Ultralight Ultralight Rifles

[FredBear86]

A quick-detatch stock makes for a pretty compact package. With the foam cheek riser it's about 3.1oz, without the foam it was about 2.5oz including the threaded buffertube part.

Is your buffer tube spring just floating inside the removable carbon buffer?

 

[Trackselk]

That's the switch-barrel Kimber 84m mentioned a few posts back. It was light as hell, took forever to build, and cost three or 4 times what these ARs do. It was a very sweet rifle though. Total weight with the 16-inch .308 barrel was 3 pounds, 10.6 ounces. I think that was with scope rings, too.

Yeah, crazy money. My mountain ascent with hunter stock and mag is about 3 ounces heavier with a 22 creed barrel and set me back around $3500-$4k, and I got the ascent + UL leupold used for $1750! Anyhow, starting with a plain hunter +LRI machining you could get close for $1500 or so if you're willing to Swiss cheese the plastic stock and stick with the factory barrel.
Now with this ULUL all in at 4 pounds, the expensive kimber will collect dust waiting for backup duty...

 

[Trackselk]

Yeah, but it doesn’t appear to be protruding inside the barrel, so I'm thinking I can still use a gas block or something.

I'd hit it with some brake cleaner, let it dry, and then carefully work some JB weld in there to permanently lock it in place, just like a cap screw

 

[Trackselk]

What cartridge and barrel are you using?

I don't know how much it helps (because I've not tested it without), but are your lugs greased well? The friction between your bolt lugs and barrel extension lugs may be the main issue after the fired case is tightly stretched into the chamber.

A gasser hits the bolt carrier like a hammer blow and breaks everything free. With the solo...it's just a gentle pull, so anything to help likely makes it easier to cycle.

Just catching up on this thread, but you just made me think of something. These new NAS3 nickel cases don't expand like brass (and cause ejection difficulty), so I think a potential fix for those that need or want a bigger caliber would be to expand the neck on these and make a 5.56 case that holds the 6mm bullet, if such a cartridge/barrel exists? I'm not after the bigger calibers so I don't know what's available, but after talking with a reliable source, I'll be approaching 3000fps with 79 grain bullets in a 16" barrel. Hopefully there's a 223-6mm cartridge and the cases cooperate with being expanded a bit.

Edit: NAS3 cases
Another edit: putting the 300 blk on steroids with these cases will likely help people trying to use this platform and get some more range that can't hunt with 223 in their jurisdiction.

 

[Trackselk]

It’s the pencil profile barrel with the .625 gas block size in 5.56 1/7 twist. I can get specific measurements if that doesn’t answer it.

I just screwed one of these on as well, if it shoots MOA or better it'll replace my shaw. Has anyone that's posted up good groups gone to the effort of bedding the barrel extension into the action? There's a good article online "accurizing the AR15", he got an impressive improvement of accuracy with some simple steps. I have the loctite 620 on order...

 

[Thegman]

I was shooting my solo 300 yesterday and it got super hard to eject, had to bump the handle on the shooting bench to get it started and then it would slide back fine. Any tips on what to do to make it better? It may just need cleaned but I haven’t shot it that terribly much

Thinking about this, it's a good idea to keep your cam pin greased as well, especially the interface between the cam pin shaft and the bolt carrier. That area adds friction when unlocking and the aluminum bolt carrier of the Solo, aluminum being softer, might be a little "stickier" against the cam pin than a typical steel carrier would be.

 

[BREAKCONTACT]

Thinking about this, it's a good idea to keep your cam pin greased as well, especially the interface between the cam pin shaft and the bolt carrier. That area adds friction when unlocking and the aluminum bolt carrier of the Solo, aluminum being softer, might be a little "stickier" against the cam pin than a typical steel carrier would be.

Ever try a roller cam pin to see if it aids in cycling?

 

[ezwy]

Just catching up on this thread, but you just made me think of something. These new NAS3 nickel cases don't expand like brass (and cause ejection difficulty), so I think a potential fix for those that need or want a bigger caliber would be to expand the neck on these and make a 5.56 case that holds the 6mm bullet, if such a cartridge/barrel exists? I'm not after the bigger calibers so I don't know what's available, but after talking with a reliable source, I'll be approaching 3000fps with 79 grain bullets in a 16" barrel. Hopefully there's a 223-6mm cartridge and the cases cooperate with being expanded a bit.

Edit: NAS3 cases
Another edit: putting the 300 blk on steroids with these cases will likely help people trying to use this platform and get some more range that can't hunt with 223 in their jurisdiction.

The 6mm-223 is the same as the 6x45 talked about on here. any 223 based cartridges seem to work good in the straight pulls. I think the kicker with the NAS3s would be reloadablility. If they really don't expand when shot, how difficult or practical with they be to "neck up" the cases to 6mm, 25, 277 or 30 cal.
I don't have these answers because I know nothing of the metalurgy of the NAS3, but If they don't expand, and they also operate at higher pressures, I don't think the will be easy to reload or modify cases.
I hope I'm wrong because a higher pressure 6mm 223 would be awesome. Maybe equal to 6 ARC performance.

 

[packgoatguy]

Is your buffer tube spring just floating inside the removable carbon buffer?

No buffer or spring necessary on this straight pull AR15 build.

 

[The Guide]

No buffer or spring necessary on this straight pull AR15 build.

Just to add, this is a manual action system using a specific upper design that uses no gas and therefore no buffer or buffer spring is required. The Solo 300 upper is basically a straight pull bolt action on an AR-15 lower.

