Ultralight Ultralight Rifles

[DoveBlaster]

I have enjoyed reading this thread and I too built a lightweight AR recently, although some of y’all might think otherwise. A few impressively light builds in this thread.

Build Specs;
Aero Lower
CMC Trigger
Smoke Composites Grip
Bravo Upper
Wilson Combat 16” Pencil Barrel
Faxon Carbon Handguard
Superlative Arms Adjustable Gas Block
Area 419 Hellfire Brake
Smoke Composites Stock
Brownells Lightweight BCG
JP Silent Captured Buffer Spring
NF NX8 1-8 in NF Mount

I’ve been shooting some run and gun style matches and wanted something lighter than the AR I was running. I could of gone lighter but wasn’t willing to give up some creature comforts from my last build (brake, JP captured spring and fwd assist).

Side note I’m not completely sold on the accuracy of the Wilson Barrel and will likely end up with something else after I get 5-10,000 more rounds through this barrel.


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[ThatDUDE]

Just when I get the Rokslide Special all bought now I need to look into a "GMAN" Special. This place costs me way to much money.

 

[The Guide]

This has me thinking about a UL WSSM build. I know there were WSSM AR-15's built by couple of makers. The biggest down fall if I remember correctly was getting them to gas right. If you are making it a bolt action AR, no gassing issues. I found some 25WSSM brass at a LGS last week so this could be fun!

Jay

 

[hereinaz]

This has me thinking about a UL WSSM build. I know there were WSSM AR-15's built by couple of makers. The biggest down fall if I remember correctly was getting them to gas right. If you are making it a bolt action AR, no gassing issues. I found some 25WSSM brass at a LGS last week so this could be fun!

Jay

Extraction of a wssm brass without primary extraction cam might be a challenge based on what others have said about Grendel cases.

Isn't there a company out of Utah making straight pull ARs?

 

[Thegman]

Are you also using the 155eldm in the 300hamr?

Unfortunately, no, they take up too much room in the case. I use C Products 350 Lengend Duramags for the HAM'R. They allow loading out to 2.325", which helps, but not enough for the 155 ELDM. I used a Speer 150 BTSP on that moose, and we took another with the same. They expanded well, but didn't shed much weight. Probably don't kill as fast due to that. I was hoping the HRT would work out as it has enough capacity to make that bullet work in AR mag constraints.

These were the Speer BTSP from the two moose.


A grizzly from earlier this summer. Same bullet, worked well. Went about 30 yards and piled up. That's the first HAM'R I built in the picture. Used a Taccom stock on that one I never shortened so it looks a little funny, especially at that angle.



Didn't recover that bullet.

 

[rsltid13]

Unitah Precision, but don't see any weight specs listed

 

[Thegman]

That’s pretty cool. There is no way that you could make a 3.5# bolt gun yourself with a standard action. What kind of accuracy are you getting out of those? I find ARs to be finicky for me to shoot. Having the grip so far below the bore axis just magnifies any error with the trigger hand. I’ve got one in gas gun form with a Faxon pencil barrel that is a 2.5-3 MOA gun. It doesn’t get shot much.

I've built 4 so far, or at least run 4 barrels. 2 Wilson HAM'Rs, a 5.56 Wilson and a Faxon 223 Wylde. They've all been sub MOA for 3 shots with the right load. One HAM'R with almost every load I've run trough it.

I think I know what you mean though. I had change shooting techniques to get ARs shooting well for me compared to my traditional bolt rifles. Since then though, they've shot as well or better than any of my bolt rifles.

 

[Thegman]

So you've had no trouble with the .223 loads extracting at all?

Does the detent ball in your upper's bolt carrier reliably return to the correct position and keep the action in-battery?

Have you tried shooting it suppressed?

I've got a similar build started in .223 but am currently having a few persistent issues so I am curious.

FWIW, the owner of Solo 300 said he didn't design it for the higher-pressure, bottle-neck chamberings, but rather, as the name suggests, the 300BLK.

No extraction issues at all, and during load development, I've run loads that were too hot even for a gasser where I had to back off. That's running 223s and 300 HAM'R. (may have had a Blackout barrel on at at one time as well, but not sure). Running Lake City for the 223 and mostly for the HAM'R as well.

