New Uberlight AR build. Pic heavy.

[Handsome Rob]

The goal was to build the lightest weight rifle I possibly could on a realistic budget (as cheap as I possibly could) 

I decided to go with a non gassed gun, making it a simple, straight pull bolt action. 

I just got finished making the carbon buffer tube/stock tonight & I believed she's done. 

Faxon pencil weight barrel, gas port blanked off. Wiland USA 10" carbon hand guard. TN Arms carbon lower. BCA side charge upper converted to left hand charge & milled extensively to reduce weight. NFA poly LPK, with 3lb Timney trigger ($68 on sale at Dvor) & bolt hold open omitted. Hogue grip, only $20 & just over 1oz! Home made carbon buffer tube with cheap, Amazon clamp on butt plate. No-Name ambi side charge bolt, cut off behind the firing pin (no need for the back half, since there's no buffer or spring) Charging handle from a Ruger PC Carbine, drilled & modified to fit. 

It ended up right at 3lb 11oz, bare weight. 4lb 8oz with the temporary old Tasco 4x. I have an ultralight SWFA 2.5-10x32 ordered that'll bring it down even further, to 4lb 4.5oz but I can't wait until then to try it out at the range! 

Edited March 12 by Handsome Rob

[Alleycat72]

What cal?

[Handsome Rob]

23 minutes ago, Alleycat72 said:

What cal?

D'oh! .223 Wylde, 1:7 twist. 

[KahrMan]

Looks good. Nice job. 

[RED333]

Nice looking, are you going to hold the rifle or vice mount fire it for the first few rounds? You did take a lot of meat off the upper.

[Handsome Rob]

53 minutes ago, RED333 said:

Nice looking, are you going to hold the rifle or vice mount fire it for the first few rounds? You did take a lot of meat off the upper.

It's still about twice as thick as a regular forged upper. But it is a Bear Creek..... Vice mount. 

[Alleycat72]

Are you going to put a return spring in it. You'll be able to pull it back and just let go.

[Handsome Rob]

37 minutes ago, Alleycat72 said:

Are you going to put a return spring in it. You'll be able to pull it back and just let go.

No way of doing it without a full length BCG & that's a lot of weight to add.

I did think about an aluminum BCG but they're a little spendy. I'd still like one to play with at some point, but dollars spent vs weight saved it's not a priority. 

[leroy]

I like it Rob..!  What are ya goin to use as a buffer to catch the bolt..?

leroy...

[Alleycat72]

42 minutes ago, Handsome Rob said:

No way of doing it without a full length BCG & that's a lot of weight to add.

I did think about an aluminum BCG but they're a little spendy. I'd still like one to play with at some point, but dollars spent vs weight saved it's not a priority. 

A delrin spacer can be placed between the cut down bolt and spring. 

[Handsome Rob]

29 minutes ago, leroy said:

I like it Rob..!  What are ya goin to use as a buffer to catch the bolt..?

leroy...

Not a thing. Without a gas system, the bolt can't move after firing. The locking lugs hold it in battery until the charging handle is moved backwards, rotating the bolt head out of sync with the lugs.

[Handsome Rob]

23 minutes ago, Alleycat72 said:

A delrin spacer can be placed between the cut down bolt and spring. 

Seems like it's just overcomplicating things. A quick flick of the wrist returns the bolt easily enough.

[leroy]

Rob.. Thanks Brother. Got it..!  I forgot how the bolt unlocked... CRS.. 

leroy...

[Erich]

NIce! you dont need the top of that gas key, mill it off flush with the bolt heads get for a free half ounce or so

You could probably just remove the entire key and replace with square piece of delrin or aluminum and run nylon bolts in place of the steel since no longer doing anything other than keeping the bolt from rotating when you manually cycle.

Was it had to resist slotting holes in some of the other bits that are solid?

[Handsome Rob]

4 minutes ago, Erich said:

NIce! you dont need the top of that gas key, mill it off flush with the bolt heads get for a free half ounce or so

You could probably just remove the entire key and replace with square piece of delrin or aluminum and run nylon bolts in place of the steel since no longer doing anything other than keeping the bolt from rotating when you manually cycle.

Was it had to resist slotting holes in some of the other bits that are solid? 

I've considered replacing the gas key, I didn't think about delrin though. Good idea! 

I didn't really want to reduce the lower any further (it's only 4oz as is!) & I was worried about the structural integrity of taking any more of the upper. The butt-plate could stand some holes though. The biggest weight saving now would come from an aluminum BCG. Big difference there, but also quite a bit of cash to go cutting it to bits & drilling new holes in it! 

[Handsome Rob]

Right now, with the SWFA score & 5, 77gr rounds in the 10rd mag, it comes in at 4lb 7½oz.

I had a rough day at the range with it, initially, using the Tasco scope. I was having a hell of a time getting it into battery & a worse time extracting spent brass. Turns out my brass is a few thou too long. Function is much better now, but I haven't had chance to get back to the range to see exactly how well she shoots. Honestly, anything under 2 MOA will be more than good enough for the distances I'll ever hunt with it, but I don't see why much better wouldn't be possible. 

 

[Erich]

I was thinking skeletonize the magwell area under the release and slotting handguard. But yeah, would be more because you could vs getting anything significant. What's the barrel nut, guessing aluminum based on the spacing of the handguard bolts? probably already got lightening cuts if so.

4.5 lbs with ammo, that's great!

[Handsome Rob]

Addendum: 

Since putting this together, I've shot it a bunch! However, I realized that I really don't need 3 .223s & Wyoming has a minimum of .24 caliber for elk. 

So I rebuilt the thing with a Solo300 upper & Wilson Combat .300 Ham'r barrel. 

I'm still waiting on my thread protector to arrive, but initial testing is showing a LOT of promise with both 130gr Speer Hot-Cor & Sierra 125gr TMKs, both shooting around 1.25" for 10 rounds. In leaning heavily towards the TMK for this year's cow hunt, my only concern being that I have to clip the tip to be able to fit them in the mag. They were designed for the .300BLK & I'm reliably informed that they work perfectly at Ham'r velocities (2510fps) Clipping the tip may cost me an inch or so of penetration, but should still do what it needs to above 1700fps, which is way beyond my comfortable hunting range. 

I'm really hoping to live test a couple on pigs before October. 

I did add a couple of inches of flip flop sole to my butt plate. I was finding the LOP to be short anyway, but the Ham'r recoil is.... brisk in a 4lb gun & the dampening is very welcome! 

[Alleycat72]

https://hammerbullets.com/product/308-cal-120gr-lever-shock-hammer/

 

[Alleycat72]

https://lehighdefense.com/308-diameter-110-grain-controlled-chaos-bullets-50-count-05308110cusp2.html

This one may be a bit explosive on an elk sholder, but it's a good bullet. 

Edited July 5 by Alleycat72

[Handsome Rob]

It seems like it's shooting pretty well with the abbreviated TMKs, anyway. 2" for 10 rounds was about the best I could get, running at an average of 2488fps. Being that it's going to be a 250yd rifle, that would do, but I'll be a lot happier if I can get closer to 1½" for 10 rounds. 

The trigger is very much not helping. A 4lb trigger in a 4¼lb rifle is no bueno. I've ordered myself a LaRue MBT-2S to try out. There's a definite learning curve to shooting something this ethereal, but this Timney is killing me! My next option is a Jard, either 1½ or 2½lb, but I can't find any kind of consistent reviews on them & I don't think I know anyone who uses one. The problems I've read about them double or triple firing are negated by this being a non-semiauto, but I was still loathe to part with $150 on a whim. I know the LaRue is good, just not sure if I can get used to a 2 stage.