I'm planning on building a CA legal rifle around an Off-List Lower- my first AR build.  Is there any reason I shouldn't build a .308 variant?  Will that make it much harder, or create any problems?  I like the idea of building the .308, as I already have a .223 rifle, a Mini 14.  I plan on a removable magazine, using either a Monsterman grip or a U-15 stock.  Thanks for any info/advice you can give me.

Quoted: I'm planning on building a CA legal rifle around an Off-List Lower- my first AR build.  Is there any reason I shouldn't build a .308 variant?  Will that make it much harder, or create any problems?  I like the idea of building the .308, as I already have a .223 rifle, a Mini 14.  I plan on a removable magazine, using either a Monsterman grip or a U-15 stock.  Thanks for any info/advice you can give me.

Why not?  If you already have a .223 and you want a .308 go for it.  I went the 6.8 route myself.

Thanks to both of you for your input, and no Ko-tonics, that was not ridiculously obvious to someone who is building his first rifle, and had not looked closely at a lower in years, forgot the mechanics of the lower, and when I saw the lower I wanted to buy today realized just what you stated- so your advice is well taken.   It's not the same.  Sooo,... when I saw the OLL I just had to buy it, sooo,....I am building a .223.  The very helpful guy at the shop (Antioch Armory) pointed out that overall, the .223 parts are easier to get and cheaper than the .308 parts.  Thus, my decision is made.  have

Thanks again to both of you.