303 British Resizing Procedure Question

[epags]

Today I was shooting my (one and only) 303 British Enfield and a 'knowledgeable' shooter commented to me that since the 303 British head spaces on the rim, and not the shoulder, in order to extend the life of the brass, I should only be bumping the shoulder back a couple of thousands rather than full length resize.
If his comment is correct, what tools & steps do I need to:
1) de-prime the brass w/o full length re-sizing the brass
2) bump the shoulder back a specific amount. (However, is bumping necessary if I do step 3?)
3) size the neck? (Lee Precision Collet / Neck Sizer / Sizing Die < .303 BRITISH > # 91021)?
Presently I am using a RCBS de-priming/full length sizer die and a RCBS seating die. I have a Forester trimming tool, a Lee Factory Crimping die, a couple of micrometers and Hornday's Lock and Load systems .

 

[T3ninja]

I could be way off here, but I'd say he's right and pretty much follows the theory of a lot of belted magnum shooters. They headspace off the belt, but after a couple firings they can be treated like any other round, headspacing off the shoulder. I'm sure someone will be along shortly to confirm (or tell me I'm a fool). But that's how I'm treating my .300wm

 

[del2les]

While most rimmed cases do technically headspace off the rim, I treat all my bottle-necked rimmed cases similar to rimless. Thus, I resize similar to any case that head-spaces off the shoulder. This helps to prevent early case separation and extends the life of the brass. Often, it gives me better accuracy also.

 

[epags]

While most rimmed cases do technically headspace off the rim, I treat all my bottle-necked rimmed cases similar to rimless. Thus, I resize similar to any case that head-spaces off the shoulder. This helps to prevent early case separation and extends the life of the brass. Often, it gives me better accuracy also.

When you say you headspace off the shoulder, what is the procedure?

 

[Orange Dust]

I could be way off here, but I'd say he's right and pretty much follows the theory of a lot of belted magnum shooters. They headspace off the belt, but after a couple firings they can be treated like any other round, headspacing off the shoulder. I'm sure someone will be along shortly to confirm (or tell me I'm a fool). But that's how I'm treating my .300wm

You are 100% correct

 

[del2les]

When you say you headspace off the shoulder, what is the procedure?

Depending on the number of times a case has been fired, chamber, load etc, usually, I set my FL dies to neck size the brass without touching the shoulder. As becomes needed from firings and etc, every 3rd sizing or so, I lightly bump the shoulder back.

 

[epags]

Depending on the number of times a case has been fired, chamber, load etc, usually, I set my FL dies to neck size the brass without touching the shoulder. As becomes needed from firings and etc, every 3rd sizing or so, I lightly bump the shoulder back.

Now we are getting close to my question. How do I set my FL dies to neck size the brass without touching the shoulder? Some one on another blog said to run the FL die down to only neck size 75% of neck...how would a person measure that? Is there any validity to that statement?

 

[Orange Dust]

Today I was shooting my (one and only) 303 British Enfield and a 'knowledgeable' shooter commented to me that since the 303 British head spaces on the rim, and not the shoulder, in order to extend the life of the brass, I should only be bumping the shoulder back a couple of thousands rather than full length resize.
If his comment is correct, what tools & steps do I need to:
1) de-prime the brass w/o full length re-sizing the brass
2) bump the shoulder back a specific amount. (However, is bumping necessary if I do step 3?)
3) size the neck? (Lee Precision Collet / Neck Sizer / Sizing Die < .303 BRITISH > # 91021)?
Presently I am using a RCBS de-priming/full length sizer die and a RCBS seating die. I have a Forester trimming tool, a Lee Factory Crimping die, a couple of micrometers and Hornday's Lock and Load systemsView attachment 283807View attachment 283808.

