I see that Tannery Shop list the following types of metals for 80% lowers:

ALUMINUM / BRONZE
TITANIUM
410 STAINLESS STEEL
CMM-CERAMIC MATRIX METAL
356 ( T6 ) ALUMINUM GRADE #1

What are the merits of each and why would I want one over the other? Is this more of a color issue or do I realy get something out of the different metals? And what the hell is CERAMIC MATRIX METAL?

Thanks

Titanium is super tough & light but is hell on machine tooling.
Stainless steel is tough to machine but not as bad as Ti.  Heavy though.
Aluminum bronze is supposed to be sweet to machine, doesn't need to be anodized but is heavy.
CMM is aluminum with something else added .  Slightly better than standard 356 AL.

If & when I get around to doing a 80% lower I might go with the aluminum bronze.

I've seen pictures on the Web of a copper lower, too...

...Evidently for electricians who like to BIY...

My opinion....use only 7075t6 material for a firearm use. Anything else I wouldn't stake my life on unless you just building a wall hanger.
CMM its still a casting with ceramic and other materials added to help strenghten the casting but it still will not compare to a forged 7075 receiver. I mean dam...a few more dollars will get you a forged receiver. Skip lunch one day and you'll have enough to get a forging.

Lets put it this way...Lets say you have an option to buy a cast or a forged, 3/4 combination wrench from Sears...whats it gonna be. The choice is clear.

Okay, where do I get a forged 80% lower. I was under the impression that all of the Tanery Shop 80% lowers were casts.

www.lesbaer.com  has a lower with just the mag well done.

A guy on ebay has some forgings.

I'm making another small batch of billet machined 7075t6 around 50% done.

There are a few more sources just do a google search.

Rick

There's nothing wrong with cast lowers. Granted, forged is superior in strength and gives a superior appearance when finished, but strength isn't something that is of concern as there is very little stress put on the lower.

If your going to complete your 1st lower, go for the cast. Its better to screw up or destroy an $80 cast lower than a $150 forged.

Another source for forged lowers is [url=www.ktordnance.com]KT Ordnance[/url]

A casting is not nearly as "true" as a forging can be, too much distortion in the process. the metal of a casting (AL 356 better be T6) is only half as strong as a forging (Al 7075 T6). But if you are not expecting the gun to last forever or just want to build and shoot and maybe update later no big deal. I can tell you first hand that a 0% raw forging is a lot of work but is the cheapest way to go if you have the facilities.
Good luck