Anyone use, look, smell, or feel one? I'm really wanting a 10mm upper to chop and turn into an SBR. I was planning on getting one and wanted to know if anyone had handled one yet. More importantly, how is the mag system?

Let me know your thoughts.

I am not sure what you mean by "new" 10mm upper, but I had one about 6 or 7 years ago that worked perfectly.  It came with one modified 41AE UZI magazine.

Tony Rumore
Tromix

NEW?!  Are they now making a new version that takes Glock mags?  If so I will be ordering one.  I really like my Oly Glock9mm AR.

Ok, maybe not brand new. I meant the new Franken mags they're making.

I have one with the "frankenmags," but I've not gotten to the range with it enough to really call it tested out.

I do plan to change that soon, maybe even today if the weather holds.

Weather held, so here's my take on my gun:  Don't get one.  Unless you absolutely must have a 10mm Auto AR-15, and, for whatever reason, don't want that Ron guy to make you one.

First problem I had with it.  The magazine swells when you add ammunition to it, or at least mine did.  When empty, it was easy to get in and out, but after putting about ten rounds into it, it started getting harder to get the magazine into the mag well.  Alledgedly, this is a 20-round magazine.  With fifteen in there (it's a very hard spring, so it's hard to get more than this) I could not get it into the mag well.

It ran fine, however, though the accuracy was lacking.  I know it's an apples and oranges comparison between a 5.56mm upper and a 10mm upper, but since I was getting 12moa, I'm calling that lacking.  I don't have the best set-up on my 10mm Oly, but I can do better than this with a 5.56mm with iron sights.  Heck. I used to have a Hi-Point that did better than this.

ymmv, but I'm disappointed in mine.  Not so much as to take a hit selling the upper and then trying to find something to replace it in the 10mm auto category, but certainly disappointed.

If the magazine is swelling up, it sounds like the magazine is not wide enough to allow the rounds to fully double stack.
You can make a magazine that single stacks or double stacks, but stack-and-a-half doesn't work worth a **it.

Tony Rumore
Tromix

Are you saying he should be thinking about getting one from Ron instead of getting an Oly upper? Ron makes good stuff and I think that's what your saying in reguards to a 10mm upper.

Ok, so, who other than Oly is making a 10mm upper ?

Ron Williams has made quite a few DI uppers... other than that I don't know of any.

Considering how many people seem to have good things to say about his stuff, I'd say that's exactly what I'd recommend.

The 10mm is perfect for gas/DI. Going to test onther 10.5' this weekend. By running in gas/DI the recoil impulse is mild & the hottest loads will drop the cases about 5 feet away in a pile. With blowback, the heavyist spring/buffer combo my cases were thrown a county mile.

I kinda figured that's what you ment. Now what would somebody do for mags if they wanted to stay with a standard AR lower?

That's a good question.  I have a Glock 20, and I tried the magazine in my AR's mag well, but it won't fit.  There wasn't much overlap, so maybe a magazine from some other double-stack 10mm might work, but those aren't common, either.  Which leads to going with something like a 10mm 1911 magazine with a block inside the mag well.  What would be nice - in theory, at least - is a magazine that is double-stack outside of the mag well and tapers down to single stack inside the mag well.  I.E. a totally new magazine.

I'm sure Ron has a solution that works.

I mod GG mags the way oly did back in the day but I dont weld a block on the back. I use a block in the front of the lower.
This is the first 10mm I built.

The Witness 10mm has a sheetmetal double stack mag so it should be slimmer than the Glock one.

Yeah, I had one of those EAAs.  I'd hope they've figured out whatever magazine problems they were having at that time.  I had a full-size gun.  It was supposed to hold 15 rounds in a magazine.  I could never get more than 13 in any of the three I had (one came with the gun, sounded like a mag problem, so I ordered a pair of new ones) and they misfed multiple times per magazine.  I sold the gun, fully disclosing all of it's issues, to a guy that I presume knew how to fix whatever was causing the issues.