Gunsmithing Barrel threading where/price

I sent mine straight to Thunderbeast, took 1 week, $125 + shipping, which will run $50-$75 per rifle. I sent to rifles for $120 total.
 
I know this is old, but I’m looking for a barrel threading too. I was planning on sending just the barrel, or the barreled action with no trigger. Why the cost of $50-$75 per rifle? Is it special shipping, or a large hard box? Thanks for the help!
 

If you don't have a hard case buy one. Send it in that. I sent my 22lr to them and shipping from salt lake to South Dakota was $35-40. Box was 14x55x6 and weighed 23lbs.