Author Topic: Resolved - Accuracy problems with my 527 Carbine 7.62x39  (Read 13216 times)

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Offline truckjohn

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Resolved - Accuracy problems with my 527 Carbine 7.62x39
« on: August 15, 2012, 12:42:52 PM »
Hey guys,
Another new 7.62x39 527 carbine owner here....

Got the rifle as a brush hunting rifle...  Was really excited to get it out to the range and stretch it out...  and so far, am pretty unimpressed by the accuracy of this $700.00 rifle...  It's everything I can do to hold 3 shots within 2" with "Good" ammo...  All the Russian stuff shoots like 4" groups....  and I have tried 20 different types of ammo so far trying to find the one that shoots great.... no luck!

Called up the guys at CZ - they seemed pretty non-commital... like 2" was what I should expect out of a CZ Carbine with good ammo.. and that I probably shouldn't bother sending it in... though I could if I really wanted to..... 

Is this what you guys are seeing and getting out of CZ?  Pretty disappointed so far....  I wouldn't have spent that sort of cash if I knew that's all I was going to get... I would just hunt with my SKS....

I will probably send it back in... who knows.. The general impression I got was that "Well... we will probably find it's OK and send it back to you..."  Is that their usual customer service?

Thanks
« Last Edit: August 22, 2012, 04:52:18 PM by truckjohn »

Offline bozwell

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Re: Accuracy problems with my 527 Carbine 7.62x39
« Reply #1 on: August 15, 2012, 01:22:56 PM »
What's "good" ammo?  You aren't going to see a lot of match-grade ammo in 7.62x39, and 2" groups with standard 7.62x39 ammo doesn't scream outrageous to me.  There are other rounds (e.g., .223, 30-30, etc.) where it's much easier to find more accurate ammo.  That's not to say they can't do some things to accurize the gun, but unless you hand load for it, I suspect your accuracy is going to be limited just as a result of your choice of 7.62.x39. 

Offline armoredman

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Re: Accuracy problems with my 527 Carbine 7.62x39
« Reply #2 on: August 15, 2012, 02:43:43 PM »
Hmm, they probably meant that with run of the mill ammo you might be looking at groups like that. I don't, but I handload, too. I get 2.75 inch groups at 200 yards, and think that's pretty good for a shaky fat old guy like me. of course, I am assuming you means 2 inch groups at 100 yards, right? Off the rest?
 A lot of factory 7.62x39mm is really loaded for AK variants, and not the greatest. Get some Prvi Partisan PS hunting ammo, and that might do the trick. The cheap Winchester white box stuff at WalMart is one step above junk, only good for making once-fired brass for me to reload. ;)
Dumb question, were you using the set trigger? That helped me.

Offline truckjohn

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Re: Accuracy problems with my 527 Carbine 7.62x39
« Reply #3 on: August 15, 2012, 04:34:29 PM »
Yeah, not like there's Federal Gold Medal or anything....

Here's what I tried out so far...
Hornady SST
Hornady Zombie Max
Fioccihi FMJ
Winchester FMJ
Winchester SP
Remington FMJ
Remington CoreLoc
Federal American Eagle FMJ
Wolff HP
Wolff FMJ
Wolff 154g SP "Hunting"
Brown Bear HP
Brown Bear FMJ
Silver Bear HP
Silver Bear FMJ
Golden Bear FMJ
Tula FMJ

I would have expected at least 1 or 2 of them to have done real well (1 moa or less)... Especially when you are talking a really well made barrel...  That's when Fiocchi, Hornady, or the Remington small primer FMJ usually shine...

But.. It was not to be....  Most everything showed strong vertical stringing....  Checked the barrel channel - and as far as I can tell, nothing is touching.....

I guess I am worried... I do plenty of reloading - but if the rifle doesn't show that it wants to do better than 2".... it's not starting off on the right foot in my mind.... and reloading stuff for 7.62x39 isn't exactly common... especially in stuff like the benchrest seater dies and bushing FL or neck dies like I run for everything else....

But.. I think there might be some other things going on with the rifle...  Gonna take a closer look  The mag well was super tight against the bottom of the receiver (Most Mausers need a 1mm - 3mm gap there to run right) ... When I loosened up the action screws the front end of the trigger guard wasn't tight against the stock... it looked like there was about a 0.020" gap... but the mag well was still super jammed into the bottom of the receiver....... That trigger guard piece might be jamming into the receiver and not holding the stock right.... and that sort of thing will ruin your day....

