Lapua .284 brass problem

[expiper]

Post # 16 is spot on your resized dye and your chamber are not working in concert together. Remember there is more to achieving proper cartridge fit to the chamber than headspace. The cartridge must fit radially as well as longitudinally for proper brass life and sealing of the gas inside the chamber of the rifle. I have used Kiff Reamers for many years with much success while using Redding full length bushing type S dies you need to do a lot of measuring and figure out if the chamber is too big or the dye is too small compared to virgin brass as Dave says the smoke on the outside of the cartridge case is a dead giveaway. There's too much clearance and probably not enough pressure. You can't just mindlessly squeeze cartridge brass into some random dye and say the bolt closes on my cartridges so they must be OK and not end up with problems like this. ...Roger.

 

[MikeRu]

Did you check headspace measurement when the brass was new? I’ve seen brand new brass be say .006” to .007” shorter on headspace vs a different lot and or vs a different brand.

That doesn’t mean the brass is bad.

So from what I’m getting out of it is the brass is stretching more for some reason and or being worked to much on resizing after firing.

What powder charge are you loading it to and what bullet are you loading? You gave your velocity and you don’t think it’s a hot load etc… But that doesn’t mean it‘s not.

I’ve run the 284win with what I will call hot loads. I pushed it hard and after 3 firings the Lapua brass primer pockets you could tell where getting loose after those three firings. I wouldn’t use the brass after that. Again doesn’t mean the brass is bad… I was just pushing it to hard in this case. I’ll guarantee my loads were past 65k. Probably more around the 70k to low 70k range.

You could have a combination of things going on.

Later, Frank
Bartlein Barrels

Like Frank said—what bullet?

 

[Dave M.]

So Dave, I’m just getting into 284 Shehane, my first experience with a wildcat, necking up, fireforming, etc.
Let me see if I’m grasping this, you jam into the lands on seating and use a reduced load to avoid overpressure when fireforming?
My experience so far was all pistol, 308, and 6.5PRC.
Thanks,

Ray

I typically run 2gr less than my standard charge when fireforming, unless I need the brass to be fully formed after one firing (which is very difficult) in which case I will run my standard load.
Dave

 

[Jvance513]

Reviving an old thread. I’ve been having the same problems. 2 different reamers that I own, two different barrels, but same lot of brass. Last year I was having the same problem the brass showing signs of separating and one had separated at roughly the .600 line. At first I thought it was a reamer problem. Had a custom die made also but it was still happening. then a friend of mine who is a very accomplished f class shooter designed and released his print to me, and I’m having the same problem still. This is my last year on this lot of brass then I’ll go to a new lot and see if it continues. Just wondering if anyone has chalked this up as anything else other than bad brass. I’ll noted that I’m a seasoned benchrest shooter and am very detailed in my loading process when it comes to brass prep especially.

 

[SKWERLZ]

Reviving an old thread. I’ve been having the same problems. 2 different reamers that I own, two different barrels, but same lot of brass. Last year I was having the same problem the brass showing signs of separating and one had separated at roughly the .600 line. At first I thought it was a reamer problem. Had a custom die made also but it was still happening. then a friend of mine who is a very accomplished f class shooter designed and released his print to me, and I’m having the same problem still. This is my last year on this lot of brass then I’ll go to a new lot and see if it continues. Just wondering if anyone has chalked this up as anything else other than bad brass. I’ll noted that I’m a seasoned benchrest shooter and am very detailed in my loading process when it comes to brass prep especially.

How much is virgin brass expanding on base to shoulder datum upon firing?

 

[FeMan]

If you are having incipient case head separation you are, or have in the past, set the shoulders back too far. Did you interchange brass and barrels? That will do it unless they are headspaced exactly the same.

 

[358WCF]

Slightly (or more) short new brass can be ruined on the 1st firing in a max chamber if the brass is at min. headspace. Thinking that the "breaking point" could be as small as .005". False shoulders &/or jammed bullets can be your friend on the 1st firing.

Once the ring starts things dont heal themselves down inside the case. I also see many instances where people measure their once fired brass & subtract .002" from that dimension. I believe it's an infinitely better plan to wait until the bolt has some feel when closing after a couple... 2-3 or more full power firings... to do this while either neck or partial FL sizing in the interim.

Here & other forums (fora?) have at least weekly questions or rants about case separations/bad brass. The misunderstanding of this, by "experienced" reloaders is hard to believe. It's not pressure. It's ever so rarely bad brass. It is mismatched manufacturing tolerances &/or poorly written die set-up instructions coupled with misunderstanding. Even after 30 years, you still dont know what you dont know.

There was an article in the bulletin last week that I think should be a sticky.

Understanding Cartridge Headspace — What You Need to Know « Daily Bulletin

This illustration shows headspace measurement for the popular .308 Winchester cartridge, which headspaces on the shoulder. Image copyright 2015 Ultimate Reloader. In this Brownells Tech Tip Video, Brownells gun tech Steve Ostrem explains what headspace is and why it's one of the most critical...

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