I designed the first Bergara extension on the market and what I found in my testing was that the material the magazines are made from is not very durable, so using a stiff enough spring for a plus 5 extension wears out the feedlips rather quickly. I believe that extension uses the Volquartsen green spring which is much stiffer than the factory spring in my experience. I could be wrong but that would be my concern going in. It appears to be a very robust design so from a durability perspective I don’t think you will have any issues with its material holding up. I have PLA+ extensions that have been in use for 3 years straight and many thousands of rounds.