*sigh*

Offline buddy.223

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Re: Accuracy problems with my 527 Carbine 7.62x39
« Reply #4 on: August 16, 2012, 04:19:23 PM »
if sure mounts, scope, stock ect check out ok,  check the crowning job , on my last new 527 is was poor, where the crown was broken from the rifling it looked like someone had done it by sticking a screwdriver in the barrel and giving it a couple of twists, after it was recrowned it went from 1,5" groups to shooting ragged one holers.      on your ammo test did you clean and let the barrel cool between each make & weight  its the only real way to gain a fair assessment for each round. ive seen guys on the range rapidly shoot a box of the cheap mil surp , then complain when the next 3 hornadys dont group well out of the hot fouled barrel especialy out of the lighter profiled barrels. 

Offline armoredman

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Re: Accuracy problems with my 527 Carbine 7.62x39
« Reply #5 on: August 16, 2012, 05:31:34 PM »
Well, that's a heck of a lot more brands f ammo than I've tried, so it looks like it isn't the ammo.
Reloading supplies for 7.62x39mm are actually available everywhere. I recommend the 123 grain Berry's thick plated .311 bullet for the cartridge, works like a champ in my 527M.
I am sorry about this, wish there was something else I could do to help, as I am very fond of my rifle.

Offline ZG47

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Re: Accuracy problems with my 527 Carbine 7.62x39
« Reply #6 on: August 17, 2012, 04:18:44 AM »
if sure mounts, scope, stock ect check out ok,  check the crowning job , on my last new 527 is was poor, where the crown was broken from the rifling it looked like someone had done it by sticking a screwdriver in the barrel and giving it a couple of twists, after it was recrowned it went from 1,5" groups to shooting ragged one holers.      on your ammo test did you clean and let the barrel cool between each make & weight  its the only real way to gain a fair assessment for each round. ive seen guys on the range rapidly shoot a box of the cheap mil surp , then complain when the next 3 hornadys dont group well out of the hot fouled barrel especialy out of the lighter profiled barrels. 

I am with buddy.223 on the barrel cleaning issue. David Tubb has reported problems when shooting different bullets without removing the barrel fouling from the previous bullets.

It has to be worth a try. By the way, what was your methodology?
A good shot at close range beats a 'hit' at a longer range.

Offline eagleye

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Re: Accuracy problems with my 527 Carbine 7.62x39
« Reply #7 on: August 19, 2012, 05:50:02 PM »
Is the scope and mounts for sure trusty?

Offline truckjohn

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Re: Accuracy problems with my 527 Carbine 7.62x39
« Reply #8 on: August 21, 2012, 05:15:20 PM »
Mounts were the standard CZ mounts that came with the rifle.  The rear ring mounts have a boss that keys into a groove in the top of the receiver...  Shouldn't shift around too much (At least, I hope not)

Scope is my trusty Leupold vxII 4x scope.  Never had any problems with it before....  Unfortunately, my 36x Sightron won't fit without removing the rear sight....

On the shooting... I shot all of that stuff in 1 long range session...  I did let it cool between groups and between ammo... but I didn't clean between different types of ammo...  I would never have gotten home from the range.

Anyway... still digging... so I found that the action only "Crushed" the stock maybe 0.003" before hitting steel to steel from the mag well/trigger guard to receiver...  Shimmed the trigger guard with card stock so it was clamping the stock properly...

Also found that the stock/receiver fit was pretty loose side to side both at the front ring and the rear tang...  When I shimmed the trigger guard so that it wasn't crushing the mag well into the bottom of the receiver - it shifted the whole action pushing the barrel into the right side of the stock hard.. so I put some card stock at the front ring and rear tang to center up the barrel in the barrel channel...

Hopefully, I can get out to the range this week and see how she does....   Let's all cross our collective fingers....

Thanks
« Last Edit: August 22, 2012, 05:06:43 PM by truckjohn »

Offline truckjohn

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Re: Resolved - Accuracy problems with my 527 Carbine 7.62x39
« Reply #9 on: August 22, 2012, 04:55:03 PM »
DING!!!

Fiocchi shot 5 rounds into 5/8" at 100 yards....

If I can figure out how to post pix - I will make a post showing what I found... but it's everything detailed in the post above....  Trigger guard mag box too tall for the cutout in the stock.. Shims allowed the action to tighten down like it's supposed to...  Shims around the front receiver ring and rear tang centering the barrel in the barrel channel did the trick.

Thanks

Offline truckjohn

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Re: Resolved - Accuracy problems with my 527 Carbine 7.62x39
« Reply #10 on: September 08, 2012, 05:58:56 PM »
An afterward to this....