Once I got to the 30 HRT I started seeing sticking. Haven't figured that one out and bigger cases may simply not work in this setup without at least some sticking issues. Some may be okay with that, I'll pass though if that's the case.

The bolt closes fine and holds, but can get knocked open more easily than a traditional bolt rifle. Something to be aware of for sure. OTOH I've talked to guys complaining about their 700s getting knocked open in the brush. I generally hold the trigger down while I lower the bolt on a bolt rifle (empty chamber) to help it stay closed with spring tension. I do essentially the same thing with these if the chamber is empty.

I've never run them suppressed, or anything suppressed for that matter so not much help there.

What are the issues you're having with the 223? Now I'm curious.

 

[Thegman]

Very cool.

I haven't weighed the parts for my Howa Mini that I have for it in .223. If its not lighter, I may just do this with an SBR lower I have with a side charging upper with a 14" barrel and suppressor. The straight pull seems like a fun change.

Next time I load for my 22 grendel, I'll block the gas and see if it can be hand cycled. That would juice up the velocity in a shorter barreled AR.

Have you thought about drilling and tapping the gas port to get rid of the gas block? Never even thought about it myself for a side charger, probably something someone else has done online...

I've thought about the drilling and tapping, or even a custom barrel with no gas journal at all, but part of my goal with these was to do as much as possible with relatively inexpensive, common of-the-shelf stuff and little or no modifications needed. That would make it even lighter though, and cleaner, although I've never done it and don't know about tapping a nitrided barrel...or any barrel for that matter.

PredatorSlayer, related to the above. If you look for good deals and sales, $700 or even less is doable. Cheaper than most lightweight rifles, but also more limited chambering wise.

 

[Thegman]

@Thegman have you tested out the KE Arms KP-15 lower yet? It's not ultralight, but at least lightweight. Price isn't bad at $119 for a fully assembled lower either. I'm thinking about trying it out for 6mm ARC build.

No, I've never handled one, but they look solid. Probably not as lightweight overall as these lowers, but still pretty damn light. I'd like to try one out at some point.

 

[Thegman]

Last year, I built a straight-pull bolt-action AR in 6mm ARC as a 300-yard hunting gun. I had a custom BSF barrel made without the gas port. It turned out well and shoots better than I can. However, as others have said, the AR design is not easy to manually cycle. That part isn't fun.

This build has a steel bolt-carrier chopped after the hammer opening and a titanium charging knob. I did that so I could use a side-folding AGP Arms stock. It's a very cool minimalist AR. I added an ARCA rail and shoot it off a lightweight Leupold tripod. As shown, I think the total weight w/ tripod is just over 6 pounds.

What handguard did you use? Do you know the weight? Looks good.

 

[4090Sharps]

No, I've never handled one, but they look solid. Probably not as lightweight overall as these lowers, but still pretty damn light. I'd like to try one out at some point.

The price was right, so I'm going to try them out. It looks like the complete, stock KP-15 lower weighs ~26oz, and the stripped lower is ~18oz.

 

[Thegman]

Off the top of my head, the parts for my lightest stripped lower (receiver, grip, grip screw and stock) would be around 11oz or so, so not too much more at 18oz.

 

[fishdart]

What are the issues you're having with the 223? Now I'm curious.

I've had bolt sticking so bad I've had to hit the charging handle with a block of wood to extract the case.

Some issue with not igniting the round when I pull the trigger. Hammer falls, but no fire. It's possible the rounds I've tried so far (some older black hills and winchester bulk fodder) have hard primers because that sort of thing can happen with light after-market triggers and milsurp ammo in my experience with some of my ARs.

I've had repeatedly experienced the detent ball in the carrier get stuck in the retracted position and not engage into the receiver cut-out leaving the bolt unlocked and I can only remedy it by disassembling the action to pop it back out. The owner sent me a new carrier gratis, but haven't swapped it in yet. I can say that in just fiddling with it out of the gun, I can push the ball in and make it stick so not hopeful at this point.

I'm not giving up hope yet. I plan to try some higher-quality, new ammo as well as removing the suppressor and seeing if there is a difference there without the back pressure.

