Project Noveske Ultralight
Update on pg. 2
Original:
Project intention: To build a dedicated HD rifle weighing 96oz or less using the finest factory available parts (e.g. no re-profiled barrels), without cutting corners to shave weight (e.g. Polymer lowers), and without a SBR stamp. The target weight had to include RDS, BUIS, rail attachments and a light for room clearing.
This rifle was built for two reasons, the first justifying the second:
1) I wanted a dedicated, high-quality, reliable, HD rifle that would always be there if needed. One that was set-up well to maneuver inside and that was lightweight enough my wife would feel confident handling it.
2) I also wanted to achieve something when it came to weight. While 96oz is fairly arbitrary, I determined the target weight while looking at other lightweight builds. Most non-NFA rifles seemed to be somewhere in the mid to high 6lb range using factory available parts and including an RDS, BUIS, and light. The target weight is a snap-shot it time as far as lightweight product offerings go and as AR tech changes but I do think the 6lb/96oz goal is still an accomplishment given the build parameters and what the market has thus far to offer (01/14). I would have just fallen short of this goal if it were not for some innovative new lightweight parts recently released.
The inkling for this build was Noveske's Thunder Ranch rifle w/ 20oz 14.5" Skinny barrel. I knew a standard lower would be lighter then the Gen 2 and at the time the NSR was the lightest rail out there (since eclipsed by the MI keymod and the soon to be released BCM KMR). So I decided I would follow it as a template with standard receivers and build them with the lightest parts and accessories that could be found along the way (Robb Jensen's project featherweight was helpful and inspiring, https://www.m4carbine.net/showthread...-Featherweight ). I did not, however, always choose the lightest part if there was a strong preference for, or benefit to, a part with slightly more weight. Even without those few heavier parts that I choose in place of lighter ones, with their combined additional weight subtracted, I would still be right at the threshold of the target weight before swapping in V7's lightweight lower parts.
Parts list (decisions for heavier parts explained below, denoted by asterisks):
•Noveske factory assembled upper receiver group,
-Mil-spec upper receiver w/ forward assist*
-14.5" mid Skinny contour CHF M249 spec barrel w/ pinned Noveske lo-pro gas block.
-Permed BCE 1.5
-Noveske spec head-spaced bolt w/ colt copper spring and black insert,
-11" NSR
-Noveske/BCM gunfighter mod 4 med. latch
-LMT enhanced carrier, auto profile, Gen 5*
-V7 ultralight port door
•Noveske standard chainsaw lower,
-Geissele SD-C
-MOE trigger guard
-Noveske STS ambi 60 degree safety
-UCWRG Grip 23*
-Vltor A5SR 6 pos. receiver extension*
-Springco green rifle spring*
-A5H0 buffer (equivalent to H carbine)
- Colt N1 CAR stock
-V7 ultralight alloy castle nut
-V7 aluminum QD end plate
-V7 alloy takedown/pivot pins
-V7 alloy mag catch and alum. mag button
-Colt bolt catch
-Colt springs, detents, and roll pins
•Attachments,
-MOE Gen 2 rear sight
-Aimpoint T1 mounted on Fortis F1 fixed, lower 1/3rd mount*
-Rosch works SL-1 integrated sight/light
-KAC thumb stop
-IWC keymod handstop
-Noveske QD keymod mount
-VCAS padded sling, black w/ IWC QD swivels and 2to1 adapter (not pictured or included in target weight)
The KAC thumb stop is brilliant paired with the 12 o'clock ROSCH WORKS SL-1 sight/light!
