I’m planning a lightweight AR build for my significant other and would like some input on parts.
-Bolt carrier I’m looking at is the AP Customs Rhino Low Mass carrier, weight ~8.3 oz.
-Barrel will be BCM ELW-F 14.5" mid-length gas
-Ammo will almost strictly be M855, but will probably be fed cheaper 55 grain stuff from time to time
Is anyone running a similar setup? What spring/ buffer combo would you suggest to run reliably?
Is the wife so frail that a pound will be a deal killer? If not shoot for 6.5# with a real BCG, buffer, tube and stock. Maybe give up a few more and run an A5. She may be better off with a with a rifle that will eat anything, shoot soft and a stock that can be adjusted to fit with better cheek weld. You won’t find much love for stuff here that may sacrifice reliability.
My goal is just to go as light as reasonably possible. She likes my AR’s stock set at around the length of what the Sabertube is at, but I was also considering the MFT Minimalist or an old CAR-15 stock.
As far as the reliability goes, I’ve been seeing a lot of hubbub around featherweight builds and was hoping someone here might have some insight into making them run well. The AP Customs BCG isn’t even really that light compared to the aluminum and titanium ones out there.
I definitely would not sacrifice on function for weight. You can build a sub-6lb rifle with regular internal parts (bolt carrier). If SBR is an option, 11.5" guns are even “lighter” by merit of being better balanced.
I have a 10.3" that is right about 5.5lbs with optic and BUIS, using Larue’s lightweight T1 mount (non-QD), T1, MBUS, M4 stock, and 10" gen II SS handguard. “Lightweight” profile barrel, DD if I remember correctly. Everything else is stock stuff - receivers, bolt group, etc.
Reciprocating weight on AR’s tend not to be ideal places to save weight - worth considering if you’re trying to hit a really low target would be an adjustable gas block (since really light carbines with low-mass BCG’s and light buffers are where you’ll see the most gains in follow up shot quickness by limiting the amount of gas if using 5.56 spec M855 ammo).
If anything, a bit of weight on the back actually makes the rifle handle ‘lighter’ as far as point-ability, so I actually put slightly heavy stocks on my wife’s rifles (A5-EMOD and SR-15 tube with LMT SOPMOD) and she absolutely adores those setups. They’re not quite as svelte out front (X300 light in front of DD A1.5 Front sight isn’t stupendously light, but it’s simple, effective, and ambidextrous. The RoschWorks SL-1would be another consideration there
The weight that ends up being saved on the BCG’s tends to be lightening cuts made towards the tail of it; where weights savings are the most prominent is stuff towards the nose - and the KMR + ELW 14.5 with BCM FH is golden there.
An adjustable gas block, LW bolt carrier group, and LW buffer are my recommendations. My build weighs 5 pounds and 1/2 ounce sans magazine and uses an SLR adjustable block, JP LMOS BCG, and Taccom buffer (weighs 1 oz., no reciprocating mass). I recommend them highly.
Balios Lite receiver set, BCM KMR rail, DD .625 14.5 barrel with pinned BCM comp, Ace ARUL stock and rifle spring, T-1 in DD mount. I could change a few things and go below 5 pounds but just don’t feel the need.
This gun was built soley for LW and fun, no HD or other serious use intended. I have 400 rounds through it witout any function issues. I presume your goal is a fun gun as well and say go for it. Be warned though, LW = $$$$.
I am going with the new SLR Rifleworks ultra-lightweight titanium adjustable gas block. Your barrel is .625" diameter at the gas port, so that would be the Sentry 6 Titanium Adjustable Gas Block. It weighs a mere 0.776027 oz (22 grams), and helps keep the weight off the muzzle end. You can very easily tune the gas block to the weakest round you intend to shoot, so it will eat anything you feed it from there up, while at the same time allowing you more lightweight options to pick from in the buffer/spring combo. In my case, I was going to go with a light buffer combo, light BCG, and Sentry 6 Titanium Adjustable.
At least that is what I intend to do with my girlfriends ultra-lightweight build.
