Can a machinest make modifications to a handgun slide for someone else.

Can a machinest, who is not a gunsmith, make modifications to the slide of a handgun,for another person. I mean modifications such as adding front cocking serrations on a Glock side, not modifications that would change the action or classification of the gun. I have been told that only a gun smith with a manufactures license can make modifications such as this.

First step to becoming a machinist is to learn how to spell it.

Not sure on the answer to your question, just wanted to say I spelled machinist the same as you on 35 years worth of form 1040s before I learned how to spell it.
Sorry, I could not help on the question.

The slide is not considered a firearm, they can be bought and sold freely without the services of an FFL. There is nothing wrong with a machinist working on a slide as long as the machinist does not take possession of the serial numbered frame. Possession is generally understood to be control of the firearm overnight. However if I were the machinist I would want the owner of the firearm to be present while I am doing the modifications if the serial numbered frame is also on location.

Also anyone can technically legally modify a firearm as long as possession is not transferred and the modifications are allowed by law. From a liability standpoint it would make sense to have an insured gunsmith do any modifications to critical components.

Not enough information.
How often will you do this? Done "for the principal objective of livelihood and profit" is what separates those of us that need/have an FFL, to a guy barreling his buddies rifles on occasion (no FFL needed).

Then, there's DDTC/ITAR, which is relevant if you manufacture ANY part for a firearm (USML) , and is required whether or not you need an FFL.

DDTC Issues Guidance on ITAR Registration | Prince Law Offices, P.C.

tobnpr said:

....Then, there's DDTC/ITAR, which is relevant if you manufacture ANY part for a firearm (USML) , and is required whether or not you need an FFL.

DDTC Issues Guidance on ITAR Registration | Prince Law Offices, P.C.

Click to expand...

+1

Note that penalties are, and have been, retroactive.

Note that guidance was a long time coming, remains vague and arbitrary, and can change again, almost certainly unfavorably, not favorably.

Not that "machining" is a common hot-button, as is "add capability" and that both may become more so, yet.

Serious "show stopper" as far as most folks should be concerned.

Let a properly credentialed gunsmith do it.

He's paying more fees and f*****g with more paperwork than he should HAVE to do, but at least doesn't have to drop the entire cost of that onto just ONE customer, one instance.

Give professional gunsmiths a bit of credit for their pain. Seek out good ones. Pay their fees.

In a manner of speaking, they are "buying in bulk" on their customer's behalf.

You wouldn't pass up such a deal on gasoline, tires, steak, fresh salad greens, or roast chicken, would you?

Especially not if there were million-dollar fines and 20 year prison terms for picking the wrong side of a "bargain".

I don't LIKE that legislation or the manner in which it is applied. Neither do I f**k with it.
All pain, no gain.

And I DO like nearly every Gunsmith I've ever met, personally, and more yet whom I have never met.

So there. Easy choice.

Most especially if one buys decent firearms, doesn't BREAK shit, and doesn't kid themselves the makers were so ignorant that everything they ever made needs "modified".