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Discussion Starter · #1 ·
At my ripe old age I've decided that it was about time to build my own AR. It's primary goal will be surgical hits out to 350 yards. I haven't decided on a caliber yet.

I've been looking at matched upper and lower receivers and see that some are forged while others are billet machined.

MEGA Arms

Seekins Precision

Other than these two attributes, is spending the additional cash beneficial for the machined?

What will the machined set give me that the forged set won't?

Any thoughts or suggestions?
 

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Billet receivers are pretty, but provide no additional benefits for the price paid over forged receivers. Matching an upper and lower has no additional benefits. The main part of the AR that contributes most to accuracy, is the barrel. The manufacturer and the barrel profile should be carefully chosen. Match grade ammunition is the other half of the AR accuracy equation. Keep in mind, that some available AR calibers are more accurate at longer ranges than other AR calibers.
 

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The caliber depends on a few things.
What are you shooting?
How much are you shooting?
Where are you shooting?
 

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Discussion Starter · #4 ·
Thank you for the reply!

This is great to hear because I would essentially be wasting an additional $300 or so on a machined set and other than appearance it brings nothing to the game.

I agree, the barrel and chamber are the key to premium accuracy. Concentricity between the chamber and the bore are paramount to ensure alignment if the bullet to the bore is as perfect as possible.

For years I've tailored loads to specific bolt guns to wring out the best aggregate accuracy and this AR will be no different. I'm still undecided as to what platform of cartridge I'll build for.

Accuracy, performance, reliability, brass availability are essential. What I'd like this to be is a semi-custom rifle that allows me to use standard shells, not a wildcat cartridge.

Two cartridges that come to mind are:

.223 Remington
.308 Winchester

Both calibers offer a host of caliber possibilities will numerous bullet weights and lengths.

Who offers premium barrels and bolts for AR style rifles?
 

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Discussion Starter · #5 ·
The caliber depends on a few things.
What are you shooting?
How much are you shooting?
Where are you shooting?
I'm leaning on the .308 Winchester platform but more toward the 7mm stye bullet so probably the 7mm08 cartridge.

I shoot at the range and also in rural / wooded settings. I could easily go through 50 to 75 rounds per shoot unless I'm out for a specific purpose.
 

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First thing. If you go with a 308 you will need the larger AR10 type platform. This platform is not nearly as universal as the smaller AR15 platform where nearly everyones parts fit each other. IN the AR10 platform you have 3 basic lowers. DPMS LR, ArmaLite AR10, & Rock River. This will have a limitation on some of your upgrade choices. If you're looking at the larger platform and it's not one of these 3 brands, it will almost certainly be a clone of one of these 3.

In regards to billet vs forged, this is a copy and paste from my AR15 designers guide... http://chicagogunsmith.com/blog/ar15-lower-receiver-options/11/

1 ) The Lower Receiver
The stripped Lower Receiver IS the firearm. This is the part that has the serial number, everything else attached to the lower receiver are just parts. Lower receivers are available in a variety of types.

A "Forged" lower receiver refers to the process of forming a block of aluminum by pressing raw metal into its almost final shape. Much of the detail is outside detail is pressed onto the forgings, which are then machined to the specification with cut outs and holes etc… Forgings are the most common lower receivers, and can be considered the standard, on the market because they tend to be the strongest and nearly the cheapest to manufacture.

A "Cast" lower receiver is the process of pouring liquid metal into a shape. Though casting is possible there are not many manufacturers using this process to make lower receivers. After casting, the receivers are then machined. Cast receivers are considered to be weaker than the standard forged receiver. Cast lower receivers can typically be identified by the raised lettering and a rougher appearance within the mag well.

"Extruded" Lower receivers are not very common. Extrusion is the process of forcing heated aluminum through a shape . The Extruded lower receiver is then cut and machined to specification. It is then cut to length and final machined to final configuration. Extruded Lower Receivers tend to have less detail and shape than other receiver types.

"Billet" Lower Receivers are the 2nd most common fabrication method used for fabricating lower receivers today. A billet lower receiver starts as a block of aluminum which is then completely machined and shaped to the final shape and specification. This type of receiver is generally referred to as a "billet" receiver because the block of metal is what is known as a billet. Billet lower receivers tend to require the most investment because of the extensive machine time necessary in fabrication of the part. Billet Lower receivers typically are of the highest tolerance due to the total machining process but are not always completely "mil spec" because of some size variations.

A newer lower receiver to enter the market in recent years is the polymer lower receiver. Polymer lower receivers are the cheapest to make because plastic is cheaper than aluminum and the molding process is quick and fairly accurate allowing the manufacturer to form almost all of the detail into the raw part. However polymer lower receivers tend to be the weakest of all the lower receivers on the market. Some manufacturers are attempting to overcome the weakness of the material by utilizing metal inserts in the critical high-stress areas. Polymer is also more prone to size fluctuations due to temperature differences than aluminum. This may cause some "fit" issues.

Which is a better lower receiver? The general consensus is that a forged 7075 aluminum lower receiver is certainly the most common and perhaps the best on the market when made to meet or exceed military specification (mil spec). 7075 Aluminum is much tougher then 6061 aluminum. 6061 Aluminum is lighter, and often referred to as air craft grade aluminum.

Billet, though technically weaker than forging, are very popular because they tend to be the most pleasing in appearance and any weakness deficiencies can be designed out by adding more material where necessary. Cast is generally not preferred due to the rough appearance, and the weakness incurred during the manufacturing process. Polymer lowers are not yet time proven and are still an experiment as the bugs are worked out of the designs.
FWIW, my receivers are all forged, not that I wouldn't own a billet, only that I haven't found one I thought justified the extra cost. My $0.02.
 

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I would, personally, go with 5.56 simply for cost of ammo for range shooting.
And it will be easier and cheaper to find all the parts for your build if its for 5.56
Things to think about:
5.56 is affected greatly by crosswinds. 308 is far more steady and can travel with power a lot further. But this isn't critical at the ranges you're going to shoot.

A medium-heavy barrel will be more accurate if you fire quickly and heat up the barrel. If you take your time between shots then any profile barrel will do.

A freek float rail and a good trigger is a must for accuracy.

Good barrels.. There is a bunch. Wilson and Noveske off the top of my head.
 

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Discussion Starter · #8 ·
Thanks for the quick response and all the information!

I've been shooting and handloading for over 40 years. I love precision and the idea of building my own AR is something I've been panning on doing for a long time but until recently it's been on the back burner.

I naturally want to the rifle to look good but I'm not into expensive looks with little to no benefit. To tell you the truth, I've looked carefully at the forged vs the CNC machined and other then some neat features I went away scratching my head because the prices were / are nearly double...

A agree, a free floated barrel is how I achieved the best accuracy in my bolt guns and this will apply here. A good trigger is a must and I've basically settled on the Geissele SSA or SSA-E.

The barrels you mention are the ones I've been looking at so I'm headed in the right direction..

I'm going with the standard bolt vs a low mass setup because for what I intend to do I won't be able to realize any benefit from it.
 

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Keriger Barrel in 7.62x61

At my ripe old age I've decided that it was about time to build my own AR. It's primary goal will be surgical hits out to 350 yards. I haven't decided on a caliber yet.

I've been looking at matched upper and lower receivers and see that some are forged while others are billet machined.

MEGA Arms

Seekins Precision

Other than these two attributes, is spending the additional cash beneficial for the machined?

What will the machined set give me that the forged set won't?

Any thoughts or suggestions?
If you want a precision AR you need to put one of these on. The caliber is up to you depending on what you're shooting as others have said.

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