Help with CZ527

[herkyguy]

Morning,

I've been loading and shooting a fairly new CZ527 lately. 1 in 9" twist, .223 American model. I had it dialed in with Hornady 40grain VMAX bullets for a while (shooting 3 shot groups at 200 yards at 1.3"). But I wanted to see about working up a good load with Nosler 60 grain partitions, so I set out to do so.

My results have been bad. Nosler's guide lists a COL of 2.26" which is also obviously the factory max COL for .223. Well, I've found that the bullet is up against the lands at about 2.240" COL. I tried some initial loads at 2.215 and the groups were horrible. Last night I loaded up some with increasing COL from 2.220 up to a COL of 2.237.

My initial loads were using 21.5 grains of 2230-C and with the newest batch, I've got different powder loads between 21.5 and 22.5 for each COL. With the 2.215 COL and 21.5 grains, they're averaging about 2900 fps. I'd like to see up to about 3000 fps.

In the quest to dial in this gun with the Nosler partition, I also picked up the Hornady COL tool, but my measurements weren't as accurate as actually loading bullets with increasing COL until the bullet actually was set back into the case

How is it that Nosler can recommend a COL that doesn't fit in my factory CZ 527? Had it not been for me tinkering, I would have loaded rounds that jammed up against the lands. Also, besides switching bullets, what else can I do to get better accuracy? I've already bedded the action btw. Th scope is not loose either..... I had initial problems with that, and I've used loctite to correct the problem.


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[GooseGestapo]

I know your pain!
I picked up a CZ527 in .222Remington.
Besides a crummy 2-stage trigger, the accuracy with 55gr bullets was "off", particularly, considering that my Remington M700 in .22-250 shoots them (Sierra's) into the .3's and .4's.
The barrel is marked 1-14" twist. However, by actual measurement, it's closer to 1-17" !!! 1-16.9" measured several times.
It shoots "ok" with traditional 50gr flat base or hollow points, but run a V-Max or such, and accuracy , well, isn't! 53gr V-Max shoots 12" groups with visible yaw.
Although it shoots slightly better than my Ruger M77/.22Hornet, I expected MUCH better.

It's going to disappear from the gun room soon.

 

[sirgilligan]

Could it be that you should use the 5.56 Nato COL of 2.250"? I know that the CZ 527 is 5.56 NATO rifle, I talked to CZ at the NRA show and now the even say it on their web page.

Maybe a heavier bullet?

I am looking at the Nosler info and it says COL of 2.220" with 22.8 H335.

Here is the results of what my brother loaded:

 

[herkyguy]

Just double checked my Nosler manual. It says COL of 2.26" - my measurements via the Hornady tool show a max of 2.235"

I'm just all of a sudden confused about if my chamber/barrel are out of spec.

Lastly, I've heard mixed reviews of a 1 in 9" twist and bullets above 55 grains.

I really want to knock a NC deer down with that bullet.


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[scottishkat]

A 1 in 9 twist at 3000 fps is turning at 250,000 rpm I would try a heavier bullet and some benchmark or H335.

good luck and shoot straight

Bob

 

[sirgilligan]

Just double checked my Nosler manual. It says COL of 2.26" - my measurements via the Hornady tool show a max of 2.235"

I'm just all of a sudden confused about if my chamber/barrel are out of spec.

Lastly, I've heard mixed reviews of a 1 in 9" twist and bullets above 55 grains.

I really want to knock a NC deer down with that bullet.


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I looked on line at Nosler. Evidently Nosler has changed the COL since the printing of the book.

Mine is a 1:9 twist, it is the Varmint model.

I have shot 35 grain up to 75 grain and everything shot well. I can post pictures for any that doubt.

I find it interesting that my Hornady book says the ".223 Service Rifle" has an COL of 2.250 and not 2.26. I tried to find specs on line and all of the things I found says the 5.56 NATO COL is 2.26, so I don't know what to think.

The Accurate 2230 powder is faster than H335, TAC, Varget, IMR 4895, and many of the commonly used powders for .223.

I would suggest a powder change as well.

The Nosler page does say that the most accurate powder they tested was A-2230, but also note that their rifle was a 1:7 twist rifle.

 

[herkyguy]

I've got 50 rounds loaded up varying COL and powder charge.

If no luck with those, I'll definitely take your advice and switch powder.

Those Nosler partitions aren't cheap and I've burned almost 100 of them so far. Errrrrg.


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