The SL-1 deserves a high place in innovative acclaim. At 3.3oz it is the lightest sight/light combination available and that is saying nothing of its brilliant sighting solution and ambi ergonomics.
http://www.roschworks.com/site/9c405...ks.com%2F#2749
Part selection rationale:
-Upper with forward assist (8.6oz) vs. Upper minus forward assist(7.3oz--7.5oz)
I wanted a factory Noveske upper receiver assembly which limited my ability to have a lighter, mil-spec profile upper minus a forward assist, 7.3oz-7.5oz vs 8.6oz (weights include mil-spec port door assembly, https://www.m4carbine.net/showthread...g-Vltor-MUR-1s,
https://www.rainierarms.com/?page=sh...roduct_id=2940). I am ambivalent to the FA, if Noveske would have made me an upper without it, I probably would have taken it. Now as seldom used as the forward assist is, and as germane as deleting it might be to this ultralight build, it is not wholly unwelcome on a fighting rifle. It is insurance the bolt is in battery after the rifle gets bumped around. It allows for chambering a round through soft obstructions (i.e. snow). And it helps when silent chambering a round by riding the charging handle forward. On the other hand, the forward ridge on the bolt carrier preforms these functions just fine, as originally intended by Stoner himself.
-Auto-weight bolt carrier vs. low mass carriers ( https://www.m4carbine.net/showthread...h-Bolt-Carrier )
Since this carbine is meant for HD, messing around with lightweight carriers was not territory into which I wanted to venture for the sake of reliability. I am no expert but all of the experts who do play with lightweight carriers and adjustable gas blocks recommend that for defensive guns, where reliability is life or death, standard weight carriers should be used. From what I understand, reliability with standard weight carriers is better than lightweight carriers because the BCG reciprocates more slowly and with more inertia. The slower reciprocation/cyclic rate allows the magazine spring ample time to feed the next round while the greater inertia of the assembly strips the next round and chambers it with more momentum, allowing for function when the rifle is fouled, dirty or in extreme cold.
https://www.m4carbine.net/showthread...recoil-impulse
https://www.m4carbine.net/showthread...-Low-Mass-BCGs
As far as the LMT enhanced carrier goes, I chose it over a standard auto carrier because much testing by other members here has determined that it is more useful than just treating the symptoms of over gassed guns via the extra gas vent hole. As the carrier begins to move rearward the revised cam pin track geometry delays the bolt unlocking long enough to allow for more of a drop in chamber pressure before extraction begins. Less chamber pressure means less force pushing the case walls against the chamber walls and thus less resistance to pulling the round out of the chamber. In this way the E-carrier seems to actually increase the guns reliability, so long as there is enough overall gas pressure to cycle the action. Which, so far, seems to be a non-issue on most set-ups using the e-carrier, even with 14.5" mid-lengths.
Though a LMT technical rep told me in no unclear terms that I was wasting my money on the E-carrier if I wasn't running full auto on a long barrel w/ carbine gas system, it seems the e-carriers reduction on cyclic rate is its secondary benefit next to the revised cam pin track that allows chamber pressures to drop more before extraction begins, thus allowing the case to be removed with less friction against the chamber walls.
The extra venting capacity comes through the tiny weep hole, which vents the chamber directly behind the bolt tail/gas rings when the BCG is locked in battery and then the extra/third vent hole that is uncovered after the the bolt unlocks and the carrier is already in motion reward.
FWIW, my theory of the e-carrier is that as long as you have enough gas pressure to cycle it, the main benefit is the revised cam pin track. I don't know if this is 100% accurate but it does seem like either the e-carrier is quite modest in reducing gas pressure in the gas system or most guns are over gassed, or both. But since the e-carreir allows cases to be extracted with less work due to lower chamber pressures/friction against the case and chamber walls, and because the revised cam pin track allows the carrier to gain more velocity moving straight backwards longer before the cam pin is engaged laterally by the unlocking lobe in the track, the e-carrier can get away with venting more gas because it preforms less overall work.
see: https://www.m4carbine.net/showthread...riations/page2Originally Posted by tom12.7
https://www.m4carbine.net/showthread...cal-Comparison
https://www.m4carbine.net/showthread...s-system/page2
https://www.m4carbine.net/showthread...essed-SBR-Ever
https://www.m4carbine.net/showthread...arrier-Testing
https://www.m4carbine.net/showthread...4-5-quot-middy
https://www.m4carbine.net/showthread...C-Enhanced-BCG
-UCWRG G23 (2.35oz) vs. original MOE-K (2oz):
As light as the MOE-K is it just was not comfortable. The G23, alternatively, fits me perfectly and is still one of the lightest grips available. Its thick tang places my hand perfectly for perch of my trigger finger pad upon the slightly extended reach of the flat Geissele trigger face.
