Marine Cpl
.577 Tyrannosaur.
In this video, the flashcan is shot first as per his written comment followed by a linear compensator second.
Help me decide on an AR build direction
- Thread starter Podmonkey
- Start date
meketrefe
.450/400 Nitro Ex
This is my reasoning in the uppers... Logic at the time....
Wanted two 5.56 piston carbines for GOTO guns. Then got another two in 20" for long range.
Built a 6x45 upper that uses the same 223 brass, mags and amazing bullets with great deals. This is the easiest upgrade that
gives the most out of all the other calibers. Later I increased the freebore to take advantage of the 90gr and up including loading from a centerfire magazine. Amazingly simple and super accurate. This was a bench rest round that won world titles for many years.
Got the 300 whisper to shoot subsonic loads. Later this was renamed and commercialized as the the 300 blakcout. It is what it is, nothing else.
Got the 6.8 SPCII due to the amazing ARP barrels and a great all around cartrige. This is very accurate, repeatable kind.
Got the 7.62x39 to shoot super affordable ammo and reload lapua brass for nice performance. Since ARP released the beefed
up bolts this was huge otherwise I would not do this in an AR.
Got the 6.5LBC due to an amazing deal on a melonite barrel and having a large stock of 6.5 bullets.
Got the 6.5BR uppers because I wanted more performance out of an AR15 magazine. This like the 6mm is known for extreme accuracy.
Got a 6.5TCU to use 6.5 bullets but use inexpensive virtually free brass. This requires magazine modifications to stack into a magazine.
Later I increased the freebore to shoot long VLD loads centerfire giving performance very similar to the LBC/grendel.
Over the years I acquired S800 bolts that allowed me to do some wildcats using the .473 bolt face and AR15 magazines.
The first 7mm was a TCU but after that I built the 7mm Gunner using a 284 case as baseline. This required case forming, annealing
and trimming every case. The result is something as if one took the 30 RAR and necked it down to 7mm for better ballistics but
it did better due to the stronger bolts than the Remington ones.
using the same case I built a 30 caliber version that performed better than the 30 RAR but I didn't develop further because
in the end there is no way to get more performance in the AR15.
Inside the AR15 the maximum caliber that one can get decent performance is with 7mm in the lighter bullets up to 150gr and
then things go downhill. 30 and 338 calibers are not good choices due to OAL / bullet weight if we look at good performers
ballistically. Then when we hit the 35 and 375 calibers another window opens entire of possibilities.
The reason I built the gunner was to give big game momentum out to 300 yards with affordable bullets and better ballistics
than the 45 and 50 calibers where poor ballistics kills them in long shots.
Just to give you a reference the 35 gunner has the same punch (momentum) at 300 yards than the 7.62x39 and the muzzle
with comparable trajectories. That is a key differentiation that puts the round into the brush hunting category to hunt
from a tree stand in dense forest. These rounds leave the socom and beo in the dust in terms of ballistics.
The issue with calibers is on one side we have the fashion, marketing and tacticool forces and on the other we have the
people with real needs.
Aside from all the fun of building and the initial infatuation period I would stick with a caliber that is true to your style of shooting
and philosophy of use. Simple wildcats are very rewarding too.
Now I am working in a 7mm-08 AR10. I have done other cats so let me know if you have any questions about the performance
of any of the rounds. I have tested extensively against each other because when I devleop a new cartrige sometimes I take other
uppers and test the different rounds both commercial and reloads to compare how they perform.
This includes all sort of 5.56 and 223 loads comercial. Of course I have more data from popular 16"-18" carbines but also some
short barrel and unusually long ones for long range.
I also did a 6mm BR just because I had so much brass for the 6.5BR and bullets from the 6x45, 6 TCU and other wildcats.
The 6TCU is another one that works great out of the AR15 magazines and gives a tad extra perormance than the 6x45.
Wanted two 5.56 piston carbines for GOTO guns. Then got another two in 20" for long range.
Built a 6x45 upper that uses the same 223 brass, mags and amazing bullets with great deals. This is the easiest upgrade that
gives the most out of all the other calibers. Later I increased the freebore to take advantage of the 90gr and up including loading from a centerfire magazine. Amazingly simple and super accurate. This was a bench rest round that won world titles for many years.
Got the 300 whisper to shoot subsonic loads. Later this was renamed and commercialized as the the 300 blakcout. It is what it is, nothing else.
Got the 6.8 SPCII due to the amazing ARP barrels and a great all around cartrige. This is very accurate, repeatable kind.
