Headspace question

[absolutchris]

Hey guys-

Got a question on headspace and pressure issues

Did a ladder to just check for pressure signs on virgin brass.

Deprime, clean, anneal, size, clean, prime powder bullet.

Once fired base to shoulder measurement 1.630".

Bumped back 0.002" with competition Redding FL die and competition shell holders to 1.628"

Reloaded and did another ladder test looking for nodes. Started seeing light extractor swipes earlier than my virgin brass (saw ejector marks at 43.6 gr of varget on virgin brass and vs 42+gr of varget on once fired).

Went back and checked base to shoulder measurement of that batch of brass and now it's reading 1.625 to 1.626". So I guess I set the shoulder back farther than I thought?

Can excess headspace cause slightly flattened primers or more extractor marks on the brass from the case slamming backwards?

What is a dangerous amount of headspace? I know 0.005" is too much? But is it excessive?

I've read so many different opinions on the Internet I wanted to ask the hide. Thanks in advance

 

[ken4570tc in WY]

I know some others here may have an issue with my method but it has worked well for me many many years.

For bolt rifles only:
When starting with unfired brass I only full length re-size the first time. After the first firing, I only neck size during subsequent reloads until I begin to feel some resistance when closing the bolt. I use that case dimension as my base line for that particular rifle and will start bumping the shoulders back only enough to eliminate the resistance when chambering the round. I don't measure, I simply make a sample dummy round (no primer or powder) to setup dies.

 

[spife7980]

Can excess headspace cause slightly flattened primers or more extractor marks on the brass from the case slamming backwards?

Yes, starting with a smaller volume and giving the case more space to wiggle around can lead to indications of pressure before you might other wise expect to find them in a properly fitting case.

What is a dangerous amount of headspace? I know 0.005" is too much? But is it excessive?

Dangerous? That depends on how much the case is stretching and how much you stretch it again. A case could probably stretch .020 once and not have failed on that firing. Size it back and do it again and you will have issues. Maybe you can do it .005 four times and be fine but that fifth will fail. No real way to tell but its best to keep it minimized in order to maximize brass life and case consistency.

I think youll be fine with these.
I bet you were using a new clean die? I have found that if you watch the lengths over the first few handfuls of cases that the die builds up lube and that can actually take up more space inside the die pushing your shoulders further back than it did on the first case you ran through the die.

 

[absolutchris]

Yes, starting with a smaller volume and giving the case more space to wiggle around can lead to indications of pressure before you might other wise expect to find them in a properly fitting case.


Dangerous? That depends on how much the case is stretching and how much you stretch it again. A case could probably stretch .020 once and not have failed on that firing. Size it back and do it again and you will have issues. Maybe you can do it .005 four times and be fine but that fifth will fail. No real way to tell but its best to keep it minimized in order to maximize brass life and case consistency.

I think youll be fine with these.
I bet you were using a new clean die? I have found that if you watch the lengths over the first few handfuls of cases that the die builds up lube and that can actually take up more space inside the die pushing your shoulders further back than it did on the first case you ran through the die.

Spife-

You're the man. Yes it's a new die and that makes sense. Is it cool if I send some PM's if I have questions that come up?

 

[spife7980]

Sure but posting them here in the public will also get you answers from lots of other more knowledgeable people than just me.
I didnt come into this world reloading, I started when I was 15 but I learned most everything of substance from others here on the hide in these past few years.

 

[Huskydriver]

I will add that doing load work up on virgin brass is not exactly ideal either. Neck tension is going to change between the 1st and subsequent firings. Also hs becomes minimized once you get that die under control. Both of these factors will change group size and pressure between the 1st and follow on reloadings.