Case Head Separation

[Lee Goodwin]

Yes sir, be safe, start fresh, newer brass, resize just enough to close the bolt snugly. Start low on powder charge. Be patient, not a patient. There is probably an "accurate node" on the lower side of your powder charge data. Be happy with that.? No mistakes, cause it only takes one...
Throw some rocks.

 

[antelopedundee]

This can happen because when the chamber was opened up to AI the barrel was not set back.That is why it is important that you do what was suggested above and make a false shoulder by sizing the neck up to 6MM and then neck it back down to 22 caliber.You do this in increments until you get a tight fit when you close the bolt.This guarantees proper headspacing.Also using a bullet other then what was shown in the loading manual is a bad idea as it will have a different ogive and and a lot of HP bullets have a thicker jacket so they don`t deform.BR shooters want clean holes in their targets.JMHO,Huntz

He is talking about a T/C Encore which is a break open design and doesn't have a bolt.

One thing might be to create the false shoulder by necking up to 6mm and neck sizing until the case chambers with resistance. Also seat the bullet until it jams. When you close a bolt 100% of the bolt face contacts the case head whereas when closing a T/C action the first contact is with the edge of the case head so upon full close there could still be a little bit of a sloppy fit between the case and chamber.

 

[maximini14]

I was doing some load development this morning with my T/C Encore 22-250AI and had my first case separation in over 35 years of reloading. Brass was twice fired Lapua 22-250 Rem. Load was 40.0 grains of a Varget which Nosler lists as their max load for a 52 grain bullet. I worked up to this load starting at 37.0 grains and saw no pressure signs. Speed was 3,983 from a 26" barrel. Brass was annealed and full length resized with .002 shoulder setback. I checked the remaining brass with a paper clip and felt nothing inside the case that would indicate this is anything other than an isolated instance. Interested in your thoughts. View attachment 203817

Perhaps you should neck size only after fireforming instead of full length resizing....maybe too much headspace causing excessive case stretching and weakening the brass.

 

[Huntz]

He is talking about a T/C Encore which is a break open design and doesn't have a bolt.

One thing might be to create the false shoulder by necking up to 6mm and neck sizing until the case chambers with resistance. Also seat the bullet until it jams. When you close a bolt 100% of the bolt face contacts the case head whereas when closing a T/C action the first contact is with the edge of the case head so upon full close there could still be a little bit of a sloppy fit between the case and chamber.

TCs are noted to have bad headspace from the factory.Mike Bellm has created shims to correct this.How ever bumping up the neck and resizing will accomplish the same thing.That is why rimmed brass works better in single shots as you are head spacing on the rim instead of the shoulder.

 

[Coldfinger]

Good catch Steve. Thanks all for your input.

First time trying Varget in this chambering. Sucks because the 40 grain load put four shots, including the ruptured case, inside .4" at 100 yards with ES of 8 and SD of 3. Also sucks because it took a like of time and components to get to this point, but safety is paramount. Amazed that the shell that burst was #195 of 200 on their 2nd firing. Brass is in the trash and two boxes of Lapua on the way

Just be glad it was just a separation I've got a couple 98 bolts laying around with part of the bolt face blown off!

 

[Gone Ballistic]

Several things here happening. First, you are shooting a 52gn. bullet which is 2 grains over the 50 grain load tested. As a bullet increases in weight the volume of powder decreases. So you are too hot on your load to begin with and this is if your rifle is matched identically with the testing rifle listed in the book. Your cases have been fire formed, and from the way you load to the max, I suspect you fire formed them also too hot. This caused a very fast stretching and stress to the brass coupled with overloaded reloads. I would really like to see your primer on this piece of brass. Question, why do you want to destroy your barrel life using such hot loads when 3400fps will double it?

 

[antelopedundee]

TCs are noted to have bad headspace from the factory.Mike Bellm has created shims to correct this.How ever bumping up the neck and resizing will accomplish the same thing.That is why rimmed brass works better in single shots as you are head spacing on the rim instead of the shoulder.

