Does it affect the fitment of the weapon to mix match brands?

I was told to get a Bushmaster or RRA lower, and a kit from either:


Model 1

http://www.model1sales.com/


or

J&T

http://www.jtdistributing.com/


Who makes the uppers in these kits? and does that make a different in the tolerances in how the kit might fit together?

Sorry for all the questions, this is my first DIY kit. Thanks for all the advise.

All the combo's you listed will work fine. There are, truely, thousands of those kits built by members here.

I just put together a kit from M&A Parts with a RRA lower, everything fit perfectly, no problems at all.

[url]http://www.m-aparts.com/[/url]  [8D]

THanks for the replies. I was beginning to wonder with all the manufactures, what standards they stick to inorder to assure all the tolerances are met when mixed and matched with other lines.

While almost all lowers will properly fit almost all uppers, it isn't always so. There are a number of threads that deal with this.

If you're shopping at a gun show, it is a good idea to buy either the lower or the upper and take it with you to buy the other part.  Usually, it is easier to buy the lower first, as you can more easily choose the upper to fit.

If you're mail ordering both, of course, you couldn't do that.  

But the cases of poor fit are not common, whichever way you choose to do it, so although it's a good question there isn't a lot to be concerned about. For what it's worth, my next build is going to be a J&T kit on an Eagle lower. Bushmaster lowers are a little too expensive in my opinion, but their quality is excellent. Never used a RRA.