New partial AR-15 build ... not sure where it's heading

I have a few AR-15s and an AR-308 and have added another ... well, kind of. My local crack dealer aka ex-coworker/friend sold me one of his partial builds yesterday. He has some seriously nice firearms and typically has multiple builds going on. He wanted money to put towards a TP9 that's arriving soon and a few months ago mentioned that he might sell the partial build that I show below. I paid him $750 for everything shown which is a fair price.

FALKOR supposedly suggests using a heat gun to expand the upper receiver to allow the barrel extension to fit. Also, the fit between the upper and lower is excellent. Overall a very well made upper/lower that exudes quality.

FALKOR FD-15A upper/lower receiver
Geiessle Super Dynamic Trigger
Radian Raptor-SD charging handle
Radian take-down pins
HERA pistol grip
Magpul UBR Gen2 stock

So what direction would you take this build in? I'm thinking something other than 5.56x45mm NATO, .300 Blackout and .450 Bushmaster since I have those covered already.

wiscoaster said:

Well, you're kind of already stuck with those calibers already, aren't you? You don't sound like the type who'd want to do a .22 LR conversion.

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I have a S&W M&P 15-22 so definitely don't have any interest in another .22LR. I was thinking something along the lines of 6mm ARC, 6.5 Grendel, 6.8 SPC. The cheapest option would probably be another 5.56 since I have a new Bergara barrel that I could use. I think it's 18" and is one of their heavier variants but I'd rather not go that route. I have a spare Daniel Defense lower so I could build a simple upper around the Bergara for the DD, but do something a bit special with the FALKOR. Maybe a Proof barrel.

wiscoaster said:

Oh, heavens, if you're already got a Bergara barrel, that's the way to go. Don't even think twice about it.

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But I could use that for another ho-hum upper for the DD lower that just sits in the safe. Combining a FALKOR receiver with a Proof barrel seems kind of cool given that both companies are here in the Flathead Valley.

Yeah, the more I think about it the more I like the idea of a Proof barrel in 6mm ARC, 6.5 Grendel or 6.8 SPC and they offer all three. I'll have do some research but the ARC is out in front at the moment. I'll be handloading for this AR so powder, case and bullet availability will be important factors. I'll also be running it suppressed so that's another consideration.

spazzy said:

7.62x39?

I like the build so far! Love that stock

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I have a Vz.58 so probably won't go that route. Thanks ... but nothing to do with me. My friend does a very good job of mapping out builds. He sent me a build list with links to all of the additional parts he was planning to add and I'll definitely be ordering some of the items on his list.

wiscoaster said:

.350 Legend? Willing to spend a few bucks?

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Another straight-walled cartridge that requires a proprietary magazine ... not really on my radar. I think the .450 BM is enough. I'll read up on the three that I mentioned and go from there.

Chuck R. said:

Due to the trigger and stock, I'd lean towards an SPR or DMR type rifle, at least 18" for the SPR and 20" for the DMR, both in match grade "something".

I have both in my SPR build. The Geissele is superb and is "kinda" wasted on a short range rig. The UBR2 is a fantastic stock, but isn't exactly lightweight, so I'd put that on a rifle that I was planning on being a little heavy. Both fit nicely on something built for precision.

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I think you read my mind on this. A 20" barrel with a rifle length gas system in a cartridge that is capable of accuracy/precision out to 700 yards. I don't have any intention of using this build for hunting but that option would always be on the table. If I can keep everything i.e. rifle, optic and suppressor to around 9lb or less I'm ok with that.

Demi-human said:

An advanced rifle should have a cartridge that is, too.
A very nice set as this needs a very nice barrel. I like the local connection.
With a very light hand guard to show off the barrel, or a carbon one to match.

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Again, another mind reader! I like the local connection for sure and at this point see no reason to not use a Proof barrel. This is not an urgent project so if I have to wait 6 months that's fine. I'd rather take my time and get it right.

BreechFace said:

Proof research barrel and a Coda Arms carbon fiber handguard. This route would have me wondering on the UBR due to weight but I’m sure it would balance like a dream with it on there. If it was me and using for hunting I would be looking at 6.8 SPC or 7mm Valkyrie but the latter one would be more of a custom build with a proof.

If one is looking for long range target shooting and predator hunting than 6ARC would be fun to try. But then weight isn’t going to matter as much so the. I would wonder if the proof research and carbon handguard really is necessary.

