AK doctors: I need your diagnoses


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Big45
May 31, 2008, 04:46 PM
Bought a Century Yugo M70AB2 last summer. Shot it once at close range last fall, went in the safe. Pulled it out couple weeks ago, went out to 50 yards from a rest, shot horrible, no semblance of a group.

Only then did I notice that the rear sight is warped. The metal bows and twists upward to the the right. Pics aren't great and it's not terribly noticeable but here's what it looks like.

http://i200.photobucket.com/albums/aa5/bethanyloffredo/DSC01790.jpg
http://i200.photobucket.com/albums/aa5/bethanyloffredo/DSC01789.jpg


Took it out today to try to see whats going on a bit more. All shots are from 25 yards.

First try, 20 rounds off hand, sight picture is generally the bull.
http://i200.photobucket.com/albums/aa5/bethanyloffredo/DSC01785.jpg


Second round, 20 rounds from a rest. I added the white paper for the pic to show where I kept my sight picture.
http://i200.photobucket.com/albums/aa5/bethanyloffredo/DSC01786.jpg


Finally, 20 rounds, again from a rest, this time I adjusted to hit the bullseye. The black pasties show where I kept my sight picture. Also, disregard the 4 shots off to the left. I let a new guy at the range shoot it and that's what he produced (I did not tell him about the rear sight problem).
http://i200.photobucket.com/albums/aa5/bethanyloffredo/DSC01788.jpg


It may seem eye rollingly obvious, but would you all concur that it is the rear sight that is causing the problem? I want to make sure it's not the front sight (cant) or crooked barrel or anything else.

Anyone know of any websites where I can find a replacement?

Anyone have the same experince with their AK variant?

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wally
May 31, 2008, 05:01 PM
Rear sight block looks like it might be cockeyed a bit. I usually have to look at four or more Century guns to find one right enough to be worth buying.

Cheaper Than Dirt has Williams AK aperture rear sights for $20. Might be worth a try. If you got a side rail, get a mount and a cheap red dot.

I find 2-4" groups at 50 yards the norm for AKs Saigas might get below 2" with the "right" ammo.

If you want good groups the AK is not your gun. Continuing to shoot with minute of pie plate accuracy when everything else has fouled, is where it shines.

I love the you tube video of the guy shooting the AK so fast and much the front handguard bursts into flames and he continues thru several more mags with the fire burning!

Your second target is typical of what I get off a rest -- vertical stringing really opens up the group size, but in a battle rifle your target is a lot taller than it is wide.

Edit, saw your targets were 25 yards, saw 50 yards in the first paragraph, so yeah this one is shoot a good bit worse than most.

--wally.

Big45
May 31, 2008, 05:22 PM
If you want good groups the AK is not your gun.

No, I am not concerned with groups. My concern is hitting 6 inches to the left of POA at 25 yards. I believe it is the rear sight twisting upwards to the right.

DMK
May 31, 2008, 05:35 PM
Get a new rear sight leaf at www.e-gunparts.com (http://www.e-gunparts.com/product.asp?chrProductSKU=517900B)

I just bought two for $5 each. They are brand new.

... and straight. :p

AK103K
May 31, 2008, 05:40 PM
Have you actually zeroed the rifle? It looks like the rifle shoots fine, just needs some minor sight adjustment.

If the sight is bugging you, there are cheap replacements available at a number of places. I wouldnt bother with the Mojo type, they really are not a true peep, at least they really dont work like one and the stock sights are fine. If you like the front post centered, a windage adjustable RPK type rear sight will fix that for you.

I have an earlier Century SAR1 that has slightly canted sights, and it will shoot 4-6" +/- at 200 yards with no troubles using the iron sights and ammo it likes.

wally
May 31, 2008, 06:01 PM
I believe the front sight is eccentric on an AK and you adjust windage by a +/- 90 degree rotation of the front sight Whole turns adjust POI up or down. Unfortunately the windage adjustment range is not large

The Williams sight I mentioned has some windage adjustment which might help get the alignment you want if the front sight adjustment range is not enough.

--wally.

Big45
May 31, 2008, 06:14 PM
Get a new rear sight leaf at www.e-gunparts.com


DMK, would those you mentioned fit a Yugo?

wally, it's not a windage issue as much as it is a defective rear sight issue. I just wanted others to take a look at what I was seeing and hopefully confirm my suspicions.

AK103K
May 31, 2008, 06:22 PM
There is actually a lot of windage adjustment on the AK's. It is adjustable for both elevation (the post) and windage (the post barrel). They, or I should say, all I've seen, have been this type, and did not have the offset post, or eccentric as wally put it.

The annoying part of all this is, many rifles will zero with the post offset way to one side. This drives me crazy, and on guns that did zero like this, I always put one of the RPK type rear sights on the gun. The difference was only really noticeable by looking at the witness marks.

W.E.G.
May 31, 2008, 06:23 PM
Just pop-out that rear sight leaf and hammer it flat.

No reason to buy a replacement.

