7mm RM splitting necks 2 firings

[Buckreed]

Hey guys,
Looking for some help. I'm getting split necks at 2 firings. Here is some info.
Savage 110 action
Criterion Barrel 1:9 twist
Winchester Brass
CCI 250 Magnum Large Rifle Primers
68.0 grain of RL26
Berger 180 Hunting VLD
3010 ft/sec
Full length sized brass before and after first firing. RCBS dies
No annealing

No pressure signs (heavy bolt, loose or flat primers, etc.)

 

[Jud96]

Measure the outside diameter of a fired case neck, the outside diameter of a loaded round, and the outside diameter of a sized case neck.

 

[Buckreed]

10-4 give me 10 min and I'll post what I get.

 

[Buckreed]

Fired Case Neck 0.315
Loaded Round Neck 0.309
Sized Neck 0.307

 

[Jud96]

Hmmm that's odd. You're not overworking the brass. How old is the brass? Is it brand new? Or is it old? How long was it loaded before you shot it?

 

[J E Custom]

Fired Case Neck 0.315
Loaded Round Neck 0.309
Sized Neck 0.307

That is within the limits and should be ok.

Many ammo manufactures stopped annealing there cases during the ammo crunch and have not returned to this step. I recommend annealing all factory loaded ammo after the first firing or buy new cases with annealing heat marks.

Case brass comes from the mill annealed for forming the cases. this process work hardens the brass and it needs to be annealed again before or after polishing. years ago, we liked to get our brass shiny, so they polished it as the final step. now they just polish it and don't do the second anneal very necessary for case life.

I look for this sign that it has been annealed or anneal it my self. this is just one brand that it is very obvious.

Prvi Partizan Ammo 300 Winchester Mag 165 Grain Pointed Soft Point

Since 1928, Prvi Partizan has been producing custom ammunition in Serbia for competition, indoor ranges and big game hunting. This ammunition is...

www.midwayusa.com

J E CUSTOM

 

[Buckreed]

Hmmm that's odd. You're not overworking the brass. How old is the brass? Is it brand new? Or is it old? How long was it loaded before you shot it?

The brass is a couple years old. Haven't had time to shoot this particular rifle. The rounds that split were only loaded for about a week before firing so I don't think they bonded at all.

 

[Buckreed]

That is within the limits and should be ok.

Many ammo manufactures stopped annealing there cases during the ammo crunch and have not returned to this step. I recommend annealing all factory loaded ammo after the first firing or buy new cases with annealing heat marks.

Case brass comes from the mill annealed for forming the cases. this process work hardens the brass and it needs to be annealed again before or after polishing. years ago, we liked to get our brass shiny, so they polished it as the final step. now they just polish it and don't do the second anneal very necessary for case life.

I look for this sign that it has been annealed or anneal it my self. this is just one brand that it is very obvious.

Prvi Partizan Ammo 300 Winchester Mag 165 Grain Pointed Soft Point

Since 1928, Prvi Partizan has been producing custom ammunition in Serbia for competition, indoor ranges and big game hunting. This ammunition is...

www.midwayusa.com

J E CUSTOM

Thanks for the advice. I have always used Winchester brass. No reason way just one less variable I suppose. I do not remember seeing any annealing heat marks when new. Do you think that even without the original annealing it would split with just 2 firings? If yes, than it sounds like I need to start annealing.

 

[WeiserBucks]

I've bought new Winchester brass in the past and 10% of the BRAND NEW brass in the bag had split necks. Junk.

 

[jpd676]

I've had bad batches of 7rm Win brass. I had about 50 out of 150 split the necks on the first firing in a new Criterion barrel. It was pretty frustrating.

 

[J E Custom]

Thanks for the advice. I have always used Winchester brass. No reason way just one less variable I suppose. I do not remember seeing any annealing heat marks when new. Do you think that even without the original annealing it would split with just 2 firings? If yes, than it sounds like I need to start annealing.

I used a lot of Remington brass for the rifles that i could not get Lapua, Norma and DWM brass for and never had any problems with them until the ammo shortage and then I noticed that the new 375 RUM cases were splitting all of a sudden ,so I ran some hardness test on the new cases and some brand new "Older purchased cases" and found the newly manufactured cases were very hard compared to the Old cases so I started annealing all new cases and the problem went away.

There are 6 to 8 forming steps depending on the type of case, so this is like firing the case 6 to 8 times unless it is annealed. When a case splits in this location, it is normally because the brass is to hard. so now I anneal "ALL" cases when they are new just to make sure unless they have the hear marks from annealing.

J E CUSTOM

 

[Buckreed]

I used a lot of Remington brass for the rifles that i could not get Lapua, Norma and DWM brass for and never had any problems with them until the ammo shortage and then I noticed that the new 375 RUM cases were splitting all of a sudden ,so I ran some hardness test on the new cases and some brand new "Older purchased cases" and found the newly manufactured cases were very hard compared to the Old cases so I started annealing all new cases and the problem went away.

There are 6 to 8 forming steps depending on the type of case, so this is like firing the case 6 to 8 times unless it is annealed. When a case splits in this location, it is normally because the brass is to hard. so now I anneal "ALL" cases when they are new just to make sure unless they have the hear marks from annealing.

J E CUSTOM

Thanks. I will start my research on annealing and also try some higher quality brass too.

 

[Rhett Crider]

I've bought new Winchester brass in the past and 10% of the BRAND NEW brass in the bag had split necks. Junk.

Same here. It's cheap brass so I use it for breaking in barrels then switch to best available. Inspect before loading.

 

[fiftybmg]

Anneal all the brass, the problem should go away.

Annealing is simply enough done without fancy tools.

Brass anneal by hand.

I've tested this method, and use it successfully on all my rifle brass.