AR upper in 7.62x25

vader_z said:
US$850 per upper and US$25 a mag?

Even if we could order that out of the states, that is a little pricey. 7.62x25 isn't that cheap compared to .223. For CAN$900 I can get 2000 rounds of PMC out of a Quebec dealer.

I have a case of 7.62x25 for my Tokarev and I welcome a conversion upper for my AR, but I ain't buyin if it costs a grand by the time it gets to my house.

Just my $0.02
Click to expand...
^^^^^^^^^^^^^
That's 45 cents per round for 223.
7.62x25 is about 15-16 cents per round at the very most.
Only rimfire is cheaper than that
(according to my broken math, anyway).
 
I guess I don't shoot enough bullets. It would take me a while to get through the 2000 rounds of .223 that I could buy for the $1000 cost of that American conversion.

If I had a lonely complete lower that needed an upper... maybe. But as an accessory to my assembled AR? I just don't see spending $1000 so I can THEN go out and BUY $0.15 ammo.

If you read my earlier post. I am a fan of 7.62x25's price. I bought a whole Norcarev Type 54 just so I could shoot cheap centerfire in a pistol.

Pre-Questar's creation of the 10 round pistol mag .223, the only other game in town was a 9mm pistol mag upper. Now that we can get .223 10 rounders for $30, pistol mag uppers aren't as necessary.

I am a potential customer because I have a crate of 7.62x25 already, but at a $1000 for an upper... I'll have to wait and see what the Canadian conversion costs when it is ready before I decide if I need it.
 
How about blowback using the regular stock, very heavy buffer and stiffer spring? I'd also want one of Dlask's side cocking uppers with a big charging handle to overcome the big spring.
 
Deckard, they tried almost everything in US.
Everywhere there are reports of
too much energy projected backward.
I have also talked over the phone with people who
have both the blowback and the gas builds in US.

The heavy mass (bolt and buffer) and the heavy spring
are solutions relatively easy to achieve.




As a general rule, in a straight blowback,
heavy bolts with or without a modded spring
are used mainly to alleviate reliability problems
and manage the increased gas pressure
in some builds using silencers.
Slightly heavier bolt + lighter spring is used mainly
when using very short barrels.

But for straight blowbacks, there is no straight-forward solution
that would protect the receiver from the energy of the moving parts.
Heavy mass and heavy springs would only distribute that energy
differently in time, but the receiver still has to take it.
Don't get me wrong: it will work,
but I am concerned about the long-time effects.

Also, most of the people would like a simple plug-and-play solution
(they wouldn't have to change the spring/buffer
when swapping receivers).
Installing the mag-block is enough for them.



On the other hand, in gas-oped guns,
for a fixed barrel lenght (this project), there shouldn't be problems
if the gas systems is correctly dimensioned
(but I have that covered).

The bolt can be modified without problems
to accomodate the new cartrige,
since the 7.62x25 rim is bigger than 223
only by about .012" or so (I think).
The interaction rotating-bolt/mag-lips is something I considered
knowing that the AR-15 solution of bolt-indexing always sucked sh!t.
However, I have much confidence in J. Dlask
(that is if he will take this project).



The price is something I didn't debate nor considered,
so I have absolutely no idea about that.

But the choice between blowback/gas-op is still under debate.

I might be able to shoot in US
both the blowback and the gas-op at the same session
sometime in the following weeks, if I have time,
and I will have a better idea beside my calculations.

Thanks to everybdy who contributed in any way to this thread.
 
On blowbacks, what would be the effect of barrel length on the impulse - Five inch, 8 inch, 12 inch and 16 inch? Was the PPSh's 10.6 inch barrel very deliberate because the bolt and spring are not that heavy compared to, say, the Grease gun.
 
Deckard said:
On blowbacks, what would be the effect of barrel length on the impulse - Five inch, 8 inch, 12 inch and 16 inch? Was the PPSh's 10.6 inch barrel very deliberate because the bolt and spring are not that heavy compared to, say, the Grease gun.
Click to expand...

Then again, it was an open-bolt design.
 
On blowbacks, the longer barrel
increases the energy projected back in the bolt, spring, receiver.

Example: Kel-Tec 9mm folding carbine was designed for 16".
On the very small Canadian order (18.5"),
the recoil is considerably bigger,
even impressive (for that cartrige).





On shorter barrels (like 10"-16" in the case of Kel-Tec),
that energy is smaller, manageable.


On very short barrels, the energy is even smaller,
but reliability suffers.
Therefore, less spring tension is one of the solutions,
BUT: that has to go hand in hand with increased bolt mass
(if you want reliability and a gun that lasts).
 
Deckard said:
On blowbacks, what would be the effect of barrel length on the impulse - Five inch, 8 inch, 12 inch and 16 inch? Was the PPSh's 10.6 inch barrel very deliberate because the bolt and spring are not that heavy compared to, say, the Grease gun.
Click to expand...

I don't know deck, the ppsh bolt is pretty damn big...
ppsh419.jpg
 
There was a company at shot show 2 years ago that had a 7.62x25 upper they where using a standard 5.56 mag only 10's and straight 20's if I remember right. They where running handloads with .308 rifle bullets. A alternative to the .300 whisper. The guy I was talking to claimed they had run a far quantity of regular 7.62x25 ammo in the set-up and it worked fine. I tried it once with a 10rd. Questar mag and a 7.62x25 round and it seemed to work. Somewhere I have a couple of 7.62x25 dummy rounds I made out of 5.56 brass. Should fully chamber in a 5.56 chamber unlike a real 7.62x25 round. If I can find them I will run some tests.
 
Rob Leatham was shooting the 9 X 25 Dillon in a standard Springfield frame in the 80's. So those mag should fit. Send an email to Dillon Precision or Springfield Armory for more info.
 
I have pics of a 7.62x25 Sten that's on display at the IWM in London.

I can dig those out if you'd like. Theyr'e kind of messy pics, hard to zoom and get flash working through glass.

NS
 
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