Jay

 

[Thegman]

Ever try a roller cam pin to see if it aids in cycling?

Great question. I have thought about it, but haven't tried it, I should. I'm thinking most of the friction is between the bolt carrier and the cam pin shaft, but can't know if you don't try it. I do also grease the head of the cam pin, but a roller might make a much bigger difference than some grease.

If anyone does try that, it would be interesting to hear the results.

To add: Part of the reason I haven't tried the roller cam pin is that I haven't personally had sticking issues with any 223 based cartridges, but maybe that would make a difference with the larger cases(?).

 

[FredBear86]

No buffer or spring necessary on this straight pull AR15 build.

I didn't think so. So what applies pressure to the bcg to keep it forward?

 

[StupidLightweight]

To add: Part of the reason I haven't tried the roller cam pin is that I haven't personally had sticking issues with any 223 based cartridges, but maybe that would make a difference with the larger cases(?).

As the Godfather of these SOLO builds, please design a lightweight solenoid powered by a 2032 battery that pops the carrier rearward when the charging handle is retracted. Shouldn't be too complex.

 

[Thegman]

As the Godfather of these SOLO builds, please design a lightweight solenoid powered by a 2032 battery that pops the carrier rearward when the charging handle is retracted. Shouldn't be too complex.

Leave it to you to come up with the solution to the problem!

 

[KyleR1985]

I just screwed one of these on as well, if it shoots MOA or better it'll replace my shaw. Has anyone that's posted up good groups gone to the effort of bedding the barrel extension into the action? There's a good article online "accurizing the AR15", he got an impressive improvement of accuracy with some simple steps. I have the loctite 620 on order...

I use blue loctite. Maybe it's a bad idea. Here's what I can tell you. Zero play on either the shaw or the bca pencil going into the receiver with the wet loctite on there taking up space. Torqued them to "1/2" x 18" breaker about 75% of my dad strength".

Small amount of blue loctite on receiver thread too.

Broke barrel nuts both free with about twice the effort as torquing them, but still easily manageable.

with barrel nut removed, Neither barrel will budge in the receiver, after being tapped on with wooden dowel trying to push them out I know I can force them out. But I don't want them out. It proved to me the "bedding" works.

I can't tell you if it helped with accuracy. But it 100% reduced the potential for the barrels to shift in the receiver.

Both barrels shot better than expected.

 

[StupidLightweight]

Leave it to you to come up with the solution to the problem!

Electronics puzzle me. However, if we could devise a way to funnel gas from the barrel to the carrier, making it an internal piston, that should provide the force needed to cam the bolt out of battery. Hmmm...let me think on this one. It might add a few ounces, but it should work.

 

[Thegman]

Electronics puzzle me. However, if we could devise a way to funnel gas from the barrel to the carrier, making it an internal piston, that should provide the force needed to cam the bolt out of battery. Hmmm...let me think on this one. It might add a few ounces, but it should work.

And I'd think if you added a spring or something in a hollow stock it could possibly automatically return the bolt carrier and bolt to battery and even load another round on the way. Genius. Why didn't we think of this earlier!

 

[HighUintas]

And I'd think if you added a spring or something in a hollow stock it could possibly automatically return the bolt carrier and bolt to battery and even load another round on the way. Genius. Why didn't we think of this earlier!

Gman, I was thinking of this a couple weeks ago. I wonder if you'd be able to do a different extraction handle that has a lever that acts on a protrusion from the receiver when pulling backward.... Similar to ARC's actions that have the pivoting bolt handle to break the cartridge free.

So you'd be levering the bcg back

 

[Trackselk]

The 6mm-223 is the same as the 6x45 talked about on here. any 223 based cartridges seem to work good in the straight pulls. I think the kicker with the NAS3s would be reloadablility. If they really don't expand when shot, how difficult or practical with they be to "neck up" the cases to 6mm, 25, 277 or 30 cal.
I don't have these answers because I know nothing of the metalurgy of the NAS3, but If they don't expand, and they also operate at higher pressures, I don't think the will be easy to reload or modify cases.
I hope I'm wrong because a higher pressure 6mm 223 would be awesome. Maybe equal to 6 ARC performance.

Ok, 6x45. From what I've learned from someone that has a lot of experience, the cases can be recharged several times at at least 60kpsi, and I think they said much higher (didn't take enough notes). They are getting several firings by just using a case gauge, and once it no longer fits, the case is toast (until someone invents a sizing die for them). They already have sizing dies for a few pistol rounds.
I'm going to try about 70-75k in the 5.56&wylde chambers, and the brass and case gauge is on the way. I'll be really happy with 2-3 firings. No sizing, and no trimming necessary!
Can you just expand a 223 case to 6mm and send it/fireform it, or is the shoulder incompatible?

 

[ezwy]

Ok, 6x45. From what I've learned from someone that has a lot of experience, the cases can be recharged several times at at least 60kpsi, and I think they said much higher (didn't take enough notes). They are getting several firings by just using a case gauge, and once it no longer fits, the case is toast (until someone invents a sizing die for them). They already have sizing dies for a few pistol rounds.
I'm going to try about 70-75k in the 5.56&wylde chambers, and the brass and case gauge is on the way. I'll be really happy with 2-3 firings. No sizing, and no trimming necessary!
Can you just expand a 223 case to 6mm and send it/fireform it, or is the shoulder incompatible?

You should literally just get the 223/5.56 case, run it through the 6x45 die and done. the expander ball will take the neck from 224 to 243...... with brass cases.