17 Mach2 overpressure...

[std7mag]

My neighbor just got a great deal on a Marlin in 17Mach 2.
For those who don't know, this is essentially the .22Stinger necked down to .17. It is .10" longer than standard .22LR.
Shooting Hornady factory 17gr. ballistic tips.

Gun/cartridge accurate as all get out.

Problem is that about 10 of the 50 cartridges we shot had the casing crack from the neck about 1/2 way down to the rim.
When I say crack, I mean split open, as in you can see inside the casing.:eek:

Has anyone else experienced this???

Kinda scary that it's factory ammo!!

Std7mag

Staff, please feel free to move as you see fit. I didn't know where to start this thread.

[wild willy]

Split cases are pretty common in 17Hm2.Go toRimfireCentral the 17 hm2 ammuntion forum plenty of info

[std7mag]

Was scared it was just us... :rolleyes:

[Mobuck]

There may be some issue with the chamber but both 17M2 and 17HMR have problems with neck splits. I use a Green Mountain 17M2 barrel on a modified 10/22 and have not seen any splits. It may be a difference between the closer tolerances with the GM barrels or better quality control of the earlier production Eley ammo.
Unless there's gas coming from the bolt/chamber area during firing, it's probably not a safety issue. Always wear glasses when shooting these little hotrods.

[Magnum Wheel Man]

I do a lot of shooting with an old Marlin bolt action converted to 17 Mach 2...

OP didn't mention if it was an auto, or bolt, factory, or custom, or the brand of ammo... but I'd venture to guess, that auto chambers are a bit looser to allow the light bolt to fully chamber the next round... I've never spit a case yet, using a chamber reamed with a reamer I bought from PTG... also did a Contender barrel with that reamer, so no split cases in several 1000 rounds in 2 guns...

I use almost exclusively Elley ammo, as I bought 8 - 10 bricks of it several years ago... been holding off on extra shooting, hoping this rim fire cartridge back log passes... this rifle has put down uncountable numbers of raccoons, & red pine squirrels though

[std7mag]

Stock Marlin bolt action with stainless varmint barrel, laminated stock.

Factory Hornady ammo...

[wild willy]

I've had my .17 HM2 since they first came out mine's a Savage. Most of the neck splits are with Hornady I never had any trouble with Eley or Remington (made by Eley) I don't think I had any splits with Federal.But now you have to shoot what you can find.