Just do the penny mod
Been modding for 6+ years, don't use this spring, it damaged my blaster massively and it now no longer works. I suggest the penny mod as you will only notice improved performance for about a day with this spring upgrade where as penny mod has worked for years in other blasters. I did all relevant tests to see why performance was dropping, added supports to the blaster and ensured the seal was correct, I also added a better catch spring. Bar in the priming handle shot out when I was firing and has damaged the blaster itself as the springs draw is too heavy. Just do the penny mod, you'll save yourself a broken blaster and a few quid.
Verified purchase: YesCondition: New