A 6 mm hole will be drilled in the nylon round, well centered : it's better to do it with a hand drill.
Then a 10 mm hole need to be drilled only at one end, 80 mm deep.
Go a head gently and at low speed even if it means to take several intermediate size drills to get a 10 mm hole. (because when the drill plunges, it is sometimes too late !)
As for the other end the rule is : diameter of the screw x 0,8 = drilling diameter a 6,5 mm hole will be drilled.
A 10 mm hole will be drilled at one end of the aluminium plate which will be adjusted with the small round file to make slide the tube.
The center of this hole is a 25 mm radius half-circle.
Round the angles with the shear to give it the shape of a corsair's sabre.
A 8 mm hole will be drilled at the other end which while also be rounded.
To form the aluminium plate, find a round such as an ashtray, bottle..., which has got a 100 to 120 diameter.
Place the plate on it and push on each end until you get the shape you wanted.
Do not close too much this trigger guard because it has to remain a bit elastic to be maintained on the tube and the screw, which it will prevent from unscrewing.
Force the tube's way in the nylon round : don't forget to protect each element with plywood offcuts and to locate the length which has to be forced in.
Then, you can slip the trigger guard on the tube and maintain it well closed it to be able to screw thouroughtly the plastic hexagonal head screw.
Force down the stopper.
Options :
You can engrave a first name on the trigger guard with a small drill machine and a 2 mm drill : be careful, do it before forming it.
The trigger guard can be made out of plexiglass (minimum thickness : 3 mm). In in this case the engraving will be done inside, the wrong way.
Be careful because drilling plexiglass is a very delicate thing to do.
Prepare your fixed gauge, put gloves on and heat the plexiglass with a hot-air paint stripper without burning it for about 30 to 60 secondes. (always keep your eye on it)
Put the plexiglass on the gauge and form the trigger guard in one go.
Take the plexiglass off the gauge by preventing it from opening and pass it under cold water.
This way, it will keep it's final form with little elasticity and do not try to heat a second time to draw it a side, it breaks like glass !