We make a range of leg extensions from 20cm to 70cm (7.8 inches to 27.6 inches) which can be retrofitted to either your Javelin Bipod or Spartan 300.
Simply unscrew and remove the lower legs and insert the leg extension into the upper leg. If installing permanently consider moving the unscrewable ankles and red collets (pictured below) over to your new extensions, however, this isn't necessary.
These leg extensions increase ground clearance and will allow you to take seated shots from your bipod.
The leg extensions shown below are 50cm with a long 'Javelin original, making it ideal for seated shots.
For kneeling shots 60cm, or 70 cm leg extensions provide a little more height.
These are only compatible with the original Javelin Original design, They will not fit Pro Hunt or Lite designs.