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CZ 527 Sporter 23.5” / A2460/ 90 TNT’s - Printable Version

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+--- Thread: CZ 527 Sporter 23.5” / A2460/ 90 TNT’s (/showthread.php?tid=24601)

CZ 527 Sporter 23.5” / A2460/ 90 TNT’s - Harpoon1 - 06-05-2022

Reran this test I did last week but I screwed the brass prep up being in big hurry. Cases were too big and really had to cam over the bolt to load them. Both sets of data are very similar, and apparently it had little effect but, i didn’t know that at the time.

So……..

A2460/Hornady Brass/ 205 AR-M primers
90 TNT 2.200” COL
Powder dropped with an Autotrickler to within .02 of a grain
LabRadar
82F/sea level

Brass has 4-5 maybe 6 firings on it.

.2 of a grain increments

Grn/FPS/ES/ SD

32.8/2997/5/3

33.0/2998/10/6

33.2/3016/11/5

33.4 3019/21/11

33.6/3033/16/8.1

33.8/3061/2/1.2. (Only 2 of 3 were recorded)

34.0/3079 single shot

34.2/3077 single shot and first sign of pressure. Faint ejector mark starting to shine

——————————————————————————————————————————————————

33.2 was the smallest group at around .75 MOA, and the rest varied between 1 and 1.5 MOA.

33.2 is a grain less than the pressure sign, POI was consistent the group before and after, along with good ES/SD spread.

I’m going to focus my attention there with a seating depth test to see if I can shrink it a little more.

CZ 527 Sporter 23.5” / A2460/ 90 TNT’s - MOW - 12-02-2023

Harpoon1 Wrote:Reran this test I did last week but I screwed the brass prep up being in big hurry. Cases were too big and really had to cam over the bolt to load them. Both sets of data are very similar, and apparently it had little effect but, i didn’t know that at the time.
How did you screw up the brass prep and what did you do different to fix it?

CZ 527 Sporter 23.5” / A2460/ 90 TNT’s - Harpoon1 - 12-02-2023

MOW Wrote:How did you screw up the brass prep and what did you do different to fix it?

It’s been so long since it happened I’m not positive but, I think I was doing a quick turn around and just used a Lee neck collet die to size the neck. However, I think I used brass from another Grendel, have all three, Ruger, CZ and Howa. So, no shoulder bump with Lee collet die and the brass was a little too snug chambering.