Anybody have an opinion on a 5.7x28 upper for ar ?

It is really pointless when compared to the 223. The only advatage is less recoil.

223 has better range, is faster, has more energy, better ammo selection, cheaper, etc.

Don't try to fix something that isn't broke. Now the PS90, that's another story. I wouldn't mind owning one of those.

expensive and pretty hard to find ammo

Thanks for the input ! Just thought it was a pretty cool round and didn't know anybody that had one to ask questions !

why not just get the 5.7 pistol?

5.7 in an AR... I don't see an advantage

Have the PS-90 and it is a fun little pea shooter. In reality ballistics is about like shooting a 22 Hornet. Some say that is a useless cartridge also but I do not think so. It is quieter than a 223 and still effective on yotes to 200 yards. The PS-90 is accurate enough for that as well without brass flying all over the place. Load up a mag will cost you $50 dollars but then again that is 50 rounds without a long mag hanging down to get in the way and catch on things. The one 5.7X28 AR upper I have played with worked well and was accurate enough to be fun.

5.7 x 28 ammo is a bit pricey. I can tell you as a rifle cartridge it is very particle. I have the ps90 and an eabco custom 5.7 x 28 g2 t/c barrel. the 27 gr HP ss195lf (cooper lead free) is my favorite round.on the ranch it makes an excellent pest bullet. Have a pond out front. Beaver come down the creek and want to tunnel into dam. I don't have to worry about ricochets into livestock.

I like it.

Rusty

I have FiveseveN also. 40 + 1 with extra mag. You can also buy 30 round mag for pistol and 30 round mag for ps90. You could carry hunting small game mag and a pest mag for carbine

Rusty

There are 50 round mags for the PS90 and AR Upper. As far as cost it is about 50 cents a shot with factory ammo and a little cheaper than the 223 to reload since it takes less powder. Find expanding bullets for your 223 that are any cheaper. That is as hard to do as finding good 223 ammo or 5.7 ammo on the shelves now.

Brass life is not very good since the shoulder has to be pushed back every time if shot from a PS90 not sure about the AR.

It's very fun to shoot with absolutely no recoil! I used mine to take down several piggies. Downside ammo can be expensive and hard to find but then again so is my 6.8 and 300blk. It's also supposed to be a good home defense round since the bullet isn't supposed to go through walls