300 Win Mag FL vs Shoulder bump

[Bee3440]

I am getting ready to start loading for a 300 Win Mag and I was wondering what everyone suggests for dies. I was thinking about trying the Forster bushing bump die to try and save brass life by not constantly resizing the whole body. This will be the first belted case I reload for so any personal experiences would be much appreciated!

 

[Dgd6mm]

I prefer a FL Sizing die.

 

[Walt Krafft]

Full length bushing die. Get a bushing to just size the neck as much as you need. Adjust the die to just bump the shoulder.

 

[alchemist]

Remember, there is no full length sizing die that will size the case just above the belt. Bump the shoulder. When you end up with any cases that will not chamber, measure the case immediately above the belt. If it exceeds 0.512 inches, a collet die is sold by Innovative Technologies (larrywillis.com) that will solve the problem but it is expensive ($119.99) but does work.

 

[DaveTooley]

You have to FL size to prevent the brass from work hardening at a larger diameter, which then creates extraction problems. Once work hardened, FL sizing gets the brass back into the chamber but does not alleviate the extraction issues. FL size every time.

 

[Woofie]

I have a Redding neck sizer with inserts that came with a body die. I also have a Forster FL die which I use most of the time. I size to a 0.002" shoulder bump and so far have no cambering problems in my R700 .300WM.

 

[jepp2]

This will be the first belted case I reload for so any personal experiences would be much appreciated!

It only headspaces off the belt for the first firing. The shoulder will normally move forward about 0.016" +/- on the first firing. Just treat it like a normal bottleneck cartridge on sizing (case head to datum) and ignore the belt.

If you don't, this is what your brass will look like on about the 3'rd firing.

 

[jepp2]

I was wondering what everyone suggests for dies.

I used a Redding body die to size the case and a Lee Collet die with an undersize mandrel to size the case neck.

 

[DocBII]

Cheap 300 Weatherby sizing die to size down to the belt an not touch the shoulder.

Rewinder,

Didn't work with the Redding 2 die set I have on hand. Case stopped at the cutout and was still 0.512" or larger. Guess I need to find a less expensive brand of die.

alchemist,

Larry's die will only size down to 0.509-0.510" diameter. I asked him about an insert which would size smaller, but he didn't seem interested.

HTH,
DocBII

 

[RegionRat]

A diameter just above the belt that is below 0.5126" should work.

The chamber diameter specification right next to the belt is 0.5136 - 0.5166.

If your chamber is very different, then you probably need to have the smith cut custom dies when they are making your chamber.

That Larry Willis Collet Die has been very good for the belted magnums, and I find they need a bump from that die after about the third or fourth cycle, which then lasts a few cycles before they need it again.

I am also a fan of the Redding Body die and Lee Collet Die and use only enough bump to chamber the brass.

 

[Ledd Slinger]

I ran a 300 win mag for over a decade hunting in Montana. Don’t use one now, but shave continued to make ammo for friends who use that round and don’t reload. FL size the cases for sure, but only bump the shoulder .002” on fired cases and you’ll be fine. Same goes for any belted magnum. Been loading for 6.5 Rem Mags for well over a decade as well. Also plenty of 7mm Rem Mag over the years. Neither myself nor anyone else I made ammo for has ever had a case head separation in the last 15 years I’ve been doing it that way.

Innovative Technologies belted mag die works very well if cases start to get sticky at the rear. But you usually only run into that issue with cheap brass running hot loads. Shouldn’t need to worry about the base bulge with good quality brass from ADG or Lapua even when pushing max pressures. But cheap brass is fine if you don’t push it too hard.

 

[Tusker6N]

I use RCBS full length sizer on brass new to my rifle and a neck sizer afterwards.

I get around 6-10 reloads depending on how hot I load them. I've only had one brass break as jepp2 said. I normally get a split neck or shoulder.

 

[boltfluter]

When I ran my .300WM I used to neck up to .338 and then neck back down to .308 and set the head space to fit nicely. Saved the cases from the initial .016 stretch on the first firing. Never lost a case to body separation that way and the rifle was a tac driver! Great round for sure.

Paul