All those zillions of threads of excitement about ATRS MS, and really hard to find a summary info. Do I understand correctly that both upper and lower are proprietary and standard upper is no-go for ATRS MS lower? So if I want ATRS MS in two calibers I'll have to buy two MS uppers ($485 to $625 each)? XCR-L doesn't look that expensive now, after some basic calculations for MS.
Is there a break down on what AR parts will fit and what won't?
You want a summary of information on the MS? Try emailing the manufacturer with your questions. Maybe try looking in the ATRS page under the dealer network tab above, they have a lot of info there. Maybe it's not that hard after all if you don't expect to be spoon fed all the answers and look for yourself.
You obviously know nothing about this or the law and how these receiver sets actually got an FRT that said non restricted. If the MS lower was compatible with AR-15 uppers it would be restricted.
No one ever said that these were budget parts priced so that everyone can afford one. You pay $1000 for an upper and lower that allows you to build a non restricted ARish rifle that takes most AR-15 mil-spec parts. This is why the ATRS and MDI offerings both use a different way of connecting the uppers and lowers. I am not a fan of the MDI design but that's just my opinion and irrelevant to this as it is another option for those that choose to go that route.
Your XCR-L comment is lacking any thought as well.
Do some math, you're looking at $1000 just for the receiver set then you're going to have to spend close to $1000 more in parts just to finish it as a budget build. If you want a precision build with high end parts you'll probably end up closer to $3000. So then you want another complete upper in a different caliber? Gonna cost around $1000 to put one together with a decent barrel and forend. Yes, you can build it cheaper but if you want it to perform you don't get to install a $50 Norinco barrel. Now I'm sure you're one of those guys that thinks that any rifle over $1000 is a rip off if it won't shoot sub moa with your $100 eBay scope, cheap barrel, and bulk ammo, but in the real world sub moa is reserved for rifles with quality barrels shooting quality ammunition with a capable shooter behind the rifle.
The XCR-L is around $3000 new if I recall correctly and a complete caliber conversion is $700-$1000 if my memory is working today. So you're looking at around $4000 either way you go but with the XCR-L you're going to be lucky to get one that shoots 2 moa with good ammo and the MS or SLR (if you chose a good barrel) should be able to easily shoot 1 moa or better with quality ammo and shooter.
Break down of parts that will fit a MS? All milspec parts except upper receiver and lower receiver which will only fit other ATRS MS receivers due to the design that was used to separate it from an AR-15 in the eyes of the firearms lab.
Few rifles that are AR like in term of ergonomics missing from the list:
Robinson Arms XCR-L
Bushmaster ACR (in NR barrel length)
B&T APC223
XCR is actually the one with best ergonomic by far, decent trigger too. But too bad mine was only mediocre in accuracy department, and aftermarket barrel isn't really an option.
ACR is way too heavy and the trigger sucks. Not my cup of tea.
I have no experience with APC223, but given the price, I wonder if it's really twice to 4 times better than the other options.
Not sure how you can say the XCR has better ergo's than the ACR, have you actually handled both or just going by what you've read on here? As far as I can tell as a guy who very recently had both of those rifles in my collection (just sold the XCR) they are almost identical for ergo's, the controls are almost identical and other than the XCR-L (quadrail version) being about half a pound lighter than my ACR (converted to NR model with medium contour barrel and polymer forend) they feel quite similar other than the thicker forend of the ACR. The ACR on the other hand is capable of much smaller groups if accuracy is a concern to you. I liked my XCR but it is not as nice as an ACR in my opinion.
Bad trigger on the ACR? change it. It's a standard milspec AR trigger with a different hammer spring.
Your comments about the APC price? Not that far off what you'll pay for any other
quality non restricted black rifle. Swiss Arms green and black rifles have been $3000+ for the last 15 years so is this one that far off? Is it 4x better? Depends how you evaluate them, I can guarantee that it is 4x better than an FX-9, WK180c, SU-16, Sub2000, Mini-14, Norinco M-14, T-97 or any other $1000 non restricted option you can find. Don't like the price? Buy something cheaper then spend a grand changing out parts you don't like.
The price isn't only about it being that much better than others, did you consider where it was made? Do the Swiss have a reputation for building crappy rifles (or anything)? Perhaps the quality is more than a little better than the options built in Canada by companies like BCL and MDI that have a high percentage of products come out that are out of spec and need to be fitted by the customer when it was advertised as being compatible with other milspec parts. Or complete rifles just plain not working from day one in BCL's case. Consider the import fees to bring it in? The APC is not high on my list of rifles to buy but I know that if I did buy one the quality would not be a problem, My SA classic green was a beautiful rifle but it didn't fill my checkboxes for a keeper like my ACR does.
Not to disparage your product in any way shape or form, but unless you could promise this gun to shoot SUB MOA with available off the shelf match ammo (IE Hornady or Frontier) I really couldn't see myself being interested.
Why on Earth would you expect it to shoot sub moa? Do all of your $2000 black rifles shoot sub moa? Have you ever shot a 5 round sub moa group from any semi auto? They are not precision build rifles, they are civilian versions of military rifles and those rifles were originally designed for less than 4 moa is good enough. It's not impossible to do but to say you wouldn't buy it if it couldn't is silly, do you know anything about the rifle it was based off of? Not a precision semi. You want consistent sub moa? Not going to happen even for some of the guys that spend $3000+ building an MS or SLR.
But if you just want a rifle that can occasionally fluke off a 3 shot sub moa group then you can start saying that your Norinco or Kel-Tec will shoot sub moa so these should as well.
To be honest these Canadian non AR 15 things are complete trash and manufacturers are getting away with selling low quality firearms because we are eager to buy non restricted black rifles.
Not all of them.
They get away with it because guys refuse to send things back and force the companies to fix their screw-ups. Until people stop accepting poorly made products and just fixing it themselves and these companies start spending more money fixing stuff on warranty than they're making selling the crap in the first place nothing is going to change.
Try an ATRS product, I own a Modern Hunter and it is amazing. The fit and finish is perfect, I did take it back and have them tweak a couple little things for me but it runs reliably and is very accurate.