Author Topic: "Accurizing" the Yugo - a journey......  (Read 4640 times)

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skid00dl

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"Accurizing" the Yugo - a journey......
« on: September 13, 2010, 05:29:48 PM »
This is a "brief" description of my attempt to improve the accuracy of a Yugo.  Understand that advice and opinions from many on these boards lead one to believe there is not much that can be done to a Yugo to improve accuracy.  The following is my experience and may not be repeatable in every case.  And truth be known, the experts on these pages are correct and "accuracy" with a Yugo is a relative term!  Of all the things that make a rifle/carbine accurate, the barrel is by far the most important.

First I must define a couple of terms:

Group Size (in terms of Minute of Angle) - Five shots within a one inch circle at 50 yds. is 2 MOA.  Three shots in a one inch circle at 50 yds. with another "flyer" two inches above that and the fifth shot two inches above the fourth equals a 5" group, or 10 MOA.  A "group" includes the widest flyers.  You don't get to call the tightest few shots in the bunch a "group" and discount the flyers.

Accuracy - We all agree it means hitting what you are aiming at.  I would add repeatability and consistency.

I started with an unaltered Yugo with matching numbers and appeared to have not been fired, or at least minimally.  It was, and is in excellent condition.  Using iron sights at 100 yards I was getting 18" groups.  (18 MOA)  Even with hand loads I had worked up to tighten up the majority of the shots in the group, I was still getting flyers to 18 MOA.  In my opinion, that sucks.

1.  Trigger job per Murray and addition of Wolff springs.  This vastly improved the trigger and reduced groups to perhaps 14 MOA.
2.  I noticed the lead points of the hunting rounds (hand loads) were literally being ripped in half when feeding from the magazine.  So I ramped the breech similar to the double ramp seen in the M4 carbine.  This corrected the problem and reduced the groups to 12 MOA.
3.  Still puzzled why I was getting the wild flyers, I closely examined the barrel and muzzle and found that the grenade launcher was not in line with the bore(?!)  I removed the GL and discovered the worst crown I have ever seen on any barrel.  I crowned the muzzle using a quality PGI crowning tool and purchased a Tapco muzzle brake.  I had to drill out the interior "shoulder" of the brake because the bore in this Yugo barrel is not precisely centered.  I shot groups without any brake and with the brake screwed on.  The brake made no difference.  But the crowning of the barrel improved groups to 4 MOA! and eliminated the wild flyers.
4.  I glass bedded the action.  If this helped at all it was only minimally.
5.  I glass bedded the barrel.  No perceptible improvement.

Conclusion:
The trigger job, ramping of the breech and crowning the barrel resulted in the greatest improvement.  I started with 18 MOA and reduced it to 4 MOA.  That would be a 78% improvement in accuracy.  Other than possibly playing around with loads, I think I have squeezed everything I will get out of this carbine.  With a 10-shot group, I consistently get two to three shots in the one inch bullseye, two the three within the two inch ring, and all shots within the four inch ring at 100 yards.  As the man said, "That'll do pig.  That'll do."

If anyone has any other ideas to improve accuracy with a Yugo I would love to hear them. 

I want to thank all those that offered opinions and advice, both serious and humorous!

jds912

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Re: "Accurizing" the Yugo - a journey......
« Reply #1 on: September 13, 2010, 06:38:11 PM »
how did you ramp the breech?
When I die, I want to go peacefully like my Grandfather did, in his sleep--not screaming, like the passengers in his car.

skid00dl

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Re: "Accurizing" the Yugo - a journey......
« Reply #2 on: September 13, 2010, 06:59:20 PM »
Very carefully! :lol:

With a dremel and a cone-shaped stone with the tip a little blunted.  I tried to grind off as little as possible and still be effective.

I'll try to post some photos.

skid00dl

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Re: "Accurizing" the Yugo - a journey......
« Reply #3 on: September 13, 2010, 09:30:56 PM »

Still not satisfied with the scope.  Looking for a quality compact that enables use of strippers.