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7mm Valkyrie wasn't on my radar but I'll have to check it out. I agree with you re 6ARC for long range target and 6.8 SPC for hunting so I have to be honest with myself as to what the rifle will be mostly be used for and it's the former. I don't have any brass or dies for either cartridge but have suitable powders on hand for both.

I'll check with Proof this week on price and availability and probably place orders for other needed parts. I have a Superlative Arms adjustable gas block on my .450 BM so might go that route again.

OK ... 6mm ARC it is. I called Radian today and asked if they're going to offer a bolt/BCG for the 6mm ARC but have yet to hear back.

@js8588, thanks for that build list. The Radian Talon ambi safety is already on my list along with one of their forward assists. I always run TUBB flatwire springs in my ARs so that's on the list too. My friend had put together a list of parts that he was planning to buy and kindly forwarded it to me. I'm not up on the latest and greatest so it's helpful. I have three POF rifles so am familiar with that system but don't plan on a push rod type upper (a.k.a. piston upper) but he was thinking of going that way. Here's his list of the parts he was planning to add with his comments in ().

Buffer system:
https://www.jprifles.com/buy.php?item=JPSCS2-15
(A standard buffer is fine but I really like these JP captured units. I think they are a really nice upgrade although a bit expensive. They are a little cheaper from places like opticsplanet etc.)

Forward Assist:
https://radianweapons.com/accessories/rifle-parts/forward-assist-aluminum-black-anodized-ar15
(Matches the Radian logo already on the takedown pins. )

Safety:
https://radianweapons.com/accessories/talon/talon-ambidextrous-safety-selector-2-lever-kit-ar15
(Best safety selector on the market in my opinion and I've tried quite a few of them. I would get the (long) length levers on both sides if you can, I think that is the best option especially using a 45 degree throw. )

BCG/Gasblock:
https://suparms.com/collections/ret...tem-rifle-length-solid-melonited-low-pro-ar15
https://www.srcarms.com/shop/all-products/sharps-xtreme-perfomance-bolt/
(For this build I wanted to try out one of the Superlative arms piston kits as I thought it would suppress well. With all these parts I was also trying to come up with a build that would be a good suppressor host and have the least amount of gas blowback coming back at the shooter. The kit comes with the gas block and carrier but doesn't include an actual bolt, cam pin or firing pin. I was probably going to order one of these Sharps enhanced bolts to try with it since the design seems interesting. A POF roller cam pin would pair nicely with it. Then you just need a firing pin and firing pin retainer pin, any option would work for those. )

Alternative DI option: https://radianweapons.com/accessories/rifle-parts/enhanced-bolt-carrier-group
(If you didn't want to go with the piston system this would be a nice alternative to go with the rest of the Radian parts. Or you mentioned having an extra POF BCG and I'm sure that would work great too. Then you can just pair it with whatever gas block you want, I like the look of the Fortis ones personally to match the aesthetic of the rifle. https://fortismfg.com/accessories/gas-block/ar15-fortis-low-profile-gas-block)

Barrel:
https://faxonfirearms.com/match-ser...ngth-416r-nitride-5r-nickel-teflon-extension/
(This was the barrel I was planning on using. I like the 18" length for a SPR type build and it seemed like a nice weight for a heavy fluted profile. That being said a 18" Proof barrel would be really nice too but I wasn't willing to spend the extra money for one.)

Handguard:
https://www.rainierarms.com/rainier-arms-m-lok-switch-5-56-rail/
(I was planning on getting the 15" version of this handguard as it's the longest they offer. It's made by Fortis for Rainier Arms. I think the style matches well with the receiver set and it also has the "SWITCH" mounting system. That means you can quickly remove the rail if you want with no tools. You take it on and off by releasing a throw lever on the bottom. This was an important component in conjunction with the Superlative adjustable gas block/piston system. Normally when you look at piston guns the piston has to be at the end of the handguard so it is accessible for cleaning, or a cut out has to be made in the handguard so it's accessible. With a quick removable handguard it can be longer and extend past the gas block but still offer easy access to the gas piston for adjustments and cleaning.)

Muzzle Device:
(Whatever attachment system you have in mind for the suppressor you plan on using. I was going to do a Surefire Flash hider but of course that doesn't make sense for your build. )

Nature Boy said:

You are on a spree lately!

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Not intentionally! I bought the Tikka from the same friend back in July and used it on some critters this fall. I got back into the Kimber 8400 6.5 PRC Proof build and now this so not going too crazy or anything. It might seem that way from my caffeine induced posts but it's not that much really. Both the Tikka and FALKOR were opportunistic purchases with zero regrets.