Minimum Shoulder Bumping - The Old Fashioned Way

[cycloneshooter]

I will be ordering a Hornady tool in order to measure the amount of shoulder bump based on the datum lines.

Typically I do a true FL size and have been getting pretty good groups.
My goal is to go to minimum sizing for better case life and better chamber alignment, which might help groups a bit.
Something around a 0.002 shoulder bump is my goal.

All that said, in the meantime, I was experimenting the old fashioned way, by trying to chamber a case until the bolt manipulation is easier. The method being, to keep turning the FL die down, size the case (shoulder), test in chamber.

The problem I am having with this method is that even fired/unsized cases chamber easily in my rifles.
I am not seeing any noticeable bolt manipulation force change even when I get down to a true FL sized case.

I have done this both with a Weatherby Vanguard 300 Win Mag and a Rem 700 257 Roberts.
Same scenario with both.

What am I missing here?

 

[Colorado Cowboy]

My goal is to go to minimum sizing for better case life and better chamber alignment, which might help groups a bit.
What am I missing here?

I don't really see that going thru all the steps you did accomplished your stated goal. I've been reloading for over 50 years and have my rifle reloading/brass sizing down to some simple steps.

First is to make sure the brass you are using has been fired in the rifle you are loading for. (Fire forming)
Second- when I reload these cases I neck size only as they already fit your chamber.

I only do full length sizing if the brass has never been fired in my rifle. In my experience continually full length sizing stretches the case and the brass will get thin at the base and eventually crack and you might pull the head off and leave the brass stuck in the chamber. That happened to my Dad because he insisted on F/L sizing every reload.

 

[cycloneshooter]

All brass fired from the firearms I am loading from. None of the fired cases produce what i would call a stiff bolt throw to chamber.

There are two extremes right. FL is most brass movement. NK is least brass movement. The risk with NK only is tighter fit and the possibility of less ease in chambering in the heat of the moment.

Shoulder bumping is pretty common place in the match shooting realm. Its in between FL and NK sizing. More movement than NK only and less movement than FL sizing.

I am just surprised that I can feel any difference in the actual bolt manipulation force.
If my memory serves me right, when I have NK sized only in the past, I could feel a noticeable stiffer bolt throw than FL sized cases.

 

[WapitiBob]

I full length size because my brass won't chamber after 2 firings if I don't. Regarding your shoulder bump, I am now bumping .001 if at all. Reason being is my brass has about .0015 spring back at the shoulder. Also, you have a belted case, as do I so your std brass will head space off that belt. Your shoulder will grow as you shoot and eventually the shoulder will bump. At that time you can bump the .001 but until it grows it's spacing off the belt. A better way to check the shoulder is to light a candle and run the shoulder of the case thru the flame to "smoke" the shoulder. Run that case thru your FL sizer and lower till it just touches the soot, not wipe it clean. After your cases grow enough, you can also chamber a smoked brass to check to see where the shoulder of your chamber is.

 

[LaHunter]

You may want to look into the Redding Competition Shell Holder set. These are very useful for a consistent / precision shoulder bump using your FL sizing die.

 

[meat hunter]

What is your AOL measurement? How much jump do you have? Smoking the shoulder is/has been mentioned