I fired 20 rounds today from my 25.06 that i had left from last season and noticed that after shooting them about 7 of the cases had split necks. I know for a fact that they weren't split before i shot them. Afterwards i checked some previous fired brass and found about 5 out of roughly 30pcs that also had split necks. All the brass is Remington and the loads aren't hot. What is the main cause of split necks? Thank You! Mike

How many loads on the brass?

craig,
At least 3 loads on the brass and everytime was sized full length.

The case necks were work hardened outside the brass elastic range. Not pressure problem. The solution is to anneal the necks about every two-three reloads. Also, factory ammunition may not have had necks annealed, especially in the less expensive products.

You must have gotten a hard lot of brass. I typically load brass cases 8-12 times without annealing and I replace them when the primer pockets start to feel loose. I get maybe 1 split neck out of a bag of 100 cases before I throw them away.

I have had the occasional brand new piece of brass split at the neck but I assume that it had a defect to start with.

quote:

Originally posted by Fjold:
You must have gotten a hard lot of brass. I typically load brass cases 8-12 times without annealing and I replace them when the primer pockets start to feel loose. I get maybe 1 split neck out of a bag of 100 cases before I throw them away.

I have had the occasional brand new piece of brass split at the neck but I assume that it had a defect to start with.

Pretty much the same here. I'd just use the brass you have until the neck splits and shit can it when it does. Then buy yourself another lot of brass.

You did not state the rifle. I have noticed that my 308 Tactical Ruger expands brass much more than my match 308 rifles. The match rifles are cut with commerical reamers, nothing real special. What must be going on is that Ruger is cutting chambers with a special reamer. One that ensures that no one is going to have an overpressure event due to a pinched case neck.

You may have a rifle cut with a large reamer. When case necks are expanded, they are workhardened. Sizing them back workhardens them again. The more workhardening, the sooner they split.

I once had case necks split from a box of 300WM factory ammo.They were the Winchester/Nosler combined technologies failsafe molly-coated 180 grain rds.They were shot from a new Sendero rifle.These rds had plenty of recoil and hot velocities compared to most of the 300WM factory offerings.The cases were split from the necks down to the shoulder.They were also the least accurate rds I ever fired from a rifle.They shot so bad that one bullet would strike near bullseye at 100yds and the next would miss the target completely.When I replaced them with Remington core-locts I got key hole groups.