Ring apears on .220 Swift brass?

W

Wyoredman

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I have a Winchester Model 70 Heavy Varmint .220 Swift that makes a shiney ring around the case head on every round fired from the gun. I am perplexed!

At first, I thought that the cases were starting to seperate, then after asking on the reloading forum, I checked them with a bent paperclip and could feel no "ridge" inside the brass. So, I cut some cases lenghtwise with a saw in order to inspect them. No sign of case head seperation.

Finally, I went and bought some brand spankin' new Hornady factory ammo. after inspecting each case, I shot them. Yep, a bright shiney ring around the case head! Right where you would expect to see signs of case seperation. I shot the whole box of new factory ammo, every one has a ring after being shot in my gun.

Finally, I was starting to think that the chamber has too much head space. I purchased a Hornady cartridge headspace gague, measured the factory ammo, fired it and measured the factory cases. 0.003" differance.

After resizing, I measured the case again, shoulder mover back 0.002" (0.001") longer than factory.

It doesn't appear that the gun's chamber is too long. The brass looks good when cut in half and inspected, and factory ammo gets the same ring when fired for the first time.

What is going on? This is the only rifle I have owned that does this to the brass!

Help me out here! Thanks.
 
If it were my gun, I would not do any alteration/polishing until I got a whole lot more input. Close up pictures of what you are calling a "ring" would help. From your description, it could either be the normal expansion ring of all fired rifle cartridges, or something more serious. Once you remove metal, even polishing, it cannot be undone.

One of the things that occurred to me was that the .220 Swift is a semi-rimed cartridge. As such I would neck size only (which I do anyway with most of my guns), and fire, and see if the ring is indeed caused by stretching of the brass.

One of the first questions you should ask is; Does the .220 Swift head space on the semi-rim or the shoulder of the case.
 
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Pictures soon to follow. When I get home, I wil take several. I am pretty sure that the Swift Headspaces off the shoulder, but correct me if I am wrong.
 
With my 220 Swift, I get best accuracy with Partially Resized cases. The case has enough taper that a partial resize won't force the shoulder forward - causing difficult chambering. It works just fine and shoots just great - at least mine does.
 
I don't recall ever chambering anything for the .220 Swift, but IIRC, it is a semi-rimmed case so it should be supported (headspaced) on the rim, not on the shoulder. That doesn't make much difference as far as that bright ring goes. I am willing to make a small wager that the ring is the result of excess headspace, but there is probably not enough case stretching yet to detect it inside the case.

Since, as noted above, the Swift headspaces on the rim, neck sizing will keep cases from stretching but won't correct the basic headspace problem. Eventually, cases will back out enough to lose chamber support and there will be problems.

I would like to see pictures.

Jim
 
If it headspaces on the semi-rim I've been mistaken for decades. Pretty sure it does not headspace on the rim. And even if it did, the case would fireform and could then be necksized.
 
Here are pictures:

From left to right.

Factory unfired; Factory fired once; reload (4 times); reload (4 times) cut open

swiftbrass003_zps80c29632.jpg


ETA: How can they headspace off the rim when the rim is completely enclosed inthe bolt face?
 
and fire form, they like to say that a lot, chamber a round pull the trigger and now they are a fire former....with shine rings abound the case in front of the web.

Me? I am a case former, I form first then fire, difference, I cut down on all that case travel. I want to know the length of the chamber from the shoulder of the chamber to the face of the bolt.

Then there is the taper, the 30/40 Krag, 30/30 and the 303 British have rims, they have large tapers, they have short case life when there is a total disregard for the length of the chamber from the bolt face to the shoulder of the chamber.

F. Guffey
 
F. Guffy, The gun was manufactured in 1994.

James K., What would cause the once fired factory loaded brass to start seperation? All factory loaded brands come out of the gun looking like that after being fired.
 
Today, 01:16 AM #13
Wyoredman
Senior Member


Join Date: September 6, 2011
Location: Wyoming
Posts: 877 F. Guffy, The gun was manufactured in 1994.

James K., What would cause the once fired factory loaded brass to start separation? All factory loaded brands come out of the gun looking like that after being fired.
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#12
F. Guffey
Senior Member


Join Date: July 18, 2008
Posts: 1,446 and fire form, they like to say that a lot, chamber a round pull the trigger and now they are a fire former....with shine rings abound the case in front of the web.

Me? I am a case former, I form first then fire, difference, I cut down on all that case travel. I want to know the length of the chamber from the shoulder of the chamber to the face of the bolt.

Then there is the taper, the 30/40 Krag, 30/30 and the 303 British have rims, they have large tapers, they have short case life when there is a total disregard for the length of the chamber from the bolt face to the shoulder of the chamber.

F. Guffey




“total disregard for the length of the chamber”, From the big inning the purpose of the rim was secure the case to the rear, most of what happened in front of of the rim was to be filled with the case, then the belt, same thing. The firing pin strikes the primer, somehow the case gets driven forward leaving space between the case head and bolt face, then, pressure builds, the case locks onto the chamber, then, the case head is driven back into the bolt face. All that travel is a little rough on the case because the case body is locked onto the chamber, if the case head takes up the slack between the case head and bolt face the case must stretch between the case body and in front of the case web.

