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AR “Billet” lower vs. Standard Lower - Any significant advantages of the Billet over the cast/forged?

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March 17, 2019, 07:27 PM
sigarmsp226
AR “Billet” lower vs. Standard Lower - Any significant advantages of the Billet over the cast/forged?
I am looking at purchasing a new AR-15 rifle and I very interested in the Springfield Armory AR...

The one I am really interested in is the 2019 released SA Saint Victor but I see that they also have their Edge model that has a Billet lower...Any feedback on the SA Victor or the SA Edge and/or a Billet vs. Non-Billet lower is appreciated...Thanks Mark
March 17, 2019, 08:12 PM
gearhounds
^^^^
I don’t think it really matters; millions of standard non-billet lowers bears this out.




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March 17, 2019, 08:24 PM
striker1
There are cast lowers out there, although I’ve never seen one. Not as “tough” as a billet or forged lower. I wouldn’t buy one.

Billet is 100% milled from extruded (or forged) aluminum bar stock, usually 6061, which is not as hard as 7075. IMHO, just a way to get the end user to spend extra money. Not that there’s anything wrong with that. Many newer billet lowers are now made from forged 7075 stock.

Billet lowers might get extra points for the cool factor or better aesthetics, but generally offer no additional functionality.

Forged lowers are usually 7075 aluminum, forged to a near-net shape and then finished with milling.

All the above will work.


My preference is “mil-spec” 7075-T6 lowers, uppers, and receiver extension tubes.



RB

Cancer fighter (Non-Hodgkins Lymphoma) since 2009, now fighting Diffuse Large B-Cell Lymphoma.


March 17, 2019, 09:12 PM
arcwelder
"Non billet" means forged, most AR lowers are forged. Some are cast.

The cast/forged/billet issue has greater importance in other firearms and parts. In the case of an AR lower, first, you're not all that likely to run into a cast lower.

The AR lower sees almost no wear. Particularly in a semi-auto gun. The wear a lower does see, is fire control pins egging out the holes in the lower. This happens in guns that see a lot of automatic fire.

AL is not a strong material. between a cast or forged lower, it boils down to machined tolerances, and how it fits with other parts.

It's not something you _need_ to worry about. It is optional.


Arc.
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March 17, 2019, 11:15 PM
IndianaBoy
Some billet lowers have slightly altered geometry which will prohibit the use of some magazines like the Magpul D60.
I don't recall which ones but I have seen that reported before.
March 18, 2019, 01:32 AM
mo4040
If you are looking to build a special rifle with an ambi selector, ambi mag release, and an ambi bolt release, then consider a billet lower. As you will usually find those features (especially the ambi bolt and ambi mag releases) exclusive to billet lowers.

Outside of that, a forged lower will be just fine (and weigh a little less, also).


__________________________
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March 18, 2019, 07:47 AM
fritz
I can't speak to the Springfield ARs. Never shot one, never handled one.

I have both billet and forged uppers/lowers. Both work fine. The billet models seem a nicer aesthetically.

I will note that my most accurate AR-10 and AR-15 are billet builds, however they also have my best barrels -- Kriegers. I suspect the barrel quality is more important to the great accuracy than the type of upper/lower.
March 18, 2019, 12:28 PM
IndianaBoy
quote:
Originally posted by fritz:


I will note that my most accurate AR-10 and AR-15 are billet builds, however they also have my best barrels -- Kriegers. I suspect the barrel quality is more important to the great accuracy than the type of upper/lower.



Some investigation has been put into added rigidity in the area of the upper receiver which surrounds the barrel extension. It is less important than a good barrel and good ammunition but I have seen it asserted that some billet uppers may offer some accuracy gains due to additional beefiness in this area.


I believe the video I saw was done by Glen Seekins.
March 18, 2019, 01:03 PM
esdunbar
For me: I will not buy a cast lower.

I would be happy with either a billet or forged. Only real difference for me is that billet lowers are CNC'd from a block so they have some different things you can do to them (e.g. integrated trigger guard, different aesthetic cuts, etc). Zero difference in strength between billet and forged for me. Having said that, I don't any billet lowers simply because I don't see it worth paying extra for some fancy CNC work.
March 18, 2019, 02:05 PM
lyman
is anyone still making a cast lower?

Essential Arms and some very early DPMS lowers are all I can recall



https://www.chesterfieldarmament.com/

March 18, 2019, 08:41 PM
loki993
I don't know that I've ever even seen an actual cast lower for sale. Any quality gun is going to have either forged or billet lower. The only difference is the billets can look nicer. Quality and strength wise you'll never notice a difference. I've read forged is stronger but it's not something that would make any difference in a lower. I wouldn't spend extra money for s billet lower unless it was for aesthetic reasons and I've always been more of a function over form sort of person.