I would have thought that resin would have been a bit fragile and would have a go at making one from mild steel. Mark out the shape on a suitable thickness of steel. chain drill the shape leaving on a small amount of material. File and grind with a flexible drive and carbide bits. File and polish with emery cloth job done.

David

I have reproduced a few things using resin and it can work well. I used a silicon rubber to make a two-part mould and cast the pieces using GlassCast resin. The resin can be coloured with dyes or you can mix powders into it when it is liquid. This adds strength. The silicon and the resin reproduce the fine details of the original perfectly, including any scratches. Side by side, with careful colouring, the original and reproduction are virtually indistinguishable.

The resin is strong, at least in bulk. I have also used it to cast small press tools to stamp out floor covers for steering columns from body-panel thickness steel.

I bought the products from a company called Easy Composites. Their technical support, both by their on-line tools and by phone, is excellent.

Good luck.

James.

The resin that I use is an expoxy resin. To add strength if the piece is thin and potentially fragile, I imagine that you could shape some flat steel or thin rod into the profile of the part and embed it in the resin.  Any colour will then hide it.

James.

The link below will take you to a BSA parts supplier they show trigger guards for various BSA rifles, they have lot of pages to scroll through.

Link https://www.airgunspares.com/gunspares/airgun-spares/bsa-air-rifle-models.html?p=30

https://www.airgunspares.com/166568bsalightningtriggerguard.html

Another vote for David George’s answer.  Mild steel is fine for this, and a traditional gun-maker, probably a specialist ‘finisher’, would  have filed it without a flexible drive and carbide bit.   The main objection to this method is it’s hard-work!

CNC is possible too.   If Peter can model the guard in 3D-CAD, it could be outsourced to a CNC service.   Cost and the difficulty of finding a service prepared to do business with a hobbyist are the main problem.   Plenty of UK CNC firms supporting businesses, anyone know of one who will work for a Model Engineer?  Or maybe a kind member with CNC kit would take pity on him.

I keep my metal-working capabilities low-profile because it attracts the kind of neighbour who believes I’ll enjoy spend a few days making him a complex part out of expensive metal for the price of a pint, or less!  Same people are also likely to take offence when the answer is ‘no’!

Dave

It’s just dawned on me that if you can produce a mould you must have access to an original part, so with a photogrametry expert you can produce a 3D model. Then get it 3D printed in metal, or in wax and get it investment cast. Alternatively, carve one out of wax and get it cast.