The reason for the Model 1 buy was it is inexpensive...
A few notes: I placed the upper on my Bushmaster M4 and it shot great. and it is accurate. However, we are looking at an extra gun. The lowers that are available are old (1960's) M-16 versons.
I called Bushmaster and they have recommended the same about the buffer and D-ring... Both are on order as I type, so we'll see what it does.
Thanks for the help...