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

[horsemen61]

I switched out the UBR stock for the PRS stock this morning, switched out the LaRue mount for a 20 moa ADM mount, threaded on a SilencerCo Harvester .30 cal, bore sighted and shot this 5-shot group after making a gas block adjustment. I've never shot a group this small, at least I don't think I have. I could see the first two hits but after that I wondered if I were missing the target altogether. Function is absolutely perfect with the POF receiver and ASC magazines. This is just one group, but to shoot a group like this with all rounds fed from the magazine, and the last round resulting in bolt lock back is pretty neat.

I don't know what I'm going to do with this rifle, or what role it'll play but I'm pleased with how it performs now, with one caveat and maybe two. The Geissele trigger has some creep in the second stage and this is the first time I've ever experienced that with a Geissele trigger (I have a bunch) so I might swap it out with one from a carbine I have that doesn't need such a good trigger.

The other thing that's bothering me is the reticle in the Vortex Viper PST Gen 2 3-15x scope. It's the EBR-7C version and it's just too fine and too busy, at least at 100 yards and shooting at the type of target shown above. There's not much I can do about it except change scopes.

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Nice shooting! Greeting looking gun!!!

 

[Gtscotty]

I switched out the UBR stock for the PRS stock this morning, switched out the LaRue mount for a 20 moa ADM mount, threaded on a SilencerCo Harvester .30 cal, bore sighted and shot this 5-shot group after making a gas block adjustment. I've never shot a group this small, at least I don't think I have. I could see the first two hits but after that I wondered if I were missing the target altogether. Function is absolutely perfect with the POF receiver and ASC magazines. This is just one group, but to shoot a group like this with all rounds fed from the magazine, and the last round resulting in bolt lock back is pretty neat.

I don't know what I'm going to do with this rifle, or what role it'll play but I'm pleased with how it performs now, with one caveat and maybe two. The Geissele trigger has some creep in the second stage and this is the first time I've ever experienced that with a Geissele trigger (I have a bunch) so I might swap it out with one from a carbine I have that doesn't need such a good trigger.

The other thing that's bothering me is the reticle in the Vortex Viper PST Gen 2 3-15x scope. It's the EBR-7C version and it's just too fine and too busy, at least at 100 yards and shooting at the type of target shown above. There's not much I can do about it except change scopes.

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Yep, I'd say you got it dialed in pretty well! Maybe I missed it earlier, but did you do any fitting of the barrel in the upper, thermofit, shims, Loctite 620, etc?

Also, what load was that? Surely not 105 gr H Black?

 

[Nature Boy]

This is just one group, but to shoot a group like this with all rounds fed from the magazine, and the last round resulting in bolt lock back is pretty neat.

I should say so!! I think you have arrived at your goal

 

[MCMXI]

Yep, I'd say you got it dialed in pretty well! Maybe I missed it earlier, but did you do any fitting of the barrel in the upper, thermofit, shims, Loctite 620, etc?

Also, what load was that? Surely not 105 gr H Black?

I didn't do any fitting of any sort. I did open up the feedramps on the Proof barrel to match the Falkor upper and luckily they matched the POF upper too. The ASC magazines are excellent with no feeding issues at all. I am going to play with the JP Rifles buffer spring. I bought their spring kit so can reduce bolt velocity perhaps. I'd like to reduce ejection velocity/distance if possible and even with the Superlative Arms adjustable gas block allowing gas to bleed off, I feel that ejection is still excessive.

Yeah, I've only shot Hornady Black 105gr in this rifle. I think the last group above was as much luck and probability as anything and I don't think it's representative of typical performance with that load. I'd like to try some of the Hordady ELD Match 108gr load but might start load development this winter using the Berger 109gr bullets that I have.

 

[MCMXI]

I should say so!! I think you have arrived at your goal

Thanks. I'm quite pleased with the rifle given that a 6mm ARC wasn't on my radar. I sold the Falkor upper/lower on Gunbroker for close to what I paid for the POF P415 upper/lower. Ironically, if not for the Falkor from a friend I would never have set out to assemble this rifle. Funny how things work out sometimes.

 

[45/30-06OKIE]

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.

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I'd go for a 6.5Grendel build. I have a 22" build with a UBR Gen 2 stock actually, and a bright 6-18x50 Bushnell scope on it. I snagged 440 rounds of Wolf steel case 100gr FMJ ammo JUST before the pricing went to heck a couple months ago lol and I have some Privi Partizan 120gr HPBT and some Hornady 123gr SST as well. I also have 10 25rd ASC mags that I got for $10 a piece from Midway on sale. I'm not really a huge fan of the new 6.5 stuff overall, as the good ol' 6.5x55 Swede is one deadly round for sure, but I was looking for something that packed more punch in an AR-15 platform and saw the ballistic performance of the Grendel and was impressed so much, I went out and got all the parts and built it myself for a reasonable price. EDIT: I replied before reading the whole thread like an idiot lol. I saw you went 6ARC, it is getting crazy hype online and I haven't seen any on the shelves or at a gun show surprisingly, I'll have to keep an eye out for that caliber and see if we (me and dad have an FFL and do gunshows in OKC and Tulsa) can find any to sell. A 109gr .243 bullet sound like it's a dang needle lol.

