AR Sponsor
Posted: 8/13/2008 6:23:16 AM EDT
|
I'm not even done with my current build and already planning my next--that's EBRD for you. I'm intrigued by the KISS carbine concept and the idea of a lightweight rifle, which was one of the original boons of the AR compared to its peers. I want a carbine that is as light and as short as possible for quick target engagement. I don't want any frills: no rails, no flip-up sights, no optics. Here's what I am thinking: Fulton Armory A1 upper with A1 sights, no forward assist or brass deflector Colt Commando style 11.5" barrel with permanent flashider (I'm in AL, so no SBRs) Standard handguards, gas block, and front sight tower Standard lower ACE ARFX-E ultra lightweight entry buttstock Concerns I have: -Will the 11.5" barrel with permanent FH be any lighter than a 16" barrel? -How does an 11.5" barrel do with respect to velocity? Is overpenetration in an urban environment still a large concern? -I assume a CavArms lower might save some overall weight, but aren't those hard to get right now? -What kind of overall weight will I get with this configuration? -Any other ideas to make it lighter or simpler? Overall thoughts? Any existing examples? |
|
I didn't know they make a 4.5"+ flash hider. But why would you want one on your rifle? I think you would make better use of your 16 inches by getting a 14.5" barrel with a 1.5"+ flash hider. The longer sight radius alone is enough benefit IMO. If you get a lightweight barrel profile it won't be too heavy. Overpenetration will be a concern regardless of barrel length. No matter what type of firearm you're using, it is able to shoot through the walls of your home. I thought CavArms was up and running but that is totally unreliable info coming from me. I haven't ordered one of their lowers so I dunno how easy they are to get. It's worth trying if you really are trying to shed weight off the rifle. |
|
I'd consider a 14.7" Pinned if you're set on it being KISS, and short. CMMG would be first on that list, for price and value. The 11.5" is only marginally lighter, and you're losing muzzle velocity. You could consider a carbon fibre free float handguard - DPMS are cheap, PRI is top end. Not much weight savings, and is pretty flashy, but you'd drop a bit more weight. Lighweight BCG is an option, if what works for you. CavArms lower might be a much better choice for lightweight, if you're content with fixed stock length - I'm personally going with one of the Falcon M93 units once they're out - until them I'll get by with a standard 5 position unit. |
|
I'm talking about a barrel configuration similar to this kit at J&T. Why would I want one? Because I've played with 16" and 20" barrels but never something like this. I'm intrigued by the niche utility and length. I'm not looking to get max velocity and sight radius. The furthest this build would be designed to shoot would be 75 yards. I suppose overpenetration within a single house is always going to be a concern with a rifle. Perhaps the reduced velocity would help outside a single house. Of course, I suppose a subgun is the optimal tool for the task I'm describing. |
Velocity is part of what reduces an ARs penetration. It aids in bullet break-up/fragmentation. Subguns fire heavier bullets that stay intact, and penetrate more than 5.56. The 14.7" with A2 will be the same length as the 11.5 w/ 4.5" FH. So, I guess it's all about what look you want. |
|
Go with the 14.5" and a pinned Phantom. As to using a 5.56 inside a home. It's by far and away the BEST choice! Use Hornaday TAP ammo, I'd go with the 40 gr bullet for home use. I've seen demos of it by Hornady on drywall, its as safe as you are going to find. PursuitSS |
just a tad it will loose quite a bit, but not worth the same length imo; always yes, its about 1 lb less; no, check the EE not too much simply: get a 14.5o r 14/7+ perm FH; lightweight (.065in bbl) profile bbl; std rest; i would run a CAR stock and AL lower FWIW |
|
Govt profile 1/7 barrel Carbon fiber FF tube CavAid Lower  Lighter than my 16" carbine. Somewhere in the 6.5-7lb range with loaded mag. If you used the Cav Arms lower, carbon fiber FF tube and a lightweight barrel cut to 14.7" + FH, I'm guessing you could get under six pounds easily. |
A 16: Bushmaster LW barrel is lighter (those 5.5" FS are heavy compared to barrels). 1.9 LBS for the 11.5+5.5 (that's assumuing you can find a LW profile version - as most are HBARs for 2.4lbs) vs 1.7 lbs for the 16" LW Even lighter (about an ounce or so IIRC) is one of the 16" LW barrels cut to 14.7" with a permanently added A1 flash supressor. Minimum lenght and weight. The upper one I built for my wife, about 5.5lbs: 
|
|
Flashiders of that lenght are usless IMHO. I don't understand why you would not want to go with a 14.5, 14.7, or 16" barrel. Same overall length as what you're talking about, right? I really like one of my Bushmaster superlites. It looks almost identical to Forest's A1 above, but with a teardrop forward assist and a brass deflector. I have it set up on an A1 receiver and a Colt fiberlite 4pos stock. Very very light and handy, I think trying to set it up any lighter would be diminishing returns. You could do something like that, and if you still wanted it lighter, go with a carbon fiber forarm or ace lightweight stock. But shaving a few ounces off of an already really light carbine, for the amount of extra $ it would take, just doesn't seem worth it. |
No the 11.5" LW with the 5.5 is a 0.1 oz heavier than the LW 16". It's about half a pound heavier if you have to go with an HBAR 11.5". Lightest non NFA with shortest barrel is a 16" LW cut to 14.7" with a permanetly atteched A1 flash supressor.
