Short throat on a CZ 527?

huntnfish08

huntnfish08

New member
I've got a CZ527 American in .223Rem. I was working up loads for it the other day and found my rifle has a very short throat. Published COL for my bullet is 2.250". I was getting marks from the lands at this length. So I seated my bullets til I had no marks. 2.150" Then I tried a bullet slip fit into empty brass. Loaded into chamber and carefully extracted, measures right around 2.150 again.
I've been told I'm lucky. Also that it seems like a fluke. Either way I loaded just short of the lands and found a load that grouped 5/8". I'm happy, just confused.

Any help, better way to measure distance to the lands? I searched for RajnCajns tool to no avail. Any one have the link?

The load is a Hornady 52gn BTHP Match over 25.8gr of Benchmark. In Lake City brass and Rem 7.5 Bench primers.

Adam
 
With bullets seated at 2.150, how do they shoot?
Do bullets seated as above work through the magazine?
Do bullets seated a 2.250 work through the magazine?
 
Congratulations on having a great little varmint rifle.

In my .223 CZ527 I seat bullets routinely 0.020" off the lands.

40g V-max measures 2.258" OAL, 1.858" base to where the ogive contacts the lands.

40g Nosler BT measures 2.273" OAL, 1.860" base to where the ogive contacts the lands.

The most accurate load I have for the rifle is the 40g Nosler BT seated at 2.273" OAL, 28.0g of AA2460 (use a 4" or 6" drop tube and it fits better), CCI400 primer, Winchester brass. It will shoot three shot groups into slightly larger than caliber sized holes if I do my part.

Here are two groups I shot with this load earlier in the summer. The top one was in the sprng with the rifle cooled after 3 fouling shots when it was taken from the safe for the beginning of GH season.

CZ223secondgroup-1.jpg


This second group was shot to check the scope after a dissapointing test with 36g Barnes Varmint Grenades. The problem wasn't the rifle!

CA527223w40gNoslerBT-3shots100yards.jpg


I've only been hunting with the rifle this summer, but it's dropped all 18 GH I've shot at with it, OSOK DRT at ranges out to 169 yards. I have to say it is rapidly becoming my favorite rifle. When I reach in the safe it is the that seems to jump into my hand. I'm new at GH hunting (4 years) and just learning to see the GH farther away. Serious fun.

This same load works just as well in my friends CZ527.

The 40g V-MAX isn't quite as accurate with the same load, but it seems to be more frangible so I use it where that property is important.

FWIW, I seldom end up shooting at the published COL. I seat them out to where they shoot well, or as far as I can and still get them in the CZ's magazine, which ever is longer.

Fitch
 
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With that COL they shoot great. I did some load development right after I started loading these first rounds.

Shooting prone, off a backpack w/ 18x I grouped 5/8 and 3/4" with 25.8gr and 26.1gr. All loads previous to that were around 1.25"-1.5". So I've found the sweet spot in powder just curious about the short chamber.

I'm tickled with the accuracy I'm getting and have loaded up some more rounds to confirm. But its been raining here in Wisconsin for the last week. Any break in the rain and I'm bear baiting or working, so not much range time.

I'll report back and see how she shoots next time out. If I can repeat with 5 shot groups instead of 3 I'll be loading up 200 or so to have on hand!

Praying for a great coyote season!
wink.gif


Adam
 
I thought I must have measured wrong so I checked my loaded cartridges in my rifle.

COL was 2.210". I chambered 5 rounds and remeasured them. The bullets seated themselves more. Down to 2.190". So no fluke. I HAVE a short chamber. I think I'll run all my loads down to 2.170" and go shoot. That should be 20 thou or slightly less off the lands as they must have been jammed into the lands to seat the bullets further.

Does anyone else have a short chamber on their rifle?

I'm thinking that since it is a 12 twist barrel they must have chambered it with less freebore for the light bullets?

Adam
 
One more thing, the last batch I loaded and shot was FL sized. This load is fireformed to my chamber. I neck-sized and trimmed only. Didn't know if that would change my groups so I loaded 25.6, 25.8, and 26.0gr of powder. 5 each to see what groups look like from fireformed brass. I can only hope that will shrink my groups up a bit more. This time I will shoot off a bench and maybe run a group under 1/2"! That would impress me a bunch.

This is a used rifle new to me last March. I just started reloading and have only made 40rds so far. I would have to say that my learning curve was shortened quite a bit. Thanks to replies from the helpful members on PM and other sites.

Adam
 
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