22 K-Hornet ruptured cases

[1raggedhole]

I had a Browning 1885 low wall rechambered to 22 K-Hornet. Bought 500 rounds HSM ammo loaded with 35gr VMax. It all appears to be Win brass. Shot 20 rounds today and half of them are cracking the cases above the web. Even those that didn’t crack look like there is a bulge in the same area. I assume the chamber is too large? Never shot it with standard Hornet chamber, so can’t compare before the rechambering. Any other thoughts/experience?

 

[stacy]

DONT KNOW WHAT WINCHESTER HAS DONE BUT THERE BRASS IS TO HARD AND BRITTLE I HAVE HAD THE SAME PROBLEM WITH REG 22 HORNET BRASS

 

[PigButtons]

I've never tried to Fire Form ( FF ) factory ammo in my K-Hornets. I don't find the proposition too inviting because anything close to even a 3/4 load cracks a large percentage of the cases. In order to fend off case failure when handloading 1) Cases need to be annealed prior to FFing. 2) A 'safe' load needs to be established ( for the cases to survive ). 3 ) ( and this is the only hope you have using factory ammo ) Put a light film of gun oil on the body of the case before firing. It allows the case to stretch more easily against the walls of the chamber ( or at least that's what I think it does; but whatever it does it helps more cases survive FFing. )

I like PVRI cases better than Nosler and much better than Hornady. Recently another member here told me that Remington has the best cases but come to find out they only make them periodically so they are seldom available. The problem with Hornady is the primer pockets tend to run large and even some brand new brass won't hold a primer. Nosler is slightly more prone to case failure than PRVI but annealing ups the percentage of success in both dramatically.

 

[1raggedhole]

I've never tried to Fire Form ( FF ) factory ammo in my K-Hornets. I don't find the proposition too inviting because anything close to even a 3/4 load cracks a large percentage of the cases. In order to fend off case failure when handloading 1) Cases need to be annealed prior to FFing. 2) A 'safe' load needs to be established ( for the cases to survive ). 3 ) ( and this is the only hope you have using factory ammo ) Put a light film of gun oil on the body of the case before firing. It allows the case to stretch more easily against the walls of the chamber ( or at least that's what I think it does; but whatever it does it helps more cases survive FFing. )

I like PVRI cases better than Nosler and much better than Hornady. Recently another member here told me that Remington has the best cases but come to find out they only make them periodically so they are seldom available. The problem with Hornady is the primer pockets tend to run large and even some brand new brass won't hold a primer. Nosler is slightly more prone to case failure than PRVI but annealing ups the percentage of success in both dramatically.

Lubing the factory loaded cases is an interesting idea. I’ll have to give that a try. Thanks.

 

[edwardware]

Even those that didn’t crack look like there is a bulge in the same area.

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

 

[PigButtons]

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

Not necessarily, because the K-hornet spec is very loosely defined compared to most and the variation in wall thickness and the asymmetry of the wall thickness of the cases, a slight bulge just above the base of the case head webbing is not that uncommon. The brand of case also has something to do with it apparently because the Hornady cases show it more than the PRVI or the Nosler in all three of my rifles. It doesn't however affect the case long term, nor does it seem to affect accuracy.

But I do keep the cases separated by rifle and only neck size them, never full length size.

 

[Tommie]

Bad chamber.

 

[biggun2869]

That chamber is the problem

 

[screaminweasil]

Chambers fine....its the brass. Lightly lubing the cases will help.....been there done that....newer winchester brass, same split in 2 different k hornet chambers.....
More info on this very thing can be found on Saubier.com
Myself and others have seen this with newer win brass.....Not older WW headstamps.

 

[JSH]

I don’t quite understand the idea of lubing the case to fire form.
Fooling with TC pistol in 22 Hornet taught me a fair bit. Long enough bullet to hold the case back against the action solved problems.

 

[Geno C]

Lubing the cases let’s the brass slip over the surface of the chamber instead of gripping and tearing then it’s trying to form. I’ve done it with shouldered cases but never a rimmed one

 

[SmokinJoe]

Lubing allows the cases to slip back against the bolt face to help reduce or eliminate case stretch, but I don't know if it would help with the type failure being discussed here. By the looks of the brass, you have maybe a combination of under size brass (diameter in failure area) and an oversize, or at least generous size, chamber. I would recommend trying a few different brands of brass, like PRVI and Nosler to see which brand gives the best result. Since quite a few Hornet shooters seem to like PRVI these days, and it is inexpensive, that is where I would start. Good luck; I have had my share of frustrations with Hornets, too. You just have to work through the problems.

