I have a .244 H&H Magnum bolt action rifle. I have some old brass for this which is burden primed with powder loads not cordite. I have also bought some new cartridges from Kynoch (boxer primed ofcourse) for this as well as new brass from their supplier in Germany.
The problem with the new brass is that it is tight when closing the bolt - when the lugs start locking - The extraction is also delayed till after the chamber has cooled down. Its not excessive pressure nor high velocities and noth these are as the same as the old brass.
With the old brass I have no problem.
I have cleaned the chamber etc. and there does not seem to be much grime there which will block this.
Please advise me as to where I should look to solve this problem.

Sounds like the new brass wasn't formed right and is to tight. Or maybe anealing the complete new brass case may help it to form better in the die. Measure the old ones and the new shot ones and see if they are the same after firing. May have to back off the load on the new brass but I think they are not forming right.

The dimensions seem right - The problem with the new brass actually starts before firing and even after firing, the brass on reloading does not go into the chamber smooth. The load is not the problem - Its something related to the brass. All the measurements in terms of brass length, thickness etc. seems to be Ok.

If you have to allow it too cool to get extraction whatever the problem is its creating high pressure..Lots of things can cause pressures to jumb even a bullet touching the lands can run pressure up...somehow you are creating a headspace problem in the process of what I will refer to as fireforming that case.

I would first take a cast of the chamber and compare that to the cases you have...they I would resize the cases and fireform them with a dose of whatever and cornmeal in all probability...

The only way you will arrive at the correct answer is to take tht chamber cast, and thats an easy and inexpensive thing to do....

The brass goes in tight at the beginning and post firing it needs to cool down - The presures seem ok but its something with the brass.
What is the best way to do a chamber cast ? ources where I live a limited unlike in teh US

Omer,

What are some other details such as rifle type, brand of brass, reloading dies and so on. Do you your dies include a full length sizing die. Do you load the new cases as they come from the packet or do you full length size them first

When you say you have to wait to it cools to extract, how hard is it to extract if you try and extract straight after firing.

On the surface it sounds like a combination of a dimensional problem (the hard chambering) and shit brass that does not spring back.

Mike

Hello,
I would wager that your new brass is oversized for your chamber. Yes, you can take a chamber cast, or you can measure the datum line on brass that does not stick vs the new brass and believe you will find the shoulder is not pushed back enough with the new brass. Stoney Point sells items to measure the datum line-halfway down the shoulder and back to the rear of case- You will need a caliper to measure this, but believe that would tell you quickly if the brass is the problem.
Favor Center!!
dsiteman

I resize the new brass before reloading - Will try a full neck resize again and see if it helps pushing the neck down a bit. The brass is original Kynoch - the same as is used in the .244 H&H Magnum by Hollands. I am actua;ly surprised with having a problem with the brass - Specially when you consider the cost of the damn things.