Seems like the chamber must be oversized a bit on my ZKW-465. ALL fired rounds (including Winch., Remington, RWS) grew about .006" just above the rim recess. But, look at the photos of the Hornady Varmint Express cases after firing the V-max 35 grain. A couple of the cracks went almost the entire circumference.
Note: The case at the top is a RWS case fired in the same rifle.
Anyone else experience this issue? This is a first for me.
P.S. I emailed Hornady the lot number with a description to see what they have to say.

STOP!!! Rechamber or rebarrel or re-something. roger

It's a bit hard to tell, but are the primers on the 3 blown cases in the second photo protruding noticeably?

I'm also curious as to the diameter of the fired cases at the expansion ring (where they're cracked ). I have a CZ Hornet and mine expand to about .295" with moderate loads in Remington brass.

Cases (RWS at top of photo included) all measured .2975 to .2985 at the widest point just above the expansion line and all primers were flush with the case with crisp edges and no distortion.
I may grind off a couple brands on the fine emery belt and compare the case thickness and go from there. Seems like the Hornady cases are thin or too hard.

It seems that your chamber is about .003" larger than mine, which probably shouldn't be a huge big deal. My other thought and the reason I asked about the primers, was possible excess headspace. This, combined with a bit larger diameter might lead to something like this: firing pin drives case forward, hot load really "sticks" brass to chamber wall. Case expands a bit more than "normal," weakening a bit in the process. Pressure then "pistons" the base to the rear more than spec due to excess headspace, splitting already weakened brass.. Does this sound plausible?

A quick way to check this might be to fire one or two lightly oiled cases (will slip rather than stick) and see if separation still occurs.

Plausible for sure H47. Yet, in the event a case is moved forward, a driven forward case condition suggests that the primer would move rearward by the same amount. Headspace seems to be fine.
I compared the case length of unfired and fired cases in several brands used in this rifle and although the Hornady were a thou or two longer than the rest, there was little difference between new and once fired brass.
***I discovered last night that case diameter on fired and unfired Hornady's on the rim side of the expansion joint were about .003" less than the other brands. I'm inclined to think this is a quality control issue which might just be specific to this batch. I doubt that this alone is the straw that broke the camel's back. I'm leaning toward a combination of four factors that contributed to the failures.

1. Undersized case.
2. Slightly oversized chamber. (still under Saami and CIP maximum)
3. Higher pressure load (assumed).
4. Inherent thin wall of .22 Hornet cases.

A possible fifth: brass too hard.
Crazy notion on a sixth: really fast twist.

Might check another batch of the Hornady's elsewhere. Until then OR some word from Hornady, this one gets standard velocity loads only.

Thanks.
CB

quote:

Originally posted by H47:
It seems that your chamber is about .003" larger than mine, which probably shouldn't be a huge big deal. My other thought and the reason I asked about the primers, was possible excess headspace. This, combined with a bit larger diameter might lead to something like this: firing pin drives case forward, hot load really "sticks" brass to chamber wall. Case expands a bit more than "normal," weakening a bit in the process. Pressure then "pistons" the base to the rear more than spec due to excess headspace, splitting already weakened brass.. Does this sound plausible?

A quick way to check this might be to fire one or two lightly oiled cases (will slip rather than stick) and see if separation still occurs.

A few thoughts......

A "stretching" case wall will re-seat a backed-out primer.

Headspace, on the hornet case, is the rim thickness.

A lengthwise sectioning of a case, will show whether the case datum point is thinning, due to case stretching.....or failing due to case cracking/over-pressure.

Hope this helps.

Kevin

I had a hornet do the same thing excessive head space is your problem.

Thanks for the input everyone. Since I don't have access to a go, no go gage set I'll just add thin tape to the head to see if it snugs up at all.

You don't need a no go and go gage, you need to return those cases and the gun back to CZ, you, my man, have a BAD chamber, end of story..They will install a new barrel at no charge I'm sure.

tape ain't gonna fix that no way no how.

measure your fired cases they are telling you the story here.
now if you could make the brass from another case and fit it to the rifle you'd gain some serious capacity.
but I don't see that happening.

get a new barrel.

