Cr0-Magnon

If moving parts are lighte, with the same air pressure / chamber capacity pushing a standard weight vs pushing a lighter weight will have less resistance
To maintain equal muzzle velocity the air pressure ought to be dialled down if ‘lighter’ / more efficient parts are fitted 
 
If effect you’re giving a light puff on standard parts and a harder blow on lighter parts
 
 
Classifieds item descriptions from sellers may also be very subject to ‘buyer beware’
 
 

If you're desperate to sell, you'll likely need to reduce your price. I could get a brand new TM MP7 with four leak free mags (and a warranty) for £400. There's no way I'd spend the same on an AAP build that the seller even admits isn't working as it should.

£136 brand new with a warranty and not two-toned, or save £21...a "serious buyer" would be making this face:
 
 

This is very clearly a WE, it states as much on the frame. It's the same as this one below, you should update your ad.
 
https://wolfarmouries.co.uk/we-glock-26-gbb-pistol-tan.html

used a lot but not used much?
bits work but also don't work

Yes, now you've deleted the pic of the Hi-capa, all is clear 👍

Your pictures show two different pistols. Which is for sale in this listing?

Maybe he means it was well looked after UNTIL he broke it 🤔🤣
 
No mention of what's actually broken, perhaps the seller could give us a bit more info, considering it's high price for an apparent boneyard paperweight ?. 

"Well looked after" but also "Broken"?

I'll add, bravo for putting the posted price first. Too many ads on here look OK priced until people want to put on £30 for delivery and PayPal fees.

I'll add, bravo for putting the posted price first. Too many ads on here look OK priced until people want to put on £30 for delivery and PayPal fees.

Probably the worst sales post I've ever seen, gives a whole new meaning to the word lazy 

Is this locked to semi? You've stated it's 430FPS.

They don't look like Glock Magazines?
More like M92 mags?