Well what are you planning on using this on/for? How much do you want to spend? The AR-10 is not as "standard" as the ar-15 as far as parts interchangeability. Alot of manufactures parts are proprietary. Now i would suggest that you look into the DPMS rifles/kits. Keep in mind that if you are thinking you will save money and by parts and assemble them yourself let me assure you it will not save you money. They offer there rifles for just as good as you can build it for plus you have to obtain the tools to build one(ie barrel wrench,torque wrench,action vise). DPMS is the best bang for your buck so to speak and i would start with one of there LR260 or 6.5 creed. Parts availability (not now but) is usually good and price is great. All the ar-10 i have built have been of the DPMS style and all have been great shooters with proper assembly and good load development.