Might be that the brass is saami minimum so it will chamber in ALL chambers.

quote:

Originally posted by Atkinson:
You don't need a no go and go gage, you need to return those cases and the gun back to CZ, you, my man, have a BAD chamber, end of story..They will install a new barrel at no charge I'm sure.

Ray's right! Head space gages won't show you what's wrong with that rifle. roger

quote:

Originally posted by Atkinson:
You don't need a no go and go gage, you need to return those cases and the gun back to CZ, you, my man, have a BAD chamber, end of story..They will install a new barrel at no charge I'm sure.

The Brno ZKW-465 hasn't been manufactured for many years (mine is a 1949 model), so I doubt that CZ-America would do anything in regard to a 60+ year-old rifle imported by one or another company which is long out of business.

These little Brnos are famously well-made, but it is certainly possible that the headspace is out of kilter. It is also possible that the lot of ammunition is the problem. How about checking the ammunition by firing it in another Hornet?

By the way, I was shooting my Brno Hornet just yesterday and almost had to giggle when the first shot from a cold barrel went exactly through the center ring of the target. The set triggers on these are just heavenly.

Gentlemen,

I'm not the greatest writer, I'm sure. But, here are my thoughts in a nutshell.

The rifle was made in 1967. I don't own a CZ527. Would be good to try these round in one with safety glasses of course. My BRNO (pictured below) shoots 3 major brands with no issues although groups are only around 2 inches at 100 yards. When compared to Winchester, Remington and RWS ammo, the Hornady's were the only ones that failed.

Only the Hornady 135 grainers opened up their case or distorted the case. So, first things first, I compared measurements on the NEW Hornady's to all 3 other NEW rounds and the other 3 were consistent in size. Only the Hornady's were different. They were about 3-4 thousandths undersized in length, shoulder width, base width and possibly the rim thickness although those were hard to measure because of the tiny rim. All fired cases were within SAAMI specs and essentially the same within a thousandths or two including the failed Hornady cases. So, essentially the Hornady cases "grew" more than the others because they were undersized to begin with. The ONLY unknown here is the powder load. IF and only IF the Hornady loads are loaded to higher pressures, then this COULD add to the other deficiencies. Add in the inherent thin walls of the Hornet case and there's one more potential shortcoming. I think the failures were caused by a number of shortfalls that on their own seem slight. But, added together, the end result is a failed case. 3 failures out of ten is quite poor. The other seven rounds were likely almost at the point of failing as well. ALL Hornady cases were distorted. None of the other brands showed any signs of stress.
After a bit more research, I found out that only 80% of the Hornady Hornets are actually made by Hornady. The rest are farmed out to who knows who, who knows where. That isn't necessarily a bad thing. But, one still has to wonder.

ABOUT the tape on the head of the round.....this is a technique I heard about for years and wanted to try to check for excess headspace. Theoretically, adding additional layers of tape until the round chambers with the proper resistance and then measuring the thickness of the tape will give a person some idea of how severe the shortfall is.
I realized that this technique is not suitable for checking shoulder head space on "rimmed" cartridges when you would only be checking the rim thickness for an undersized condition.

It made total sense to check bolt resistance with the understanding that the shoulder should be snug against the chamber. I tried all 4 brands of new ammo from the aforementioned manufacturers and paid close attention to the resistance when the bolt was turned to its' final closed position. Three of the four rounds had the same (what seemed like normal) resistance like my other bolt action rifles. Only the Hornady rounds gave no resistance. Sounds like excess headspace at the shoulder Or a undersized rim.
It sure quacks, walks, waddles and takes a dump like a duck.
I may try some from another batch sometime. In the meantime, I'll use the other stuff for plinkin'.

Excellent idea by the way. Wish I had one to try.

quote:

Originally posted by Stonecreek:
How about checking the ammunition by firing it in another Hornet?

.

quote:

My BRNO (pictured below) shoots 3 major brands with no issues although groups are only around 2 inches at 100 yards.

That's probably pretty typical accuracy for Hornet factory loads. Try some handloaded 40 grain spitzers and I'll bet your little Brno will shrink its groups to less than an inch.

Loaded to the proper (modest) pressures, Hornet brass will last forever if you use a Lee Collet die to resize. This will also allow the little case to headspace on what tiny shoulder it has (yes, Virginia, the Hornet does have a shoulder and fireformed brass will headspace on it.) Taking any slop out of the rim headspacing helps most Hornets.