Even belted cases [where headspace is on the belt] will have head separations if the fit of the case and chamber is too sloppy. I expect it will be similar for rimmed cases under the same circumstances.

 

[Australia]

Take it from someone that has probably loaded and fired over a million 22-250 rounds while commercial kulling there is no need to overload any of these calibres - the only thing you achieve is burnt out barrels - if you havent got the range that a 22-250 has then go to a 7mm rem mag or a 300 win mag and don't over load anything

 

[Hueyman]

Good catch Steve. Thanks all for your input.

First time trying Varget in this chambering. Sucks because the 40 grain load put four shots, including the ruptured case, inside .4" at 100 yards with ES of 8 and SD of 3. Also sucks because it took a like of time and components to get to this point, but safety is paramount. Amazed that the shell that burst was #195 of 200 on their 2nd firing. Brass is in the trash and two boxes of Lapua on the way

I used a lighter load to fire form my brass, also 41 grains of Varget was the max load on my 40 gr bullets so 40 grs seems wrong for a 12 gr heaven bullet, this data was from my nozler number six book, I noticed this when I was working up my 22-250AI, may be nozler needs to redo the load data for that round

 

[antelopedundee]

I was doing some load development this morning with my T/C Encore 22-250AI and had my first case separation in over 35 years of reloading. Brass was twice fired Lapua 22-250 Rem. Load was 40.0 grains of a Varget which Nosler lists as their max load for a 52 grain bullet. I worked up to this load starting at 37.0 grains and saw no pressure signs. Speed was 3,983 from a 26" barrel. Brass was annealed and full length resized with .002 shoulder setback. I checked the remaining brass with a paper clip and felt nothing inside the case that would indicate this is anything other than an isolated instance. Interested in your thoughts. View attachment 203817

Any pics of the primers? I'd try a few more and see if it wasn't something with just that case. I assume since you mentioned using twice fired cases that that one case came apart on the 3rd firing. If you plan on trying for a 4th time, neck size your cases until they just fit in the chamber with a bit of effort.

 

[montana west]

from the looks of your sholder being black mabe your dies are moving the sholder back too far..
so screw them up a round, so the case fit tight in the rifle. and you may never have to change because the same rifle chamber.. I had this problem with a 35 whelen AI AI or Brown- whelen and I changed to 64 mm 280 cases and my problem was solved . but you do not have this option..

 

[just_jon]

No pics but the primers were slightly flattened, but that is typical of my TC even at starting llads. I plan on pulling out my Bellm headspace gauge in the morning. Thinking I may need to shim the firing pin bushing after 4000 or so rounds fired on that action.

I set the shoulder back .002".

 

[nicholasjohn]

Here's one more vote in favor of the "false shoulder" fire-forming method. My reason why is that when just using the bullet jammed into the rifling, you are dependent on neck tension to hold everything tight against the breech face. Maybe that one ( and possibly others in the lot ) was a little loose. The false shoulder that all the other guys mentioned has worked very well for me with the 30-06 AI, but in a bolt gun. It might be a bit of a chore to close the breech on your gun multiple times with the crush fit you'll be getting with the secondary shoulder. Some rubber grip work gloves may be helpful. Good luck, and let us all know how it works out for you.

 

[Don Garlow]

It is obvious from the soot on the shoulder that the case never sealed in the chamber. The brass split well forward from where normal case head separation occurs but others have stated pretty much the same thing. My one additional comment is make sure you check the chamber where the separation occured with a bore scope. If the hot gases pitted the chamber or ringed it, you'll have to set the barrel back and rechamber to eliminate the future compromise of your brass. Future firings in a damaged chamber will cause the brass to flow into the pit or ring and eventually ruin any brass that did not split. I had a similiar problem with a 270 Win and while searching for a solution, ruined the chamber. It only took 3 additional test firings to ring the chamber! SO, be careful. My gun is back at the smiths to correct the problem. Good Luck!