I'm gonna have to send my Henry back. It is a .22 magnum and I've owned it for about 5 months - less than 300 rounds down the bore. Yesterday it went crazy - CCI 40 gr bullets went from 1" groups to 12" clusters. Federal 50grs began key-hole strikes at anything beyond 10 yards. I already knew it wouldn't shoot Hornady 45gr bullets - they key-hole too.
Others I know with Henry have had the same issue - either the twist rate is wrong or the bore size is wrong. In any case it now has to go back to NJ for them to figure out what's gone wrong. I hope to see it again later this year...I suppose I'll have to pay postage both ways and miss the state silhouette match in May.
I didn't buy a rifle to shoot only one type of one brand of ammo.
On the other hand my Henry 24".22LR is an upgrade from that cranky 39A I used to own.
Having mixed feelings about Henry today.
I have a big loop short carbine. Installed a cheap scope and at 50 yards can keep cci minimags within a half inch group. Very nice smooth operating action and lever. The only problem or dislike I have with the gun is its not blued. Has some kind of cheap black paint that I have managed to scratch off on one side of it. It is a very inexpensive gun though so not complaining.
All the .22 mags I own prefer one ammo over another. They usually either shoot the lighter or heavier bullets, but not both. I have one that shoots sub moa all day with the old Winchester Dynapoint .45 gr. And of course, they discontinued the ammo. The 50 gr federal game-shock shows promise, but the POI is different. The maxi mags are ok out to 50 yards, but more like a 2-3" group. All the 35gr poly tips are a waste of time.
Another shoots the poly tips well, but heavy bullets won't group.
I went through several .22 mags thinking they were inherently inaccurate before I learned they are very ammo biased.
If it shot one inch groups and then changed, I would be looking for another variable than the rifle. Especially if I switched ammo.
Have a standard Henry in 17 HMR. Half inch groups at 50 yards is no problem with a Redfield 2-7 scope and I am only an average shot. Read somewhere online that 17 HMR generally was more accurate than 22 mag because ammo for 17 is manufactured to more consistent specs. Never owned a 22 mag rifle so that may just be BS.
Barrels don't get shot out in 300 rounds. Is it scoped? I have had scopes lose zero, have had a couple with reticle problems. One, the reticle was floating around inside the scope. I will say any 22 WMR shouldn't keyhole, ever. Something is amiss.