Ultralight Ultralight Rifles

[Trackselk]

Mine are all new cases. I was under the (incorrect) impression that your new cases wouldn't chamber, so nothing to do with my neck thickness idea. I doubt the neck has enough contact to affect extraction after firing as long as the round chambers.

The cases are sticking for some other reason, possibly what you're thinking with length. It could also be that they're just "stickier" than brass cases and need more force to extract than the Solo system provides, like it's inability to extract with larger diameter cases. A gasser has way more extraction force which is why gassers work with those larger cases as well.

I think that this "stickier case" might be the actual problem. Sometimes I have a case that's sized a little too long for a particular rifle and have to pull the Solo bolt all the way back and smack the bolt forward to get it to go into battery. Those cases are stuck in tightly enough that they're pretty much jammed in and are really difficult to extract without firing. Once fired though, they extract fine, almost like they rebound enough to fit more loosely. These NAS cases may just react and extract very differently than the brass cases we're used to using.

When I get time, maybe today, I'll run a couple through a Solo, a BCA, a gasser and my Tikka to see if there are differences in extraction.

Good thoughts. I think I vetted the length theory out with a ton of measurements, and it was fine. Then, as for the stickier idea, they are actually slicker, which is part of their appeal, especially for smooth running gas guns. After being fired, you can easily feel that they're too big for the chamber, and the case gauge helped me narrow it down to the shoulder, if I'm not mistaken. Here's a Pic of a new case sticking up .001" over max. So, add one thousandths of case stretch to the fired case and it's holding significant pressure against the bolt face. Phantom has seen a couple instances of this with bolt guns also, although we didn't get into the exact reasons for it.
I should have documented my measurements better in a devoted thread when I started trying to figure this out. But, multiple theories are better anyhow...

Edit: and if anyone isn't familiar with the case gauge tool, the other end is open, so the neck is free to extend through/not affecting the measurement in the pic. Or, in other words, this is a measurement of shoulder to the case head.
Looking at the other end, You can see if the neck is too long or short, which it isn't.

 

[Thegman]

Good thoughts. I think I vetted the length theory out with a ton of measurements, and it was fine. Then, as for the stickier idea, they are actually slicker, which is part of their appeal, especially for smooth running gas guns. After being fired, you can easily feel that they're too big for the chamber, and the case gauge helped me narrow it down to the shoulder, if I'm not mistaken. Here's a Pic of a new case sticking up .001" over max. So, add one thousandths of case stretch to the fired case and it's holding significant pressure against the bolt face. Phantom has seen a couple instances of this with bolt guns also, although we didn't get into the exact reasons for it.
I should have documented my measurements better in a devoted thread when I started trying to figure this out. But, multiple theories are better anyhow...

Edit: and if anyone isn't familiar with the case gauge tool, the other end is open, so the neck is free to extend through/not affecting the measurement in the pic. Or, in other words, this is a measurement of shoulder to the case head.
Looking at the other end, You can see if the neck is too long or short, which it isn't.
View attachment 855313

Shot three of the NAS cases loaded with 26 grains of LVR under a Hornady 75BTHP at 2.280" OAL
1ea through my UL-UL with a BCA Pencil barrel, Tikka T3 and BCA upper
All cases were 1.755" long before firing
All extracted okay (the Solo was sticky but manageable, but a lot more difficult than it would be with a brass case and the same load)
All rechambered okay (Solo was a little tight)
Tikka case grew to 1.760" in length, the other two to 1.767"
All cases very sooty, so not expanding much during firing

I'd say your guess about the cases wedging themselves in the chamber between the shoulder and base is probably correct. Need to measure the outer case dimension and compare to a typical brass case expansion, but suspect it will be fine there. This wasn't a terribly hot load. I imagine if it was, the cases would lengthen enough to lock up the Solo and at least start getting sticky in the other two.

Additional info:

I measured the base of the cases to see how much they expand after one firing. Figured not much with all the soot I saw on them...wrong once again...!

