I've never made a flintlock, from a kit or anything else. But I have made, from kits:

a left-handed half-stock Hawken-style .45 caliber rifle (for my brother);
a right-handed .45 caliber full-stock rifle (given to my nephews);
a right-handed .50 caliber half-stock "Plains rifle";
a .44 caliber repro of the 1858 Remington New Army revolver;
a .44 caliber repro of the 1861 Colt Army revolver;
a .45 caliber "Kentucky" pistol;
a .36 caliber double-barreled pistol ("The world's smallest double-barreled shotgun");
a .45 caliber "Derringer",

all to see if I could. All of these were percussion locks (caplocks).

The revolvers share a partitioned box I made for them, the "Kentucky" pistol lives in a leather holster/case I made for it, and the "Derringer" resides in a fancy box I bought with a repro deck of early cards, some lead dice and a "racy" picture -- the "Gentleman's Entertainment Center."

I've shot all of them, they all work, I'm intact, and I've found that the best way to test fire them the first time is to take them to the range, get everything ready, hand the gun to your brother and say, "Dammit! Go on ahead, I left my sunglasses in the car."

Kendall, I was shooting on of my black powder rifles at a range when I heard the two twenty-somethings on the next lane cussin' out the M-1 they were shooting. I wandered over and ask if I could help -- I'd trained on the M-1 in the Army. So they handed me ("What the heck can a black-powder shooter teach us?") the rifle and a clip of 8 rounds. I showed them how to load it, how to lean into it, how to keep their thumbs off the neck of the stock so that the recoil didn't mess up your glasses -- and at a hundred yards, shot a tin can into the air and with the next seven rounds kept it spinning in the air. Best shooting I've ever done! When the clip went "SPOING" and ejected, I handed them back the rifle with the comment, "GOOD gun!" and walked away from a couple of slacked jawed young men.

I'm sure you must have heard of the City type who roared up in front of a small store in Maine and yelled at the young feller on the porch, "Hey, old timer! Good huntin' around here." "A-yup," was the reply, "Plenty of good hunting around here," and the car roared off. A week later, the same car came back the other way, and the same loud driver yelled at the same young feller, "Hey! You said there was good hunting around here! I didn't shoot anything! Didn't even SEE anything!" And the young feller replied, "Lots of good hunting, just not a lot of things to shoot."