Do you own a tool for adjusting the front sight for windage?

jackdanson
May 31, 2008, 07:06 PM
I believe it is the rear sight twisting upwards to the right.

Bingo. You can find a replacement, you will probably need some help from a wife/friend replacing it though, that spring is TOUGH! It took my friend and I about 10 minutes to get it out and we trashed our hands.

wally
May 31, 2008, 07:21 PM
Right, I forgot about the front sight pusher on SKS/AK that does have a large range. You need the tool to do it though.
Unless the sight is moving with shooting, its only cosmetic once you adjusted POA to POI. Can't really tell from your pictures if its the sight leaf or base that's cockeyed, maybe a bit of both.

--wally.

Big45
May 31, 2008, 09:17 PM
Ahhh I see what you guys are saying now...ok, so I need that tool to adjust the front sight then? Availability of them online? I know for sure that my rear sight leaf is crooked and needs replaced but it could also be a windage issue with the front post I suppose.

Next question; I am going to put an Ultimak/Ampoint setup on this rifle. Will the iron sights even matter afterwards?

nalioth
May 31, 2008, 09:21 PM
Next question; I am going to put an Ultimak/Ampoint setup on this rifle. Will the iron sights even matter afterwards? When your Aimpoint goes t***s up, they will.

SJDigriz
May 31, 2008, 09:23 PM
http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=368914

blkbrd666
May 31, 2008, 09:31 PM
I would just take the rear sight off and bend it back to its original shape and put it back on, get the adjustment sliding up and down correctly, then take it out to the range and shoot it again...make adjustments on the front sight at that time. You can buy a new one cheap, but 30 minutes on the workbench is even cheaper as long as you don't charge yourself.

Coronach
May 31, 2008, 09:41 PM
AK doctors: I need your diagnosesPound the rear sight flat or replace it. Sight it in, adjusting the FSP for windage and elevation. Repeat this process after you install your Ultimak rail and your aimpoint, as POI may shift.

After that, shoot two cases of Barnaul and call me in the morning.

Mike :D

Big45
May 31, 2008, 09:56 PM
The self fix suggestion is not going to apply in this case as I have been legally diagnosed as mechanically retarded. Usually when things of mine break I repair by purchasing new things.

Sight it in, adjusting the FSP for windage and elevation. Repeat this process after you install your Ultimak rail and your aimpoint, as POI may shift.

Won't this only be the case if I cowitness both the red dot and irons? If I were to go with an EOTech instead, which does not allow cowitnessing in this case, would I still have to adjust the FSP?

AK103K
May 31, 2008, 11:09 PM
The dot will cowitness regardless where the post sits, if its zeroed.

The Ultimak/Aimpoint combo is the only way to go with the AK's. The gun shoulders and shoots just like it does with the iron sights only, and you have the same exact cheek weld. You really dont even need the iron sights, and probably wont use them much once you do go that route, but its nice to have instant verification the dot is still zeroed, especially if the gun gets banged around (been there, done that, and gave up on all but Aimpoint at this point). The red dot does bring the AK into the 21st century, and right up with the AR's.

Coronach
June 1, 2008, 12:20 AM
Won't this only be the case if I cowitness both the red dot and irons? If I were to go with an EOTech instead, which does not allow cowitnessing in this case, would I still have to adjust the FSP?You should be making all "permanent" adjustments to the iron sights to the FSP. As in, set the rear sight for the range of your target and center it (if you have a windage adjustable rear sight, which most are not). Once you do that, make all other adjustments to get the thing zeroed to your front sight. Left, Right, Up, Down- do it all to the FSP. Be aware that everything will be backwards- to bring your groups down, move your FSP up. To move your groups right, move your FSP left.

If you have an optic that allows cowitnessing and it is not on a QD mount (as in, if the thing goes down you just plan on shooting through it, not ditching it) rezero the weapon with the Ultimak rail and the optic attached. If you go with a sight like the Eotech that blocks the irons, rezero the sight with just the Ultimak rail and no optic, since you'll have to shed the optic to use the irons. Yes, you should rezero the irons even if the only modification you made was to add the Ultimak, because that puppy clamps to the barrel in two places and will change the POI of the bullets, even if nothing is sitting on the rail. It may not be much, it may be a whole lot.

Mike

Big45
June 1, 2008, 12:26 AM
Great information. Thank you.

Prince Yamato
June 1, 2008, 01:20 AM
pound the rear sight. That's what a Russian would do. :)

benEzra
June 1, 2008, 08:48 AM
Do also be aware that benchresting an AK can result in really erratic groups due to the rifle bouncing off the rest when fired (due to barrel flex when the heavy gas piston launches off the gas block), though this is usually manifested as vertical stringing and group enlargement rather than moving the POI to the side. I've had the best results with the bag as far back as possible, either right in front of the magazine or even under the back of the magazine, just forward of the trigger guard.

If you rest your elbows on the bench, with the rifle not touching anything, and shoot it, you can rule out POI shift from the rest.

I suspect your problem in this case is the bent rear sight, though. I'd replace it; you can probably drift the front sight over enough to compensate, but then it will be asymmetrical in the front sight shroud, and I hate that.

