Anything to do with firing mechanism and or pressure baring parts in a real firearm is restricted so i could see making triggers could get you in hot water if the police were looking to boost arrest statistics.
Read the room you have been acting like a tool. You haven't been doing your research you have been asking to spoon fed. if you had done any research you wouldn't have asked the question you asked. either actually listen to the good advice you have been given or just go away.
Bought this as a fixer up project got the gun working. shooting at 1.2j. fixed two mags so theY are gas tight but all the mag shells were all too badly cracked to be repairable (replacements can be bought or there are 3d printable files available) .
so gun, 5 mags (2 gas tight, 3 leaking, all need shells) box and manual £150.00 posted and paypaled.
Shocked to say service was excellent. They had M2 in-stock almost £150 cheaper than anyone else so took a chance. Good coms notified me my UKARA was lapsed. I Received the gun two days after confirmed my UKARA was renewed. So yeah good experience.
Make: Tokyo Marui
Gun/Model: Kel-Tec KSG Gas Shotgun
Accessories: 1 TM shell, 6 cyma shells, foregrip.
Condition: 6 months old used once at a CQB day been gathering dust since.
FPS: gas dependent
Splits/Swaps/Part Exchange: N/Y/Y
Price/Payment: £265.00 P&P and PayPal Part ex for an GBBR M1/M2 carbine
I use 0.28g out doors in a TM HK45 but i only use it as a back up i am not going for max range i just want consitance. though a lot of CQB sites I have played at limit to 0.25g for every thing.
Same experience with an AA-12 (pretty much the same gun) it can be used out doors successfully but consider it more of a support gun. Even with out the range the noise can keep heads down.
In CQB i have single handily Cleared rooms by charging in getting a single kill, dying, then respawning and repeating till the jobs done while my team mates just stack up at the choke point.