What I found is that with a fresh, clean barrel - the 1st shot would hit 3" high and 1" right..  Then it would shoot 5 rounds into a small group...  Then - as the barrel fouled further, groups would scatter...

So... I went ahead and removed the roll pin rear "Pillar" (Which was also too tall for the stock) and properly bedded the action into the stock.  I am still using card shims on the magazine.

Then - I firelapped the barrel using the LBT Firelapping kit (It's a roll your own deal where you supply soft, oversized lead bullets...)  It took about 25 fire lapping rounds total (In 3 separate sessions, each followed with shooting and cleaning an additional 20-30 rounds of jacketed in between to gage progress)

The barrel is settling down nicely - the 1st round "Flyer" goes closer to the rest and every ammo is shooting much more consistently...  I was surprised to shoot a 1/2" 3 shot group with Cheap Tula HP.... but handloads really do make the rifle hum....

Anyway - if you get one that won't shoot, you can look at the above to see if it's the sort of thing you are willing to fool with.... If you are the sort who likes to tinker a bit - these rifles won't disappoint...  Just remember - you can't do this sort of stuff then send it back if you mess it up...  so think hard before you jump in.....

But.. my concern for CZ is that these are $700.00 rifles... and people will read the travails of folks like me who get rifles that shoot 2-4" groups out of the box - and just walk away.... They really need to sort out the stock to action fitment issues...  We shouldn't be getting stocks that are inletted too deep and letting the action flop around, killing accuracy...

Thanks

Offline painter

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Re: Resolved - Accuracy problems with my 527 Carbine 7.62x39
« Reply #11 on: September 08, 2012, 06:09:49 PM »
Glad you got your problem worked out.

I agree...at the price point they should shoot well out of the box.
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Offline ZG47

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Re: Resolved - Accuracy problems with my 527 Carbine 7.62x39
« Reply #12 on: September 11, 2012, 09:10:30 PM »
Hammer forged (actually swaged) barrels can be a bit of a lottery. Even Blaser has sold bad ones.
A good shot at close range beats a 'hit' at a longer range.

Offline JackH

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Re: Resolved - Accuracy problems with my 527 Carbine 7.62x39
« Reply #13 on: September 29, 2012, 12:52:20 PM »
Truckjohn,

I recently picked up a carbine just like yours. I'm excited about its potential as a hog gun and all-around plinker. It's been to the range once and overall I wasn't that impressed with the accuracy: at 50 yards the best I could do with open sights was around 1.5 inches and most were more in the 2-inch range.  I tried four different factory loads and was cleaning the barrel after every shot for the first 20, then after every three or four shots afterward. I fired about 40 rounds total.

I'm going to scope it which will probably improve the results (the eyes just aren't what they used to be) but after all the MOA reports I found while researching the gun, I was hoping for better.

The improvements you made by adding shims are really impressive. You mentioned you would post pictures if you could and I would love to see them just to make sure I'm clear on the details. If you aren't able to post pictures, would you be so kind as to email them to me? It would be great to have that knowlege available in case the accuracy is still so-so even after I get a scope mounted.

BTW, I'm looking hard at a scope like the Leupold VXII 2-7x28mm Ultralight for this rifle. Not sure yet what I'll need for rings but will cross that bridge when I can afford it.    "->

Thanks in advance!

Jack


Offline truckjohn

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Re: Resolved - Accuracy problems with my 527 Carbine 7.62x39
« Reply #14 on: September 29, 2012, 04:58:26 PM »
Rings come with the rifle in the box....  Those are the ones I used...  If you bought it new - check through all the stuff in the box to make sure you got those rings... If not - give CZ a call.... 

I gotta dig up those pix....

Next - what ammo are you shooting?  Fiocchi gave the best accuracy by far out of Factory ammo..  Hornady and Remington green box FMJ also shot very well....  None of the Russian ammo really shot all that accurately for me...

With the shooting and cleaning...  I found that even up till last week - I got in between 5 and 8 shots before accuracy went south....  I was out yesterday and accuracy was doing well up till shot 14 - when I ran out of ammo...  I am probably right at 350 rounds + 25 or so of firelapping loads.. 

My best advice is to shoot it and see how many you can shoot before the groups open up... then just wait till you get close and then clean it then...

One thing I noticed was that with slower burning powder ammo - I seem to be getting diagonal stringing... where with faster burning powder ammo - it's either vertical or no stringing at all....  This makes me suspect the rifle's crown needs work...

Thanks
« Last Edit: September 29, 2012, 05:11:00 PM by truckjohn »