I had a similar requirment for casting real steel end caps for Sterling 9mm SMG's.
You need to approach a casting company & enquire about what you need. I would not say exactly what they Are! As in this Dangerous world we live in at present. You dont want a knee jerk reaction to ANYTHING concerning a weapon or indeed. A look alike.....
They will make a mould from silicone of one of your bolts. Then wax casting will be cast from this Mould.
Then in fine casting sand, they will insert your wax castings. Molten metal of your choice will be poured in the Mould.
This will instantly melt the wax, & it will evaporate away out of the vent holes in the mould.
When cooled, the mould will be separated & the sand knocked out. This will leave you your cast bolts.
The process is known as Lost wax casting.