22 K-Hornet ruptured cases

[PigButtons]

So good to hear that things are moving in the right direction. Glad I could help.

Please keep us posted on any further developments. You do a great job of writing things up.

 

[screaminweasil]

Way to chase it down and actually report back with accurate findings to help others in the future. Great thread and follow up!

 

[JSH]

Huh, the way the brass split I would not think lube would have done anything.

I get the K Hornet is a different critter than the AI.

I was always told, lube on the case isn’t good as it doesn’t let the brass grab the chamber wall and do its job.
I have seen guys do the lube thing with other wildcats, vorgin brass, first firing all but break off at the web from improper fire forming method.

 

[B23]

I get the K Hornet is a different critter than the AI.

I've heard a few say this before. Why is it any different improving a Hornet case to a K Hornet than it would be improving any other case whether it be to an Ackley 40 degree or any other amount for that matter??

 

[JSH]

Never having had a K Hornet, just repeating what I was told. It supposedly doesn’t need the barrel set back and the cases don’t grow like an AI

Lol, we went down this rabbit hole else where.
Take the taper out of the case, it can’t or shouldn’t be able to go rearward, so it will go outward, pulling the brass back from the mouth end. If it moves from the wrong end you get cracks or seperation.
Bottom line it has to come from some where.
AI a case and don’t set the barrel back, it’s not a true AI and now has a longer throat.

 

[Tommie]

AI a case and don’t set the barrel back, it’s not a true AI and now has a longer throat.

Well, except when dealing with cases which headspace on the rim.

 

[B23]

Never having had a K Hornet, just repeating what I was told. It supposedly doesn’t need the barrel set back and the cases don’t grow like an AI

Lol, we went down this rabbit hole else where.
Take the taper out of the case, it can’t or shouldn’t be able to go rearward, so it will go outward, pulling the brass back from the mouth end. If it moves from the wrong end you get cracks or seperation.
Bottom line it has to come from some where.
AI a case and don’t set the barrel back, it’s not a true AI and now has a longer throat.

Not to be a nudge but what if we are making an Ackley Hornet not a K Hornet, does it then change things? Just for my own knowledge I'd like to hear a good explanation from someone why it's "different" when improving a Hornet case to a K Hornet versus an Ackley Hornet.

 

[chuckshooter]

it's hard for me to put my thoughts into words, so I pre apologize if this doesn't come across just right.

In my opinion. fire forming is fireforming whether it's ackley, Kilboun, rimmed or shoulder. bullet into the lands or COW. the goal is to form and expand the brass without failure. most 22 hornet brass is crap and very thin to start with. the ruptures are a sign of to much pressure for the task, the evidence is undeniable, the brass has failed. because of the fact that the op is starting with factory loads, the choice is to find some method of reducing the failure rate (oiling the cases) or pulling the bullets and reducing the load. I have already suggested other things a person can check that can cause increase of pressure. you are not left with many options after that. it's not vudoo , it's pressure

 

[JSH]

I will apologize to the OP for some what of a derail.

I have seen similar results on other Hornet projects and wildcats. Some me lube, some don’t.

I think from my findings, you have got to keep the base of the cartridge up against the face of the bolt/breach what ever the case maybe. I have done false shoulders and bullets jammed into the lands, both with success.
Some will say jamming is dangerous, no doubt it raises pressures. Read up on the JDJ cartridges, on fire forming.
I shot some of the COW loads, once. What I declared a waste of time,primer and powder at least for my purpose. Good fire forming loads were very accurate 9 out of 10 times.

The initial first post in this thread, I still think is a headspace issue. Pull the bullet and jam it or make a correct false shoulder I would bet a cold beer and steak dinner it goes away.

Just because it is rimmed doesn’t mean it will headspace on the shoulder. That is dependent on how much space between the bolt face and the barrel. There are rim thickness issues with different brass. I have a wildcat based on 30-30 case. The rim thickness has to be shaved to close the action.

 

[chuckshooter]

There is one more other possibility. I know it's a little remote or obscure. Do you know for sure the diameter of your Barrel. There are hornets with a 223 Barrel. And there are hornets with a 224 Barrel
I doubt it's a headspace issue. that shows up very fast as case head separation

 

[PigButtons]

There is one more other possibility. I know it's a little remote or obscure. Do you know for sure the diameter of your Barrel. There are hornets with a 223 Barrel. And there are hornets with a 224 Barrel
I doubt it's a headspace issue. that shows up very fast as case head separation

You are absolutely correct about the different diameters for Hornets, but most if not all of the .223 ( actually the bullet diameter required not the bore itself ) barrels were very early barrels that were made in the black powder era of the 22 Hornet. So since the early 1940's Hornets have been made in the .224 diameter. I have one antique rifle and had Lee make a custom bullet sizing die so I didn't have to depend on finding .223 bullets. Now I just buy standard .224 bullets and size them for my old 22K Hornet.

 

[JSH]

Hard brass will hide things with low pressure, I had some virgin RWS cases that had hardened from age.

I am still scratching my head on the lube the way the crack is in the case I would think it was expanding in OD rather than length?

 

[Uncle Ed]

I would not blame your chamber or anything else until you try some Prvi Partizan brass.

