Split cases..........?

[Bill M.]

I seem to be splitting a lot of cases in my .41 mag. Cases sorta pull apart over a broad area like the metal is too thin. I do not know exactly how old the hulls are or how many times I have reloaded them. What should I be looking for? Is it worth measuring the cylinders? Is there a way to measure a sized case to see if it is too small? Or maybe just start over with new hulls and keep track of what is happening? Up until today it has been old factory cases and I have been dumping the headstamps it occurred in. But today it was a Starline case and that had to have been new and not reloaded many times I think. Load is 8 gr HP 38 under a 210 gr Nosler. Extraction is easy and smooth unless the case splits.

 

[Dewey 68]

Are you putting a lot of flare on the case mouth before seating the bullet?

 

[Bill M.]

Not much. Loading jacketed bullets. The split occurs down in the body of the case. The mouth is generally still intact.

 

[edwardware]

Splits at the mouth? Brass is work hardened from flaring, crimping, repeating. Normal failure mode for heavily crimped revolver brass.

Longitudinal splits mid-case? Brass is work hardened from sizing, expanding, repeating. Less common, and indicates too much difference between your sizing die and chambers; not really any good fix except looking for a not-so-undersized sizing die.

Other splits? At this point I've seen every split I can imagine, and I few I couldn't.

 

[tightgroup tiger]

The only thing I can really say about it is when .327 FM first came out I had only factory cases to reload and I could split as many as 7 out of 100 cases every time I shot it.
They were almost split stem to stern.

I then bought 500 .327 FM Starline cases and I have split 1 case in 5 years. And it was with a low powered load. I wonder if the brass they use to draw their cases with sometimes have hard spots in them the they split rather than stretch.

You may have gotten the one Starline that was going to split already. You can mic your cylinder if you want, but you will need an expanding hole gauge to do it.
I got a set of these at MSC back in the 1980s.
You can use them with a set of dial calipers but micrometers work best with them. You would have to check them against SAAMI chamber standards to see if the chambers are in spec.

I use nothing but Starline brass in my .41 Magnum and I haven't split one yet but I probably will some day. I have never had factory brass to shoot in it so I don't have any thing to compare my Starline brass against in .41 Mag, but I did with the .327FM and Starline was a Major improvement with one piece in 5 years.

But, you will always split one now and then, even with the best brass. The chamber dimensions can be found here.

https://saami.org/technical-information/cartridge-chamber-drawings/

 

[buck460XVR]

I'd start with new brass and see what happens. Could there be a possibility that your brass may have been exposed to something that may have deteriorated it? Any chemical with ammonia solvents in it can cause "Season Cracking". Storing ammo close to bore solvents and cleaning rags is the most common culprit. The cracking then turns to split cases when fired. You might have oversized chambers which means there ain't much you can do except live with it or put a new cylinder on. Using an oversized sizing die will mean little or no neck tension which will give you other issues.

 

[noylj]

I find that no cartridge has cracked cases like .38 Spl or .357 Mag. Worst of the worst are .38 Spl and .357 Mag nickel-plated cases.
I always considered cracks along the length of the case more indicative of inclusions in the brass than anything else, and magnum loads just acerbate the issue.

 

[Ru4real]

Well, it might be inclusions in the brass. But I think more likely it is because each firing makes the brass harder, weaker, less ductile, more brittle and less tough because of rapid heat and cooling and work hardening when the case expands and contracts creating stress in the brass.

The cases are splitting, cracking and pulling apart along the built up stress lines in the brass. You can anneal the cases to relieve the stresses if you want longer case life, say after 5 firings.

 

[tightgroup tiger]

I have pistol brass that I have been loaded since the late 1980s and loaded hard. I have been shooting these same 500 cases every week for 30 years. Mostly .357 Magnum and they are still alive an kicking. Most of what I have had to throw away was because of loose primer pockets. I split very few, maybe a 10 over the last 30 years.

I would hate to speculate how many time my original Winchester .357 magnum brass has been reloaded. To say it needs annealed after 5 reloading is ludicrous.

This isn't bottlenecked, high pressure brass, it's straight walled pistol brass. Yes some will split over time but most of my non-nickeled .357 brass is still alive and doing well and I load to above midrange for practice and full bore for some practice for hunting in both .357 and 41 magnum.

My favorite .41magnum load is 19 grs of 2400 with a 210 grain XTP. It shoots like a lazer out of my 57 Smith.

As soon as my 500 210gr Nozzle JHPs get here from RMR bullets I'm going to start a work up with H110 to see if it's any more accurate than the 2400 load is with the same bullet.
I'm not worried about my .41 magnum Starline cases.

 

[Bill M.]

Thanks very much for the replies. And for posting the link to the dimensions. While cleaning tonight I did some measurements. My chambers are about .436. The chamber specifications are for .4368 plus or minus .004 is the chamber is well in specifications.

I have a few Rem factory loads. They measure almost the same diameter as my reloads. Maybe my loads are .001 tighter but you would have to measure a few and average to tell the difference. The SAMMI drawing says .434 for the cartridge and both my reloads and Rem factory are .428 to .429 so there is something that I do not understand from the drawing. And .434 would not go into a .437 minus .004 chamber. I guess I missed the tolerancing for the cartridge.

Any way I am going to load up new brass and watch it for a while. I will use all the old brass for Trail Boss and Bayou Bullets.

I personally have not seen many split cases in my .357 loads.

Thanks to all who responded.

