First let me post a link to a thread that you might want to read before reading this one. There is some good information and some what would have been great information to have BEFORE I made my purchase.
http://www.ar15.com/forums/t_3_15/640620__22_Upper_chambers.html

Now then, I bought a TacCom Tracker upper around March/April. Don't remember exactly and delivery took a little longer than advised. I chose that specific upper because I wanted to copy my M4gery as close as possible. The uber lightweight CF forearm is useless to me personally, but that's the one offered. After numerous discussions with TacCom directly, they recommended the S&W M&P15 .22 magazines and their slip in adapter. Tim - the owner - swore that despite my wants, nobody makes an AR22 that gets better than about 1" @ 50 yards because "they won't function unless it is a SAMMI .22LR chamber.". Hmmmmm.

That fact alone kept me from getting one for a couple of years. Well I could wait no more (awaiting BATF paperwork approval for my Suppressor! ) but neither could I afford $1,000 .22 upper so I ordered it up, with the adapter and magazines as recommended. Well Tim was right about one thing... HIS AR22 would do no better than 1" at 50 yards. Actually 2 loads did do about 3/4", but the rest were all 1.5"+. BUT function was not good. Lots of FTF & FTE. Now he warned me that aftermarket triggers do not do well. It requires quite a bit of trigger force to make these rounds go off & I also found that to be very true.

All of my lowers have aftermarket triggers. I don't even like National Match triggers if that gives you any indication. So a couple were out, but one I could adjust up enough that it went off about 75% of the time. Well being a 10/22 Nerd this was all not acceptable to me. TacCom basically said "told you so!" and I had what I had. BUT... I knew better. I know I can get better accuracy from a .22. I just know it. I got some help from a dear friend (who I won't name) to help me. He has all the tools, all I had was ideas. Anyway after a couple of back and forth trips and his machining and massaging I ordered two black dog magazines and finally got to the range again today for the first time since May.

Well lemme tell you something... Old Tim was wrong! HIS AR22 WILL shoot reliably (with Black Dog mags anyway) and much more accurately with a modified chamber! I went from about 1.5" averages to only 2 of 9 loads shooting that poorly anymore. Here are averages of 2 x 5 shot groups of some of the better ones:
CCI Mini Mag - .612"
CCI SGB - .706"
CCI Blazer - .562"
Wolf MT - .478"
Wolf ME - .264"

That is the best average I have ever shot with Wolf ME in ANY firearm. That is lights out for a non-match type gun and included one group of .199". Wow. This build is strictly for fun. It is built to match my M4gery so I can have cheap shooting practice. I will probably not ever even hunt with it - BUT shooting and not hitting what you aim at is zero fun, thus the need for better accuracy. I had 3 FTF, but all with the same load - which was not an accurate one - so that is a non issue.

I still have quite a bit of Blazer and Mini Mag stashed so I am golden for plinking ammo hopefully until .22 ammo supply squares up again. So for anyone considering one of these, I hope this little report helps. And before anyone fires up the flame thrower, I am not bashing anybody - I got exactly what I was told I was going to get and I paid my money and took my chances. I decided on my own to not settle for what it was. I know I am not the first one to ever modify a new rifle/upper after getting it, huh?

All the best
Mark

Actually......there are couple of things that you thought I said, which I would never say. So I will re-state:

1) the SAAMI sporter chamber is the most reliable chamber....a shortened SAAMI chamber comes in a close second, depending how short you chamber it. A modified bentz chamber will work as well, but can cause issues with live round extraction.

2) As for accuracy.....1" 10 shot groups AVE for 10 groups @ 50yds......is VERY hard to do and I doubt that any manufacture out there can build a production AR15 that will do that. ALSO.....if anyone claims that they have an AR15 22LR that can do 10 groups, consisting of 10 shots that ave under 1" @50yds........I want to come witness it. If you can do it, while I am there, I will give you a brand new top of the line TACCOM AR15 22RF upper. If you fail to do that....you pay for all of my expenses for the trip. To date no one has taken me up on that offer.

3) 1.5" groups at 50 yards is great if you are not using wind flags, bench rest and match ammo. And TACCOM uppers will do that or better.

4) Getting a sub 3.5 pound trigger to work on 22RF is tricky....can be done, but tricky. Sharpening the firing pin can help.....but head space can be key in this set up and in this case, less is better.

Of course, I was not there.....so I really have no idea how many rounds that you shot thru your barrel before you modified it, however there is a lot to be said about break in, 'seasoning', etc.

Bottom line......you've got a nice shooting rifle there.....and got there well.

Tim

Seems to me that there is some useful information, modifications  and tweaks that the community might find helpful in improving accuracy and reliability of their  uppers.  Can you be more specific in the mods and especially the mods to the chamber. Did you re-chamber the Taccom3 chamber to a Bentz or some other magic?
I think this is the type of info that the community should welcome and embrace.

YES, to the above!
Inquiring minds want to know.

Actually....back in the day before all the 10/22 bull barrels.....we used to take that std stock barrel. Cut the rear face off by .010/.015"....set back the shoulder if needed, file out the extractor groove a little. Re-crown and have a VERY accurate barrel.

Tim

That actually that is exactly what we did with TacComs barrel. And reamed it out with a Bentz chamber reamer. Despite Tim's advice that it would not operate reliably, it has so far been just as reliable as before any mods. More so in fact because of the change to BD magazines. As long as the bolt is lubricated like it likes and I use a trigger with sufficient force, it is completely reliable. Now if I can just find the right barrel nut for the AM forearm I want to put on it, it will be just about perfect.

I've never said that it would NOT be reliable.....I said that in a production setting, we would not do a modified bentz chamber as the is a greater potential for that chamber to be less reliable.

Please, don't quote me.....you are getting it all wrong.

Tim

Not to contradict Tim but here are some of my groups from a Taccom Ultra Light




Dave N

Tim, I didn't "quote" you, but I stand by what I said. You told me on the phone that in your experience the Bentz chamber is NOT reliable in your builds and you would not use it. That is not verbatim I'm sure as it was many months ago, but that is the gist of the message because I even asked you if you would cut a Bentz chamber for me on request and you declined. Whether in a production setting, would, wouldn't or potential - whatever. That is semantics to me. I stand by what I said. I am getting nothing wrong.

Shadowcop, I guess I got a bad one. Prior to working on it, I couldn't get ANY ammo near what you got.

nevermind