Poorly with 5.56. You're much better off with the 14.5"-16" barrel length with 5.56. Wth 6.8 you'd be good to go.
They will save a little weight compread to an aluminum lower with a CAR telestock, but you lose the ability to collapse the stock. They can be purchased thorugh the Cab-Arms aid deal - see the thread in General Discussion.
Figure it out yourself and download the AR Weight Table spreadsheet from the Documents section at www.MD-AR15.com if you're a member. If not ask around I know I sent it to several of the members here.
See my wife's above. The CAR stock is the lightest telescoping stock and it uses a 4 position receiver extension (so it can be adjusted for my wife's short stature). It's the shortest "standard part" non-NFA AR possible at 30", and will fit into some tennis racket cases. It has a TDI rail mounted at the 10:00 position along the left side of the handguard so mounting a light is possible (light was removed for the photo). As a light is a critical part for a defensive/urban carbine. |
|
Thanks for all the replies. Looks like a LW 14.7" barrel plus pinned A1 FH is the way to go for minimum length and weight. The only reason I was interested in the 11.5" + long FH option is that I thought it might save weight (and it was interesting). It now appears that it doesn't have any real benefits. I don't really care about a collapsible stock. I think a fixed stock is simpler, and I hope I can save a few ounces by eliminating components for a telescoping stock. I do not have access to the weight calculator that Forest mentioned. If anyone can email it to me (email user link is active) I would be greatly appreciative. [edited to add: I submitted for membership. I'll see what happens.] Besides Bushmaster mentioned above, what's the best source for an ultra lightweight 14.7" barrel. Does the guy at AR15barrels.com still do custom work? What's the weight savings of a CavArms lower over the lightest possible aluminum lower? BTW, I think AL law specifies 26" as minimum OAL for a rifle. Is 30" mandated by NFA, or is that in the state you live? |
CMMG has light weight 14.7 barrels/uppers. The seventh product down is the 14.7" barrel... Seventh one down |
I'll get you approved ASAP, but it probably won't be today. as I'll be unavailable in a few minutes.
Colt, BCM shold have them, CMMG should have them. ADCO also does custom barrel cutting and pinning.
IIRC it was a few ounces - you should be able to compute it on page 2 of the weight table (the rifle worksheet).
