I bought my NMV 357 two years ago and shoot the same "full" power loads in it that I do in my 357 Colt Trooper and Ruger GP100 with no problems. All are handloads that I've gotten out of the powder company manuels and from magazines such as 'Handloader', 'Guns', 'American Rifleman', Shooting Times' and are not loaded to the max specs of each powder/bullet load combination. I don't believe any of the factory loadings available would give you a problem either. None of the printed material I received with the NMV had any ammo restrictions printed that I could see, nor have I read or heard of any. As with any thing, if ya handload your ammo, ya gotta use reason, common sense, and control in your loadings. Watch for any hard extractions, split cases, seperation rings around the base of the case, primer condition, etc. I've used hefty loads of Unique, Blue Dot, 296, 4227, and Acc #9 with 125 and 140 grain HP's and good loads of 2400 with 156 grain gas check cast bullets with no problems. As with any handgun, sustained use of heavy, high presure loads will take its toll someday, but that will take many thousands of rounds and ya gotta use judgement on what ya stick in the cylinders. I'm not in the shoot as heavy a load as ya can handle crowd, I don't want to wear my guns out, but if I wanted to shoot 'marshmellows, I would have long ago bought the cheapest 38 Special I could find and shoot target wadcutters out of it or joined the paint ball circuit.