I want a 6.5 grendel. How I get there, I haven't decided. I hope you all can help me decide. So, I found a 6.5 upper made by Anderson for about $475. It is completed, so all I'd have to do is slap it on my preexisting 5.56 lower. Easy and done deal. OR, should I build this thing from scratch? My lgs has a large assortment of stripped lowers, and I could start there and then build the upper from scratch as well with the parts that attract me. I don't think there's anything wrong with the Anderson, but do you think I'll get more utility out of two separate rifles instead of one and to have one that I built specifically to meet my wants?

OK, so this is my opinion only, so take it as just one of many view points.

6.5 Grendel is a bit different than 5.56 in terms of shooting dynamics.  As you tune your rifle for the best configuration for your new upper, you may find that your existing 5.56 lower may need a different buffer, spring, and in worse case a different FCG.  Not that what you have won't work, it probably will, just not optimized.  So I think you'll find yourself making some compromises between the two calibers that will bug you.  I know it would probably bug me.  You could easily swap buffers and springs around when you change uppers, but that will get old...  ask me how I know.

My vote would be to build out a matching Anderson lower, and get that lower receiver outfitted to optimize your shooting experience with your new 6.5 Grendel upper.  Whatever you decide, be safe and have fun.

One lower to rule them all. For now, do more later when you have the time and money.

Building an upper is easy and fun.

Make sure you get an adjustable gas block.
Lap the upper face, and bed the barrel with loctite.
I forget which one, it is 6xx green and for cylinders.

I just built another rifle from scratch when I wanted a Grendel!  A lot more fun!

I’m in the process of a building an 18” Grendel from scratch. The lower is an 80% I did from New Frontier. Vltor MUR upper, and X-Caliber is spinning me a barrel in RLGS.

I’m going to try T2 buffer and mil-spec carbine spring to start. Hopefully that will run Hornady 123 and FGMM 130 Berger just fine.

Few more weeks on the barrel.

Good luck OP. Just remember, when in doubt...build another out.

If you were to build one, think of exactly what parts you would use. Does the completed upper have those parts? If not then I'd build, but compare the cost of building to the cost of the completed upper including the cost of replacing the parts you would prefer to have on it.

I always build that way you always get exactly what you want, don't pay more for crap you don't want and end up spending more to upgrade parts I don't like. Building is always a win win.

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