Okay, I laid hands on some FEDERAL generic M193 and shot the thing again today. Three 5 shot groups, all of them in the 1.24" neighborhood, all of them with 4 of the 5 shots well under an inch--4 in .671 in one case. THAT's more like what I expect this gun to do.

But dunno if last week's 2+ inch "patterns" were the fault of Rem ammo or not. Someone suggested I check my scope mounts so I did. Found that what I thought was finger-"tight" MIGHT have been allowing a little movement so I laid some pliers upon the carry handle nut. Whether it was the ammo or strapping down that nut, I can't say but the gun seems to be running fine again. Oh, BTW, when it was shooting good BEFORE the Remington ammo, I only had the scope nut down "finger tight" so draw your own conclusion.

Thanks to all who responded with ideas and words of encouragement in the original thread.

I'm glad your situation has improved.
Sincerely,
Craig

No, Remington ammo is not necessarily junk. I would say what you experienced was the result of one of these 2 things:

A. It was the scope issue
B. Your particular rifle may not like that particular ammo

I've seen some guns that will shoot pretty poorly with one brand of ammo. Switch it and it may run just fine. You may bring out another identical model weapon and get exactly opposite results. It's weird, but some rifles simply favor some types of ammo more than others. FWIW, a  group in the 2" range @ 100 isn't horrible. But it's not great either.

I might be able to take the ammo you had poor luck and get nice groups in one of my guns. Guns are just like people....they have different personalties. Some like different foods. Hehe.

Oh yeah, I know all about individual rifles having their own personal preferences, having just bench-tested 17 different .22s with five different kinds of ammo each. I've just never seen a centerfire give a 100% discrepancy between two similar types of ammo before. But I guess it happens.

Was looking at those targets again today and something else struck me. With both ammo types, the dispersion is mainly--almost all--horizontal. Even stranger, I fired one five-shot group with the open sights and those were in a nice circular cluster of about an inch. I am beginning to suspect something is going on with that scope or mount.

Usually horozontal stringing implies trigger control.  But I don't know what it could be if you shot nice round groups with open sites.

Remington UMC in my bushy 20" HBAR gave me bad groups.  It scared me.  It was the first ammo I tested for accuracy in my AR.  I was getting about 1 1/2" at 50 yrds.  Then I put some XM193 in and got about 3/4"(I'm not a good shot either) at 50 yrds.

Yellow box is a piece of crap. Mine keyholed the bullets. That's all it took me to never shoot it again.