Reloading.....Shoulder Set Back

[NCVarhtr]

OK Guys, When you are resizing your cases, how much do you set your shoulders back??? Do you acturlly measure it with something like the Stoney Point Tool??? I would appreciate the benefit of your experience>>>>>>>

 

[Preacher]

I generally set the shoulder back just enough to have a positive fit in the chamber.
I pull the firing pin assembly out of the bolt and then keep sizing the case until the bolt will just fall on a sized case when it's in the chamber. You can not feel this if the pin assembly is still in the bolt.

 

[jb1000br]

Bumping by feel is only safe if you know you have a good set of dies that move the right brass, the right distance.

Once you have a proven good set of dies, and a good feel, you can get pretty good with this method,though I still like to measure).

Without a proven set of dies, the resistance you feel could be coming from nearly anywhere else EXCEPT the shoulder and it would still "feel" the same on closing.

I use the Stoney point headspace gauge.

I could actually measure to the half-a-thou, and predict when I would "FEEL" the case chamber or not.

whether the numbers from the caliper are "real" or not I won't argue, but with my 6BR I found this:

1.137 was the closest I could measure my chamber's headspace.

1.1365 would give a little feeling for the last 1/2-1/4 of the bolt closing.

1.1360 would give just a BIT of feeling in the last 5-10% of the bolt's closing.

I aim for 1thou bump, but take 2thou if that is the closest my setup will get.

YMMV,
JB

 

[Forum Boss]

I aim for .0015" shoulder bump. There is a pretty easy way to measure this.

1. Decap a fired case,but don't body-size it yet).

2. Get a .45 acp case. Make sure it's been trimmed square, the mouth is round, and the primer's been removed.

3. Place the .45 case over the neck of your 6BR brass. You'll note that the mouth of the .45 case seats right at the shoulder of your 6BR brass.

4. Measure base of .45 to base of 6BR, using calipers,.45 acp case in on the left in these photos.)

5. Now run your 6BR case through your FL sizer or body die.

6. Adjust your sizing die up/down as necessary to get about .0015" pushback to the shoulder.,In your particular gun you might want a bit more/less).

You can also use Redding graduated shellholders, while leaving the die where it is.

FYI, when I was measuring bump by "feel" alone, I was getting close to what I wanted--about .0025" bump. But by actually measuring, I was able to minimize the amount of bump to just what I needed. Cases still chamber smoothly, and there is less effort to run the case up into the die.

 

[NCVarhtr]

Thanks guys for your suggestions........I used the Stony Point tool to measure shoulder set back and then I used the Kleinendorst tool to remove the firing pin assembly to check for "feel" and following your suggestions, my groups tightened up quite a bit......55 Gr. B Tips shot abut .250 and the 58 Gr. V-Max shot 5/16" to 3/8"..........Much better....Thanks again....

 

[tootalloutdoors]

I certainly don't want to hijack this but my 6br when measured like that grows .007" when fired after f/l sized. Also the same thing,just checked) when fired new lapua brass. It's happening in the body and the cases are "EXTREMELY" hard to extract. I thought it s just old brass, which it is. Found a couple of new ones and expected good results but the same symptoms are there as well as the .007" growth. Very consistent on that number. Does a person ever need to re-set the head space. Savage model 12 with a barrel nut. Thanks and sorry for the hijack. But I'm completely dead in the water here. I was thinking I just needeed to wait for new brass. Now I'm not sure. PLEASE HELP!!

tootalloutdoors