No wonder my CZ 17 HMR groups like crap

One of my goals today - before my chronograph decided to act up - was to chrono three different types of 17 HMR ammo to see which was the most consistent. I had done this years ago when the 17 HMR was still very young (2004 or 2005) and at that time the limited ammo on the market (CCI TNT and Hornady V-Max) had an E.S. typically in the 50-60fps range.

Let me tall ya...that sure isn't the case with today's 17 HMR ammo!

My chrono took a poo while shooting today so I can't download the data from it at present, but reviewing the strings at the range as I was shooting them the Hornady 17gr V-Max ammo had and E.S. of over 120. The CCI 17gr TNT ammo was even worst with an E.S. topping 200. I wanted to chrono some CCI 17gr V-Max as well but that's where my chrono crapped out on me so I wasn't able to.

Now I know why all my groups with this rifle are 1" plus at 100 yards lately - it's the ammo! Each shot I'd look at where it printed in relation to my POI and I could tell you immediately if it was fast, slow, or right in the middle where it should be around 2,550. The fast ones (2625 - 2650fps) would print an inch high, while the slowest ones (high 2400's) would print about 1/2 to 3/4" low.

Was able to get my load data off the Chrono manually (transcription), so here's the data for the 17 HMR ammo. Strings were shot 5-shots at a time then the barrel was allowed to cool for 5 minutes between mag changes.


CZ 452 American 17 HMR - 20" Bbl.
89-degrees; Clear & Sunny
Light SW breeze 3-5mph

CED Data Collector - 7/14/18

String 1 17HMR 17gr Hornady V-Max

1) 2548
2) 2442
3) 2504
4) 2491
5) 2500
6) 2514
7) 2469
8) 2512
9) 2513
10) 2478
11) 2476
12) 2521
13) 2502
14) 2541
15) 2546

High: 2548
Low: 2442
E.S.: 106.0
Ave: 2503
S.D.: 28.8

String 2 17 HMR 17gr Hornady V-Max

1) 2526
2) 2516
3) 2566
4) 2541
5) 2489
6) 2554
7) 2541
8) 2481
9) 2607
10) 2551
11) 2559
12) 2542
13) 2544
14) 2546
15) 2531

High: 2607
Low: 2481
E.S.: 126.0
Ave: 2539
S.D.: 29.2

String 3 17 HMR 17gr Hornady V-Max

1) 2644
2) 2516
3) 2559
4) 2567
5) 2566
6) 2565
7) 2543
8) 2582
9) 2554
10) 2560
11) 2557
12) 2603
13) 2573
14) 2575
15) 2556

High: 2644
Low: 2516
E.S.: 128.0
Ave: 2567
S.D.: 27.6

String 4 17 HMR 17gr CCI Speer TNT

1) 2534
2) 2446
3) 2596
4) 2628
5) 2636
6) 2626
7) 2650
8) 2581
9) 2626
10) 2489
11) 2485
12) 2627
13) 2501
14) 2638
15) 2534

High: 2650
Low: 2446
E.S.: 204.0
Ave: 2577
S.D.: 66.9

String 5 17 HMR 17gr CCI Speer TNT

1) 2654
2) 2637
3) 2673
4) 2649
5) 2655
6) 2683
7) 2686
8) 2685
9) 2658
10) 2657
11) 2673
12) 2696
13) 2493
14) 2525
15) 2669

High: 2696
Low: 2493
E.S.: 203.0
Ave: 2646
S.D.: 56.4

String 6 17 HMR 17gr CCI Speer TNT

1) 2608
2) 2611
3) 2651
4) 2647
5) 2664
6) 2642
7) 2638
8) 2659
9) 2656
10) 2636

High: 2664
Low: 2608
E.S.: 56.0
Ave: 2641
S.D.: 18.2