Ultralight Ultralight Rifles

[Thegman]

I’ve got everything on order or here except the butt stocks. I want one fixed as light as possible and one folder. Or else just a folding adapter for the fixed stock.

The green mountain barrels are going to LRI to get turned down to a Faxon pencil profile. I may or may not have a spare or two when the dust settles.

Building one with a Faxon barrel as well for a more budget friendly build. (And to play with while waiting on the custom barrels Did we ever decide if it’d be ok to just leave the port open with a 7” hand guard? If not what is the preferred lightest gas block to reverse and will it fit in a kaw pcc hand guard?

A Guntec or other aluminum block works fine for covering a port. If it's a little tall, it's easy to take some off the top with a hacksaw and a file.

Post some pics and weights of your unported barrels if you will when you get them finished.

 

[Thegman]

Speaking of barrel pics, Shaw happend to have -one- test barrel left after they built StupidLightweight's barrel. I got lucky enough to get ahold of it.. It's basically a twin to StupidLightweight's. 17.7 oz. Tapers to .50" at 9" and straight .50" to the end. They could even go a little lighter if they wanted to, but I'm happy with that.

I'm getting parts together for the "Red Ryder II" sub-3# rifle with this barrel. Should be about the lower practical limit of what I'm building.

The good news is that Shaw mentioned they were getting a lot of requests for portless barrels and would likely be making a run of them, and they're light.

Sounds like Wilson is hearing the same and Bill Wilson built his own portless straight-pull AR. I also sent him some pics and description of the Solo Upper, so they're aware of them at the top. You guys are turning the tide!

 

[Taudisio]

Did we ever decide if it’d be ok to just leave the port open with a 7” hand guard? If not what is the preferred lightest gas block to reverse and will it fit in a kaw pcc hand guard?

No issues with mine over ~150 rounds. I am going to film/take photos with cardboard over the port. It snowed all last weekend so I haven’t been out to do so yet, and rain so forecasted for this weekend. If I find a good gap this weekend, or maybe next weekend if I’m not out scouting for bears and get some time at the range I’ll give a report. I assume it is no different than a port on a muzzle brake and treat it as such.

 

[robtattoo]

Did we ever decide if it’d be ok to just leave the port open with a 7” hand guard? If not what is the preferred lightest gas block to reverse and will it fit in a kaw pcc hand guard?

Drill it out, tap it to 6-48 & use JB Weld as threadlicker to hold an old scope mounting screw in place. File it flush & file down the gas block stop until it's flush with the journal.
You won't get any lighter than that!

 

[StupidLightweight]

Drill it out, tap it to 6-48 & use JB Weld as threadlicker to hold an old scope mounting screw in place. File it flush & file down the gas block stop until it's flush with the journal.
You won't get any lighter than that!

Use a titanium screw, and it’ll be even lighter!

 

[JBradley500]

I tapped mine 4-40 but it was a tedious job. Even with a really good tap it felt like it was on the verge of snapping a lot. I was only turning like 10* in then backing it out. Took a while but worth it.

 

[JBradley500]

So I had a better idea for the buffer retainer plate... I had an ar308 buffer tube that has the extended threaded end with a slot cut in it. I use that with the buffer retainer pin/spring rather than the end plate to keep the tube from rotating. I ordered an aluminum castle nut also. This should shave 1 OZ off and look a little sleeker too. Here's a pic of the buffer tube and pin.

 

[Thegman]

So I had a better idea for the buffer retainer plate... I had an ar308 buffer tube that has the extended threaded end with a slot cut in it. I use that with the buffer retainer pin/spring rather than the end plate to keep the tube from rotating. I ordered an aluminum castle nut also. This should shave 1 OZ off and look a little sleeker too. Here's a pic of the buffer tube and pin.

That looks like it will work fine. Once the castle nut is tightened, I wonder if rotation is much of an issue anyway? Once I get mine tightened, it seems like they hold pretty well (although I do bring a mini strap wrench on hunting trips just in case).

