Redding competition shell holders - headspace

[Rhunter2]

i am working up loads for my mrc 7mm rem mag. I used the Redding competition shell holders that come in .002 increments. I started with the shellhopder marked .010 which should adjust the shell the least. Press was lowered on shellholder and adjusted 1/8 more turn. When I measured the cases using my headspace gauges, the shoulders moved .012 on average. That sounds excessive. If I would have just used my full length die I would have moved the shoulder twice that. I see where guys are moving the shoulder .002. Does it sound like I have to much headspace? Also, I just loaded 30 shells to do a ladder test. Am I wasting my time if I over adjusted the case? Any help would be appreciated!

 

[dok7mm]

.002" bump on cases fired in your rifle should be all you need. Going past that will cause early case head separation.
You are inducing excessive headspace.

 

[Rhunter2]

I looked at the instructions for the shell holders and it said to make sure the shellhopder made firm contact with the die. I think that is where I got a little off. I tightened it down very firm. I decided to reset the die to barely touch the shell holder and tested another case. Now I am moving it back .003-004. If I adjust it to get to .002 the shell holder and die won't touch. Is that a mistake?

 

[dok7mm]

You can put in the #10 shell holder and re-adjust your die to give a light cam-over. Take another unresized case and measure before and after resizing. If it's not giving you .002 bump. Go to a #8 and resize another case. Each SH will add to amount of bump. How many you have to step down will depend on how your die is adjusted.

 

[nmbarta]

Just back your die off a little bit and you'll be good.
Your shell holder doesn't need to make "firm" contact with the die, in some rifles it might not quite touch the die.
1/36th of a turn is about .002, so if your bumping .004 you barely move your die out.
Bumping shoulders is a bit a feel thing. 1/8 is moving way too much at a time.
I don't see the need for special shell holders unless you CAN'T move your shoulder when your shell holder makes contact with the die when FL sizing, meaning that you have a short chamber.

 

[Rhunter2]

I got adjusted to .002. I am ticked that I didn't check that measurement before loading shells for a ladder test. I don't reload a lot but I try to keep learning and do things the right way.

 

[nmbarta]

That's an important one.
I'd start over on the ladder test. You just can't have those kind of known variables and then try to take your gathered information as truth. You'll second guess your test because you know that you already have problems with your loads.
I wouldn't be too concerned if a couple cases were bumped plus or minus 1 or 2, but your head space is way off now.
I hate to say it buddy, but your ladder test isn't going to do you much good if your cases all have excessive head space.

 

[el matador]

Sounds like you had the right technique to begin with. The problem with backing the die off is that you'll be sizing each case differently because none of them will take the exact same amount of force to resize. This is because your press has some spring to it, and varying amounts of pressure will cause the ram to arrive at different places. A firm "cam over" will remove all the spring and give you consistent sizing. Sounds like you have too much headspace for the +.010" shell holder though. Put a piece of tape on top of the shell holder and trim the edges with a razor blade. You might need to use 2 pieces, or glue some card stock in place, or figure out some other way to make a shim. With the right combination of shell holder and shims you should be able to dial in your sizing operation so that a firm cam over gives you the right shoulder bump.

 

[Rhunter2]

Do you think I should try another die to see if my die possibly has a short chamber? Maybe I am looking at this wrong but if my full length die would move the shoulder back .025 if I set it according to the manual, something has to be off. Either the die is cut wrong or my headspace is way off. The gun has already been back to mrc once. I may need to get it checked by a smith.

 

[nmbarta]

Do you think I should try another die to see if my die possibly has a short chamber? Maybe I am looking at this wrong but if my full length die would move the shoulder back .025 if I set it according to the manual, something has to be off. Either the die is cut wrong or my headspace is way off. The gun has already been back to mrc once. I may need to get it checked by a smith.

I agree that something is off. You should not be able to move your shoulder .025 with a standard shell holder and fl sizing.
Maybe somebody has a set of go no-go gauges you could use?
Sounds like your head space is off.

 

[Rich Coyle]

When I size brass I take several fired cases. Next I knock out the primers. Then I checked the headspace on all of them to make sure they're the same. With the dye not touching the shell holder but very close I size 1 and check the headspace. If it's right at .002" I try another one and measure it. I never lock the die down.

It may be Overkill but I check every case after sizing it.

 

[DocDoc]

Belted magnums headspace on the belt, but often have what is excessive room for the shoulder to move forward. You want to set the shoulder back only .002 or so. You ended up doing that, so you are good to reload. If you pushed the shoulder back a lot more, the case would fail just above the belt in a few reloads.

Belt less cases typically have a better match between rifle and dies, so this is not often such a problem. In any case you have the tools to measure shoulder bump and set it right.

 

[CatShooter]

i am working up loads for my mrc 7mm rem mag. I used the Redding competition shell holders that come in .002 increments. I started with the shell holder marked .010 which should adjust the shell the least. Press was lowered on shell holder and adjusted 1/8 more turn. When I measured the cases using my headspace gauges, the shoulders moved .012 on average. That sounds excessive. If I would have just used my full length die I would have moved the shoulder twice that. I see where guys are moving the shoulder .002. Does it sound like I have to much headspace? Also, I just loaded 30 shells to do a ladder test. Am I wasting my time if I over adjusted the case? Any help would be appreciated!

The comp shell holders are primarily designed for use with non-belted cases where the headspace of the chamber is closely measured (with gauges) when the barrel is fit, so it will fall insided a range of 10 thou... so you get shell holders with a range of 10 thou.

But belted cases have two headspaces... the formal "headspace" on belted cases is determined by the belt, not the shoulder. But the working headspace for handloaders is on the shoulders, just like standard cases.

It is common for belted cases to have a lot of space in front of the shoulder before being fired.
The shoulders on my 264 Win Mag cases blow forward 32 thou on the first firing, but come out of the chamber perfectly formed.

Then I set up the dies on the shoulder.

The common rule on belted cases is: Belted cases headspace on the belt for the first firlng, and then on the shoulder after that.

So adjust your dies for the shoulder, not the belt.

Your ladder will be fine.

 

[el matador]

Rhunter2, you're correct that the die could be short or the chamber too long. Either way it doesn't matter much if you're getting a good shoulder bump.

What kind of barrel are you running, and what brand of dies? Cheaper factory rifles tend to have roomy chambers that are several thousandths larger than the SAAMI minimum dimensions, and cheap dies tend to resize brass to well under the max case dimensions. With such a combo you can end up working your brass a lot (both the length and the width). Match-grade chambers and good dies don't usually have the same problems.