This one I don't get - I simply can't find the reson why!

I'm loading 200 brass of .300 win mag.

83 of them are made by PMP and the rest (=127) is made by PMC - the difference I don't know.

I have trieded them like one bach, full leght sized in the same die (Lee) with the same seating of the die.
I've trimmed them to 2,610 ince.

But now the triagy part - the PMC cases chamber well in my rifle and the PMP doesn't - why?

Some of the PMP I can close the bolt on - but then I have to use alot of violence to get them out! But the main part I can't even close the bolt on even with violence.

The brass' should all have been fired once in the same rifle - but not mine. So everything but the brand is eqaul for the brass'.

I can't measure any difference on the PMP and PMC even with the micrometer.

Help - what is happening here?

Mads

[ 09-02-2002, 19:43: Message edited by: Mads ]

I haven't loaded PMC or PMP, but had the same problem with a .300 Win. mag one time. I loaded 40 rounds without checking to see if they would chamber in my rifle. A few did, and most didn't. My sizing die liked a hair being screwed down far enough, and tha cartridge was not being sized next to the belt.

Mads I suggest you can smoke the case and try to chamber to look where the case hit the chamber , PMP are on the HEAVY side , it means a lot of brass ( weight and compare ) maybe the neck it's a bit thick and hit the chamber , should be no problem with belt as it was fired ( or you have a minimum headspace and the brass it's on the maximum ) try to smoke different areas until you find the spot , on my 7 x 64 I need to reduce the shell holder 0.1 mm on a sharpening stone to have complete resizing in some fired cases .
Saludos

Daniel

[ 09-02-2002, 18:46: Message edited by: Daniel M ]

Seems you have a loose chamber.

PMP is Pretoria Metal P... Rep of SA

PMC is Precision Made Cartridges ??? South Korea?

Perhaps a small base die? An interesting problem.

Hermann

Now I have been smoking three brass over a candel. What they showed didn't make me wiser.
they showed that the brass actually in apr. � of the leghtwise area was in contact with the
chamber - from neck to belt!?

I tried sizing the brass once more - so much that my loading bench tipped - so I can't size them
more in my die. And the brass' stil wouldn't chamber in my rifle.

Hermann - how is this showing that I have a loose chamber?

Regards

Mads

Hola Hermann why you think a loose chamber ? I understand if it is on the maximun side he can chamber any 300 winch cartidges , maybe a tight chamber min specifications and maximum Lee dies ?.

Saludos

Daniel

Lets say that my rilfe has a min. chamber and my die is on the max. dim. Would both brand of brass not be set back to the same outer size?

I have never exsperinced this with my .300 win and the die and I have only use the two together?

Mads

Measure the neck diameters of loaded rounds (with the bullet in the neck)....I would bet the rounds you are having trouble have a larger diameter due to thicker necks. If you have a tubing micrometer you can measure the actual thickness of the brass in the necks. Another check might be the differences in the weight of the brass before it is loaded.

It could be both:

loose chamber and rounds not sized enough - the weaker cases will give troubles?

max die - the stronger cases will give trouble ?

On rethinking it might be a case neck thickness problem.

Keep us informed about your results. Good shooting

Hermann

Mads

PMP and PMC brass is NOT the same !

PMP brass is made in South Africa and has the thickest case walls you are likely to find on any cartridge case. PMC cases have very thin walls. Both work fine, but as the case volumes are not the same, the same chargeweight will not give the same results.

As to your problem with chambering them...

Some time ago I posted a reply on a thread regarding problems a guy had with resizing .243 ammo. There I explained how I went about solving my problem.

It could be that your dies are not sizing the PMP brass down enough because they have such thick casewalls. One way of getting the cases deeper into the resizing die is to reduce the length of the die.

Johan

OK - now I have done what Bill tolled me !
The results are listed below and I guess that they confirm Bill and Johans statements.

PMC:

weight of brass and primer in grains

256,5
256,5
255,0
258,0

neck diameter of loaded roound in mm

8,49
8,49
8,50
8,50

PMP:

weight of brass and primer in grains

282,0
281,5
281,6
284,5

neck diameter of loaded roound in mm

8,52
8,52
8,51
8,51

So I must conclude that the PMP brass is much heavy than the PMC.

First that can cause thet the neck is so thick that it can go in my chamber (eventhough the neck is less
than the standards I can find for the round????).
Second the brass can be so "solid" that sized in my maybe large die, It will be bigger than my chamber
made to smaller standards? The latter can be proved or measured with my tools.

But what can I do about it? Is the only way to solve the problem really to shorten the die?

Hope that you stil will be able to help me out on this?

Mads

By the way - I don't think and have never done so - that the PMP and PMC are teh same brass!

Hola Mads , first you need to know where is the problem , if the problem it's on the thick neck you need to turn the necks to dimention , a reduced die no solve the problem , also if you don't want to touch the base of the die in a lathe , you can reduce the height of the shell holder 0.1 mm you end with the same result , I suggest you to measure the neck of a fired case from your rifle then you'll see if it's enough space to allow expansion on the neck of the fired case ( maybe your tight chamber is at the neck 8.50 mm OK for PMC not for the PMP thick neck )

Saludos

Daniel

After clearing the neck thickness:

if you want the cases to go deeper in the die ( take care of headspace!! We are talking tiniest amount here! ) DON`T touch the die. Take a minimum amount off the top of one shell holder. Mark this shell holder! Its cheaper to throw away a shell holder than a die!

Hermann

Sorry Double post

Daniel

[ 09-04-2002, 13:15: Message edited by: Daniel M ]

mads, the ammo was fired in another gun not yours. That may be the problem.

Mads,
the neck diameters are below those stated for this round. That does not mean that the problem does not lie there. You may have a very tight chamber. If you have access to a supply of ferrosafe, it would be a good idea to take a chamber cast. It shrinks a minimal amount on cooling and will give you the best idea of your chamber dimensions. A fired round is a second best alternative. It has to be related to one of those areas, you just have to find out where. I just sold a neck turning set up but only because I did not use it. The brass problem if that is it is not worth that kind of investment and grief.

Good luck to you, hope you find the problem.

Chic

New informations......

I have measured some loaded Norma brass, which I normaly use and they measure 8,56mm
in the neck. That'll say that they have a thicker neck tahn the PMP brass's that will not chamber.
Therefore I must conclude that the neck isn't to thick on the PMP brass.

Next I tried to resize the same PMP brass twice and two out of three would then chamber with
out problems. This must lead me to the conclusion that the PMP brass is so massive in construction
that my die can't size them enought. But if I have to size every brass 3 - 4 times before it will chamber in my rifle, then I guess that the brass have hardened so much that it will not make a another reloading?!

I guess that I can try making the shell holder thinner - but then again I think that I'll stay away from the PMP in the future.

Regards

Mads

Mads - try and anneal the necks before you resize.

I clamp a piece of 4.5mm steel rod in the vice, angled slightly upwards. Aim my Gaz blowlamp at the place where the shoulder of the cartridge is going to come and when the wire is red hot I slip a cartridge into position and spin it with my fingers.

The finger-temperature at the rim will tell you when its time to flip the cartridge off the wire and into a bucket of water that is standing just in the right position.

I judge the time to anneal by the amount of soot that collects on the outside of the neck of the cartridge after firing.

First firing after annealing is absolutely clean - by #3 there is a bit of sooting - when the soot reaches the shoulder - out with the Gaz blowlamp.

nice problem - good luck edi