 

[JBradley500]

Yeah I thought the same thing, that the nut should do enough for hunting, but I had fun trying to have a backup with the stuff laying around the house. This is a fun game.

 

[FullyTorqued]

I 3d printed this stock from UV stable ABS (ASA). Found the files on Thingverse. 2.9oz without castle nut.

 

[Thegman]

I 3d printed this stock from UV stable ABS (ASA). Found the files on Thingverse. 2.9oz without castle nut.View attachment 685000View attachment 684999

Impressive, that's lighter than any aluminum buffer tubes or stocks singly, let alone together. Does it adjust and lock as it is, or does it need additional parts for that?

Nice work!

 

[FullyTorqued]

Impressive, that's lighter than any aluminum buffer tubes or stocks singly, let alone together. Does it adjust and lock as it is, or does it need additional parts for that?

Nice work!

It uses this little 3D printed dowel to lock in the adjustment.

 

[FullyTorqued]

I also thought the Solo 300 ball detent spring was causing too much friction in the upper, so I clipped a few coils off the spring and created a bedding for the detent ball into the upper with some Devcon epoxy. It gives a much more solid lockup and moves more smoothly. This was on a Cross Machine Tool UPUR-3A, since I wanted a right side charging handle (I also drilled and tapped Solo BCG to move the handle to the right side).

 

[robtattoo]

I got into my buddy's machine shop today & modded the cheap, nasty BCA upper.
Cut it for a left hand charging handle, slabbed ⅛" off each side & knocked off all the picatinny rail in not going to use. Unfortunately we didn't have the tooling to do everything I wanted, but we still managed to shave 2.3oz, so no complaints. Well, one complaint: it was roughly 22 thou out of square.... there's a reason it's a $40 billett upper We also roughly hacked an ounce off the butt plate.

The Wiland handguard also arrived & was a little lighter than advertised. For $89, I don't think there's much off the peg could beat it for a 10"

The bare rifle is now weighing 3lb15oz & I still have the buffer tube to cut & modify, once my carbon pipe arrives. I'm thinking that'll be another 1.5-2oz.

I'm rethinking my scope choices.....

But at least it's fugly as hell!

 

[robtattoo]

There's still a bunch of blending & sanding to do to smooth out the sharp corners & transitions, but I'm knackered, so it can wait until tomorrow.

 

[FullyTorqued]

Wow, you milled that down a lot. If these ATI poly uppers ever come back in stock they only weigh 7oz.

American Tactical Imports AR-15 Stripped Poly Hybrid Upper Receiver ATIHUP200 Color: Black, Finish: Matte, Fabric/Material: Polymer, 20% Off

Shop American Tactical Imports AR-15 Stripped Poly Hybrid Upper Receiver | 20% Off Highly Rated on 61 Reviews for American Tactical Imports AR-15 Stripped Poly Hybrid Upper Receiver + Free Shipping over...

www.opticsplanet.com

 

[JBradley500]

There's still a bunch of blending & sanding to do to smooth out the sharp corners & transitions, but I'm knackered, so it can wait until tomorrow.

I think the ugly is what attracted me to these builds. They put off that backyard mechanic/end of the world vibe. Love it.

 

[cricket1974]

very nice rigs here

 

[JBradley500]

I think I'm done messing with mine. I changed the red dot mount and got rid of the standard buffer plate and castle nut and just used an aluminum buffer nut. Saved around 2 oz between those two changes.

Final scale says 4 lbs 4 oz with optic, sling, and magazine. 3 lbs 15 oz without the mag. Not sure what it would be without the optic and sling but probably close to 3.5lbs. Good enough for me without compromising any strength.

 

[Thegman]

I think the ugly is what attracted me to these builds. They put off that backyard mechanic/end of the world vibe. Love it.

UGLY!?!? I would be deeply offended, but I'm sure you were talking about someone else's builds...