 

[rdnktrkr]

Glad your back is improving, I have pinched nerves so I can relate to back issues. Your build looks great and seems to be very accurate, I think Hornaday came up with a great little round for the AR.
I'm helping a friend build his 6ARC and we're using 10rnd metal Grendel mags with no problems. He purchased a Faxon barrel from Brownells and is using a spare BCG I had for my Grendels until he can get one. We have found the <100gr bullets like the upper load range of LVR powder and the >100gr prefered the lower range, that is the only powder we have tried so far, we created brass from 6.5 Grendel brass without any problems only crushing 1 neck out of 101 using lanolin/alcohol. I think he needs a brake to help him see the hit (it helps on my Creedmoor) but so far all he has is a cap. He was hitting steel at 600yrds consistently and was ringing 4in at 200yrds without a miss, at 100yrds he stayed in the 1" bull easily, we will hit Talladega CMP in the spring for a more accurate group at 600.

 

[Gtscotty]

I have some 6mm ARC with 112gr Match Burners and 6mm GT with 108gr ELDs loaded up for some development this weekend. The 112gr looks funny next to the ARC, almost as tall as the case, I'll be interested to see what kind of velocities I can get with LVR under the 112gr.

 

[horsemen61]

I have some 6mm ARC with 112gr Match Burners and 6mm GT with 108gr ELDs loaded up for some development this weekend. The 112gr looks funny next to the ARC, almost as tall as the case, I'll be interested to see what kind of velocities I can get with LVR under the 112gr.
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I hope you get the results you want also I really really hope someone aka Howa or CZ does this in a mini action and I’ll be on it like a chicken on a June bug

 

[Gtscotty]

I hope you get the results you want also I really really hope someone aka Howa or CZ does this in a mini action and I’ll be on it like a chicken on a June bug

Thanks, my rifle likes the 108gr factory load @ ~2,700 fps, really hammers at 750 yds and was respectable out at 1,250 yds. My 105gr MB loads at about the same speed were dropping off pretty heavily by 1,250 and the ELD BC advantage was very apparent. I'm hoping if I can get a good 112gr load @ ~2,650 fps, that .62 G1 will really let the little ARC shine.

I will say I was having neck tension issues with the 112gr in my 6mm GT, but my FL ARC dies size the neck more and seems to have plenty of bullet grip, so maybe that's how I address the GT as well.

Howa has said they are bringing out a Mini in 6mm ARC in '22, hopefully they follow through. Once Winchester brings out the long rumored Varget speed StaBall, we'll really be set.

 

[horsemen61]

Thanks, my rifle likes the 108gr factory load @ ~2,700 fps, really hammers at 750 yds and was respectable out at 1,250 yds. My 105gr MB loads at about the same speed were dropping off pretty heavily by 1,250 and the ELD BC advantage was very apparent. I'm hoping if I can get a good 112gr load @ ~2,650 fps, that .62 G1 will really let the little ARC shine.

I will say I was having neck tension issues with the 112gr in my 6mm GT, but my FL ARC dies size the neck more and seems to have plenty of bullet grip, so maybe that's how I address the GT as well.

Howa has said they are bringing out a Mini in 6mm ARC in '22, hopefully they follow through. Once Winchester brings out the long rumored Varget speed StaBall, we'll really be set.

Please tell me more about the stuff I highlighted in red! I haven’t heard

 

[Gtscotty]

Please tell me more about the stuff I highlighted in red! I haven’t heard

Well there's not much to tell, just that there are rumors that StaBall is supposed to be a line of powders and Winchester is developing/has developed a Varget/LVR speed version. I think I heard murmers first on The Hide, and in one thread (either here or there) someone confirmed that some folks were already testing a pre-production version the powder in competitions. But that was a while ago and I haven't heard anything lately.

The only real downside to the ARC I've seen is that to hit it's potential, velocity wise, you have to use more dense but temp sensitive powders like LVR, CFE223, and AA2520. I think a LVR speed StaBall would really shine in the ARC, not to mention other smaller 6mms like the Dasher, BR/A/X, GT.

 

[horsemen61]

Well there's not much to tell, just that there are rumors that StaBall is supposed to be a line of powders and Winchester is developing/has developed a Varget/LVR speed version. I think I heard murmers first on The Hide, and in one thread (either here or there) someone confirmed that some folks were already testing a pre-production version the powder in competitions. But that was a while ago and I haven't heard anything lately.

The only real downside to the ARC I've seen is that to hit it's potential, velocity wise, you have to use more dense but temp sensitive powders like LVR, CFE223, and AA2520. I think a LVR speed StaBall would really shine in the ARC, not to mention other smaller 6mms like the Dasher, BR/A/X, GT.

Ahhh I see thank you for the info!

 

[Gtscotty]

I had another question for Hodgdon and also was curious if they could tell me anything on the topic of new StaBall powders so I called on the drive to work. The technical support I talked to said that we could expect to see more StaBall powders rolling out, when I asked him if there were any rough timelines, he paused and said there might be something coming out next year. Given that StaBall 6.5 is been 4350 and 4831 burn speeds, it's inconceivable to me that the next StaBall would be anything other than Varget speed. So I'll go out on a limb and bet that we see a Varget StaBall in early '22.

 

[horsemen61]

I had another question for Hodgdon and also was curious if they could tell me anything on the topic of new StaBall powders so I called on the drive to work. The technical support I talked to said that we could expect to see more StaBall powders rolling out, when I asked him if there were any rough timelines, he paused and said there might be something coming out next year. Given that StaBall 6.5 is been 4350 and 4831 burn speeds, it's inconceivable to me that the next StaBall would be anything other than Varget speed. So I'll go out on a limb and bet that we see a Varget StaBall in early '22.

I hope so!