If I am right the Titan was the forerunner to the Falcon FN19, Titan rifles was an early venture by John Bowkett so they have some pedigree.
You can use any rifle for hft as long as it is sub 12ftlb, so this is what i would recommend. get a chrono and check the rifle, fill it up to its pressure and shoot a 40 shot string.
If the rifle can put about 40 pellets down range at about the same power, then that is perfect for HFT.
If it doesn't, then you may need to fill the gun halfway round the course, but no matter what, it sounds like fun and I would love to have a look and a shoot of it.
all the best
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