Ultralight Ultralight Rifles

[robtattoo]

With my new 6x45 barrel, I'm less than an ounce over 4lb now, with 5 in the mag

 

[SoFLBeachBum]

I first found this thread nearly two years ago, I was searching for lightweight gasser builds. I came back to this thread and actually read it. Now I’ve gone and built an ultralight bolt action straightpull. I blame you all.

 

[Tailwind5sw]

I applaud the dovetail and latcjh!! Now cut a grove in the rail matching the mount clamp, than drill and counter sink the bottom and screw the pa riser to the upper with out the clamp!

 

[SoFLBeachBum]

I’m built it using spare parts from a gasser carbine. I saw the ATL opp straightpull, I read about the Solo here, and had the idea to do one but reuse the charging handle latch. I built the gas key/latch from a piece of 10mm by 15mm aluminum and another 8mm by 25mm price, hollowed it out and installed a latch. Several months later, my little monster was built:

 

[SoFLBeachBum]

I applaud the dovetail and latcjh!! Now cut a grove in the rail matching the mount clamp, than drill and counter sink the bottom and screw the pa riser to the upper with out the clamp!

I almost did that! Instead I filed the bottom of base to clear the charging handle. But I did add two more grooves to the rail (the Microprism now sits closer to my eye)

 

[Thegman]

Fantastic job, @SoFLBeachBum !

I really like seeing all these great ideas.

 

[SoFLBeachBum]

Fantastic job, @SoFLBeachBum !

I really like seeing all these great ideas.

Thank you, TheGman, for the praise! You started all this. Turning the AR15 into the ultimate ULUL took some original thinking. I’m grateful you did it and shared it. And it’s awesome so many have joined in and keep the idea growing. I hope this thread gets pinned.

 

[Thegman]

My best UL-UL experiment to date:

My "hypothesis" was that the long throats on 5.56 and 223 Wylde chambered barrels might be reducing accuracy and consistency, especially with trying to load longer bullets like the 75, 80 & 88 ELDM and now 88 TMKs. With AR mags, the jumps most bullets have to take in a 5.56 barrel, especially the previous four, is ridiculous.

The more I thought about it, the more I thought these rifles should be treated more like a bolt rifle with more typical bolt rifle chambers rather than 5.56 and 223 Wylde AR-15 type chambers.

I thought about just getting a standard 223 Remington chambered barrel, but figured I might lose too much velocity having so much less chamber volume with the shorter throat. Figured a 223 Ackley Improved might be the best of both worlds; less throat length, but more chamber volume. Seems to be working.

My X-Caliber 223 AI arrived and I've been shooting it some, mostly fireforming, but a few loads through formed brass as well. The barrel is 0.57" profile diameter and 22.2 oz, so not terribly heavy, but heavier than most I've been using.

I didn't try to shave any weight putting it together. Figured I'd start heavy and lighten later if I wanted to. I used a 4.5 oz Kaw Valley handguard rather than my 1.9 oz version so together with the lower I've been using, the bare rifle is 3# 5oz - a veritable pig of an UL-UL.

Also has an Airlock Nano screwed on, which only weighs 3.6 oz with the 1/2x28 thread adapter. I'm far from a suppressor expert, but I think this is THE suppressor for a 22 caliber UL-UL.


So...enough of hearing me blah, blah, blah...how does the damn thing shoot?

Well, not only better than any UL-UL I've ever built, but literally, better than any rifle I've ever owned, including all the Tikkas I've ever owned.

So far, there's no load development, there's just load picking. The hardest part so far is deciding what you want to shoot; everthing shoots more than well enough.

This was about an hour ago, messing with 88 TMKs @ 2.325" (and one at 2.365") trying to find max reasonable velocity. This is 5 shots, 5 different loads using 3 different powders (Shooter's World Match, CFE 223 and 2000 MR)



See what I mean?

This is several (typical) fireforming loads with 77 TMKs. No load development. Just seeing what velocity I'd get from various powders.






Okay, you probably get the point...

Anyway, apologies in advance. You'll probably have to listen to me go on about this set-up for a while. However, if you're thinking of building one (or another one), I do think going to bolt rifle type chambers will, on average, pay big dividends over sticking with AR based chambers.