garbage....

sorry to be so blunt...but that's a bunch of bunk...the 10.5 is well within the weight limit...the problem is when you use REALLY heavy pellets like 17gr Cobras...That will cause some problems...did it on my R1 .177 at that time..never again! Caused major double piston slam..super loud and super rough. So I don't recommend loading 2 pellets to fire is a safe bet.

One hint you might know is that the firing cycle will be harsher...I've found out with Kodiak pellets on my Webley Patriot..the firing cycle is so harsh that it kinda tingle my fingers.

Will heavy pellets stress the spring...on occasion with certain ones..yes...on the gamo? I seriously doubt it. I found out I have 4 gamos springers... the 890..shadow (what not..it sits in storage)...hunter extreme..and hunter 1250...the ladder two MUST use the heavies...and the fore two didn't really feel much difference but they ended up not being accurate...but to be honest..those guns twang so much that really, you don't notice much of a difference.