Replies following ***.

quote:

Originally posted by Stonecreek:

quote:

My BRNO (pictured below) shoots 3 major brands with no issues although groups are only around 2 inches at 100 yards.

That's probably pretty typical accuracy for Hornet factory loads. Try some handloaded 40 grain spitzers and I'll bet your little Brno will shrink its groups to less than an inch.
***Good to hear that 2 inches is the norm...I'm sure it would improve with hand loads. I just have little interest in hand loading to make it shoot since it is a novelty to me, not a hunter. Cool little mini Mauser.

Loaded to the proper (modest) pressures, Hornet brass will last forever if you use a Lee Collet die to resize.
*** We're on the same page there as well. I'm sold on neck sizing on fire-formed cases.

This will also allow the little case to headspace on what tiny shoulder it has (yes, Virginia, the Hornet does have a shoulder and fireformed brass will headspace on it.) Taking any slop out of the rim headspacing helps most Hornets.
*** Taking any slop is the way to go for many calibers. Thanks for the input.

My TC Contender did almost the same thing, not as bad though. I had case head separations only after loading them a couple of times. I now only size the top quarter inch on the case and after many hundreds of rounds never another one.

The Zkw465 was known for this, usually an issue with thinner rimmed US brass compared to Euro brass ie a headspace issue. It's why many were K'd. In your case, just avoid Hornady brass! Bores were also 0.223" upto a certain point. Mine was a fussy think to shoot well, very bench sensitive to how it was held. Best accuracy always came with traditional 45gr semi RN pills at 2600-odd fps. My Browning ABolt is easier to live with in that respect.
Cheers...
Con

Thanks Con. I'll take your opinion under advisement. Speaking of ZKW-465's...I have a question for you.
Do you think that in 1948, quality may have been the best that year? The reason I ask is because most all positive reports on this rifle were from the 1948 build. I think 1948 was the highest production for this one. My rifle was built in 1967 and I don't have a 1948 model to compare it to. CB

Ream it to "K" Hornet & headspace off the shoulder?

wildcat junkie--I thought of doing just that or even having the barrel set back one thread and then reamed and head spaced for RWS ammo. I just can't see the expense of any machine work as I don't intend to hunt with it. I'll just use standard velocity ammo for plinkin' until I get bored with it or run out of ammo. I had fun making it feed anything I put in it and learned a lot about these little guns and the magazines and of course variations in Hornet ammo.

It is going to be hard to get bored with. I absolutely love both of mine. I can't think of a better gun for ground squirrels than a Hornet. Now I am shooting a Barnes Varmint Grenade 30 grain bullet. Oh I know that the ballistics are horrible but inside 100 yards they take a ground squirrel in half. All that with 12-13 grains of powder. My Contender shoots everything I have tried into an inch and a quarter. The mini mauser is about the same but they are both minute of squirrel. Fun little guns.

quote:

I emailed Hornady the lot number with a description to see what they have to say.

What did they have to say? Looks like a bad batch of ammo to me. Did you ever grind/section any of the cases? I'd bet the hornady is much thinner with a sharp inside corner where you're seeing those cracks.

I'm also curious about your rifle custombolt--I've never seen one up close. Are they still being made? It seems like feeding a rimmed hornet round from a magazine would be tricky.

Well I suppose one could probably fireform the cases with a mild load, in other words wildcat it!, but that IMO is a band aid...or rechamber to a .218 Bee perhaps?? not sure.

I would return the gun and cases to the maker and tell;em to fix the damn thing so I could shoot factory ammo in it..

I found out many years ago the best thing one can do with any 22 Hornet is Improve the chamber (I like Ackley), it saves a ton of grief and its so simple you can do it with your fingernail!! ..and its a dandy round. The other option is getcha self a .222 Rem..Its the berries!

might be able to have the chamber bumped up one thread. if you go with a k-hornet you can get a set of wilson 22 hornet dies and have the smith ream them to k-hornet.the cases are so soft you can neck size & seat bullets with the heel of your hand. i did this with an a-bolt and it works well and the rifle is very accurate.