New rifle reloader question

[dockimura]

I'm sure this is a silly question, but I am new to rifle cartridge reloading. The way I understand it, when your cartridge is fired, the brass expands in the chamber and the casing gets longer, specifically the shoulder. This is why there is a need to resize and "bump" the shoulder, typically a few thousands. If that understanding is incorrect, please let me know. My issue is that I am shooting 6.5 Creedmoor and I have taken a new and fired cartridge for comparison, but the headspeace dimension measured with a Lock N Load headspace comparator is exactly the same on both. Does that mean the casing shoulder will not be resized, just the neck?

 

[SSL]

I'm sure this is a silly question, but I am new to rifle cartridge reloading. The way I understand it, when your cartridge is fired, the brass expands in the chamber and the casing gets longer, specifically the shoulder. This is why there is a need to resize and "bump" the shoulder, typically a few thousands. If that understanding is incorrect, please let me know. My issue is that I am shooting 6.5 Creedmoor and I have taken a new and fired cartridge for comparison, but the headspeace dimension measured with a Lock N Load headspace comparator is exactly the same on both. Does that mean the casing shoulder will not be resized, just the neck?

It can take several sizing and firing cycles for cases to grow. That's why a person can neck-size up to a point, and then have to bump the shoulders to allow ease of chambering after the case grows a bit. I generally adjust my sizing dies to stop just short of touching the shoulders until I start to get the first hint of resistance when chambering. At that point I adjust the sizing die to just "kiss" the case shoulders and readjust a tiny bit at a time until the case chambers easily and lock the die down. Others have various ideas on this subject, but I'm not a competitive shooter and this process works for me.

 

[dockimura]

Thank you so much for your detailed response and it makes sense! I'm aspiring to be a competitive shooter some day, so I'll use this method unless there are some radically different approaches for a PRS competitor.

 

[SSL]

Thank you so much for your detailed response and it makes sense! I'm aspiring to be a competitive shooter some day, so I'll use this method unless there are some radically different approaches for a PRS competitor.

You are welcome...and welcome to the site! Lots of good advice here from knowledgeable people. As you get experience and become comfortable with the process of loading, you can experiment and try new things. Just take it slow and follow all safety rules. The name of the game is "precision", not "how fast can I get this done?"

 

[K22]

SSL provides an effect approach in my opinion.

You want to avoid over sizing. The only reason to size cases enough is so that the cases will chamber without excessive resistance and adequately hold a bullet.

While I use a little different method than SSL, the principle is the same and results are the same, i.e. I don't start pushing the shoulder back on new cases until it's necessary. If you're using a full-size die which I do to accomplish this, you just need to make sure you are not extruding the case, i.e., lengthening it.

 

[D-4297]

To the OP . As has been said ; It may take two or three firings of new brass , for the case to "expand & lengthen , to fit your particular chamber . As you begin this process of re-sizing your case , it becomes easier to accomplish getting the correct "Bump-back" on the shoulder , if you remove the Expander from your Die until you have that "Touch" of the Die contacting the shoulder . It doesn't take much movement of adjusting the Die to go even a little to far , very quickly .

 

[Twicepop]

Case length growth is the result of a few different reasons. Body taper is one of the reasons, shoulder angle is another and finally internal pressure. A case with a lot of body taper (the shoulder being a smaller diameter than the case above the extractor groove) and a very gentle shoulder angle loaded to high pressures will almost always grow in length when fired. An example of a case I described is the 30-06, it has a lot of body taper, it also has a very gentle shoulder angle (17 degree) and it is usually loaded to fairly high pressure. It and others like it have to be trimmed usually because of the aforementioned issues. Minimal sizing will slow the case growth but won't stop it. Case growth is brass migration, it is brass flowing from the base area of the cartridge towards the body, shoulder and neck of the brass. If it keeps going unchecked, there will eventually be a case head separation. The P.O. Ackley versions of many cartridges almost totally eliminates case growth. These have almost no body taper, a 40 degree (usually) shoulder angle and is usually loaded to a higher pressure than the parent cartridge but seldom ever exhibits any case growth.

 

[Adam in WI]

One thing you might find is when trying to neck size with a full length sizing die, is that if you don't have the die set down far enough you can actually squeeze the shoulder further forward. You'll know you're in this situation if after "neck sizing" your brass has more resistance to bolt closure than a fired case. If that happens, you'll have to screw the die in until it hits the shoulder enough to make for easy chambering.