Home Forums Hunting & Shooting Rimfires Chrono'd a 17HMR today

Results were a little unexpected. The 20" fluted bull barrel from Green Mountain and a Spectre II supressor gave higher average velocities than the published velocity on the three different loads I fired.

Hornady 17gr V-Max (2550fps), I averaged 2641 fps out of 19 rounds with a low of 2515 and the highest 2713fps.

Norma 17gr Vmax (2560fps) I got 2614 out of 5 shots.

CCI 20gr Game Point (2375fps) I only fired three rounds and got 2496, 2518, and 2395.

I guess I'm not used to actually getting higher than published velocities. Anyone else have similar results? Maybe I have a fast barrel? Suppressor make the difference? Screwed up chrono?

I wish I would of ran them thru without the suppressor as well.

My apologies if this has been discussed previously.

Every 17hmr chronograph reading that I've ever seen has averaged higher than on the box numbers. I've been watching them for 7 years. Try some CCI A17 rounds. They are the hottest I've found. It narrows the gap between HMR and WSM.

Did you have any split necks? That seemed to be an issue for a while. Just watched a video from the UK yesterday where the guy complained about it. Was trying another ammo and still had it happen. POI with the split ones was off, besides the obvious downside.

Seems a lot of guys like that A17, including our benefactor Mule Deer.

Split necks on regular HMR or the A17?


No telling how much regular I have shot in the last 20+ years, cannot recall a single split neck.

Thanks for the replies.

My experience is the split necks were due to certain batches of ammo. I "collected" over 10,000 rounds of .17 HMR ammo in between various shortages whenever I found it at lower prices, and the only ones that split were some from an older batch of Hornady 17 V-Max Varmint Express. This started happening last summer when Eileen and I were doing a lot of "gopher" (Richardson's ground squirrel) shooting on a rancher friend's land.

The cases split in both her new Ruger American and my 20-year-old CZ 452, but tended to stick in the chamber of the Ruger, while I had no problems in the CZ, perhaps because the CZ's chamber has been slicked-up by a lot of shooting. Anyway, the split cases were all from the same lot#, and we only had a few boxes left--so I just kept using them in CZ, while she switched to another lot# in the Ruger.

As for this thread, .17 HMR "standard" 17-grain ammo chronographs right around the advertised 2550 fps in both rifles, while A17 goes around 2850--which is 200 fps more than advertised. This might be due to using it in bolt-rifles rather than the Savage A17 semi-auto, but dunno.

I reserve the A17s for shooting prairie dogs, which are much larger than gophers, and the extra zip makes a noticeable difference, both in killing and trajectory. The A17s shoot to the same place as the Varmint Express at 100 yards in both rifles, but land about 4" higher at 200 yards. Accuracy is also excellent with either kind of ammo in both rifles.

There's been discussion here in the past about, IIRC Hornady ammo, which was also mentioned in that video. That guy decided to try Winchester, and quickly had some splits with that as well in his CZ 452. I know formerly all HMR ammo was made by one outfit, then Winchester started making their own at one point, but in today’s world, who can say who makes what or where components are sourced. Definitely a moving target, and all the consolidation of brands there’s probably more cross-pollination going on than ever.

With a nice, accurate .22 Hornet in hand, I’m probably not a serious candidate for any of the .17 RFs, but I think about it now and again.

Yes,one lot of Hornady Varmint Express from about 5 years ago would split necks. The same lot would also push the bullets into the case fully, allowing powder to spill into the action. It was a pain to clean out of the lever action. The split cases did not stick in any of my chambers.

I have a Savage 93R17 BVSS I purchased a couple years back and a Tikka T1x .17 HMR. Both of these rifles have produced split necks and with various brands of ammo. It seems to be worse with Winchester. However, I've also seen it with Remington and Federal. I realize there are supposedly only two producers of .17 HMR. However, I've relegated split necks to being a .17 HMR issue and how they can't anneal after neck down due to priming.