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Knobgoblin

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That 74 type from CNC warrior looks appealing.

I will go run a couple mags today with the 4 prong and see what's what.

Since the purpose of my Dracos is to convert cash into noise, I want the loudest muzzle device I can find.
 
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While in both litterboxes (A-stan and Iraq) had a Polish Tantal as a backup weapon. Going from village to village you accumulate seized weapons. Cleaned it, zeroed it. I can't recall finding one (AK) that could hit a fat woman's caboose at 10 M. I was lucky the Tantal still had cosmoline all over it when discovered in a hillside weapons cache.
 
I dug into this a little.
I did not know that there were 2 different 7.62x39 chambers.

7.62x39 CIP chamber vs. 7.62x39 SAAMI
CIP is Euro and SAAMI is US
The SAAMI chamber is slightly longer than a CIP chamber.
US ammo is built to SAAMI spec and Euro ammo is CIP spec.
There is a slight difference in the shoulder angles as well.

The OP can determine the actual length of his chamber without buying more gauges.
He would need tape (not soft electrical tape), calipers and his CIP gauge.
Measure tape thickness, put one layer on the head of the gauge (cut edge of tape clean) and try to close the bolt with hand pressure.
I would think that the bolt should be stripped for the most accurate readings.

I found this in an old thread at Gunco :
The "datum" (.3622") is a (diameter) point along the shoulder that the chambers are measured to.


Headspace gauges 7.62 x 39

SAAMI (based on modified Lapua chamber with larger .3138" throat)(SAAMI breech face to case mouth = 1.543")

Go - 1.252" to .3622" datum with 17 degree 30 minute shoulder

No-Go - 1.257" (Go plus .005")



CIP (standardized 4th Jan 1989 from USSR)(CIP breech face to case mouth = 1.614")

Go - 1.2513" to .3622" datum with 16 degree 42 minute shoulder

No-Go - I think it's Go plus .006" (misplaced the data)



Finland military armorer's manual (Valmet) (two gauges only)

Go - 31.800mm (+/- .010) 1.252" to .3622" datum on shoulder

No-Go - 32.075mm (+/- .015) 1.2628" to 9.20mm datum on shoulder



Soviet AKM Armorer's manual (two gauges only)

Go - 32.65mm (+/- .005) total gauge length (marked "K-3")

No-Go - 33.05mm (+/- .005) total gauge length (marked "K-4P")

Edited to note that further reading in SAME manual calls the K-3 Go gauge 32.85mm and mentions the K-5 Field gauge without giving a measurement for it.





East German

Go - 32.85mm total gauge length (marked "K-3 GUT")

No-Go - 32.95mm total gauge length (marked "K-4 AUS")

Field - 33.15mm total gauge length (marked "K-5 AUS")



Chinese (chamber shape has rounded shoulder, ammo does not)

Go - 32.85mm total gauge length

No-Go - 33.05mm total gauge length

Field - 33.35mm total gauge length
 
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Nice! I wish they had more 556 and 545 AKs available!
You'd like the M85's nice guns

PXL_20210731_180338804.jpg
 
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Legion sells a 5.45/5.56 Ukrainian Strela cone for the CNC warrior 4 piece. 30 bucks and it makes the CNC unit functional for small bore guns.
 
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Nice, Now if only someone would make a titanium 4pc to lighten that front end. Come on CNC Warrior if you are listening.
To won't lighten it up much if they keep the same profile. A couple of ounces. Ti really only works if you optimize whatever you are building for titanium. I've got some silencer tubes that are absolute pigs because the maker just substituted Titanium for aluminum and didn't change wall thickness. They're strong but it's not necessary.
 
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