Ok what did I do wrong? Splitting Max brass

[swampcrawler]

Ok guys I loaded up some 180 gr Nosler partitions and went and shot them today. Performance was incredible (to me) about .5 inch 3 shot groups at 50. Shot through 4 and a half inch wet phone book, and the 1 gallon bleach jug behind it.. And 2 1/2 inch boards behind it, and about 3 inches infinite log behind that.

But I had some split cases.

First we fired some of my 158 gr JHPs loaded over 22 gr IMR 4227
Those were fine as expected.

Next were 2 rounds with 180 gr partitions over 21 gr of IMR 4227, but I had crimped these REALLY hard, like I can barely pull them with my kinetic puller, if I can pull them at all. They both split. One about .05 inch from the mouth, split was about .3 inch long. The other split .09 from the mouth and was about .325 long.

I boxed the remainder of those round and shot 7 rounds, same load, lighter but still quite firm crimp. 6 of the 7 were fine, but the last one split in the same mannor as the others.

I'm thinking it has to do with my crimp. (rcbs 357 mag dies)
Should I try backing the seating/crimp die out and turning the seating stem down to get a lighter crimp? (I think these dies taper crimp)

I don't think I'm loaded too hot, as the splitting was far less frequent with the lighter crimp.

I'm so happy with the performance of this load but somewhat heartbroken that it's obviously not safe.

 

[nix4me]

Your lucky you didn't blow yourself up. You loaded a 357 Mag with 180gr bullet with 21gr of IMR-4227?????

Max load is 14.6 in my book.

Your 158gr load is way over max too.

Please don't load anymore rounds until you consult a manual.

 

[swampcrawler]

Also looks like I got some case bulging. Cases are .378 at the mouth, .376 at the base, and .383 about .23 up from the head. Think I just need to knock a little off of my charge.

 

[nix4me]

Please consult a manual before someone gets hurt.

 

[Jesse Heywood]

You loaded a 357 Mag with 180gr bullet with 21gr of IMR-4227?????

NO! It was a .357 MAXIMUM!

 

[rcmodel]

+1!!!!

Your crimp has nothing to do with it.

You are over max with both loads according to latest Hodgdon/IMR .357 Rem Maximum load data.
Cease & Desist immediately!!

If not sooner!!!

IMR shows 22.5 Max with a 160 Hornady Silhouette bullet.

20.0 Max with a 180 Speer TMJ.

But that is Not a Nosler Partition which will raise pressure even more due to the bullet construction.

The partition bullet is harder to squeeze down in the forcing cone & bore.


On the other hand, it is possible your old .357 Max brass is nickel plated, has been reloaded several times, and has reached the useful end of it's life span??



PS: Did you just jump right in with both feet and start out with max+ loads?
Or did you start lower with starting loads and work up as you should have??

rc

 

[swampcrawler]

Lol yes guys it was a 357 maximum, not magnum.

My Sierra manual states a startin load of 20.4 and a max load of 21.2. So I'm actually a hair under max load.

 

[nix4me]

NO! It was a .357 MAXIMUM!

Loads are still too high

 

[swampcrawler]

It's new never fired Remington brass. I didn't realize bullet construction was so much of a factor. My siera load was for sierras 180 gr fmj silhouette bullet. I pulled up IMRs data on their website an it shows H4227 with a 20 gr max for the Speer as said above.

Ok. I screwed up. Thank god my contender contained everything. This Is my first major goof so far in reloading.

What would be a good charge to start with for the Nosler?

 

[rcmodel]

Nosler's starting load.

I just don't know what that is, as I don't have a Nosler manual.

If not that?

Reduce the Max load by 10% and work up slowly, watching for hard extraction, blown primers, split brass, etc!!

rc

 

[swampcrawler]

Thanks RC. Guys I'm beyond embarrassed and humbled by this. Il definitly be more careful hence forth.

 

[nix4me]

I'm not familiar with IMR4227 vs. H4227 - are they the exact same powder?

 

[rcmodel]

No.

IMR 4227 is same as H-4227 only if made in Australia recently.

IMR-4227 used to be made here, and H-4227 there, or somewhere else.

More recently, I believe Hodgdon has discontinued H-4227, and only sells IMR-4227 now.

rc

 

[gamestalker]

Fortunately you were working with a slow burner, other wise things could have gone much worse. Still though, proceed with caution and respect within this hobby, or you'll being learning to work with fewer fingers and eye's.

GS

 

[swampcrawler]

Thanks guys

 

[bluetopper]

Your case splitting has everything to do with too much crimp.

No need for a crimp near that firm in a Contender barrel and especially with good burning 4227 powder. Just crimp enough to not be able to move the bullet by hand when seated. Your brass will last much, much longer.

And your loads are NOT too hot either.....again, especially with 4227 powder and especially in a MGM Contender barrel.

The more 4227 you use the better your performance and accuracy will be in whichever bullet weight you choose.