If the Winchester cases do not have a uniform case body wall thickness the case will bulge on the thin side. Meaning you could have defective brass that is causing the case splits.

Lubing the cases will increase bolt thrust up to 50% more than normal. And over time this can increase your headspace faster than normal.

P.O. Ackley did an experiment with a 30-30 improved cartridge in a Winchester 94. He made sure the cartridge and chamber were dry and oil free and removed the rifles locking bolt. The rifle was remotely fired and nothing happened, the cartridge case gripped the chamber walls and never contacted the bolt face. No kaboom, and no damage to the rifle with only the primer protruding from the base of the case. At 38,000 cup or 42,000 psi the chamber pressure was not great enough to make the case stretch and contact the bolt face.

I do not have a Hornet but I do use Prvi Parizan brass in my .303 British Enfield rifles because of its quality.

Below both cases were fired in the same 1943 No.4 Enfield .303 rifle. The Privi case on the left has thicker rims, a larger base diameter and .010 thicker in the base web area.

I fire form my .303 British cases by slipping a thin rubber o-ring or a small rubber band for braces over the case.. This holds the case against the bolt face just like a false shoulder or seating the bullets long and jamming them into the rifling.

Below I was using .312 pistol bullets with reduced loads of SR-4759. Today you can use Train Boss powder if you do not have any SR-4759.

You can also seat a fired spent primer in your cases with just your fingers. And then chamber this case and let the bolt face seat the primer. The amount the primer is protruding is your head clearance or the air space between the rear of the case and the bolt face.

Note, on a Enfield rifle at max military headspace of .074 and a rim thickness of .058 you will have .016 head clearance.

Below with a resized case and minimum shoulder bump you would have .001 to .002 head clearance.

Bottom line, before you blame your rifle get some good quality brass. And this will not be Winchester brass, case diameter, and chamber diameter effects case expansion.

A RCBS Case Mastering Gauge can be used to measure case wall thickness and the quality of your brass.

 

[Tommie]

There’s some very good information here..and some “not so good” as well. This thread is on the verge of becoming another pissing match.

To the OP-
If you haven’t read volumes I & II of PO Ackley’s handbooks, now is the time to dive in. You’ll find the answers to your question.

Peace out.

 

[searcher]

If you do a casting of your chamber, a lot of the "guessing" here will be answered in short order. Your chamber could have been egged out oversize enough to cause a problem - and that would have been due to VERY careless rechambering. If the neck is undersized, thereby crimping the bullet - causing high pressure - that would have entailed using the wrong, undersized reamer. Possible, though a bit unlikely. A call to the gunsmith that did the work - if possible - could verify the possibility if he can merely measure the neck on the reamer. Chambers can't shrink smaller than the reamer. It is just as plausible it was not throated enough to prevent hard bullet contact with the lands- thereby increasing pressure significantly on full-power factory ammo. If there is a possibility your problem is to do with your chamber, this is the first thing I'd look at. Either put black magic marker on a round and load/unload to see if there appears to be any contact with the lands or use a tool (like Hornady's) to measure how deep your bullet can be seated before it contacts the lands - then measure your factory ammo to see if it is long enough to make contact with the lands - which it should not. If there is evidence of this - that is very likely your problem. As hand loaders, we'd never want to take a book max charge and jam it without trying at lower powder charge. But this may be the very situation you have with factory ammo having bullets seated too long for your chamber. My bet is that your chamber is not compatible with your ammo. You just need to do a process of elimination. If it IS the throating - that is a very simple and inexpensive fix. I'd neither fire or discard your ammo until you determine this.

 

[chuckshooter]

It is certainty not my intentions to start a pissing match or hurt someone's feelings, I thought I could be of some help. here's a picture of my PPU brass after firing factory loaded PPU 22 hornet in a perfectly good 22k hornet chamber. similar results


to quote Forest Gump "that's all I have to say about that"

 

[PigButtons]

Chuck, wow! Thanks for sharing that pic. My Fire Forming failures are usually just below the shoulder but look the same otherwise. I've never tried factory ammo in my K's.

 

[kenacp]

I have two Hornets. A TC Contender "K" by Bullberry,(known for their tight chambers) and a Browning 1885 "standard. The K will work fine with Win & Rem brass. Factory PPU will sometimes split at the neck. Maybe 10% failure. I then anneal fireformed brass and have no issues. That tells me the PPU is not too thin, just too hard and brittle. The 1885 standard Hornet does just fine with all three brands of brass. Have Hornady brass too, but have not tried it yet.
I would be willing to bet that I could shoot your ammo in either of my guns resulting in no splits or bulges.
If you can, do a chamber cast as searcher said. Then measure both the casting and your intended ammo. Brass will only give so much if it is unsupported.
Not saying lubing it won't work for you......just don't like the bulge.(Have one like that from MGM in 30-30AI)

 

[kenacp]

Sorry, I should have said PPU splits at the neck/shoulder junction.

 

[TAJ45]

I think that bit of data answers it. If the cases are bulging, especially asymmetrically, the chamber's oversized or egged.

Do a cerrosafe cast and measure. My first thought was egged chamber.
But, from the majority of what I've read, the Hornet is finicky on many fronts.