Created only enough ramp to feed softpoints without damage.

Bedding.

Bedding.

Stock inletted to accommodate Choate mount.

TurboJet6

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Re: "Accurizing" the Yugo - a journey......
« Reply #4 on: September 15, 2010, 10:37:37 AM »
I never expected much accuracy from any of my SKS rifles. The only modifications I have made for accuracy is to make sure the barrel is "floating" and not actually resting on the front end of the furniture.  This seems to make a huge difference when using an after market stock.  My Yugo with the TAPCO stock is the most "accurate" of the bunch with 8-10 MOA at 100 yard using iron sights. It also does really well with the BSA panoramic sight at shorter distances from 40 to about 80 yards. For ammo, almost exclusively use the steel casing FMJ from Bear.  I have tried other brands including more expensive ones with no substantial improvement in accuracy.

Lafayettegregory

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Re: "Accurizing" the Yugo - a journey......
« Reply #5 on: September 15, 2010, 11:05:21 AM »
Good post skid00dl. Sounds like the main culprit was the bad crown.  Glad to hear you improved your groups. I have a Romak 991 that I need to do a crown job on. You have given me the desire to fix it. Thanks 

skid00dl

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Re: "Accurizing" the Yugo - a journey......
« Reply #6 on: September 15, 2010, 01:00:43 PM »
Thank you, Shark Man!  Yup.  I think the stinky original crown was the main problem.  Had I discovered that problem first, I could have avoided all the other "upgrades."  Though I probably would have tried bedding the action anyway.  On another thread concerning failure to fires, Mr. Murray is in the process of getting Wolff to make a quality hammer spring.  I get a few FIF's with both the original firing pin and Mr. Murray's pin.  He seems to believe the problem folks are having could actually be the original hammer spring.

Have a great day.

How 'bout that Delaware primary?!  Can you smell the TEA brewing?

Lafayettegregory

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Re: "Accurizing" the Yugo - a journey......
« Reply #7 on: September 15, 2010, 01:29:57 PM »
I believe bedding the stock AND the barrel did help. I have tried using a sling to the front sling attatchment, and if you tighten up "as appleseed teaches" It will throw your rds all over the target.  So anything that strengthens the stock and the barrel to reduce flex will help.
 I was once a believer that there was nothing you could do to improve the accuracy of an sks. Well-- live and learn :roll: If the sks is not already getting at least a 8in group at 100 yards, you can do some improvement. And as you proved, with practise and a little more effort you can improve on that. They will never be tack drivers, but they can make some close holes on paper.

skid00dl

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Re: "Accurizing" the Yugo - a journey......
« Reply #8 on: September 15, 2010, 08:14:57 PM »
And it's fun to do, too.

dmax

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Re: "Accurizing" the Yugo - a journey......
« Reply #9 on: September 15, 2010, 10:05:54 PM »
great work on your SKS.

this really kinda of urks me once again about being in California and getting stuck with a modified SKS. i cant re-crown my barrel without taking a cutting wheel to the tack weld CAI put on the muzzle brake to make it CA compliant :evil:

I'm not sure mine really needs it though but i need to take it out to the range more to find out as i've only shot 40 rounds through it so far and only 20 at 100 yards, once i got on target (i failed at adjusting my rear sight correctly for the first 15 rounds and was hitting below the target and couldn't see it with my binoculars) the 5 last shots i got on my 12" shoot N C target were within 8" of each other but still not great with the stock iron sights as they came with no adjustments

first thing first though is getting a solid scope mount on my rifle and then i will go back out and see how she performs

