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What's the difference between 7.62x39 and 5.45
3/15/2012 8:20:36 PM
Other than caliber. Could on change the bolt out and the barrel to go from one to another or is there more to it?
3/15/2012 8:59:13 PM
Nope more to it.. Sorry to say it's not like a AR-15 where you can just change uppers....you should build both as I have...
3/15/2012 9:05:58 PM
They are basically different guns, and it is totally not worth it to try and convert one to the other. Trunnions, reciever, barrel, and bolt, are different, off the top of my head. And that's most of the gun already right there.
3/16/2012 8:07:52 AM
The only MFG that reused a lot of parts between 47 and 74 was the Romanians.
They changed the absolute minimum.
Receiver, Barrel, Bolt, Bolt Carrier, Bullet Guide, Magazine, Muzzle Break.
While we're at it, the Romanians are the only ones to use the regular AKM 23mm (907 in) trunnion across the board, 7.62, 5.45, 5.56
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The only caliber swap easily done is 5.56 to 5.45, then all you absolutely need to buy is the barrel and magazine.
The 5.56 bolt can be opened by a gunsmith to fit the 5.45 case head.
Some have gone from 5.45 to 5.56, but I wouldn't recommend it because the chamber pressure is higher in 5.56.
All 5.56 AKs are somehow stronger than the 5.45 version.
Yugos use 5.45 sized bolts and RPK trunnions.
Bulgys, Polish and Romanians, bigger bolts and 74 sized trunnions.
Also, the 5.45 extractor just barely holds the 5.56 rim, so reliability is lower.
They changed the absolute minimum.
Receiver, Barrel, Bolt, Bolt Carrier, Bullet Guide, Magazine, Muzzle Break.
While we're at it, the Romanians are the only ones to use the regular AKM 23mm (907 in) trunnion across the board, 7.62, 5.45, 5.56
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The only caliber swap easily done is 5.56 to 5.45, then all you absolutely need to buy is the barrel and magazine.
The 5.56 bolt can be opened by a gunsmith to fit the 5.45 case head.
Some have gone from 5.45 to 5.56, but I wouldn't recommend it because the chamber pressure is higher in 5.56.
All 5.56 AKs are somehow stronger than the 5.45 version.
Yugos use 5.45 sized bolts and RPK trunnions.
Bulgys, Polish and Romanians, bigger bolts and 74 sized trunnions.
Also, the 5.45 extractor just barely holds the 5.56 rim, so reliability is lower.
3/18/2012 1:54:45 PM
the difference? about 2.17mm . 
3/18/2012 2:03:57 PM
Originally Posted By BulletBait:
The only MFG that reused a lot of parts between 47 and 74 was the Romanians.
They changed the absolute minimum.
Receiver, Barrel, Bolt, Bolt Carrier, Bullet Guide, Magazine, Muzzle Break.
While we're at it, the Romanians are the only ones to use the regular AKM 23mm (907 in) trunnion across the board, 7.62, 5.45, 5.56
末末末末末末末末末末末末末末末末末末末末末末末末末末末末末
The only caliber swap easily done is 5.56 to 5.45, then all you absolutely need to buy is the barrel and magazine.
The 5.56 bolt can be opened by a gunsmith to fit the 5.45 case head.
Some have gone from 5.45 to 5.56, but I wouldn't recommend it because the chamber pressure is higher in 5.56.
All 5.56 AKs are somehow stronger than the 5.45 version.
Yugos use 5.45 sized bolts and RPK trunnions.
Bulgys, Polish and Romanians, bigger bolts and 74 sized trunnions.
Also, the 5.45 extractor just barely holds the 5.56 rim, so reliability is lower.
The only MFG that reused a lot of parts between 47 and 74 was the Romanians.
They changed the absolute minimum.
Receiver, Barrel, Bolt, Bolt Carrier, Bullet Guide, Magazine, Muzzle Break.
