Resizing FL - Belted Magnums

[maltbuck]

Starting to reload for 300 win mag (factory chambering) and 338 win mag (custom) and reading up on the "issues" encountered with belted magnums, and looking for some advice please.

 

I realise "best practice" is to headspace off the shoulder and not the belt. But my question relates to possible case expansion in front of the belt after a couple of firings, thus preventing/impeding chambering/extraction.

 

Does this really happen to any great extent, and is it necessary to look at getting resizing collets such as the Larry Willis belted magnum resizing collet/die?

 

Many thanks, from a slightly confused

 

MB

[terryh]

MB

 

When I loaded 300WM for an AI AWM I used one of Larry's (rather nice) dies.

 

The die also had a gauge function at one end which allows you see the amount of expansion ahead of the belt and therefore decide what you should do sizing wise. I used it as part of my loading regime.

 

It is a nice tool to use and does exactly what it said on the tin!

 

If you are looking for load data for the 300 then Uncle Sam paid for a lot of development work for this round then published the findings

 

Brgds Terry

[Foxshooter]

I shoot a 300winmag and would say without a doubt buy the Larry Willis die. It will pay for itself in recovered cases without a doubt. One of my better purchases.

 

Yes the cases do expand and chambering will become a problem, regular resizing dies will not work the brass far enough down towards the belt, there is nothing more embarrassing than getting a loaded case stuck in the chamber on the range, if you choose not to buy the die make sure you carry an old cleaning rod or similar in your vehicle/bag to hopefully hammer it back out from the pointy end. If that doesn't work the riflesmith will probably charge you more than the cost of the die to do it for you!

 

Mark

[Hatzi]

I just set my die to bump the shoulder a thou, im on about 8/9 firings and never a problem. In my non AI AWM. Im dveloping enough pressure to launch 208's at 2850fps and 180's at about 3050fps.

 

Dies are plain jane RCBS

[Andrew]

The US Army's Comp team back in the Seventies/Eighies used the 300WM and their head gunsmith, a man named Thomason, retired to teach at a good gunsmithing school in Colorado. I was in his office one day and we were discussing the issue of headspacing off of the shoulder instead of the belt. He swore by it and had comparative 300M targets to prove it. They shot handloads and never reloaded their brass, but he opined that the area ahead of the belt would need to be swaged back into shape after a few firings using this method.~Andrew

[Laurie]

Yes, it definitely happens. I had a .300 H&H Mag on a P'14 action some time back with a 'tight' Norman Clark cut chamber. I only ever neck-sized the brass with a Lee Collet die - worked very well indeed with 180s at ~3,000 fps from a 30-inch barrel, not super-hot.

 

After a couple of firings you could feel the brass get tighter with each firing so that by the 4th, 5th at the outside, it took noticeably more effort to chamber and it was a cleaning rod job to get the case out. The P'14s massive Mauser style claw extractor had loads of grip on the case and there was no danger of overstressing it - it still couldn't get these cases out, just tore through the extractor rim leaving a big ragged gap in the outside edge.

 

Primer pockets were still tight so it wasn't a case of excessive case-head expansion, apparently affecting the belt itself and the case-body just above it.

[maltbuck]

Thank you all for the clarification.

It looks like I will be contacting Larry and buying one of his dies - assuming one die will cover both calibres.

 

Kind regards,

 

MB

[Foxshooter]

You will probably need one die but a seperate collet for each calibre

 

from memory.

 

He is a nice guy to deal with

 

Make sure you get yourself some Redding Imperial Sizing wax, you will find it an essential item and cheap too

 

 

I just set my die to bump the shoulder a thou, im on about 8/9 firings and never a problem. In my non AI AWM. Im dveloping enough pressure to launch 208's at 2850fps and 180's at about 3050fps.

Dies are plain jane RCBS

 

This doesnt size the case just in front of the belt though, which is where they eventually swell and stick in your chamber. I only ever neck size my brass but have to run it throught the collet die when required.

 

 

Mark

[fizzbangwhallop]

Thank you all for the clarification.

It looks like I will be contacting Larry and buying one of his dies - assuming one die will cover both calibres.

 

Kind regards,

 

MB

Just read the instructions with my LW.... quote :

1) This collet die is universal and it works on all belted magnum cartridges (except 224, 240, 378 and 460 Weatherby). There are no extra collets required. Before each use, be sure that the die and collet are ABSOLUTEY CLEAN - especially the slots on the colltet.

 

Cheers

 

Fizz