Got the 7.62x39 to shoot super affordable ammo and reload lapua brass for nice performance. Since ARP released the beefed
up bolts this was huge otherwise I would not do this in an AR.
Got the 6.5LBC due to an amazing deal on a melonite barrel and having a large stock of 6.5 bullets.
Got the 6.5BR uppers because I wanted more performance out of an AR15 magazine. This like the 6mm is known for extreme accuracy.
Got a 6.5TCU to use 6.5 bullets but use inexpensive virtually free brass. This requires magazine modifications to stack into a magazine.
Later I increased the freebore to shoot long VLD loads centerfire giving performance very similar to the LBC/grendel.
Over the years I acquired S800 bolts that allowed me to do some wildcats using the .473 bolt face and AR15 magazines.
The first 7mm was a TCU but after that I built the 7mm Gunner using a 284 case as baseline. This required case forming, annealing
and trimming every case. The result is something as if one took the 30 RAR and necked it down to 7mm for better ballistics but
it did better due to the stronger bolts than the Remington ones.
using the same case I built a 30 caliber version that performed better than the 30 RAR but I didn't develop further because
in the end there is no way to get more performance in the AR15.
Inside the AR15 the maximum caliber that one can get decent performance is with 7mm in the lighter bullets up to 150gr and
then things go downhill. 30 and 338 calibers are not good choices due to OAL / bullet weight if we look at good performers
ballistically. Then when we hit the 35 and 375 calibers another window opens entire of possibilities.
The reason I built the gunner was to give big game momentum out to 300 yards with affordable bullets and better ballistics
than the 45 and 50 calibers where poor ballistics kills them in long shots.
Just to give you a reference the 35 gunner has the same punch (momentum) at 300 yards than the 7.62x39 and the muzzle
with comparable trajectories. That is a key differentiation that puts the round into the brush hunting category to hunt
from a tree stand in dense forest. These rounds leave the socom and beo in the dust in terms of ballistics.
The issue with calibers is on one side we have the fashion, marketing and tacticool forces and on the other we have the
people with real needs.
Aside from all the fun of building and the initial infatuation period I would stick with a caliber that is true to your style of shooting
and philosophy of use. Simple wildcats are very rewarding too.
Now I am working in a 7mm-08 AR10. I have done other cats so let me know if you have any questions about the performance
of any of the rounds. I have tested extensively against each other because when I devleop a new cartrige sometimes I take other
uppers and test the different rounds both commercial and reloads to compare how they perform.
This includes all sort of 5.56 and 223 loads comercial. Of course I have more data from popular 16"-18" carbines but also some
short barrel and unusually long ones for long range.
I also did a 6mm BR just because I had so much brass for the 6.5BR and bullets from the 6x45, 6 TCU and other wildcats.
The 6TCU is another one that works great out of the AR15 magazines and gives a tad extra perormance than the 6x45.
Bump! Keep those votes and opinions coming folks, I value your input!
And to @Willjr75's earlier point about keeping the pistol build a pistol so as to avoid needing permission to take to other states is very valid. If the pistol routebis chosen that is exactlybwhat I'd do.
On the pistol build though...... I am kinda hankering for a LWRC piston gun someday and it occurs to me that the best niche in my collection for a LWRC would be in pistol guise, maybe?
And to @Willjr75's earlier point about keeping the pistol build a pistol so as to avoid needing permission to take to other states is very valid. If the pistol routebis chosen that is exactlybwhat I'd do.
On the pistol build though...... I am kinda hankering for a LWRC piston gun someday and it occurs to me that the best niche in my collection for a LWRC would be in pistol guise, maybe?
I'm thinking 6.5 or the 6.8 for the NYGF set but who knows may just do a blackout.
BDSKJCHRIS
.40 S&W
MK18-esque pistol build
Now I am think of saving the SPR build for this lower
GWACS polymer lower. To save weight for the heavier barrel and optic, and because I like the concept behind it.
Between that and wanting a LWRC for the pistol that kinda leaves the door kicker build.
GWACS polymer lower. To save weight for the heavier barrel and optic, and because I like the concept behind it.
Between that and wanting a LWRC for the pistol that kinda leaves the door kicker build.
S
stuck in ny
Guest
How strong does the polymer feel? The lop looks a1 or close.
Dunno, never handled one. My favorite youtube gunners, Ian and Karl, are very high on it though. The idea is that by molding the whole lower in one piece it can be made very strong and resilient unlike other polymer lowers molded in the more traditional form. I have embraced polymer handguns so I may as well embrace polymer lowers too.