Without buying any new tools you can easily do it the old way. Set your full length die so there is about the thickness of a nickle between the die and the ram fully up. Size a fired case. Smoke the case shoulder with a candle. Chamber it in the gun if it will go. Look at the case. is the black scrubbed off the shoulder? If so, run the die down a 1/4 turn. and try it again with a different fired case. Keep going down until just some of the black is still there, and lock it down. Use a new fired case each time. Now resize the cases you used in the trial plus all the others you want to load. You can also use this method to find throat length by smoking bullets.

 

[Orange Dust]

Now we are getting close to my question. How do I set my FL dies to neck size the brass without touching the shoulder? Some one on another blog said to run the FL die down to only neck size 75% of neck...how would a person measure that? Is there any validity to that statement?

Yes, called partial resizing. We used to do it all the time when FL dies were all we could get. Some cartridges can be hard to chamber doing this though. It used to work really well with an old Swift I had.

 

[del2les]

Now we are getting close to my question. How do I set my FL dies to neck size the brass without touching the shoulder? Some one on another blog said to run the FL die down to only neck size 75% of neck...how would a person measure that? Is there any validity to that statement?

Do you have a reloading manual? Usually, there is a section on sizing, or you can go to most any of the reloading manufacture's web sites or Youtube and watch videos. Basically, as another stated, but lower your press handle all the way until cam over, screw the die down till it touches the shell holder, then back off 1/16-1/8 turn. Run a lubed case into the die and look at the neck, and usually, you will see how far the die resized your neck. Readjust until the amount of sizing just stops short of touching the shoulder. If the shoulder shows signs of contacting the sizing die, just adjust the die up 1/16th a turn or so until no contact is seen.

There can be many variations in neck or partial sizing, and some of my cases, loads and chambers shoot better with a half neck size, but that is only until thing become tight and a full resize is needed.

 

[Orange Dust]

Do you have a reloading manual? Usually, there is a section on sizing, or you can go to most any of the reloading manufacture's web sites or Youtube and watch videos. Basically, as another stated, but lower your press handle all the way until cam over, screw the die down till it touches the shell holder, then back off 1/16-1/8 turn. Run a lubed case into the die and look at the neck, and usually, you will see how far the die resized your neck. Readjust until the amount of sizing just stops short of touching the shoulder. If the shoulder shows signs of contacting the sizing die, just adjust the die up 1/16th a turn or so until no contact is seen.

Remember to make sure they will fit in the gun. Many cartridges will "Grow" in shoulder length when doing it this way.

 

[del2les]

Remember to make sure they will fit in the gun. Many cartridges will "Grow" in shoulder length when doing it this way.

Always a given, but not to new, inexperienced loaders. Thanks for adding.

 

[epags]

Do you have a reloading manual? Usually, there is a section on sizing, or you can go to most any of the reloading manufacture's web sites or Youtube and watch videos. Basically, as another stated, but lower your press handle all the way until cam over, screw the die down till it touches the shell holder, then back off 1/16-1/8 turn. Run a lubed case into the die and look at the neck, and usually, you will see how far the die resized your neck. Readjust until the amount of sizing just stops short of touching the shoulder. If the shoulder shows signs of contacting the sizing die, just adjust the die up 1/16th a turn or so until no contact is seen.

There can be many variations in neck or partial sizing, and some of my cases, loads and chambers shoot better with a half neck size, but that is only until thing become tight and a full resize is needed.

del2les: Yep. I know how to resize (FL). And Yep, I have manuals that date from 2021 to back to 1976. But when I was told to only set the shoulder back 2 thousands your suggestion does not provide that level of precision. That is why I asked the question in my original post. 'Is there a die that you can control the amount of shoulder set back for the 303 British?'

edit: I did not mean just 'measure' the set back but provide a way to adjust the amount of set back

 

[Orange Dust]

del2les: Yep. I know how to resize (FL). And Yep, I have manuals that date from 2021 to back to 1976. But when I was told to only set the shoulder back 2 thousands your suggestion does not provide that level of precision. That is why I asked the question in my original post. 'Is there a die that measures shoulder set back for the 303 British?'

Hornady makes a gage that fits on calipers.