RTI RTI Transfer Port Screw - What Material?

What is the accepted material for the TP grub screw? There's one place on-line that sells them made of brass..but they say they are for the Priest and Prophet..which seems suspect since earlier Priest had a M6?? The one I have for my P1 is M7 and apparently steel..it's magnetic.

So should it be brass, steel, or possibly stainless?

Is there any reason the TP screw could not be 3D printed with one of the more durable materials? Or just machined from Delrin or ??

Having difficulty sourcing the 7mm grub screw size. I have found a few that are close and I could do machine work and threading to get the M7 size. Trying to make multiple screws with differing size TP holes. And would also like to experiment with TP shape..thinking that a cone shape would create a venturi effect to cause a higher velocity with less air.

Yeah..too much time on my hands. LOL.
 
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Thx for the link. I’d found a similar item but a 10qty. Still looking for something similar in brass for workability. No luck yet. Found a few possibilities at McMaster-Carr but not M7..just something close that will need machining.
 
RTI sent me some of the M7 grub screws, they were steel.

Easy to drill out, file, manipulate etc.
Got a selection of transfer ports from 1.6 mm to 3 mm.

I also have a brass M7 TP, delivered will my P1. So RTI use brass and steel.

Interesting testing, 😉. Lately I'm mainly using a 3 mm TP. .177 slugs.
Thx for the feedback. That's pretty much what I was planning on doing. Vary the TP diameter in steps of 0.5mm. The one I have that came with my latest P1, was 1mm to start. I relieved it to 1.24mm but figure it would be better to just make a "set" to have.

Not sure if my thinking is right, but it seems that having something in the TP screw hole would be better than just the threads being bare and disturbing the air flow through the port.

Also was thinking there might be an advantage if the port shape was like "/_\" to create a venturi effect. I would think that the forcing effect of the narrowing port would increase the speed of the air and possibly make for more efficient use with less volume.

Overthinking probably.