Marine Cpl
.577 Tyrannosaur.
Like polymer handguns. Makes sense. This would also take less abuse then a handgun too.
S
stuck in ny
Guest
Yeh, I hear that just cloning the ar15, swapping polymer for aluminium, is weak in the area where the buffer threads in. By going with a monolithic lower assembly, they avoid this problem.
It seems to absorb tremendous abuse nonetheless. Short of claiming "faked" it is difficult to argue the effectiveness of this design.
S
stuck in ny
Guest
I get that they wanted to go all polymer, but having a mosin style sling slot on an ar seems sorta goofy. You would think there be a way to imbed a gi style fixed "swivel" into the plastic while its being cast.
Hmmn, maybe. It wouldn't be hard to throw a stock stirrup on either. Its probably what I'd do as I prefer slings mounted cavalry style on guns with protruding magazines.
The analogy of polymer pistols and polymer AR lowers isn't 100% accurate. Most if not all polymer pistols have their lowers reinforced with metal at key stress points. Hell even 80% pistol lowers are starting to do that. The polymer AR lowers have yet to take that leap. When they finally do and the lower's longevity can be brought closer to a metal lower, you will see them taking a bigger and bigger chunk of the market.
But an AR lower isn't really subjected to any reciprocating stress like on a handgun and its slide. All the lower does is contain the FCG. Its the upper that has the parts going whizz bang in it.
S
stuck in ny
Guest
I wonder if the take down pin holes are as strong as a normal aluminium lower.
I think the real potential here is that a fairly ergonomic compliant lower could be done this way.
I am also currious about that. There may be reinforcement of that area.
It is and it isn't. The shear around the pins is minimal and can be handled by this type of plastic. The stress point on an AR lower is around the buffer tube. This is the area that needs to be reinforce. My bet would a cast in place insert of brass with the threads cut in. You could make these pieces in bulk for cheap.
I think the monolithic design beefs up the buffer tube area adequately. Check the video out, Karl is buttstroking 2x4s in half with it!
True I'm sure it adds to the durability, but most people aren't looking for an A2 style stock. Also hitting stuff hard doesn't necessarily coincide with the durability of the lower in the shear points. When but stroking with this style the stress is distributed through most of the lower. When fired the recoil is transferred to your shoulder through the ring to the stock. This also happens to be a thin spot, which doesn't do us any favors.
I
I'm down with an A2(1) stock for an SPR build, looks proper. I hear what you are saying about low frequency, high intensity stress vs high frequency, low intensity stress. But doesn't polymer handle the latter better than most metals?
S
stuck in ny
Guest
I'm assuming you're going to be using a drop in FCG?
It's been a little bit since I've done much work with polymers, pretty much just steel now days. But I will give a wishy washy answer and that is maybe. Polymers handle repeated stress better than most metal depending on how much the stress is. Metal doesn't fatigue at "low" level stress this is why aluminum is used instead of steel, the stress is low enough not to work harden the aluminum. Now for the same "low" stress the aluminum can handle might be on the high end of the polymer. So essentially the same stress might be fatiguing the polymer. I use the term fatiguing loosely, because it plastic has it's own set up characteristics.
I'm not saying that these lowers wont work for you or this application. I'm trying to say I'm disappointed in the lack of development/improvement of the polymer lowers in the industry. Light weight builds hold merit and these would shine there. I think the reason why there has been little development is because aluminum lowers are cheap and relatively light, so there has been little demand from the consumers. The only real demand out there right now is the novelty and SHTF groups, so it's a pretty small market.
Yes, also based on Ian and Karls praise perhaps one of these:
KE Arms DMR trigger.
S
stuck in ny
Guest
Well if it came to total shtf any you had an upper with no lower, then I suppose you could rig a system to hit the firing pin by jerking back on the forearm and disabling the gas system.
Well I'd say this lower is the promising development you pine for. Or can you not stand A2 stocks? I like the A2, LOP fits me and I find it comfy.
Not my thing used it when I was in the Marines. I much prefer the modern stocks, but that is a preference. If you like this stock configuration there is nothing wrong with this lower. I do believe it is stronger than the normal polymer lowers. Will it last the test of time? Well I don't know I haven't studied the specs of it enough to get a opinion.
I dug the A2 in my Army days. I think its cheap enough to give it a whirl. NYGF lower & upper build comes first though.