16" barrel + AR receiver + telestock's 7" receiver extension brings you to 30". To go shorter you'd need to make a shorter receiver (not possible if you want to shoot 5.56) or get a shorter receiver extension (with a new buffer & spring). Diemaco made such a beast for their PDW, but I've never seen one for sale. |
|
I've been accumulating parts for something similar--an Air Force GUU5P clone. See www.retroblackrifle.com/ModGde/CrbGde/USAFGdeCrb.html (scroll down). I have the upper and lower and plan to use a CMMG 14.7" 1-in-7 barrel with a permanently attached A1 flash suppressor. I haven't decided which bolt carrier to use. IIRC, many Air Force M16 variants had serrated BCs even if they didn't have a forward assist, so I could probably get away with using an LMT Enhanced full-auto bolt carrier. If I decide to go with a smooth, I'll get it from Young Manufacturing. If you want to cut the weight even further, you could use the Clark Custom Guns carbon-fiber free-float tube suggested above. It only weighs 4 ounces when cut to carbine length (which includes the Aluminum barrel nut). Les Baer also makes a flattop upper with no forward assist. It's about an ounce lighter than an M16 slick side upper . . . ETA, sounds like the OP needs the AR-15 Assembly, Part, and Accessory Weight Table at the bottom of this page: groups.msn.com/themarylandar15shooterssite/techdata.msnw. You have to sign up to access it, but it's worth it. Great resource! |
Agreed, but then you need to pull things like the pinned muzzle device and the front sight base to install. So if the OP wants to use it he better send it along to whoever will pin on the flash supressor. IIRC NewARGuy has pics of an AR built with one, maybe he'll post it (hint hint NAG) |
I have to STRONGLY disagree with you on this point. If the OP is concerned about penetration on drywall, 6.8 SPC WILL over penetrate! I've observed Hornaday's Law Enforcement Demos on drywall. Light & FAST is the key to preventing over penetration. The best load I've seen for disintegrating on drywall is the Hornaday .223 40 gr TAP. PursuitSS |
I'd go with the LW barrel pinned to 16". The extended FH is quite heavy, plus you will enjoy the velocity and energy benefits of the longer barrel. This is an SBR I just completed. Tips the scale at 5 3/4 pounds. A standard CAR handguard and fiberlite stock put it under 5 1/2 pounds, but I like the way it looks with the LMT stock and double-shielded M4 handguards. This is a 14.5" barrel, I expect the weight difference for .20" of LW barrel would be negligible. |
|
I'd recommend a 14.5 + permapinned 2" flash hider. Such as: Link to CMMG 14.5" light weight upper  DSG Arms is a board supporter and has CavArms lowers in stock.  There is another company besides Clarks Custom that makes the fiberglass tubes and IIRC they're ~$30 cheaper. I'll scratch around to see if I can find them again. |
|
Nobody has mentioned you save a few ounces by going with a flattop upper with BUIS and not a slickside 'A1' upper. Yes, you gain the FA and brass deflector on the flattop, but all the mass of the carry handle is eliminated, so it saves precious ounces. Larue BUIS FTW!! Another thing to consider is balance. A well-balanced heavy rifle has alot better feel to it than an overall light but poorly balanced rifle (*cough*AKs) Try to find the perfect medium for you. |
I was talking terminal performance meeting minium criteria, not penetration of drywall. Any round that has issues penetrating drywall has issues stopping the threat. |
Because you don't. Typical Flattop upper 8.0-9.6 oz (Fulton CMT # vs Bushmaster). BUIS run from 1.2oz (ARMS#40L) up to 5.0oz (LMT). The LaRue, which is comparable to an A1, runs 3.0 oz. Compared to a M16 upper (no FA) which is 8.0 oz Even the lightest aluminum flattop I could find (Les Baer - no foward Assist or dust cover) runs 6.9 oz, add the 1.2 oz of the ARMS #40L and you get 8.1 oz. Still 0.1oz heavier and you have NO dust cover and sights that are less durable than the field sights of the M16/M16A1; and you spend ALOT more $$ for that flattop + BUIS combo. |
|
I agree with the guys above, i'd get a 14.7-16" Lightweight barrel with an A2 flash hider(I'd get mine from Bushmaster or LMT). I probably wouldn't bother with a cavs lower, just a nice mil-spec unit with either the 6 or 4 position stock. The 4 position carbine stock is lighter, but the 6 position looks better. I'd ditch the carry handle and get a nice small rear BUIS. Wouldn't a small rear BUIS weight less than that big carry handle? Maybe an ARMS40L? Why is a flat top heavier than the carry handle? the handle has more metal on it? Then use a nice 20 round magazine to save the extra weight, should be a light mother. Figure 7lbs with the magazine full. Oh, I got a weird one, has anyone tried the Bushmaster Carbon 15 rifles? I think one of those with a 16" LW barrel and a carbine stock would be awesome as far as weight goes. Maybe 6lbs with a full 20 round magazine! |
