.17 HMR Problem

About a week ago I took my Contender in .17HMR to the range. I bought this set up brand new and put a UltraDot Pan-A-V Reflex Red Dot Sight on it. Sighted it in at 100 yards and for ever after was able to put most shots in a 2" square.
So all of a sudden my shots are all over the southwest corner of the target. Now this could certainly be shooter error.
The real problem, which has me baffled, is, every second or third (sometimes more) shot the case cracks from the mouth about 1/4 to 1/3 of the way down. I also noticed the shoulder of the case is expanded forward a miniscule but noticeable amount, almost as if the chamber is suddenly too long.
Anyone ever seen this before. Any thoughts as to a cause.
I'm gonna' have my local GS look at it for sure.

Jeff

Have you changed ammo or is this a new batch and what brand? The 17 HMR couldn't hold enough powder to damage a Contender barrel or hurt a frame. If the original frame and barrel are still together then it is most likely an ammo issue. I've had similiar issues with Hornady ammo in other calibers. I would get the lot number off the box and call the manufacturer and see if they have had any problems. The ammo could also be the cause of the accuracy issues although the sight could have been bumped but I would get the case cracking issue taken care of first.

Rod,
I originally sighted it in with CCI. Last week was shooting from the same batch. Was also shooting Remington. Both boxes are more than a few years old and both brands were showing the cracking problem.
I will deffinitly contact the company's.

Just had a side thought. I have been shooting 45-70 using the same frame. I'm hoping that hasn't compromised the frame itself as far as how other barrels lock up. When I close the .17 barrel everything seems to be tight.

Thanks,
Jeff

well it is possible the 45-70 could cause frame stretche but I would expect some misfires in there too. The fact that it's two older batches of ammo throws a curve ball in there for sure. If your local GS is familiar with T/C's and how to properly check headspace I would definitley have him check it. If you stretched the frame even just a few thousandths it could still function but be enough to cause problems with the casings. Is this a G2 or original Contender frame and are you shooting Trapdoor level govt loads or levergun level stuff?

So I called CCI and their tech guy seemed very sharp. By the lot numbers he says they're about 4-5 years old, the Remingtons about 6 years. There in lies the problem. He says b/c the case is basically a .22mag necked down, with age the neck tends to get brittle, therefore subject to rupture upon firing.
He also stated the only danger in using this ammo is if there are prefire fractures.

Obviously I don't get to the range enough. ???????

Apparently you were posting while I was typing.
It's a G2 and I'm shooting Hornady's lever stuff.
As a side note, something I wrote about awhile back concerning the .45-70. I had purchased a box of Double Taps 405gr flat nose cast ammo and found it wouldn't go in the chamber b/c of the wide meplat and as I found out also b/c of basically no throat in that barrel. I plan to eventually have the throat cut to accept these rounds or would you advise against shooting that heavy a load in this gun ?

Jeff

Yea. What velocity does DT claim? T/C frames have been known to stretch from lesser forces.

Yep the levergun loads are best kept for the encore, you can shoot warm loads but a steady diet of heavy stuff will stretch the frame. The G2 will handle it longer than the old frame, as for the Leverevolution ammo I would consider it marginal as it's still a pretty hot load but a lighter bullet. With what the tech told you I might get a box of fresh stuff and see what happens but take a sharpie and draw a line around the top of the shoulder and fire a round and see how much if any it really is moving forward. On a shouldered round that is headspacing off the rim it's normal for there to be some change and if it were a centerfire that's how we would form brass to our individual chamber. If there is alot of change and it's still splitting brass then there may be a headspace issue. If the frame is stretched which I'm really not thinking hard along those lines at the moment there are corrective actions that can be taken by myself and couple other shops that use Bellms parts.

Rod,
Thanks. I'll be getting to Cabelas soon on an ammo run so I'll pick up some new .17's and see what happens.

s4s4u,
Here's the spec's from DT.
Caliber : .45-70 Government
Bullet : 400gr Wide Flat Nose Gas Check
Ballistics : 1810fps - 2914 ft./lbs. - 22.0" bbl. Marlin

Since I don't reload yet can either of you recommend a commercial hunting load in .45-70. I'm partial to the theory behind hardcast. In one side out the other.

Jeff

Yep the chamber isn't long enough to handle heavier longer bullets. It will require having the chamber cut to handle it. I had that done to one of my contender barrels several years ago. Sent it to JD jones to have done.

sorry I didn't respond sooner. Actually those numbers aren't too bad and would be the top end of what I would run in the Contender. If your not running hundreds of them through and with the G2 frame you should be fine. I was concerned you may be running the super heavy stuff like I'm running in my Marlins where I'm running 430gr Trueshots at 2150 out of a 22" barrel and although I need to recheck the numbers my 24" showed 2400fps. Those kind of loads are destructive to Contenders although I ran a similiar load with the old 440 CP through a G2 a few years back. The thing is if you sight in and only shoot at animals or a shot or two to confirm zero you'll be fine. That's the great thing about the T/C platform is you can switch to a 22 barrel and still have the same trigger pull and characteristics so you don't have to abuse yourself or your gun with heavy cartridges and loads.