 

skid00dl

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Re: "Accurizing" the Yugo - a journey......
« Reply #10 on: September 16, 2010, 07:02:17 AM »
dmax,
You mentioned you had trouble adjusting the rear sight of your iron sights.  I believe your front sight is the one you need to adjust.  You will need a sight tool to do so.  The rear sight is graduated in meters from 100 to 1000.  Leave it set at 100.
Adjusting your front site:  Moving the sight pin up ("unscrewing it") will "lower" the point of impact of the bullet.
Moving the sight pin down ("screwing in in") will "raise" the point of impact of the bullet.  Pushing the site pin base left will move the bullet "right."  Pushing it right will move the bullet "left."
I found it only takes moving it a little to make a big difference on the target at 100 yds.  It's better to start at 50 yds.  But with patience, I got mine "zeroed" at 100 yds.  Now when I step my rear sight up to 200, it stays on target laterally, and raises point of impact vertically as it should.
That is unbelievable that Kauli-fornya would make CAI weld the dang muzzle brake on.  I am certainly not advising you to do so, but an industrious person would probably be able to carefully cut the weld with a dremel and cutting wheel without doing much damage to the barrel.  Thereby permitting one to inspect the crown, make corrections if necessary and re-weld, JB Weld, Lock-tite, the brake back on.

dmax

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Re: "Accurizing" the Yugo - a journey......
« Reply #11 on: September 16, 2010, 03:30:06 PM »
yeah i know what i need for adjusting the front sight, what happened to me was user error i had the sight set to battle position (the 1st 1) because i was shooting at 50 yards at first and when i moved over to the 100 yard lane i forgot to move it up to the 100 meter mark so my shots were all about 6-8" low of landing on the black shoot n c target that i can actually see with my binoculars (it was hitting cardboard) once i had it adjusted to 100 meters i was landing on target and even had a couple shots within 3" of the bulls eye

yeah i thought about dremeling the tack weld off but before i go that far i'm putting a scope on it and taking it out to the range with more ammo to get a better feel for how she performs to see if its really necessary, the first time i took it out it was 2 days after i got it and had just spend the 2 days before cleaning out the cosmo and getting her ready to shoot for the first time, i came sorely unprepared with only 40 rounds figuring i'd shoot my mosin more than i did but after shooting the SKS i didn't even want to shoot the mosin anymore :)

TurboJet6

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Re: "Accurizing" the Yugo - a journey......
« Reply #12 on: September 16, 2010, 10:39:09 PM »
how did you ramp the breech?

I can here the "Purist" and "Preservationist" cringe at the thought of removing metal!

skid00dl

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Re: "Accurizing" the Yugo - a journey......
« Reply #13 on: September 16, 2010, 11:08:41 PM »
Ha ha ha!  I am sure you are right, TurboJet!  My goal was to "improve" what I could.  I am sure Mr. Siminov would have ramped the breech if he could have.  But face it, the SKS is a carbine built for peasants, by peasants.  It was built as cheaply as possible.  As the Russians would put it, "Is gude enuff!!"  They would not have spent the money to machine ramps or any hand fitting.

snakebite4767

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Re: "Accurizing" the Yugo - a journey......
« Reply #14 on: September 17, 2010, 01:21:35 PM »
skid00dl :

Nice report. Certainly the "Crowning" Touch was re-crowning the barrel. I've done a fair amount of shooting myself, and have faced the unruly rifle that just would not shoot a decent group. I have a number of MOA rifles in my stable, and I know that it takes some effort to get them there. It sounds like you have covered most of the bases. Some rifles require custom loading to shoot true, while others seem to group with anything that you put in them. You might want to look at the head space, and also see just how much jump you have before the bullet hits the lands of the barrel, very ofter adjusting OAL makes for a big improvement. Another thing that has helped me in the past to really bring in some barrels is to "Lap" the barrel. There are a number of good compounds out them. Even the very mild JB Bore Cleaner can often help.

I just aquired a Yugo, and am in the process of turning it into a rifle that suits me and my purpose. So... in the not so distant future I expect that I will be tracking in your footsteps, and attempting to Accurize my new Yugo. I don't have any great expectations, since the strong point of the SKS is not accuracy, but I would like to get it to group the best that I can.

Snakebite