-Vltor A5SR RE/Springco green (6.05oz) vs. V7 carbine length RE/ Springco blue (5.2oz)
The A5 system is a winner. I was willing to add .85oz to have the smooth, continuous rifle length spring rate and the spring loaded buffer weights unique to the A5 buffers, which keep the buffer mass consistently against the BCG during unlock. Also, "The counter weights travel twice as far, when compared to the [carbine/rifle buffer]. This design produces a 'dead blow' effect rearward and forward (counter recoil), which eliminates all bolt bounce." ESK (https://www.m4carbine.net/showthread...-with-FOG-what).
The A5 allows a greater range of reliable tuning with heavier buffer weights as well. I tested this upper as configured with a A5H2 (5.45oz) buffer using Tula .223. It cycled and locked back on an empty mag 20rds in a row. Currently an A5H0 (3.75oz) rides in it for good measure. Since it is a life support gun, I don't want any surprises. I will probably step it up to a A5H1(4.55oz) and call it good. With the forthcoming lightweight V7 forward assist assembly, trap door rod and safety selector coming in, I should still hit my target weight.
The 6 position A5SR tube (4.05oz) makes the most sense with a open ended stock such as the 4.4oz Colt N1 CAR, it keeps the stock from collapsing beyond the end of the extended length tube as it would on the regular 7 position A5 RE (4.25oz) and is .2oz lighter.
http://www.youtube.com/watch?v=UnrVJT4UU10
-Aimpoint T1/ Fortis F1 combo (4.35oz) vs. Trijicon RMR/ RM34 mount combo (4.9oz measured)
I considered the RMR but decided the T1 was better and, surprisingly, is lighter when mounted. The T1 mounted on a Fortis F1 weighs 4.35oz measured (3.05oz+1.3oz). The RMR only weighs 1.25oz but the RM34 mount weighs 3.65oz and the ADM RMR mount weighs 3.5oz, for a mounted total of 4.9oz and 4.75oz respectively. In both cases the T1/F1 is lighter. As far as features go, I would rather have the T1/F1 combo with 2moa dot, mounted battery changes, longer battery life, 1/2" at 100yd click adjustment (vs 1"@100yd), lower 1/3rd co-witness, and a proven track record. But, unlike the RMR, the lightest T1 mounts (Fortis F1 1.3oz and DD Micro 1.7oz) are not QD. But I decided QD wasn't wholly necessary on a dedicated HD/nightstand rifle after watching the DD torture test video; my T1 will survive where I will not. Short of taking a round directly to the optic, the only thing it is realistically susceptible to is fog and rain, but inside the house should not be a problem there. [UPDATE] ScalarWorks LDM micro QD mount has changed the game. It is no compromise at the same weight as the lightweight fixed Fortis F1 mount but with a true quick detach securement. Thank you ScalarWorks for setting the bar!
Someone really needs to make a lighter mount for the RMR on the order of 1oz or less, something like the Fortis F1 or ScalarWorks LDM scaled down to the size of the RMR would be perfect and scary light (if strength was a concern it could be made out of the aluminum alloy V7 uses). The weight benefit of the RMR might be worth the feature trade off at 2.2oz mounted. [Update] The Larue Tactical LT827 QD RMR mount is the current lightest RMR mount at 2.35oz. It is exceptional quality and is much lighter than the ADM and RM34 mounts and actually places the RMR in almost a lower 1/3d co-witness. However, the feature drawbacks of the RMR still do not beat out an Aimpoint Micro on a ScalarWorks LDM, even though the LT827 and RMR combo at 3.6oz is finally lighter than the ScalarWorks LDM/Aimpoint Micro combo at 4.35oz. A lighter RMR mount is still needed to balance out its drawbacks.
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