Hi all,
I've been resizing some 300 brass and after resizing the bullet drops right through? What gives? I've been using a Lee Collet neck-sizing die. The brass has been fired probably 3 times with a charge of 69.5grs. of H-4831.
Am I missing something here? I haven't been reloading long, but I just don't understand what's up. I've heard that 300H&H brass has a short life span, but I don't know if this has to do with the over-sized neck.

Any clues?

300,

I think you might need to anneal the brass, but a good first step might be to take a thou or two off the mandrel by polishing with fine waterpaper. Do a search on the collet die on this site. I got one for my 300H&H and no problems so far.

Low neck tension is a result of using a collet die.

300 H&H,
If you decide to anneal your brass keep the brass head cool and don't over heat the brass neck and shoulder. By over heating the brass the stuff becomes so soft it wouldn't hold ice cream.
Corbide

Did you set the Lee Die the same? Were the other rounds tight?

Turn the die in some more than last time and try again.

Don't anneal the necks. That's not the cure.

The 300 HH's problem is headspace and web thining. It's nothing to do with the niecks.

I had this all written out, but after thinking about it further I'm going to rewrite it completely.

Let me preface by stating that I load for 2 different 300 H&H's so I have played with them a little.

Yes, as another post mentioned, the 300 H&H does have a serious problem with thinning in the web, followed by case head separations. However that doesn't have any bearing on your particular situation. You problem is in the sizing operation and how the neck is being worked.

First, you need to anneal the necks if you aren't already, but I think that's only half of your problem. I'm not familiar with how the Lee collet dies work so I did some checking around and it appears that your problem is not uncommon and you may need to adjust the die down further. Check out this post on another board for more info.

Good luck.
Tom

http://www.gunboards.com/forums/topic.asp?TOPIC_ID=7336

[ 10-31-2003, 17:13: Message edited by: Kingfisher ]

I just don't agree that necks that have been reloaded three times need to be annealed nor do I agree that annealing will make much difference anyway on the neck diameter or tension.

The Lee dies have a locking nut that uses a rubber O ring to tension them. This makes it very difficult to find where you were the last time.

I mark mine with a pen to match a line on the press. Even then they are a pain. RCBS sells a nice looking brass locking ring and I have replaced some of the Lee rings with those. Come to think of it I am going to get more of them.

Savage 99, even if you don't agree that the annealing is the problem, you have to admit that it's atleast good practice for proper case care/maintenance. It could be that the necks were a little stiff from the factory. I've split necks on brand new cases before just trying to true them up a little. I do know that my 338/378 cases will get to where the bullet just slips in and out of the case after about 4-5 reloads if I don't anneal the necks.

From the stuff that I read on the collet dies, I'd say you are right on the money with the adjustment suggestion. I don't know how they operate but if it's possible to adjust them for a tighter fit/more squeeze, that definitely needs to be done.

Your collet die may not be properly adjusted. It should be set so that the floating collet is pushed fully into the die at the top of the ram stroke -- and pushed home with some bit of authority. To ensure even and firm neck tension, I withdraw the sized case very slightly and rotate it 1/8 of a turn while still in the shell holder, then size again. This takes only a couple of seconds and will make your necks rounder and have a little more tension.

If, after adjusting properly, you still have inadequate neck tension, then your mandrel is oversized and you should reduce it as Pete suggests (or special order a smaller one from Lee).

Your dies are not returning the cases back to specs...I suspect your expander button is oversize and you should chuck it up in a lathe or even a drill press, take a few thousands with a file and smooth it up with paper....that should take care of the problem...

Why you got by three times reloading I have no clue unless you just didn't notice..I have no idea why annealing would cure such an ill, that doesn't equate to your situation.

Ray, the reason I suggest annealling the brass is to take some of the springiness out of it. With the brass unannealled 300 is squeezing down the brass but it is just springing back to nearly its old dimensions, hence the loose neck tension. Annealled brass will stay sized down.

Yeah! Your die isn't sizing the necks down enough! Get a regular full-length sizing die from RCBS or Redding!!

I know this sounds stupid, but are you using the correct sizing die. maybe you grabed the 375h&h dies instead of the 300h&h dies, just a thought. I know I have grabed the wrong dies before and experienced a similar thing to what he is going through. LLB

I actually had a sizing button crack (down the length of the decapping pin) and then spread after working its way up the threads on the decapping pin and bottoming on the pin. Luckily I didn't size too many cases (2) before deciding something didn't feel right while the case neck went over the button.

How tight is the bullet on once fired brass? If it is OK and gets looser the more the case is reloaded it is probably neck hardness and should be annealed. I think the problem is probably a little bit of both, hardness and die adjustment/modification.

I have had to reduce the mandrel diameter on every Lee collet die that I have used.

Hart

Pete,
Correct but I was implying that brass should not be hardening with 3 firings unless it is being seriously overworked...I think he needs a new set of dies...