Author Topic: CZ 527 in .223 accuracy problems.  (Read 3862 times)

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Offline 223man1

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Re: CZ 527 in .223 accuracy problems.
« Reply #15 on: March 11, 2017, 02:27:38 PM »
Hello,

I also have a CZ 527 M1 American with synthetic stock, it was purchased in mid 2014. Actually the factory 3-shot target that came with the rifle is dated november 26, 2013.

I thougt It had a 1:9 twist, because the CZ webpage says it has, but CZ apparently changed the twist rate from 1:12 to 1:9 in early 2014. I measured the twist rate on my CZ 527 using the cleaning rod and it is unfortunately a 1:12 twist...... :-[

I have problems with most bullets heavier than 55 grains, the exception is the Federal Fusion 62 grains cartridge, it groups around 1" at 100 yards. Not sure why this bullet work, it must be something in that construction that makes it work in a 1:12 gun.

The Winchester 64 grains Power Max on the other hand did not work at all in the CZ 527 with 1:12 twist, the bullets was all over the place at 100 yards with 10-12" spread. Terrible!

Same story with the Barnes 55 grains TTSX copper bullet, I could hardly hit a 2x2 feet target at 100 yards. The Barnes TTSX bullet is too long (much longer than a 55 grains copper/lead bullet) so it will not work in a 1:12 rifle.

I have now tried the 50 grains Barnes TTSX, and it seems to work OK, but I am not completely satisfied with accuracy, it groups around 1.5" at 100 yards, not that great. I have reloaded with 24 grains of Norma 201 powder, using Norma cases. C.O.L is 55.6mm (2.189"). I measured the max C.O.L to 56.6mm (2.228") with the 50 grains TTSX bullet, so i have 1mm of headspace.

The Norma case by the way has more volume than the S&B cases (and most other 223 cases), so I have to use 1 grains less powder in S&B cases.

I will now try 25.5 grains of Vihtavuori N-140, to see if a bit slower powder will work better. I tried the 55 grains TTSX with 25 grains of Vihtavuori N-140 and it cronographed at 2870 f/sec. So I assume 0.5 grains more powder with a 5 grains lighter bullet will be OK.

The S&B 55grains FMJ bulk ammo works OK, but accuracy is not that great (1.5"+ at 100 yards). The best factory ammo I have tried so far is the RWS  55grains SP and the Norma 53 grains SP, but the CZ is a "touchy" gun when it comes to ammo.
I just wish I had the 1:9 twist version...... :'(

I think I will replace it with a Howa Mini Action or a Sauer 100 Classic XT 223rem when I can afford it.

Best regards
223 gunner from Norway



Offline FieldGrade

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Re: CZ 527 in .223 accuracy problems.
« Reply #16 on: March 15, 2017, 12:41:07 AM »
Never mind.
« Last Edit: March 15, 2017, 12:46:00 AM by FieldGrade »
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Offline M1A4ME

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Re: CZ 527 in .223 accuracy problems.
« Reply #17 on: March 15, 2017, 08:25:59 AM »
223man1, the solid copper bullet should be longer than the same weight standard bullets.  To get the same weight (55 grains) it's got to be longer since there's no lead inside.

That may  be a contributor to your accuracy issues.  It's like trying to load/shoot a 65 or 70 grain bullet and your 1 turn in 12" barrel just isn't spinning it fast enough.

The most accurate bullets my 1 turn in 12" M700 varmint rifle like were the 45 grain bullets by Sierra or Hornady sitting on top of IMR4198 powder.  It's a faster burning powder than many use in .223's but a 45 grain bullet is lighter than a lot of people use, too.

I bought, but never really used, the 52 and 52 grain Sierra match bullets.
Better to have it and not need it, than to need it and not have it.  So, if you see me walking the dogs with my SIG 556R, its okay.