 

[tightgroup tiger]

Ru4real has something going on that I don't understand if he is splitting .357 and 38spl brass. I wish he would post his problem in a new thread so we can help him get to the bottom of it.
I've never even heard of a 38 SPL brass splitting. I'm sure some will that are defective, but I don't shoot enough of it to know.
@1KPerDay would be a good one to comment to this problem. He shoot a boat load of 38 SPL.

 

[Ru4real]

To say it needs annealed after 5 reloading is ludicrous.

I’ve never annealed pistol cases either, many reloadings. Rifle, yes. I’ve had 45 Colt cases split, starting at the neck after about 10 reloadings. But I have thousands of 45 colt cases, so I just toss the splits. I’ve never split a 38 special case but I’ve only begun shooting 38 special.

But the OP sounds like he wants to save his cases, and annealing is one option to try. Splitting, cracking and separating occurs along stress lines in metal, that is fact. OP says his cases are pulling apart. Why?

 

[Obturation]

I mentioned it several times on this forum but I'll comment that starline 454 casull cases split pretty regularly, it's not either of the guns or the loads used as I have some federal cases that have been loaded at least 11+ times and haven't had a single one split. Starline is good brass but sometimes they have issues too.
I've split 357 cases but my 357 brass has been loaded many many times, I'd bet some have been fired 30+ times, I don't worry too much about it, never caused any problem.

 

[Ole Joe Clark]

I shot this one and later noticed the split. I don't think I can reload it again.

Have a blessed day,

Leon

 

[tightgroup tiger]

I just figure it's bad brass but if it has hard spots in it or the chemistry is off in the alloy or tempered too hard to start with, it's going to split.
I would be afraid of defeating the neck tension if the pistol cases were over annealed. That would cause different issues like bullet set back and you don't want to go there.
Especially in .41 Magnum.
See how far that split goes down the case in the picture above. If you tried to anneal down that far you would ruin the integrity of the strength of the case head.

I wet clean my brass and dry them under an inferred heater in my garage at about 338 degrees as indicated by the stick on, indicating strip I use to get the height of the pan right.

I leave them in there for an hour to dry and I often wonder if that has any effect on why I don't have a brass splitting problem with my reloads.

Or it could be I've already picked out the bad ones that split when they were new after the first firing. Who knows.

Note:
I accidently left a batch of .357 Magnum brass under the heater over night and they are a pretty shade of blue when I discovered it the next morning.
I put a timer on the heater that same day.
I checked the temp later with my Fluke temp meter and verified the temp.

Like I said, I don't know if this is why my brass doesn't seem to split after I use this process or I'm just lucky. Brass isn't supposed to change it's structure until it hit 400+ degrees but I've never read or seen anything on a temp vs time affect and I don't have the equipment to do the experiment to find out. And how would I find a bad piece of brass that is going to split, but hasn't yet, to use in the experiment any ways. You don't know it's bad until it splits.

It just works for me and I'm happy with it.
The heater came from Lee Valley Tools many years ago. They still sell them. When I left PA to go to North Carolina I took them with me and I'm glad I did.

I wouldn't put them in a kitchen oven to try to anneal them, ovens fluxuate temperature to much and you could ruin them. I know this from cooking with my Thermoworks temp probes in there, This heater I use stays a constant temp and doesn't cycle.

This probably isn't the answer you want but it's all I have for you. By the way that bluing on the brass never came completely off from dry tumbling them and it was weird that it only affected the mouth of the case and not the head. I am still loading and shooting them, they work fine.

The only other thing I could recommend trying is using an M-style expanding die so you don't accidently over flare the mouths on your cases. That may help you with neck splits but if your using lead bullets they will scrape lead sometimes on seating because they only expand enough to get a bullet started.

I have used an M-Die in station two and a traditional flaring die in station three to stop the M-die from scraping when using oversized lead bullets and not over flare but you have to trim your brass to make that work. This was with .357 Magnum.

Edit to add: Well that sucks! Lyman doesn't make a .41 magnum die set or an M-die for it.

 

[Blue68f100]

On nickle plated brass I always wondered if there was some cleaning solution that was not removed, embedded in a flaw. With it being trapped it continue eating till exhausted. Once fired the brass has weak spot to fail. But with that said, I've seen it on normal brass too. Which leads me to thing there was a flaw in the brass prior to expanding. I think mfg are trying to squeeze every penny they can and cutting corners to save cost. Their goal is to only last the firing the first time for factory ammo.

 

[Bill M.]

The picture by Ole Joe Clark is exactly like what I am getting. Some numbers: New Starline cases=.434". My resized cases = .428 to 429 inches. Factory Rem loads = .429". Fired cases = .436 and slide in and out of the chamber easily. So the issue would seem to be there is a lot of working of the cases. As someone above pointed out there is probably no remedy. Everything seems to be in actual specs.

Are there different sized sizing dies available for revolver cartridges? Probably it would be cheaper just to buy new brass and discard it after a couple of loadings. My plan now is to load jacketed bullets in new brass and after 1 reloading to switch that brass to the cowboy action level loads until I get a failure in a batch. I am definitely going to do a better job of batching and tracking empties.

Since the calipers and the gauges are lying out on my bench now I will probably check some measurements on the .357 just to see how much better it is. The only split cases I have had for .357 were some Rem nickel.

Measure some .357. For the .357 I am getting about .005" expansion during firing. For the .41 mag I am getting .008" expansion.