Shoulder bump

[Meer Cat]

Hello everyone,
Long time reader, first time poster here.

My question is how not to bump your shoulder back, yet resize enough to where you can properly chamber a cartridge. I understand once fired, the brass will expand and fill the chamber, and for accuracy and brass life, it's best to leave it like that. But how can I tell if I have the resizing die screwed to far, or not far enough in the press? My press does not cam over, Lee single stage, if that helps.

I reloaded before, but screwed the die in until it contacted the shell holder.

Would it matter if it's a belted or non belted cartridge? As I reloaded for both. I've heard people say they resize belted cartridges so they headspace off the shoulder, and not the belt. Is that safe/reliable?

I know this is a long one gents, but thank you for your time and wisdom.

 

[ants]

I think you'll get 1000 different replies. That doesn't mean there is one true and 999 false answers. You'll have to figure out the best solution on your own. Sorry, but much of what we do in handloading is the discovery of what works best for our guns, our press, ourselves as shooters, and the Gods of Reloading poking their capriciousness at us. You got to try it yourself, and learn from failures while celebrating successes. Here are a few hints to help...


Full length resizing makes a case too long for your chamber short again, the open question is how short is short enough.

Some use the chamber of the rifle. Some use a case gauge. The former is specific to your own guns, the latter is more generic to all SAAMI standard chambers. You choose which one, but greater accuracy is achieved by the former. Greater reliability in a bunch of different guns is achieved by the latter.


So if you get cases which (after resizing and trimming) are too long for your own guns, you need to bump shoulder back. You know it's time when you can't close the bolt easily. Then you bump shoulder back. If bolt closes without a hammer and a curse, you're still OK. But still smart to load one or two test cartridges first, just to make sure.

So how do you know how much to bump back and when to stop? Easy! Use your rifle chamber. When the resized and trimmed case goes into the chamber and the bolt closes easily, you are good and golden! If it doesn't close easily, don't force it. Adjust sizing die another 1/8 turn and try again until it works.

After resizing, don't forget to trim. Then check in your chamber.

 

[Weber]

I recommend using a case gauge, and then adjust things for your particular firearms.

 

[JimKirk]

A case gauge mean your ammo will fit most chamber of that particular cartridge ..... but it does not make ammo that is tailored for one gun .... if you want the best fit for "that" one gun use it's chamber as the gauge ....

 

[243winxb]

Gauging Success - Minimum Headspace and Maximum COL http://www.brownells.com/.aspx/lid=12897/GunTechdetail/Gauging_Success___Minimum_Headspace_and_Maximum_COL

 

[Blue68f100]

My question is how not to bump your shoulder back, yet resize enough to where you can properly chamber a cartridge.

You have to have a way to measure it. Normally with a tool that measure the shoulder datum. RCBS Precision Mic will give you a reading on where it is before and after. Now these may not be exact but all you need is a reference. I use these on my 308 and 7mm Rem Mag. Mainly because I load for multiple guns of the same caliber. This allows be to install shims as needed to adj for the different guns. Some case gauges tell you this too. Have a slot that gives min and max spec. The problem with these is that you may over do it depending on you specific chamber.

 

[Walkalong]

You'll need some way to measure were the shoulder is in relation to the base of the case. Then as you adjust the sizer you can measure at each setting and see what is happening with the shoulder.

The RCBS Precision Mic is a great way to do this and very easy for the beginner to use.

http://www.midwayusa.com/product/574297/rcbs-precision-mic-308-winchester

There are lots of ways to do it, but the RCBS is easy and nearly foolproof.

I made a little "gauge" for .308 and use it. When used with a dial caliper it gives me arbitrary numbers, but I can record those and it shows me what I am doing to the shoulder.

A couple of threads that might be helpful:

http://www.thehighroad.org/showthread.php?t=759018&highlight=Headspace+Gauges

http://www.thehighroad.org/showthread.php?t=734058

Welcome to THR.

 

[stubbicatt]

Hornady make a tool for this purpose. It is a comparator. PMA tool make a great lock ring gizmo that will allow .001" incremental increases in shoulder bump.

Either that or just do like we did in the dark ages, inspect your cases for separation after each firing and scrap them at 7 uses, and start over with fresh brass.

 

[Wildfire]

Post 7 & 8

Post 7 & 8 are correct. You need some new tools.
We almost always move the shoulder back .002 to .003" for a good fit.
But, you need the tools to know that.

 

[rg1]

I have a RCBS Precision Mic for 3 calibers and also a Hornady Headspace gauge set. The Hornady set works with your calipers and measures most all calibers. The only way to know is measuring. As far as loading belted magnums, yes it's very important to have belted cases headspace both on the belt and the shoulder. My 300 Weatherby dies when set to touch the shellholder pushes the shoulders back too far. My brass shows stretching just in front of the belt and so bad that only 3 maybe 4 loadings is safe when pushing the shoulders back with the die touching the shellholder. With the Hornady set or RCBS Precision Mic you can measure fired cases and adjust your sizing die to push shoulders back and I like one to two thousandths for bolt rifles and 3-4 for semi-autos.

 

[philip brousseau]

Meer Cat, it is much better to size bottle necked belted magnum cartridges to headspace off the shoulder and in so doing you ignore the belt. this is how i deal with controlling head space when resizing brass for my rifles. i have a set of hornady headspace gauges and redding competition shell holders. the shell holders set the shoulder back in .002 increments. take about 5 cases fired with factory or full power loads. take a hand held depriming tool& hammer and tap the primer out. any burr or raised spot on the primer or cartridge base will give you at least .001 to .003 false reading on your caliper. i measure the cases with the h.s. gauge and use the longest h.s. reading to go by. then use the shell holder that gives me a .001 shoulder set back on the cases when sized. with these shell holders you firmly contact the base of the sizing die. keep notes as to which shell holder works that particular rifle and die set up is quick and never a problem. well this is the method i use and it works well for me. there are many other ways as others have stated. hope this helps.

 

[Meer Cat]

Thank you everyone for the advice. Lots of trial and error, and measuring, adjusting, followed by more measuring. Can't wait to get back and try it out. It's a lot more fun to shoot your own. So far I'm only at about 50 reloads, have to bring that up.