This might be a bit of an over-simplification, so expert reloaders please forgive me.
When a round is fired, the case stretches until it touches the walls of the firing chamber. Once the bullet leaves the barrel the pressure drops and the case contracts a bit and the empty case is extracted and ejected. The diameter of the fired case is a tiny bit more than the diameter of the original unfired case. The reloader should perform a sizing operation to compress or squeeze the case back to a smaller nominal size, with a tolerance of plus or minus some small amount. Barrels are manufactured with a nominal diameter firing chamber, plus or minus a tolerance, and are designed to accept ammo that has a case that is properly sized to *its* nominal diameter. If the case isn't the proper diameter, whether due to a sizing operation problem or a crimp problem as other posters have noted, the round might work in some barrels that have a firing chamber diameter on the large end of the tolerance, but not feed or eject ammo from a barrel that has a firing chamber on the low end of the tolerance.
What I think is happening in your situation is your FIL's guns have firing chambers with diameters large enough to cycle the ammo, but your guns have firing chambers that are smaller, but probably still within spec. The key to the problem are the statements you made regarding your guns that "...the casing always is slow to eject..." and "They work in all of his guns...", referring to your FIL's guns. The friction between the too-large case and your gun's firing chamber is slowing the extraction process and causing the rounds to extract poorly or not at all. If the diameter of the reloaded ammo was correct, it wouldn't offer much resistance during extraction. Could be your guns have smaller firing chambers because your guns are newer. Or perhaps its just the way your barrels were made. Who knows? Tiny differences in the diameters of the ammo and firing chamber make all the difference. The problem is highly unlikely to be with your guns. Its not likely to be the recoil spring, not the magazine spring, not the charge (amount of power in the case), not lubrication. The problem is almost surely with the size of the reloaded ammo. In other words, the ammo is the problem, not your guns.
You could measure your reloaded ammo with a micrometer, or you could simply remove the barrel from your gun and drop ammo into the firing chamber one round at a time. You're basically using your barrel as the measuring device or gauge to screen the ammo. If a round drops in and falls out easily, with no force applied other than gravity, it will probably function in the gun. If a round doesn't drop in and out freely, without being pushed or pulled, don't use it in that gun. It might work just fine in another gun of the same caliber (like all of your FIL's guns). I'd bet that rounds that are tight in your barrels fall easily in and out of your FIL's guns.
I once had problems with a SIG P239 that wouldn't reliably eject commercial reloads. Same ammo worked fine in *every other* 9mm gun I had. Come to find out, the ammo wasn't properly sized during the reloading process. The P239 had a barrel with a firing chamber diameter on the low end of the tolerance, but still within spec (probably the same as your situation.) The reloaded ammo had several rounds per box that were larger in diameter than the high end tolerance for that caliber. Those rounds were unquestionably out of spec (too big) and shouldn't have passed the reloader's quality control checks and made their way into the box in the first place. When I showed the problem to the owner of the reloading company, he was both dumbfounded and perplexed, but admitted the error and gave me several free boxes for my trouble. And yes, I stood there and dropped every round into my barrel until I had the requisite number of full boxes containing rounds that freely dropped in and out.
Eventually, I found another solution: I stopped using reloads. I've found that factory ammo is made to far more exacting tolerances than reloads. I'm going to use factory JHP ammo for self defense anyway, so why not practice with factory FMJ of the same bullet weight?