Need opinion's and Help!

[SSG Grampo]

I have a BSA Polaris which has a CFX power plant. Barrel & Trigger are made in England everything else made in spain.
MY mainspring is in 3 pieces.
 Gamo replaced the mainspring at 2000 shots, it now has 11000 shots.
I have a Amazon gift card that will get me a free Titan XS mainspring. As opposed to spending $50 plus shipping for an ARH kit.
From what Amazon has in stock the #11 Titan seems the closest to whats in it now?

Titan #11 230mm Length ****31  coils****Wire 3mm ****12.8mm  ID****18.8mm OD****

Titan #7 is recomended for the BSA Polaris but it's not available.

Titan #7 255cm Length****30 coils****Wire 3.5mm****13.8mm ID****20.0mm OD****

I would like to get the Titan #11 for no cost to me. Will I be able to get it to work?? It's for targrt work only, FPS and FPE is not an issue.

I need opinions please, any comment is appreciated.

Thanks, Bill.

[Roadworthy]

The #11 should work depending on the outside diameter of your spring guide.  You will probably lose a bit of power.  Your best bet would be to take some measurements from your existing spring and go from there.  I rather like the dial caliper from Harbor Freight for that purpose.  It's inexpensive and has no batteries to go dead.  It does read in inches not millimeters but any calculator can do the conversion.  There are 25.4 millimeters per inch.  I would like to know the diameter of your existing spring wire and number of turns to determine whether the new spring will need shortened.

[SSG Grampo]

Thomas.
My existing spring that Gamo put in under warranty measured in inches.
 Length 9 12/16, It's in 3 pieces so not a perfect measurement.
OD 12/16 ****ID 8/16****34 Coils
Thank You for your help.
Bill