While we're at it, the Romanians are the only ones to use the regular AKM 23mm (907 in) trunnion across the board, 7.62, 5.45, 5.56
末末末末末末末末末末末末末末末末末末末末末末末末末末末末末
The only caliber swap easily done is 5.56 to 5.45, then all you absolutely need to buy is the barrel and magazine.
The 5.56 bolt can be opened by a gunsmith to fit the 5.45 case head.
Some have gone from 5.45 to 5.56, but I wouldn't recommend it because the chamber pressure is higher in 5.56.
All 5.56 AKs are somehow stronger than the 5.45 version.
Yugos use 5.45 sized bolts and RPK trunnions.
Bulgys, Polish and Romanians, bigger bolts and 74 sized trunnions.
Also, the 5.45 extractor just barely holds the 5.56 rim, so reliability is lower.
There are some parts that the Romanians used from the AKM on the 74 but the bolt and bolt carrier is not one of them. I have an AIMS 74 kit and the bolt is much smaller. I will get some pictures later today.
3/18/2012 4:07:52 PM
Here are some differences in a Romanian G kit and a AIMS 74 kit. There are some parts that they share but most are different.
The bolt.
The rear trunnion. It looks like the rivet hole spacing is the same. G on the right and AIMS on the left.
Saftey selector. AIMS on the right.
It looks like they used the same gas block. The one from a Romy G is on the top.
The bolt.
The rear trunnion. It looks like the rivet hole spacing is the same. G on the right and AIMS on the left.
Saftey selector. AIMS on the right.
It looks like they used the same gas block. The one from a Romy G is on the top.
3/19/2012 9:35:57 AM
Great post CajunX39 , a picture is worth 1000 words.
Your read my post backwards though.
This is a list of what the Romanians changed.
I forgot to list that the Trunnion's locking recess is different between the 7.62 and 5.45/5.556 versions to accommodate the 2 different bolt head sizes.
The cast rear trunnion isn't unique the 74, they changed that across the board.
AIMS-74 safety shown is used on rifles with 3 shot burst IIRC.
My AIMR-74 kit safety looks like the one on the left, but is also a cast part.
Your read my post backwards though.
This is a list of what the Romanians changed.
Receiver, Barrel, Bolt, Bolt Carrier, Bullet Guide, Magazine, Muzzle Break.
I forgot to list that the Trunnion's locking recess is different between the 7.62 and 5.45/5.556 versions to accommodate the 2 different bolt head sizes.
The cast rear trunnion isn't unique the 74, they changed that across the board.
AIMS-74 safety shown is used on rifles with 3 shot burst IIRC.
My AIMR-74 kit safety looks like the one on the left, but is also a cast part.
3/19/2012 11:53:17 AM
Originally Posted By BulletBait:
Great post CajunX39 , a picture is worth 1000 words.
Your read my post backwards though.
This is a list of what the Romanians changed.
I forgot to list that the Trunnion's locking recess is different between the 7.62 and 5.45/5.556 versions to accommodate the 2 different bolt head sizes.
The cast rear trunnion isn't unique the 74, they changed that across the board.
AIMS-74 safety shown is used on rifles with 3 shot burst IIRC.
My AIMR-74 kit safety looks like the one on the left, but is also a cast part.
Great post CajunX39 , a picture is worth 1000 words.
Your read my post backwards though.
This is a list of what the Romanians changed.
Receiver, Barrel, Bolt, Bolt Carrier, Bullet Guide, Magazine, Muzzle Break.
I forgot to list that the Trunnion's locking recess is different between the 7.62 and 5.45/5.556 versions to accommodate the 2 different bolt head sizes.
The cast rear trunnion isn't unique the 74, they changed that across the board.
AIMS-74 safety shown is used on rifles with 3 shot burst IIRC.
My AIMR-74 kit safety looks like the one on the left, but is also a cast part.
You have an AMIR 74 kit? I would like to see some pictures!