 

[kenacp]

My 2cents. You have sloppy oversize chamber. The bulge is apparent. The split cases above the web are longitudinal, not parallel to to the head. Parallel would indicate case stretching. Not much that you can do about it, except to try some other brass that may be softer. Sell the remaining HSM ammo.

 

[screaminweasil]

Amazing all the guessing, like i said....have seen this EXACT SPLIT

its the brass....lubing the casss will help.

A known issue with win stamped brass in the k hornet, ww stamped.....ie older isnt a problem

 

[1raggedhole]

Thanks for all the input. Here is what I found:
1. Lubing the cases definitely improved the situation. I lightly lubed the HSM ammo (Win cases) with CLP and shot 29 rounds. Lost 5 to splitting (17%). This still sucks, but significantly better than 40% splitting without lubing the cases.
2. Pigbuttons sent me some of his fireforming ammo (Nosler cases, annealed one on the left, lightly oiled), and none of them split or showed any visual bulge above the webbing.

3. Pigbuttons also sent me two cases fired from same rifle, one Hornady (left) and one PPU (right). The Hornady was clearly smaller diameter and shows bulge above the web, while PPU looks like the Nosler, with no sign of bulge.

4. I checked the SAAMI drawings for standard Hornet case and chamber, and measured the loaded and fired cases for comparison. It appears that my chamber is not oversized since fired cases measure only 0.003” under the max chamber dimension.

My conclusion is that Stacy, pigbuttons, and screaminweasle are correct. Lubing cases help the fire forming, and Win cases seem to be a bit too thin or brittle.

 

[Ramblerman]

Thanks for all the input. Here is what I found:
1. Lubing the cases definitely improved the situation. I lightly lubed the HSM ammo (Win cases) with CLP and shot 29 rounds. Lost 5 to splitting (17%). This still sucks, but significantly better than 40% splitting without lubing the cases.
2. Pigbuttons sent me some of his fireforming ammo (Nosler cases, annealed one on the left, lightly oiled), and none of them split or showed any visual bulge above the webbing.
View attachment 1203324
3. Pigbuttons also sent me two cases fired from same rifle, one Hornady (left) and one PPU (right). The Hornady was clearly smaller diameter and shows bulge above the web, while PPU looks like the Nosler, with no sign of bulge.
View attachment 1203325
4. I checked the SAAMI drawings for standard Hornet case and chamber, and measured the loaded and fired cases for comparison. It appears that my chamber is not oversized since fired cases measure only 0.003” under the max chamber dimension.
View attachment 1203327
My conclusion is that Stacy, pigbuttons, and screaminweasle are correct. Lubing cases help the fire forming, and Win cases seem to be a bit too thin or brittle.

Well looky there....next up, world hunger for you and @PigButtons ? Great collaboration! Nicely done gents

 

[chuckshooter]

check the neck clearance.

I had this problem in mine, you need to get the reamer spec from your smith, especially the neck diameter dimension's. there is no such thing as standard in a wildcat cartridge. but there are two "most popular" reamers for the 22k that have different neck dimensions, about .003

tight neck causes excessive pressure.

lubing cases is the same effect as oil in a crankshaft bearing. it creates a thin film between two surfaces thereby actually making the chamber small, nothing wrong with this, but it does change pressure and fps. I have tested it.
just my 2 cents

 

[1raggedhole]

check the neck clearance.

I had this problem in mine, you need to get the reamer spec from your smith, especially the neck diameter dimension's. there is no such thing as standard in a wildcat cartridge. but there are two "most popular" reamers for the 22k that have different neck dimensions, about .003

tight neck causes excessive pressure.

lubing cases is the same effect as oil in a crankshaft bearing. it creates a thin film between two surfaces thereby actually making the chamber small, nothing wrong with this, but it does change pressure and fps. I have tested it.
just my 2 cents

Fired case necks measure 0.245” OD. Loaded rounds are 0.239” OD, so I don’t think there is a tight neck issue.

 

[chuckshooter]

I never liked my 22k hornet, it's now a 20 ackley hornet

 

[chuckshooter]

now that you have some fired brass, The other thing you could check is bullet seating depth. fire forming in general doesn't like bullets to close to the lands, again excess pressure. I lost 1 in 10 when I was fire forming my 22k. PPU factory loaded.