Did you try Google? It's likely they did.

The box the parts are in says Boulder River Foundry. I did a search and as far as I can tell they do not offer it now. They only produce Sharps castings for Shiloh. 
Cheers
Stank

This was probably ten years ago, but I took a tour of the Shiloh Factory and the Boulder River Foundry and Bob (IIRC), who was squiring us around, said that they would be amenable to making castings for individuals.  I imagine the individual would have to provide the patterns for the wax castings, and of course availability would depend on their own internal needs, but I found that interesting, although I had no particular parts in mind back then.

From the July 2019 "Rifle" magazine.

Quote:

Stank wrote on Jan 16^th, 2025 at 9:19am:

I don’t even remember where I got this but I also got a 50 caliber winchester barrel with it. I don’t know what the barrel is chambered in though.

Yes, Boulder River did make a high wall casting set. I saw them when I got a tour of the foundry in 2018 when I visited Shiloh. With the MVA high wall I doubt if they sell many of these now. I've done business with the foundry. They have excess capacity for Shiloh's needs and take in other work. I asked Kirk if there was a minimum quantity requirement and he told me, yes, one part. Randy, the foundry manager told me he has a customer that deals in high quality hammer doubles and that he will send in a hand carved wax pattern of a broken hammer and the foundry will cast it. I'm getting ready to send a new mold for a 1st Mod Maynard hammer to them for casting. They did my Maynard take down pins for me.

Bob,  lost wax is fairly easy, you just get to work in softer material than steel.  

Here's where you get the wax:  (You need to Login or Register to view media files and links)

Here's some info on the process:

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There's some nuances to it that you need to get down.  Steel shrinks about 7%  edit:  2%  I believe.  So, you need to oversize by a percentage in each direction, or leave extra material in critical fit areas to allow to machine back to shape.

You also have a casting "rind" and finish/polish loss, so you need to account for that also.  

The advantage of wax is you can shape a softer material.  Another advantage is you can weld pieces together easily by low heat, and can use sticky waxes to stick the pieces together before welding the seams to cover them up.  

The disadvantages are that the shrinkage makes it hard to get tight dimensional tolerances, since shrinkage is proporational to length, the shrinkage is different in all dimensions, and is somewhat affected by shape and bulk density of the cross sections, so it is non proportional.  There is also some loss rate; sending in one wax and having 100% success in getting a good part back isn't assured.  

What wax casting is good for is mass producing parts where working out the shrinkage is worth it because of mass production of the final part.  Or making hard to machine one-of a kind pieces.

What doesn't work, and why the casting sets on the market have some dimensional problems, is just molding original parts and then making the waxes from that mold.  The best way to do this is to take the original part, and dip it in a surface buildup liquid or slurry to evenly coat the outside to about 8 or 9 percent of the thickness.  Then, mold that part, make a wax, cast it, and compare the dimensions to an original.  Where the dimensions are too small, paint on additional slurry/buildup liquid onto the model, where they are too large, sand some off.  Repeat until you have acceptable results, and then use that mold.

A technique to use on elongated parts is to add the surface buildup as above, cast the part in brass, and then cut and paste in brass lengthening pieces as needed, surface coat the oversize brass model, and mold it.