Brass Separation Above Belt

[Edd]

......... But it looks like I will have to have a set of dies dedicated to the one rifle...that still doesn't seem right....

You are going to have to adjust the dies correctly regardless of how many sets you have. When you find the correct die height, measure the gap between the bottom of the die and the shell holder. Buy a 9/16" or 5/8" id x 1" od shim that thickness to place on top of your shell holder when resizing. Then you can adjust the die so it bottoms like you always have.

 

[curtiscd]

Just a quick update here. It turns out that a separate gunsmith looked over this rifle and bolt closure with a no-go gauge was done w/ 0 resistance. The good thing that did come from this encounter was I was able to convince him to buy a set of headspace gauges as mentioned by Alex above. I have been using a set for a little over a year now and have found them beyond useful. Thank you to everyone who responded on this. There was a ton of useful information provided here.

 

[Barrelnut]

So the first couple of us that suggested a bonafide headspace issue in the beginning. Weren't just stupid unexperienced wanna be internet experts afterall?

I'm guessing excessive headspace! And, full length resizing is exasperating the situation. Even then,separation with only one reloading seems extreme. memtb

I agree that it's a possible headspace issue. One FL resize that sets the shoulder back to standard dimensions after one firing of new brass, should not cause a head separation situation. I've loaded a lot of 7RM before and set the shoulder all the way back and not had one start to separate on the second firing.

I suggest using Hornady Comparator gauge set and measure the length of a new unfired case at the shoulder datum. Then measure it after firing the case. I think if it is more than .008 or so, that could be a problem. And may be why it is starting to seperate on the second firing. You need the comparator to tell you what is going on.

It is typical for belted magnum cases to stretch quite a bit on first firing, This is by design. They may not even reach full chamber dimensions on the first firing, It may take three firings and just neck sizing before it get hard to chamber before it is time to bump them back .002. that's the way I do with my 7RM.

 

[Scooterbum]

Well now!

Posts 1,7,12......and now 86 !

Cat, about that barrel setback I said was needed.....

Try to get a clue.

 

[bigngreen]

Just a quick update here. It turns out that a separate gunsmith looked over this rifle and bolt closure with a no-go gauge was done w/ 0 resistance. The good thing that did come from this encounter was I was able to convince him to buy a set of headspace gauges as mentioned by Alex above. I have been using a set for a little over a year now and have found them beyond useful. Thank you to everyone who responded on this. There was a ton of useful information provided here.

Did he measure how far out of correct headspace it was. I've seen a couple fresh rebarrels on belted mags where the guage hangs up on the belt and does not seat and the smith ends up cutting to deep, you gotta feel the click in the guage when it pops in on them!!

 

[CaptnC]

I seem to recall all belted mags use the same head space gauges...if that's true, I have my 264wm go/no-go's I could check my 7mm mag with them...

 

[CatShooter]

I seem to recall all belted mags use the same head space gauges...if that's true, I have my 264wm go/no-go's I could check my 7mm mag with them...

Belted case headspace gauges measure the head to belt dimension, not the head to shoulder dimension.

 

[CaptnC]

Belted case headspace gauges measure the head to belt dimension, not the head to shoulder dimension.

Yes sir...very true, but if the reamer used on 7mmRM was spec it should measure the head space so at least I would know that (head space) is correct...I suspect it's not.

I am going to get the gauges I need for that later...

 

[bigedp51]

A GO and NO-GO gauge are for new rifle or barrel setup and there is .003 between the GO and NO-GO gauge. If you look at a SAAMI cartridge and chamber drawing it lists headspace as min and max with .010 in between. Meaning there is .010 between GO and max Field gauge and headspace will increase over time.

And as I stated in a earlier post a military British .303 Enfield rifle at maximum headspace can have .016 head clearance with a rim thickness of .058. Meaning a properly fire formed case will not stretch and thin on its first firing if the rear of the case is held against the bolt face.

And I wouldn't think much of a "gunsmith" that couldn't set a new barrels headspace correctly. And then give it back to the owner saying its OK. And the only mistake made in this posting was assuming the gunsmith knew what he was doing.

And headspace depending on the firearms design can mean many things, below is a good example.

 

[ATH]

Gauges aside, a new case, a fired case, a fired case resized, and a Hornady comparator would have revealed the issue in 5 minutes of measuring.

Ditch the smith who barreled the rifle and let your friends know.

I can't speak for others but I hope threads with members insulting each other does not become the norm...plenty of other places to go for that...

 

[CatShooter]

A GO and NO-GO gauge are for new rifle or barrel setup and there is .003 between the GO and NO-GO gauge. If you look at a SAAMI cartridge and chamber drawing it lists headspace as min and max with .010 in between. Meaning there is .010 between GO and max Field gauge and headspace will increase over time.

And as I stated in a earlier post a military British .303 Enfield rifle at maximum headspace can have .016 head clearance with a rim thickness of .058. Meaning a properly fire formed case will not stretch and thin on its first firing if the rear of the case is held against the bolt face.

And I wouldn't think much of a "gunsmith" that couldn't set a new barrels headspace correctly. And then give it back to the owner saying its OK. And the only mistake made in this posting was assuming the gunsmith knew what he was doing.

And headspace depending on the firearms design can mean many things, below is a good example.

Very hard to measure the headspace - no datum line ((((

 

[bigedp51]

Very hard to measure the headspace - no datum line ((((

Bovine Scat, Your divorced, you shouldn't have any problem finding a "datum".
All you need is to call up one of your girls.

 

[Rich Coyle]

You are going to have to adjust the dies correctly regardless of how many sets you have. When you find the correct die height, measure the gap between the bottom of the die and the shell holder. Buy a 9/16" or 5/8" id x 1" od shim that thickness to place on top of your shell holder when resizing. Then you can adjust the die so it bottoms like you always have.

I tried that. It was inconsistent. That's when I started checking every sized case with the headspace gauge.

 

[Edd]

I tried that. It was inconsistent.

Then you didn't do it right.