Actually since there is a 3rd person involved ( the one who is the go between ) I suspect you will have a claim under the Consumer Gurantees Act (should not come to that)but its his job as the "retailer" to sort it no matter what the gunsmith actually says/does.
Personally If I had spent that much and got that result there would be some Major shit raining on someone
for that sort of money I would also expect all the bullets to go thru one hole by themselves
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