Good for malfunction drills
Diameter and length is not correct so they double feed every single time. They are great for malfunction training, but nothing else.
Packaging is Everything
We ordered 3 packs of the .357 Sig dummy rounds along with several others for an LE Firearms Instructor course. We received one package which was fine. The second two came in a later shipment. They were labeled .357 Sig, right skew # but the dummies were .357 magnum. We were short on the supplies for our LE Firearms Instructor course. We made do, but it wasn't up to our own expectations. Mistakes happen.
Useless.
I bought these to practice cycling my Howa 1500. These things don't extract. I now have a stupid dummy round stuck in the chamber and I'm going to have to punch the bore to get it out. Save these for your miniature bowling alley and buy something else for your guns.
significantly undersized. Double feeds.
The body diameter on these is ~ 0.010" below the SAAMI minimum material condition (0.3679, as noted in picture), and as a result, the dummies will consistently release from the feed lips before being stripped by the bolt, resulting in double feeding. The ONLY use for these is malfunction drills, because they WILL malfunction, EVERY time. It was only $10, so it's not worth sending back, when the magpul and A-zoom offerings that I have work fine.
Maybe not.....
Bought these to practice cycle my new CMP M1 Garand. Pulled the rims off two during first loading. Not very durable.
Too Thick, Jams in Gun
All of the 10 round I received were too thick for my 9mm. Some even got super jammed into my barrel and I had to dismantle my gun and get tools out to remove it from the barrel, thus destroying the round itself. Also, While cycling a round, the plastic rim often breaks because it is too weak when the extractor grips on to it.
Jam
Jammed my maverick 88' hung up on the elevator needed to remove trigger housing to remove trainer shell. Gunsmith felt the may have been to light
Very Embarassing Product
As a Firearms Instructor, I purchased these to use in my classes. So far, 3 have gotten stuck in the chamber of my 1911 and I have have to stop class to take a long screw driver or cleaning rod and pound-out the stuck dummy round. As an Instructor, this left me looking like a novice, which is not acceptable. I would not purchase these again.
Poor Design
We bought them for police training and will never buy them again. They cause double feeds because they pop out of the magazines. They also get stuck in the locking lugs and under the gas tube because they don't feed properyly. The soft plastic rims will not hold up and fail to extract frequently. The pistol calibres work fine.
Poor Quality
These thins are great in pistol calibre but terrible in AR-15 style guns. We spend more time digging them out of the locking lugs than training with them. We use them for malfunction drills and they take up way too much time. Buy dummy rounds with metal cases.