward/down position.
 

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WildRice said:
What is the purpose of the plastic trap door in the inside front of the ejection port? It has a spring loaded hinge and sliding inner part. Does it reciprocate during the firing cycle? It seems to stay in the forward/down position.
It's a dust cover. It keeps debris out of the action while it's closed and can act as a bolt hold-open device if you pull the charging handle to the rear and shut the trap door.
 

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that about sums it up.

don't think i have heard of the bolt hold open thing before- i'll have to try that when i get home. :?
 

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I thought this post was going to be a about Long Johns. :grin:
 

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Yep! The trap door is great as a "bolt hold open" devise when you are at the range. When you are ready to fire just insert the mag and pull back the charging handle and release and the trap door falls clear. Ready to fire away. :?
 

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I Just looked in my PS90 box and came across this page. I don't think many people got this addendum to the instuction manual. Hey Ship! Can you put this picture in with the PS90 Instruction Manual Sticky? Thanks!


 

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M1P90 said:
I Just looked in my PS90 box and came across this page. I don't think many people got this addendum to the instuction manual. Hey Ship! Can you put this picture in with the PS90 Instruction Manual Sticky? Thanks!


The FAQ you mean? - Oh wait... I know what U mean. U would have to reply there and just tac it on as a new reply, if you like...
 

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Thanks Chris for posting that! :?

I haven't had that in any of my PS90s!
 

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Discussion Starter #13
I got home and tried the trap door mechanism. For me, it does not work as a bolt lock back. With the mag removed and chamber empty, I can pull and hold back the charging handle as I push the trap door up and it will click in the up horizontal position and hold the bolt open. However, if I then pull the charging handle back again, the trap door will not release, either with no mag or and empty mag (I did not want to test at home with live ammo in the mag). To release it, I held the charging handle back and pushed forward the inner sliding part of the trap door from topside. If you do not hold the charging handle back, the bolt will hit your finger. So for me, the trap door is useless as a bolt hold back.

However, I did find a use for it. With an empty chamber, bolt fully forward, and a seated mag (again I used an empty mag for testing), I can easily reach from underneath and push the trap door up until it clicks shut in the horizontal position. I can do this easily by feel and do not have to invert the weapon. This seals off the bolt mechanism from below. It is sealed off from above by the mag. This would keep one's pet gerbil out of the mechanism, I imagine.

As I pull the charging handle back (on an empty mag, but I assume this is also true with a full mag) some inner part trips the trap door release and the trap door flips down to the vertical open position as the chrging handle is drawn back. As the charging handle is released, the round is chambered with the ejection port already open for business.

The trap door is not designed to open with firing. Doing so could damage the trap door or cause an ejection jam.
 

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Discussion Starter #15
Butt seriously (sic), I think the trap door is to keep out sand and mud, much like the ejection port cover on an AR-15. If you anticipate a sand storm and your PS90 chamber is empty, bolt forward, and mag inserted, it might be a good idea to flip up the trap door to seal the bolt mechanism from the elements. Once you draw the charging handle to chamber a round, the trap door will automatically flip down to the open position, prior to firing.

However, for 99% of the time it is probably best just to ignore the trap door and not use it. If you close the trap door with a chambered round, firing could cause damage or an ejection jam.

I guess if Tom Cruise drops by and wants to see your weapon, that might also be a good time to close your trap door. You wouldn't want Lemmiwinks to get lost up in there.

 
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