I'm working with my local dealer in request for the M7A1 PDW and he pointed out that he can offer the P7A1 nearly $4 or $500 cheaper. I'm trying to find the difference between the two. So far all I can tell is that the stock is different.
The M7A1 in particular I'm looking at is
http://troydefense.com/portfolio/troy-m7a1-rifles/

7.5 or 10.5 barrel in 5.56

Does anyone else have any info on the difference between these two and why such the price gap?

Thanks

The stock is worth a couple hundred on its own.

apparently from Troy, there isn't a difference except for the stock. So I saved a few bucks and put it in the optics.

I'm getting the P7A1 Pistol and the Troy M7A1 Stock which includes an extra bolt carrier with enough left over to get an Aimpoint P.O.S. and I still spent less than MSRP for the M7A1 PDW full gun.
no complaints here. Just glad to have a decent dealer to work with!!!

 
Just to make sure, but you do know that if you want to install the stock on the P7A1 pistol you'll have to pay the $200 tax and have it SBR'd?

yes sir
in the meantime, the stock will sit idle in a box (available for one of my other rifles if ever questioned) and I'll just have a pistol.
paperwork is in for the trust :)

Besides Troys past anti antics, for that kind of money you could build yourself a very nice pistol and not deal with propitiatory parts of that thing.  IMO you really should do yourself a favor and rethink this one a bit.