Agree 100%. The barrel nut options get a lot of hate on this site, but I don't give a flying F. I'll use them as long as I can get them. I sleep well at night knowing that when I screw a new barrel on my action, I will have no headspace issues due to the tolerance stackup issues Frank mentions. The barrel nut allows me the ability to do that. Most of the people on here pissing and moaning about how it's SOOO much easier with a shouldered barrel are just lazy and whiners. As a mechanical engineer I deal with tolerance stackup issues every single day and the delays/headaches it can cause, so I choose to eliminate that in my personal rifles as much as possible. Using a barrel nut is the easy button. I laugh out loud every time I read a new thread on here where someone is describing headspace issues with their shouldered prefit.
Barrel nuts fix only 1 of the potential issues. Chamber shape is not detected when you throw a headspace gauge in the barrel and run it down on the locked bolt.
The latest recurring problem we see coming into the shop these days is conic runout in the chamber and runout in the throat. The worst offender is the conic runout as it's harder to pin down and it's insidious in that the problems it creates are down the road.
They shoot fine typically, sometimes not, but when the barrel inevitably wears out and the guy buys another one he finds out there's no way to size the brass web back to fit the new chamber that has less/no conic runout in the body. Now the guy is stuck: the new gunsmith didn't do anything wrong but he's going to get an earful about how his chamber is undersize and the old gunsmith is going to say "but it shot fine for x,xxx rounds why are you calling me now". The prevalence of cheap barrels being made with minimal QA checks puts these onto the market and as of late we've seen a lot of them coming from the places that make inexpensive barrel nut drop ins.
Being an engineer you're probably pretty mechanically inclined like I am. I look at it thinking "how is this hard to put that together or take it apart." Unfortunately many people are not so fortunate as we are. When you deal with the general public that thinks it can assemble a rifle because they read about it online or watched a youtube video you'll get a better appreciation as to why some of us strongly encourage the use of shouldered prefits due to the reduced complexity. Even with shouldered prefits we still get an email or phone call at least once a month that is some form of "you guys did this wrong, the headspace is off by like 1/4"!!!
We get the photo of the assembly and tell them to put the recoil lug in the joint and the problem disappears.
Headspace issues are really not the unsafe problem that the internet makes it out to be. If they were then the entire fireforming concept wouldn't work as well as it does. Even from an accuracy perspective something that squeaks shut on a NoGo gauge is not going to cause accuracy problems; I've tried it and ended up with some outrageously deep chambers that still shoot very well and doesn't rip apart brass. Anyone that has fireformed 6BR into Dasher has done exactly this. It's common to hear about someone fireforming that's getting insane repeatability while they're forming brass. It really isn't the issue that the internet has turned it into.
Yes I'll say hand fit because then there should be no guess work as to what was done then.
The other thing not really mentioned and we run into quite a bit.... not really on new actions but a guy buys a used rifle and then someone monkeyed around with the action and did truing or repair work etc... again throws the dimensions right out the window.
I will also say this and we see it and it's happened to myself as well... a receiver gets damaged ( I had a thread gall and lock the barrel onto the receiver and had to cut the barrel off and bore out the breech area to get the rest of it out... never touched the threads) and the receiver goes back to the maker and they repair the threads but now the threads are bigger. I had to do that to one of my BAT actions years ago. It all works fine... but you need to use the actual receiver to check the thread fit.
We've dealt with that too and on the numbers of barrels we chamber every year the situation we're talking about happens about 1 time per year. It's easy to handle with the customer on a case by case basis and for the very rare occasions when it happens it's a straightforward solution.
The solution that we've advertised for years with "hand fit" actions or receivers that don't hold a stackup tight enough to do them all sight unseen is to install the barrel with the action here. Engrave the dimensions onto a tag and send it back with the action. We do additional barrels off the tag dimensions regularly, it takes about 3 mins to provide the tag.
Far be it from me to tell you to branch out the business and I know you guys are swamped. We have ways to deal with a lot of the commonly raised concerns to make the idea work.