I also chose the MFT Minimalist stock only because I want her to be able to adjust it to her comfort and also to still have the capability to extend for when going prone or other odd shooting positions. The rubber pad and butt height, in my experience, helps in maintaining the rifle in place.
Are you SBRing or are you pinning? If SBR, then like others, you can go shorter, but if pinning, V7 offers very lightweight options for brakes and comps long enough to meet the 16", and I think also 2A Armament offers some too.
If you are at all intending it for defensive purposes you want to go with standard mil-spec reciprocating assembly parts. Maybe a SLR adustsble gas-block.
DWood- That Balios receiver group is gorgeous. Nice rifle.
BetFed 1- I won’t be SBR’ing it. Planning on pinning and welding a BCM Mod 1 comp.
jerrysimons- It’s going to be for defensive purposes and will probably need to be humped with if ever used as such. It is also going to have irons, a flashlight, and (eventually) an IR laser, hence my obsession with cutting weight.
Thanks for everyone’s input. I am probably going to just use a standard BCG. I have the same barrel and comp setup on my rifle and it shoots like a dream, so there’s probably no reason to change if reliability is going to be called into question. Seems like with the right receiver and other parts I can shave enough weight to get close to my goal. I also have an inherent distrust of anything adjustable, especially triggers, gas blocks, and gas keys. Thanks again!
Your weight can be achieved with full mass bcg. I have a build right at 5lb-1oz without mag. DD14.5 mid LW .625 barrel, Mag Tactical receivers, V7 parts, JP full mass bcg, springco blue buffer spring, standard carbine buffer, v7 .625 gas block. Holosun RDS, 10" KMR, stripped down Vltor Imod stock, BCM CH, pinned Precision Armament Afab mini muzzle device. Runs everything I’ve fed it from Tula( just to function check) green tip, PMC Bronze, ZQI and American Eagle. Handles like a dream very smoothe on recoil
I guess I presumed incorrectly that HD was not the intent for this build. Based on this new info, I would use a good, mil spec BCG (BCM), buffer and low pro gas block. You will get your weight savings in the receivers, barrel, rail, and stock. You should be in the mid to high 5 pound range.
FWIW, the ARUL stock foam pad is very comfortable to shoot. I wouldn’t like a bare tube as my cheek weld.
They are light, but the magnesium alloy is not as strong as billet or forged aluminum receivers. I might use them in a fun build, but not for HD. Google them and you will find photos of broken receivers.
Model 1 Sales has the complete ARUL kit with the buffer tube, rifle buffer & rifle recoil spring at the best price I have found. I have read complaints about them but I got my order quickly.
I would stick with the Balios for peace of mind. I haven’t had any issues with the Mag Tac receivers but fit and finish is not the greatest. You can still achieve your weight goal. I just finished another build with BCM ELWF 14.5 with the BCM upper on a Tennessee Arms lower that is 5-2 with 20 rd pmag. I have the 2A titanium muzzle device on that one and all the V7 lightweight goods. Have not shot it so don’t have feedback just yet.
I picked up a couple Mag Tactical lowers because the price was reasonable and quality seemed good. I then picked up a couple matching uppers and they’re pretty bad. They’re functional, yes, but there’s significant porosity inside and the paint is horrible. These weren’t blem. I’m using them, but won’t be buying any more from them.
Good luck finding any uppers from Mag Tactical anyways. Lowers, sure, they are in stock and easy to find on Gunbroker, but the uppers… I searched and searched, no luck, their customer service sucks too, so good luck getting a hold of them. I emailed, called, left messages, Facebook, nothing… If anyone has a lead on Mag Tactical uppers, let me know, I have a .22lr lightweight build that needs one.
As I said, I won’t buy another upper from them. Maybe they stopped due to quality issues, who knows.
I think I still have one sitting around if you’re really interested. The black one from these pics: http://imgur.com/a/geKLq but it might have ended up somewhere else, let me know if you want me to look. As I said, the lowers seemed pretty nice. These were purchased around 10 months ago.