Offline 223man1

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Re: CZ 527 in .223 accuracy problems.
« Reply #18 on: March 15, 2017, 03:24:59 PM »
Yes, I know about the copper vs lead core bullets. But I bought the 55 grains Barnes TTSX bullets believing I had a 1:9" twist rifle..... which turned out to be 1:12" twist..... :-\

Well, anyhow, I get reasonable results in stability with the 50 grains TTSX bullets, surely fine for shooting Roe Deer at up to 100 yards. But I am wondering if I should try the 45 grains TSX bullet also. The 45 grains bullet is 0.698" long and the 50 grains is 0.812" long (with a 0.118" long plastic tip), so in theory the 45 grains should have better stability in my 1:12" twist rifle. But, the bullets are getting very light so not sure about penetration in wild game (European Roe Deer). Copper bullets are fine here because of no lead fragments in the meat.

Also, here up North I am shooting in below freezing temperatures this time of year. And according to this calculator, the temperature has an influence on stability:

http://www.jbmballistics.com/cgi-bin/jbmstab-5.1.cgi


Offline Coop45

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Re: CZ 527 in .223 accuracy problems.
« Reply #19 on: April 04, 2017, 10:59:23 PM »
Hello,

I also have a CZ 527 M1 American with synthetic stock, it was purchased in mid 2014. Actually the factory 3-shot target that came with the rifle is dated november 26, 2013.

I thougt It had a 1:9 twist, because the CZ webpage says it has, but CZ apparently changed the twist rate from 1:12 to 1:9 in early 2014. I measured the twist rate on my CZ 527 using the cleaning rod and it is unfortunately a 1:12 twist...... :-[

I have problems with most bullets heavier than 55 grains, the exception is the Federal Fusion 62 grains cartridge, it groups around 1" at 100 yards. Not sure why this bullet work, it must be something in that construction that makes it work in a 1:12 gun.

The Winchester 64 grains Power Max on the other hand did not work at all in the CZ 527 with 1:12 twist, the bullets was all over the place at 100 yards with 10-12" spread. Terrible!

Same story with the Barnes 55 grains TTSX copper bullet, I could hardly hit a 2x2 feet target at 100 yards. The Barnes TTSX bullet is too long (much longer than a 55 grains copper/lead bullet) so it will not work in a 1:12 rifle.

I have now tried the 50 grains Barnes TTSX, and it seems to work OK, but I am not completely satisfied with accuracy, it groups around 1.5" at 100 yards, not that great. I have reloaded with 24 grains of Norma 201 powder, using Norma cases. C.O.L is 55.6mm (2.189"). I measured the max C.O.L to 56.6mm (2.228") with the 50 grains TTSX bullet, so i have 1mm of headspace.

The Norma case by the way has more volume than the S&B cases (and most other 223 cases), so I have to use 1 grains less powder in S&B cases.

I will now try 25.5 grains of Vihtavuori N-140, to see if a bit slower powder will work better. I tried the 55 grains TTSX with 25 grains of Vihtavuori N-140 and it cronographed at 2870 f/sec. So I assume 0.5 grains more powder with a 5 grains lighter bullet will be OK.

The S&B 55grains FMJ bulk ammo works OK, but accuracy is not that great (1.5"+ at 100 yards). The best factory ammo I have tried so far is the RWS  55grains SP and the Norma 53 grains SP, but the CZ is a "touchy" gun when it comes to ammo.
I just wish I had the 1:9 twist version...... :'(

I think I will replace it with a Howa Mini Action or a Sauer 100 Classic XT 223rem when I can afford it.

Best regards
223 gunner from Norway

My 12 twist likes Sierra 1410 bullets ....52 gr Matchking

Offline 223man1

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Re: CZ 527 in .223 accuracy problems.
« Reply #20 on: April 05, 2017, 03:12:01 PM »
Coop45, you are absolutely correct !

I just tried that exact bullet (Sierra MatchKing HPBT, 52 grains) and I can place 5 shots within 0.8" or better at 110 yards.

