PDW builds - Lets see them, and share results

I"m not sure went on here after I left but obviously whatever happened it happened for a reason.

I have a CZ 858 but haven't tested it a whole lot for penetration though they have a non-hardened steel core. I would think that if this cartridge was offered in something short, it would fit this catagory aside from being a rifle caliber.

Has anyone been able to rebarrel an AR and retrofit the mags or do something there to make it work?
 
Bullet weight/type

Velocity

Energy



123 gr (8.0 g) Full Metal Jacket

731.5 m/s (2,400 ft/s)

2,073.6 J (1,529.4 ft·lbf)



154 gr (10.0 g) Spitzer SP

641.3 m/s (2,104 ft/s)

2,056.3 J (1,516.6 ft·lbf)



123.5 gr (8.00 g) Full Metal Jacket

804.7 m/s (2,640 ft/s)

2,460 J (1,810 ft·lbf)

this is copied off of Wikipedia and is very similar to the 6.8 which has, no doubt, a better B.C. then the slightly heavier 7.62 round

I think if the 7.62 casing wasnt so tapered, it would fit the AR mags a lot better and with the slightly increased case capacity show results that would be taken a little more seriously. I might actually take on this project. Does anyone see any downsides
 
alberta tactical rifle said:
OK so a serious question.
45 pages of thread yet I have not found anything on 6.8SPC mentioned.
How come?
There seems to a little interest in CQB guns from LE agencies in the 6.8.
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It seems that the 6.8 fell off the wagon after 300 Blackout came out. Remington stopped producing it, which killed the cartridge. There also seemed or still seems to be a chamber spec war taking place. The cartridge just can't make up it's mind. :D Also, you need different magazines, barrels and bolts to run it in an AR. Brass is also scary expensive.

Everyone loves the simplicity of the 300 Blackout. Same magazines, same bolt. Just change out the barrel. Brass is now super cheap and 308 bullets are abundant. over 70 companies have jumped on the bandwagon in such a short amount of time.


Want AK ballistics, but AR ergonomics?

Want the simplicity and availability of parts and components?

Want a PDW, but are worried about excessive velocity loss?

300 Blackout seems to be the clear winner. w:h:
 
i forgot about the bolt face with regards to running a 7.62x39 and I am guessing there isnt a swap out front piece for to accommodate the larger boltface.
 
Glock-a-maniac said:
i forgot about the bolt face with regards to running a 7.62x39 and I am guessing there isnt a swap out front piece for to accommodate the larger boltface.
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x39 ar's are not a new thing. and from what i have read an improved x39 does not gain much in velocity to make it worthwhile

there is also the csa compact 7.5" barrell i think it qualifies as a pdw
 
I really enjoyed reading ALL of this thread. If you ever do come shooting in Alberta send me a tell WP, some us are lifetime students and like to learn. ;)

One day I hope to post pictures in this thread as well. Wait, do sks's count if I put a folder on them? :D
 
Does anyone have any more info on the shorty barreled 7.62x39s?? That interests me. In the pursuit for understanding this caliber a little more I bought a set of dies and a 30cal bullet puller. I friend of mine uses the casings and powder to seat a soft point bullet for hunting deer actually which was what got me thinking about the consistency of the bulk ammo you can buy. I pulled about a 100rnds and found the powder to be quite consistent since I was using an AcuLab scale that measured down to .00 of a grain.

The bullet weights weren't too bad either so I started work'n on my CZ by undating the stock to A Magpul adjustable with a scope rail and front furniture to be able to mount a bi-pod. The gun jumped still quite a bit so I had a muzzle brake installed to take away most of the muzzle jump. Now all I need is some time behind the scope and with a variety of test rounds to show some result.
 
from the ballistic data ive found i cant see why people dont want the 6.8spc ?

velocity is slightly better than a .308, drop is about the same as a .308, 40%+ energy over a .223

i'll be getting a 6.8spc upper for my AR


mind you i guess this is a PDW thread, and PDW's arent exactly used for targets outside 100m
300BLK win
 
Fenix.NZ said:
from the ballistic data ive found i cant see why people dont want the 6.8spc ?

velocity is slightly better than a .308, drop is about the same as a .308, 40%+ energy over a .223

i'll be getting a 6.8spc upper for my AR


mind you i guess this is a PDW thread, and PDW's arent exactly used for targets outside 100m
300BLK win
Click to expand...

It all comes down to availability of parts. Brass is hard to source and expensive. Standard mags and BCG's cannot be used. Remington tossed the 6.8 on the side of the road. There isn't much backing for this cartridge anymore due to the popularity of the 300 Blackout cartridge.

If the 6.8 used standard magazines and BCG's with just a barrel change, you would have a serious winner.
 
Does anyone have any chrono results from 7.5" & 11.5" barrels spitting 7.62 x39?
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Its kind of pointless as the 300 Whisper does everything the 762x39 does but in a smaller, more AR friendly package.

There is no such thing as factory ammo for the 300 in this country but I have shot a lot of ammo but lightweight and heavy out of a PDW length 300 and it maintains velocity really well.
 
Suputin said:
Its kind of pointless as the 300 Whisper does everything the 762x39 does but in a smaller, more AR friendly package.

There is no such thing as factory ammo for the 300 in this country but I have shot a lot of ammo but lightweight and heavy out of a PDW length 300 and it maintains velocity really well.
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He could be cross-shopping the CSA/VZ carbines though, although if that's the case, he might find more info in the Red Rifles forum
 
Suputin said:
Its kind of pointless as the 300 Whisper does everything the 762x39 does but in a smaller, more AR friendly package.
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One can be say 300 Whisper is kind of pointless when surplus 7.62x39 cost about 15 cents a round without the pain of collecting, cleaning, sizing and reloading :p

However I just notice on Robinson Arms' website, they now have a listing for 7.5" & 10 barrels in .300-221 cartridge for the XCR Micro :)
 
The 300Whisper definitely makes a lot of sense. And for the pain of making brass, the end result is definitely rewarding I think.

When I fireformed all of my 338LM AI brass with cornmeal. That sucked!! My gun was dirty from the cornmeal and wax, blau blau blau BUT there was a large enough difference in performance, I'd recommend it to everyone wanting a 338LM Ackley Improved and the 300Whisper is very much the same way.

Has anyone tried doing the cornmeal approach to fireforming brass yet? Just a thought.
 
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Glock-a-maniac said:
The 300Whisper definitely makes a lot of sense. And for the pain of making brass, the end result is definitely rewarding I think.

Has anyone tried doing the cornmeal approach to fireforming brass yet? Just a thought.
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Are you asking if anyone has tried the cornmeal approach to fireforming .300 Blackout brass, or just the process in general?

If referring to the .300 Blackout, it's not possible or even practical to do so. The generally accepted methods of making cases is by necking up .221 FB cases or making them from cut-down .223 Rem. brass. Neither method necessitates the use of cornmeal fireforming.
 
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