Measuring just above the base part of the case, the cases start around 0.370" - 0.371", which is smaller than a typical 223 case which would be around 0.372" to 0.374". The cases measured between 0.376" to 0.377" after firing, which is quite a bit larger than a brass case (LC) would typically be, around 0.374" to 0.375" in these rifles.

I don't think this was enough expansion to cause sticking due to their diameter, but shows they do stretch a lot compared to brass cases and I imagine that's what is wedging them in the chamber. The case fired in the Tikka expanded the most (0.3770" - No brass case has ever expanded that much in that chamber), but it didn't stick on lifting the bolt. The brass fired in the BCA pencil barrel was a little smaller in diameter (~0.3767"), but wouldn't chamber in the Tikka, so the issue was most likely the length dimension stretching that was the issue with trying to chamber it, and probably what's causing the sticking in the Solo.

These things are just weird...

 

[Welldone]

This may not be acceptable but I have my latest builds listed for sale/trade in gun classified.
Thanks

 

[C Bow]

If these cases are steel when we shoot them in a AI chamber and blow the shoulders out they may split instead of stretch that much. Brass is soft enough to stretch and form a new chamber. I ask a couple engineers that today and they agree that is a good possibility I will discuss with gunsmith this weekend.

 

[Trackselk]

If these cases are steel when we shoot them in a AI chamber and blow the shoulders out they may split instead of stretch that much. Brass is soft enough to stretch and form a new chamber. I ask a couple engineers that today and they agree that is a good possibility I will discuss with gunsmith this weekend.

That's a good point. I was thinking that I'd risk it, but now I think I'll start with a reduced load and wouldn't want to send you those full power loads until I know that they're safe. It's one thing to blow up my own stuff...

 

[C Bow]

I have quite a bit of experience with AI rifles but I am for sure not saying I know everything about them . With that said like the 7mm.08 AI I built I would fire regular 7mm 08 Winchester ammo in it and it would blow case
out to form shoulder but it has always been brass . Then I would neck size for reloading. I do not have any experience with the cases that you are talking about but will help in any way I can.

 

[C Bow]

I bought some Winchester ammo to shoot and make my AI cases as soon as I get barrel Then I will weigh them and see how much capacity I can get in them I told Smith to throat them to shoot 77 gr as the lightest bullet I would shoot in it

 

[Trackselk]

Shot three of the NAS cases loaded with 26 grains of LVR under a Hornady 75BTHP at 2.280" OAL
1ea through my UL-UL with a BCA Pencil barrel, Tikka T3 and BCA upper
All cases were 1.755" before firing
All extracted okay (the Solo was sticky but manageable, but a lot more difficult than it would be with a brass case and the same load)
All rechambered okay (Solo was a little tight)
Tikka case grew to 1.760", the other two to 1.767"
All cases very sooty, so not expanding much during firing

I'd say your guess about the cases wedging themselves in the chamber between the shoulder and base is probably correct. Need to measure the outer case dimension and compare to a typical brass case expansion, but suspect it will be fine there). This wasn't a terribly hot load. I imagine if it was, the cases would lengthen enough to lock up the Solo and at least start getting sticky in the other two.

Thanks for the feedback. Just to clarify, that's the bca bolt action you tried?
I'm guessing your solo has about .001" more headspace than most. Could you actually open the action by hand? In mine, once I got to about 2500fps with 62 grain bullets and loaded long (2.36" / less pressure), it took something pounding on the handle to open it. PGG reported something similar.

On another front, the local well respected gunsmith told me he's seen a lot of AR's blown up with hot loads, and he won't build me an AI chamber for the strait pull, but sounds like he will for the bolt action setup. Regardless of the stronger cases not exploding, he's too concerned it will break the bolt and potentially cause injury or death. I think I'll listen to him and use the bca bolt action for hot loads. Just figured I'd pass thing along. He thinks 77 grain tmks at 2800-2850 in a 16" barrel is way too dangerous due to the wimpy bolt and aluminum uppers. Haven't phantom and some other ammo makers been pushing them about 2700 in our 16" barrels? @packgoatguy