Ultralight Ultralight Rifles

[robtattoo]

@Thegman @StupidLightweight

What's your opinions on the 8.6SPC in a straight pull?
You guys seem to have the most experience with these rifles, across the widest cartridge range. I'm sitting here, looking at my spare upper & lower, wondering in which direction to head. I like the ballistics of the 6.8, I'm just not sure about extraction & they're not giving barrels away, unfortunately.

 

[StupidLightweight]

Never done one, Robtattoo, but a 6.8 SPC straight-pull should work out. Assuming case diameter correlates to ease of extraction, it could offer advantages over Grendel-based rounds. With a 12.5-inch 6.8 barrel and can, it would be a fantastic general purpose ultralight AR.

 

[Thegman]

Robtattoo,

My 30HRT is based on the 6.8 SPC case (shortened and run through a 30 Herrett die). I couldn’t get it to work in the Solo without some pretty serious case sticking (to where the rifle had to be unshouldered and the bolt handle hit pretty hard).

That particular set-up was a no-go for me. -That said-, that's only a trial-of-one, so it could be other issues specific to that set-up. So, unfortunately, I'm not sure and haven't ventured further out into cases any bigger than 350L to know much more about it.

The best bet would probably be to see if you can borrow a barrel somewhere to test the idea(???)

If I have time at some point, I should re-mount my HRT barrel and see if I can troubleshoot that further (It did work okay in a full-mass steel bolt carrier straight-pull set-up, just not in the Solo)

 

[PistolPete]

I've been wondering if a simple chamber polish would solve these extraction issues. A drill, a dowel, and a rag with polishing compound might work wonders.

 

[Thegman]

I've been wondering if a simple chamber polish would solve these extraction issues. A drill, a dowel, and a rag with polishing compound might work wonders.

Was just wondering something similar, if a nitride treated barrel would have a less sticky chamber than stainless, all else being equal. Although I haven't seemed to notice any differences so far, but don't have many apples to apples comparisons either.

 

[Taudisio]

Was just wondering something similar, if a nitride treated barrel would have a less sticky chamber than stainless, all else being equal. Although I haven't seemed to notice any differences so far, but don't have many apples to apples comparisons either.

I was also reading about hbn coating bullets, and some boys also treat the barrel….that could help, also possibly “accidentally” leaving some imperial sizing wax on your brass, watching for chamber over pressure signs of course.

 

[robtattoo]

Ok, now y'all've got me thinking about 7.62x39. With its heavily tapered case, sticking would be less of an issue. Bullet selection in .311 sucks balls though.

 

[Taudisio]

Ok, now y'all've got me thinking about 7.62x39. With its heavily tapered case, sticking would be less of an issue. Bullet selection in .311 sucks balls though.

If I were considering a 7.62x39, a 300blk would be in the mail 15 minutes later lol

 

[Thegman]

If I were considering a 7.62x39, a 300blk would be in the mail 15 minutes later lol

That's probably a good point. In a straight-pull particularly, a 300 Blk might not give up much to a 7.62x39(??).

The 300Blk, being designed for higher pressure and a case that extracts really easily might close the gap quite a bit. Not that I'm discouraging you! I'd be really interested to see how a 7.62x39 would do, especially one with a .308 bore.

That said, a 300 HAM’R likely equals or beats it with most suitable bullets. But like I said, it would be really cool to see what it could do.

 

[Taudisio]

 

[Taudisio]

Finally showed up! 6x45 with a 5x scope sub 4 pounds. Any other measurements you guys want before I paint it and tighten her down?

 

[Thegman]

Finally showed up! 6x45 with a 5x scope sub 4 pounds. Any other measurements you guys want before I paint it and tighten her down?

That is sweet! No questions from me. I just want you to hurry up and get shooting to hear the report on it. I'm always interested in the 6x45; seems like a really good cartridge.

 

[Taudisio]

That is sweet! No questions from me. I just want you to hurry up and get shooting to hear the report on it. I'm always interested in the 6x45; seems like a really good cartridge.