As opposed to other chamber designs .

F. Guffey
 
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Since I don't have any 6mm Navy brass, I'm not able to form cases as FGuffey apparently does. I'm limited to fire forming and either neck sizing or partial resizing from there. In that specific rifle (my 220), I bought a neck die, but found over time that I got better accuracy with partial resizing, which works well with tapered cases.

Over 30 years with that rifle and two barrels and no case head separations. I assume that it boils down to the fact that I don't FL resize and set the shoulder back too far.

As for Wyoredman's question, if he's cut into cases and found no sign of case wall thinning at the base, I'd put it down to a little first firing case stretch. Tapered cases do tend to do that, which is why PO Ackley (as FGuffey mentioned) was always 'improving' cases and cartriges by reducing case body taper. Just neck size em from here and you should be fine, though occasionally, if you shoot em hot, you'll need to push that shoulder back a bit.
 
603, Did you take a look at the pictures?

I'd put it down to a little first firing case stretch
Click to expand...

You think the cases are stretching a bit during the first firing, not something wrong with the chamber?

As I said before, the fired case is only 0.003" longer than the factory unfired loaded round. (according to my Hornady Cartridge Headspace Gague)

I have my die set to move the shoulder back 0.002" durring sizing (FL die). Should I scrap that die and buy a NS die?

I keep thinking that something isn't adding up, and the rifle is messing with the cases....
Thanks all!
 
Today, 10:10 AM #17
Wyoredman
Senior Member


Join Date: September 6, 2011
Location: Wyoming
Posts: 878 603, Did you take a look at the pictures?


Quote:
I'd put it down to a little first firing case stretch

You think the cases are stretching a bit during the first firing, not something wrong with the chamber?

As I said before, the fired case is only 0.003" longer than the factory unfired loaded round. (according to my Hornady Cartridge Headspace Gage)

I have my die set to move the shoulder back 0.002" during sizing (FL die). Should I scrap that die and buy a NS die?

I keep thinking that something isn't adding up, and the rifle is messing with the cases....
Thanks all!
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“As I said before, the fired case is only 0.003" longer than the factory unfired loaded round”

That is a nice, tidy little bundle, a spread of .003” from new out of the box to fired then sized.....from the shoulder back to the head of the case. Sounds great, back to keeping up with more than one thought at a time.

“Should I scrap that die and buy a NS die?” I don’t, I believe you should get all the use out of the full length sizer die, the versatile die. You have the part where you are moving the shoulder back .002” down pat, the method you are using to adjust the die alludes me, HOW DO YOU DO THAT? You are assuming the shoulder requires moving back. Back to the part where I determine the length of the chamber from the head of the shoulder of the chamber to the bolt face, again, I apply the ‘LEAVER POLICY’ When I find the shoulder moved out (formed), I apply the leaver policy, ‘I leaver where I founder.

Case head protrusion, you do not have. Case head support? Support is located anywhere the case touches the chamber.Your case is supported from the ring forward, the case head behind the ring is not touching the chamber.

“According to your Hornady head space gage?”, I have a Hornady style gage, I called it a comparator, I make comparators, I make chamber length gages, not go, no and field reject gages, I make gages in thousandths. That is 14 gages between minimum length to field reject, back to I want to know the length of the chamber from the shoulder back to the bolt face.

Sizing a case, raising the die off the shell holder will prevent the die from sizing the case when the ram is raised, starts with neck sizing, eventually full length sizing is accomplished, back to my presses, my dies, both have threads. I control the length of the case from the shoulder of the case back to the head of the case, knowing when to stop sizing is like knowing where to hammer.

F. Guffey
 
I have my die set to move the shoulder back 0.002" during sizing (FL die). Should I scrap that die and buy a NS die?
Click to expand...
Try this test: Fire a factory load in your rifle. Carefully extract the case about half way. Push the case (via the bolt, with the extractor still in contact with the case), back into the chamber and turn the bolt down until it locks. Did the case re-enter the chamber without difficulty? If it did, then why are you setting the shoulder back .002? The only reason to set the shoulder back is to get the hand loaded round to chamber...if it chambers, there is no reason to set the shoulder back. On a rimmed, semi-rimmed case, only the first time the case is fired it head spaces off the rim. After that, it should be treated as if it rimless (head space off the shoulder). If you continue to use the rim for head space by setting the shoulder back, you invite premature head separation.
 
Guffey,

Here is how I used my Hornady "comparator":

Measured unfired, new factory case in the "comparator" installed on my calliper.

Measured fired case the same way. Fired case is 0.003" longer to shoulder datum than it was before fireing.

Screwed FL die into press until it touched fired case, then began adjusting die down and measuring case length to shoulder datum with "comparator" until the case was 0.002" shorter. Set lock ring on die at this point.

My question to you, as you seem to know these things, is how do I make a "chamber length gague"? Please be specific so as I can benefit from your knowledge. If I lived nearby, I would bring the rifle to you and you could explain it to me, but no such luck.

Also, this still hasn't answered my original question about why this individual rifle is doing this to my brass! Are you suggesting that my chamber is oversized? I am a simple man and need simple, straight forward answers. Thanks.
 
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