|
FYI Cav Arms Lower vs a standard A2 lower with CAR (old style) stock and A2 pistol grip: Cav Arms: 27 oz A2 lower with telestock: 30.9oz A2 lower with ACE "ultralight" stock: 29.4oz For thiking about the Skeleton stock - forget it add 11 oz to the number for the 'Ultralight', the Stubby version is only 0.3 oz lighter. And the Ace Stubby Skeleton is the lightest stock I know of. |
The M16A1 upper IS heavier by fractions of an ounce, because it has a foward assist. The M16 upper lacks the foward assist (which is 3.2 oz of weight savings). The devil is in the details, the M16 upper is NOT the same as the M16A1 upper. |
Sound ideas - weight towards the rear of the weapon helps them feel lighter in my opinion, so a bit of extra weight in the back is hardly a bad thing. (the only time I ever notice the heaviness of the rifle is when I'm firing strong-hand only, or weak-hand only from the shoulder) I'm not that into the argument for shedding ounces to shed ounces - the FA has a use, and it's not like that weight it tugging down at the nose end of the rifle. Any weight-minded AR is going to weight a couple pounds heavier tan something other than an AR, so keeping it ergonomic, functional, and controllable while light is my basic goal. IF pure weight loss were the goal, stubby pistol grips, ultrathin handguards, and probably custom cut uppers with no sights, and only a mount for a micro aimpoint. |
Not so, the 40 gr & 55 gr TAP load is designed to fragment on drywall but stop a person. In real world shootings with these rounds this has been proven time and time again. Hornaday TAP is the preferred load for most SWAT/ERT teams. As Hornaday explains during their Law Enforcement demos (I've been to three), velocity is the key to fragmenting the round on drywall. They have a demo unit that holds two small sheets of drywall spaced four inches apart (the same as a residential wall). They then shoot it with various loads. Also, they demo the rounds on ballistic gelatin showing the permanent cavity. But again, these rounds have proven themselves on the street! PursuitSS |
They underpenetrate on tissue PERIOD. They just do. Hit an arm in the way of the chest and you cant reach the heart. Just a fact. |
|
Id like to add... according to the weight chart on marylandar15shooers website the Phantom is the same weight as the A2. A 14.5" barrel will be lighter than a 14.7 plus A2 and have less flash to boot. If you were inclined to use a light ballistic tip for reduced penetration botht he Federal TRU 55 grain and Winchester Silvertip 55 grain have better penetration and wounding characteristics on tissue. There is no reason aoutside cost to not use one of those rounds over 40 and 55 grain TAP or ever 60 grain TAP which penetrates less in tissue than the 55 grain lodings I listed. A1 uppers as stated are lighter than flat tops plus BUIS. Recoil is increased in a light weapon. While I always reccomend 75 grain ammo for defense using a 55 grain load above will reduce the recoil somewhat. IMO a Cav Arms lower has too long a stock for a CQB carbine if you use a sqared up CQB stance, dont blade, and dont chicken wing. Collapsable stocks vary in weight quite a bit... even if they look identical. Pick by actual weight. Cutting off the front sling mount and bayonette lug saves more weight than youd think and its up front where it counts. Removing the rear sling mount saves weight too. If you are doing KISS you can loop a Vickers or other 2 point combat sling directly through the stock and the rear sling mount becomes unneeded so its just dead weight. |
Very true. I guess any upper with A1 sights is called an A1 upper anymore, and I fell victim to that thinking.  M16 uppers are lighter then A1 uppers, and they are both lighter than C7 uppers. Heh. |
|
If you really want light, then ditch the irons, use an ultra light weight gas block and use a J-point, Optima 2000, or Dr Optic. Here's an ultralight I built with a Bushmaster "carbon fiber" upper. I never got it on a good scale, but I'd bet it was under 5lbs. I used an Optima 2000 on it. 
|
Tell that to all of the perps who are now in a box. These facts come from the people who keep track of ACTUAL LE shootings (Hornaday). They even have a REALLY nice 75 gn 5.56 load (NOT .223) , BUT they do NOT recommend it where a possibility exists of collateral damage in a residential environment. As to an arm shot, if that occurs I keep shooting until the threat is neutralized! Using 75 gn where there is a danger of an accidental round hitting drywall would be the same as using FMJ! PursuitSS |
AR Sponsor