 

[Wilfred]

Off the top of my head, the parts for my lightest stripped lower (receiver, grip, grip screw and stock) would be around 11oz or so, so not too much more at 18oz.

I am very interested in going down this path. From their website Solo only seem to sell complete uppers with pistol length barrels, and those are out of stock. Do they ever sell upper receivers and bolt carriers alone? Or does anyone else sell a similar design in the same weight range? Did not find contact info on Solo to ask them directly.

 

[StupidLightweight]

What handguard did you use? Do you know the weight? Looks good.

The handguard on the 6mm ARC straight pull is from Wiland USA. According to them, the 10-inch version with barrel nut weighs 5.3 ounces. It's designed for PCCs, so it won't work with a gas system. Not a problem on these builds, obviously.

 

[The Guide]

I am very interested in going down this path. From their website Solo only seem to sell complete uppers with pistol length barrels, and those are out of stock. Do they ever sell upper receivers and bolt carriers alone? Or does anyone else sell a similar design in the same weight range? Did not find contact info on Solo to ask them directly.

I sent them a Facebook message and they said they are waiting on parts to come back from coating. Should have them back in stock in around 2 weeks they said.

Jay

 

[Thegman]

I am very interested in going down this path. From their website Solo only seem to sell complete uppers with pistol length barrels, and those are out of stock. Do they ever sell upper receivers and bolt carriers alone? Or does anyone else sell a similar design in the same weight range? Did not find contact info on Solo to ask them directly.

Yeah, looks like he's out of stock right now. The assembled upper alone was on page 2 of the catalog before. I see it's not there right now. I have 3, purchased as assembled uppers only. No interest at this time for a pistol version for myself, though I see that could be useful as well.

 

[Thegman]

I've had bolt sticking so bad I've had to hit the charging handle with a block of wood to extract the case.

Some issue with not igniting the round when I pull the trigger. Hammer falls, but no fire. It's possible the rounds I've tried so far (some older black hills and winchester bulk fodder) have hard primers because that sort of thing can happen with light after-market triggers and milsurp ammo in my experience with some of my ARs.

I've had repeatedly experienced the detent ball in the carrier get stuck in the retracted position and not engage into the receiver cut-out leaving the bolt unlocked and I can only remedy it by disassembling the action to pop it back out. The owner sent me a new carrier gratis, but haven't swapped it in yet. I can say that in just fiddling with it out of the gun, I can push the ball in and make it stick so not hopeful at this point.

I'm not giving up hope yet. I plan to try some higher-quality, new ammo as well as removing the suppressor and seeing if there is a difference there without the back pressure.

Yeah, I'd switch out the "detent key" part of the carrier and go from there, sending it back to be checked out if that fails to addres the lock-up issue. The detent shouldn't ever stick while in the upper; that's a no-go.

I mostly run CCI 41s which are fairly hard. Never have had an ignition issue. Another no-go. It -may- be your carrier is not out of battery, but not being held fully forward and absorbing enough of the hammer impact to cause ignition issues.

The extraction issues, I don't know. Maybe you're on the right track with the suppressor. None of my 223 based chamberings have had difficult extraction, but the Ham'r is probably the easiest. I've described it as practically falling out of the chamber on its own, and I'm on my own in loading that one. I load a lot longer than any of Wilson's loads so also use some longer, higher BC bullets than Wilson does, like 125 BTs and 125 SSTs, and at significantly higher velocities than any Wilson data, partly due to the extra case capacity from loading at 2.325, and partly, I'm sure, because I'm pushing past 57,500 PSI. I figure the AR bolt and brass were designed at 60k+ so figure I have a little wiggle room...that's what I tell myself anyway. Brass and primers both look and measure fine. No loose primer pockets and brass is lasting for many reloads.

The 125 BT has worked really well so far. Farthest shot has only been 150 yards, but lots of internal damage and pass throughs on everything. On the one deer I had to follow, I could walk the blood trail from 20 feet.

 

[Wilfred]

Yeah, looks like he's out of stock right now. The assembled upper alone was on page 2 of the catalog before. I see it's not there right now. I have 3, purchased as assembled uppers only. No interest at this time for a pistol version for myself, though I see that could be useful as well.

Thank you very much! Will try to contact them about an order. A unique project, you have broken new ground.