This is the one bullet to use in the CZ 527 in 223REM with the 1:12" twist barrel. Excellent bullet !!

I used Lapua Match cases, and 24.5 grains of Norma 201 powder. C.O.L is 55.4 mm. Velocity was around 900 m/sec. (2950 fps).

https://www.sierrabullets.com/store/product.cfm/sn/1410/224-dia-52-gr-HPBT

« Last Edit: April 05, 2017, 03:17:31 PM by 223man1 »

Offline M1A4ME

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Re: CZ 527 in .223 accuracy problems.
« Reply #21 on: April 05, 2017, 03:42:09 PM »
Doesn't Sierra also make a flat based hollow point match bullet?

I've read (read it, not proved it to myself) that quite often the flat based bullets are more accurate inside 300 yds. than the boat tailed bullets.

Just in case you run across a box of the flat based bullets.

I bought several boxes of the match bullets (Sierra) many years ago for my M700 varmint special but ended up getting groups from the flat based 45 grain spritzer hunting bullets that were just as good, so I never shot all those up.
Better to have it and not need it, than to need it and not have it.  So, if you see me walking the dogs with my SIG 556R, its okay.

Offline jameslovesjammie

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Re: CZ 527 in .223 accuracy problems.
« Reply #22 on: April 05, 2017, 09:41:46 PM »
My 12 twist likes Sierra 1410 bullets ....52 gr Matchking

That is my favorite bullet in a Remington 788 and Winchester 70 Featherweight .223 (both 1/12").  This bullet combined with a healthy charge of Ramshot X-Terminator is great for shooting coyotes and doing minimal damage to the pelts.



Doesn't Sierra also make a flat based hollow point match bullet?

It's the 53 grain Matchking.  Same thing only different.   ;D

At 100 yards, I haven't seen much difference between the two.  That being said, neither of my bolt .223's are exactly match grade.

Offline cknpro

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Re: CZ 527 in .223 accuracy problems.
« Reply #23 on: August 15, 2017, 10:40:19 PM »
Very likely ammo issue, but maybe not. My .223 is sub-MOA with 55 grain reloads, my F.I.L. Has to feed his 40 grain bullets to get that, his wont throw 55's into 2". I'm using Nosler Varmegeddons over 25.3g H335 with astounding results, at 3180 fps. I cleaned it once.

Offline shangai

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Re: CZ 527 in .223 accuracy problems.
« Reply #24 on: August 30, 2017, 02:12:44 AM »
I have 527 Varmint, 1:9". I don't have decent groups with 55gr factory ammo(I have 1-3MOA). First sub-MOA group I got with:



With this bullet(hand loaded) I got perfect group, cca. 1/3 MOA...

Offline jameslovesjammie

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Re: CZ 527 in .223 accuracy problems.
« Reply #25 on: August 30, 2017, 08:41:57 AM »
With this bullet(hand loaded) I got perfect group, cca. 1/3 MOA...

Did you shoot multiple groups with this load, or was it just the one group?  I guess I would say that the question I am having is was it repeatable or just a single good group?  If it shot multiple small groups with the 77 grain SMK...well, that's awesome!

Some rifles do weird things with different bullets.  The tightest group that I shot in my AR (5R 1/8 twist) was with a 40 grain ballistic tip bullet.  That length of bullet isn't supposed to stabilize with that twist rate, but it did.

Offline shangai

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Re: CZ 527 in .223 accuracy problems.
« Reply #26 on: August 30, 2017, 11:39:38 AM »
I shot few sub-MOA groups with that Federal factory ammo(Vo app. 805m/s), and than ordered a MK bullets. Development of load is on this photo:

https://imageshack.us/i/pm1xsOI1j

First I shot a middle target(5shots), second was left target(4shots). I was very dissapointed with these targets, and shot right target probably worst that day, but result was great - cca. 10mm/100m, 4 shots! :) Vo is cca. 890m/s!