I just painted, measured the lands, I have a long jump where I seated my 10 “working out the kinks” rounds. I shot a bear last night and we couldn’t recover it. I’m heading up there now to try again…….and shoot 10 rounds. It was a LATE night. I think I ate dinner at 1230

 

[Taudisio]

For you gman. Function’s perfectly. I still can’t make it to the lands though.

 

[Thegman]

What did you shoot it with?

You need one of these. I'm not kidding. Loosing a bear once is why I bought her. Best hunting partner ever. I've become the laziest successful tracker ever since getting her and training her.

 

[Thegman]

View attachment 702367For you gman. Function’s perfectly. I still can’t make it to the lands though.

I need to do that with at least one of my mags...thanks for the inspiration.

 

[Taudisio]

What did you shoot it with?

You need one of these. I'm not kidding. Loosing a bear once is why I bought her. Best hunting partner ever. I've become the laziest successful tracker ever since getting her and training her.

View attachment 702368

View attachment 702369

With my tikka in 30 nosler. A 210gr ablr going 3030fps. Bear was 50 yards, but rolled into a brush/blowdown canyon. I’m hoping some eager ravens take me to him.

 

[robtattoo]

Very, very cool! I'm jealous of your weight there!

It's been a busy day, here. I found a guy with both a 7.62x39 AND a 6.8spc barrel! Aaaaaand, neither of them extract cleanly Chambered just fine, but I had to wail on the cocking knob (I just like saying that...) to get the bolt open on a fired cartridge, in either chambering.

So after much soul searching, parts swapping, testing & head scratching, I decided I'm going to stick with the ol' 5-½mil NATO. I know from experience that there are no flies on a 77gr TMK & I've got a couple of thousand to play with, along with a thousand more 77gr OTM for gong-clonking.

I switched over all my existing bits from the Brown Bomber to the Solo upper & my spare, unmolested TNA lower & have birth to 'Dream Beans' (shut up, I had the sticker lying around from a previous purchase & thought it sounded cool. A spin on 'Freedom Seeds' if you will) It no longer looks like a deadly poo.
4lb, 4oz on the nose with the 2.5-10 Swiffer mounted.
However, I'm giving some very serious thought to selling a few bits & giving PA a call for one of their micro prisms

 

[Thegman]

With my tikka in 30 nosler. A 210gr ablr going 3030fps. Bear was 50 yards, but rolled into a brush/blowdown canyon. I’m hoping some eager ravens take me to him.

Yeah, and as you well know, if they're not dead in 100 yards, they can go forever. She once tracked a bear I'd hit too far forward for a mile before I could catch up to him and kill him.

 

[Thegman]

Very, very cool! I'm jealous of your weight there!

It's been a busy day, here. I found a guy with both a 7.62x39 AND a 6.8spc barrel! Aaaaaand, neither of them extract cleanly Chambered just fine, but I had to wail on the cocking knob (I just like saying that...) to get the bolt open on a fire car, in either chambering.

So after much soul searching, parts swapping, testing & head scratching, I decided I'm going to stick with the ol' 5-½mil NATO. I know from experience that there are no flies on a 77gr TMK & I've got a couple of thousand to play with, along with a thousand more 77gr OTM for gong-clonking.

I switched over all my existing bits from the Brown Bomber to the Solo upper & my spare, unmolested TNA lower & have birth to 'Dream Beans' (shut up, I had the sticker lying around from a previous purchase & thought it sounded cool. A spin on 'Freedom Seeds' if you will) It no longer looks like a deadly poo.
4lb, 4oz on the nose with the 2.5-10 Swiffer mounted.
However, I'm giving some very serious thought to selling a few bits & giving PA a call for one of their micro prisms

View attachment 702372

No flies on that rifle! You're saying what more or less went through my head after trying the 77TMK. "May not really need that 30HRT anyhow".

Also, thanks for trying those two chamberings out; that's really helpful info and mirrors my experience. I'll probably just stick with 5.56 case based stuff and be really happy with it...until maybe someone figures out a simple way to affect primary extraction. Even then though, like I said, I'm not sure how much advantage it will have in the long run. The 5.56, 6x45 and HAM’R can do a hell of a lot, it seems.