Big45
June 2, 2008, 09:18 PM
Ok here's an update to my AK saga...

First, let me just say that Ultimak is a top notch, A+ outfit in my book. Ordered the mount on Friday. Arrived today. Easy to install (and I am the least mechanically inclined person I know) and seems to be a great product. I will definitely do business with them again.

http://i200.photobucket.com/albums/aa5/bethanyloffredo/DSC01810.jpg

Anyway, I originally thought the initial problem was a crooked rear sight leaf. Well the rear sight is crooked, and can't be helping things. But...after installing the Ultimak mount I noticed something that reminded me of what wally had posted earlier in the thread. I think the whole sight block may be cockeyed. It's a tad tough to see because of the shadows, explanation follows.

http://i200.photobucket.com/albums/aa5/bethanyloffredo/DSC01812.jpg

http://i200.photobucket.com/albums/aa5/bethanyloffredo/DSC01805.jpg


Looking down at it, where the mount meets the base of the sight block, the right corner is more or less flush with the edge, the left corner of the mount has about a 1/16 inch gap between it and the sight block. This leads me to believe that the rear sight block is slightly crooked. The mount is clamped to the barrel so it seems to be straight as an arrow.

My question now is how much might this affect accuracy even with a mount/optic? I'm not about to put a $350 Aimpoint on here and still be way off:(

nalioth
June 2, 2008, 09:33 PM
My question now is how much might this affect accuracy even with a mount/optic? They are completely separate structures.

Canted sight blocks are common from Century

Identification (http://www.gunsnet.net/Linx310/cant.htm)

Coronach
June 2, 2008, 11:25 PM
It shouldn't matter too much. My Ultimak sits about that far sideways in relation to the rear block. As long as it is not touching either side, and not all of the way foreward or aft against the block or gas port, you should be OK. There should be a little space on each end.

Tighten it down and, if you have a chance, take it out and run a few mags through it for function-testing. Then bring it back in and, one screw at a time, back them out and retighten and loctite them. I know Ultimak says it isn't necessary, but I'm a pessimist.

If you don't have a chance to do that, ain't no big thing. I didn't do it, and mine runs like a top.

Mike

Coronach
June 2, 2008, 11:38 PM
Just in case you need it (from the site Nalioth linked):

http://www.gunsnet.net/Linx310/sightin.htm

Big45
June 16, 2008, 12:59 PM
Ok, so I got the sight tool from Tapco, which is a really solid tool by the way, very effective. Went out to the range and made some adjustments. I eventually had to shift the front post as far as it would go to the left.

http://i200.photobucket.com/albums/aa5/bethanyloffredo/DSC01842.jpg

Some of the replies to this thread stated a distaste for this effect but I don't mind at all, so long as it shoots straight.

Anyway I was able to finally to match up POI and POA (as best I could anyway). This is 25 yards from a rest.

http://i200.photobucket.com/albums/aa5/bethanyloffredo/DSC01840.jpg

And from 50.

http://i200.photobucket.com/albums/aa5/bethanyloffredo/DSC01841.jpg

It continues to hit generally to the left, but my windage adjustment is maxed out. At this point I'm not sure how much the rear sight leaf is affecting accuracy and I'm pretty sure that it's mostly a case of the rear sight block being slightly canted.

I'm hoping the Aimpoint makes these issues moot. However, will the FP being all the way to the left possibly affect the cowitnessing with the optic?

Coronach
June 16, 2008, 01:55 PM
Nope.

northwestneighbor
June 16, 2008, 02:31 PM
Hey I've got a Century Yugo with about the same problem. I'm just going to buy the RPK sight with windage from northridgeinc.com (since I'd rather not go the battery-op route).

Big45
June 16, 2008, 02:33 PM
Thanks for the link I may go that route since I really should replace the rear sight leaf anyway.

Prince Yamato
June 16, 2008, 03:24 PM
I think very few AK sights are "perfectly straight". I've got a Maadi with a slight cant. I needed to adjust the sight far to the left, like you did. Also, I was told by a range officer many years ago (and I sort of believe this to be true), that the shorter Warsaw Pact stocks can sometimes lead to a tendency to pull the rifle to the left for those not used to shooting with them. Solution: just get used to shooting the Warsaw style stock and your shots will be dead on.

Big45
August 17, 2008, 05:40 PM
This is serious thread necromancy but it's my thread so :neener:

Well it took two months to come to fruition but my AK project is finally done. Ultimak rail, Aimpoint CompML3 w/ arms QD mount.

http://i200.photobucket.com/albums/aa5/bethanyloffredo/DSC02079.jpg
http://i200.photobucket.com/albums/aa5/bethanyloffredo/DSC02081.jpg
http://i200.photobucket.com/albums/aa5/bethanyloffredo/DSC02082.jpg

Range report forthcoming.

AK103K
August 17, 2008, 05:50 PM
Looks good! :)

Have you shot it yet?

Big45
August 17, 2008, 07:49 PM
Not yet, but looking forward to it.

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