Just picked up a new NEF 17 hmr Sportster. This is my 1st .17 rimfire so I'm in unfamilar territory.

Gave it a good clean and went to the range to sight it in . All went well.
It shot great with no dramas but after collecting the spent cases (CCI 17gr TNT's) I noticed the base of the neck and extending down through the shoulder on 14 out of 50 cases were split.

I checked where the splits were in relation to the firing pin strike to see if it was happening in one particular spot within the chamber but no two splits were in the same spot.

Could this be the gun or the ammo and is it common with this caliber? I'm a little concerned it may errode the chamber or worse.

Cheers,
Boof.

I have the same gun. Try another brand. I have been using Hornady 17 and 20gr ammo with no surprises. If the problem persists with another brand, send the gun back to NEF.

ZM

i think you have a bad chamber

quote:

Originally posted by Boofhead:
Gave it a good clean and went to the range to sight it in . All went well.
It shot great with no dramas

Were you intending to reload these cases? If so, the split necks are a real bummer. Otherwise, they would appear to be of no consequence.

The chamber would have to be pretty outsized to cause the brass to split as you have described, although like most factory chambers it is likely somewhat larger than necessary. It is more likely that the ammunition is made with cases that are a tad too brittle in the very thin neck area. Try another lot/brand.

quote:

Originally posted by Stonecreek:

quote:

Originally posted by Boofhead:
Gave it a good clean and went to the range to sight it in . All went well.
It shot great with no dramas

Were you intending to reload these cases? If so, the split necks are a real bummer. Otherwise, they would appear to be of no consequence.

Not to be an ass but how exactly is anyone going to reload rimfire ammo.

quote:

Originally posted by mike7mm08:

Not to be an ass but how exactly is anyone going to reload rimfire ammo.

Very carefully

ZM

I noticed the same thing recently with my CZ. Ammo was Hornady 17gr. Cases were splitting in the shoulder area and not all the way to the neck. It didn't happen all the time, it was sporadic, and this was the first time I noticed it. I'm gonna keep an eye on the brass from now on, but I really think it's just some crappy brass.

There are a few threads on this at rimfire central and the general though is a bad run of brass.
http://www.rimfirecentral.com/forums/

Check the 17 HMR and CZ forums.