Originally Posted by aristoi
After many hours of research I am going along the same lines as well. I would not replace just the upper tho but build a whole new AR, perhaps in 7.62×51. Perhaps not it depends on What I find when I have a few extra dollars to spare.
I am disabled and unable to work so I only get paid once a month when the bills are paid there is Precious little left. Each buy must count so it may take a year or two to make a AR.
Keep in mind alot of the 7.62x51 stuff is proprietary to each manufacturer, the top rail height of the Armalite and the DPMS is not the same so if you go with a free float hand guard it may not match up with the top rail of the upper receiver perfectly . Along with this DPMS has 3 different upper rail heights, gen 1 lo profile , gen 2 hi profile and Oracle which is a really tall upper rail height , Barrel nuts are not all the same thread size , DPMS will not fit Armalite , etc . There are different BCGs that aren't all compatible. I wont tell people to not build their own because its their choice and you get what you want that way , however with the higher price of the .308 parts one mistake ordering the wrong parts can be very expensive and hurt when your on a budget or limited on funds to do it right the first time. If your truly going this route do your research and ask alot of questions when figuring out what you want . Mil spec Trigger groups are mostly the same between .308 and AR15 however there are some of the drop ins that dont fit between the 2 and they may have a special drop in for the .308 . If you have any questions I will help you as much as I can . I have only worked with the AR10 and the DPMS so im not real informational on the rest of the .308 ARs out there . I have not found a F/F rail out there that will match up to the DPMS oracle rail height so keep that in mind
You may also find that buying a complete and adding the parts you want may be cheaper than building the whole thing . Thats the route I went and added what I wanted . I sold off the original parts which paid for almost all of my upgrades .