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Posted: 1/11/2005 11:22:49 AM EDT
[Last Edit: 1/11/2005 11:47:15 AM EDT by Taipan]
I know this got covered at one time in a thread, but it been far too long to be able to do a search on it. What are your opinions as to the effect of the type of reciever on accuracy. Milled vs. Stamped. If I recall correctly from the thread ,consensus was that the Milled reciever would inherantly be more accurate do to its stiffness, correct? Although I think this difference would apply to all AK calibers, I'm specifically wondering about 5.45.

Thoughts gentlemen?
Link Posted: 1/11/2005 12:55:29 PM EDT
I don't think it would have a affect on accuracy.. The sight, both front and rear are mounted to the bbl.. Now maybee if you are using receiver mounted optics??
Link Posted: 1/11/2005 1:10:18 PM EDT

Originally Posted By coltshorty14:
Now maybee if you are using receiver mounted optics??



Well that is a consideration actually. Still isn't it possible that the extra stiffness of the reciever and trunnion being integrated in a milled reciever have some effect on barrel harmonics? For good or bad?
Link Posted: 1/11/2005 1:29:53 PM EDT
Here's my whack at this issue:

The difference between how the VEPR shoots (which is regarded as one of the most accurate AK variants out there today) and your basic AK-47 has more to do with:

1. The barrel (VEPR uses RPK heavy machine gun barrel; more mass can remove heat quicker and it takes more force to move it around)

2. The clearances between the cartridge and barrel's chamber (tighter chamber, generally better accuracy for most rifles, but more prone to jam if you get dirt or dust in it obviously).

3. How the barrel is mated to the gas tube. Does the barrel have its gas tube integrated with the front sight base or not (it is generally better to have it Galil/Valmet style with the front sight on top of the gas block; the VEPR still has the traditional front sight/gas block set-up). As a rule, any time you hang a mass or two off of a metal bar or cylinder, it drastically changes the system's vibrations. You have to play a game to dampen the system; this is where a muzzle brake like Browning's BOSS would help (it obviously wouldn't help your ears). I wonder how much of a role the AK-74's brake plays in its improved accuracy over the 7.62x39 variants, but I think one could wind up comparing apples to oranges, since it's not fair to compare an AK-74M to an older AKM type rifle. AK-103 vs. AK-74 would be a different story.

4. How both components are mated to the trunion and receiver (you obviously don't want it to be loose).

The problem with the AK in general is that you have a large reciprocating mass right above the barrel that imparts vibrations to the system after that "first" shot. This is where the AR-15 has a huge advantage over its Eastern (along with Finn, Israeli and Swiss) counterparts. A gas tube obviously doesn't reciprocate, unlike the AK's gas piston. Vibrations aside, heat is still the major problem with almost any gun (perhaps more important than vibrations when you shoot several rounds every minute). The heavier the barrel, the more mass is there to absorb heat. So it's a trade off between how much weight you want to lug around for better sustained accuracy vs. what's light, quick and practical.

Having said that, a super accurate 1 MOA AK that would be field duty capable is quite possible. It's just a matter of fine tuning the design and using the right components. Sig 55x's can shoot 1 MOA with a match barrel I know (sold as the PE90 I think in Canada; "Blue Star" or something rather, I forget), but nothing beats a fine tuned AR-15. Yugos and Valmets/Sakos lack chrome lining to improve accuracy, but modern chrome application techniques probably render that unnecessary. Ammo quality is another issue with AKs, because obviously eastern block ammo is not going to shoot like Black Hills match.

Then again, this whole issue becomes retarded when you think about it. If you can get 2" groups at 100 yards with a "combat" rifle, it's probably pretty dumb to be sitting here complaining about accuracy, when most engagements don't occur beyond that distance. If you need something to shoot farther, then get a damn DMR or SPR that's scoped. Better yet, a Barrett M82 or McMillan Bros .50 BMG are by far the most failsafe weapons out there

themao
Link Posted: 1/11/2005 1:43:22 PM EDT
This is all strictly academic .
You can blame Marty for posting his possible US made AK/RPK barrel for getting me thinking about this. LOL
Link Posted: 1/11/2005 2:25:56 PM EDT
Link Posted: 1/11/2005 2:56:26 PM EDT
Campy, coming from you I'll take it, but I do find your note interesting too.
Link Posted: 1/11/2005 4:07:51 PM EDT

Originally Posted By themao:
Here's my whack at this issue:

The difference between how the VEPR shoots (which is regarded as one of the most accurate AK variants out there today) and your basic AK-47 has more to do with:

1. The barrel (VEPR uses RPK heavy machine gun barrel; more mass can remove heat quicker and it takes more force to move it around)

2. The clearances between the cartridge and barrel's chamber (tighter chamber, generally better accuracy for most rifles, but more prone to jam if you get dirt or dust in it obviously).

3. How the barrel is mated to the gas tube. Does the barrel have its gas tube integrated with the front sight base or not (it is generally better to have it Galil/Valmet style with the front sight on top of the gas block; the VEPR still has the traditional front sight/gas block set-up). As a rule, any time you hang a mass or two off of a metal bar or cylinder, it drastically changes the system's vibrations. You have to play a game to dampen the system; this is where a muzzle brake like Browning's BOSS would help (it obviously wouldn't help your ears). I wonder how much of a role the AK-74's brake plays in its improved accuracy over the 7.62x39 variants, but I think one could wind up comparing apples to oranges, since it's not fair to compare an AK-74M to an older AKM type rifle. AK-103 vs. AK-74 would be a different story.

4. How both components are mated to the trunion and receiver (you obviously don't want it to be loose).

The problem with the AK in general is that you have a large reciprocating mass right above the barrel that imparts vibrations to the system after that "first" shot. This is where the AR-15 has a huge advantage over its Eastern (along with Finn, Israeli and Swiss) counterparts. A gas tube obviously doesn't reciprocate, unlike the AK's gas piston. Vibrations aside, heat is still the major problem with almost any gun (perhaps more important than vibrations when you shoot several rounds every minute). The heavier the barrel, the more mass is there to absorb heat. So it's a trade off between how much weight you want to lug around for better sustained accuracy vs. what's light, quick and practical.

Having said that, a super accurate 1 MOA AK that would be field duty capable is quite possible. It's just a matter of fine tuning the design and using the right components. Sig 55x's can shoot 1 MOA with a match barrel I know (sold as the PE90 I think in Canada; "Blue Star" or something rather, I forget), but nothing beats a fine tuned AR-15. Yugos and Valmets/Sakos lack chrome lining to improve accuracy, but modern chrome application techniques probably render that unnecessary. Ammo quality is another issue with AKs, because obviously eastern block ammo is not going to shoot like Black Hills match.

Then again, this whole issue becomes retarded when you think about it. If you can get 2" groups at 100 yards with a "combat" rifle, it's probably pretty dumb to be sitting here complaining about accuracy, when most engagements don't occur beyond that distance. If you need something to shoot farther, then get a damn DMR or SPR that's scoped. Better yet, a Barrett M82 or McMillan Bros .50 BMG are by far the most failsafe weapons out there

themao



Very informative post...thanks.

take care,
Tec
Link Posted: 1/11/2005 10:07:39 PM EDT
There is actually receiver flex as well. During the recoil, the receiver will twist just a little bit. Not enough to notice, but enough to throw off accuracy. The RPK (Yugo) and milled receivers are thicker and stronger, and dont flex as much, if at all.
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