Stretching cases???

P

pyscodog

Active member
My brass is stretching coming out of my die. Is this normal as I haven't ever notice this drastic of a change.

Dies-Old Pacific 220 Swift
Brass-Some new and some once fired in my rifle

New-before resizing-2.194,after-2.197
Once fired-before-2.193,after-2.206

I have a trim die just for the Swift but is my problem the dies or is this just the norm for the Swift? The cases aren't growing after being fired, they're growing coming out of my resizing die. Got me a little confused.
 
I think it is fairly common for sizing(non bushing type) die to be tight in the neck portion, than you pull a expander back out. Between over sizing the neck and the expander, lube just cannot prevent pulling. I have went to universal die decapper and mandrel, and allowing the brass to "relax" while at the top of sizing stroke. This is for bolt guns. Seems to give me more consistent results. Custom dies also will reduce pulling brass.
 
Your die isn't screwed down far enough. The first thing a FL die does as you run a piece of brass up through it is size the body down. As it sizes the body down brass flows on the least path of resistance which is up so it is very common for cases to actually get longer in the sizing process until you have the die screwed down far enough to push the shoulder back.

Sometimes a die can't be screwed down far enough to push the shoulder back and you are left with the case being a thou or two long. When that happens the die needs to be modified.
 
Originally Posted By: KYODENormal to get extra length after sizing.....hence you trim brass AFTER sizing.

^^^^^^This.

A small part of the growth in length is induced by pulling the expander plug out of sized case. This is also where a lot of concentricity is lost. However, the greater the difference between the sized case and the fired case, the more brass "flows" or stretches and the more growth in length you will incur. Minimal sizing increases case life and reduces growth in OAL.

Regards,
hm
 
You could be getting a small amount of growth in just the neck portion but I'll bet the majority of your growth is coming from the main body section of your brass or more technically called, the base to the shoulder datum.
 
I think your very correct B23. I took my dies apart and gave them a clean/polish job so I could rule out maybe dirty dies causing issues. I have my die screwed in as far as it can go, getting a cam over effect and the case will chamber now but the bolt is firm closing. I don't have to force it close, there is just some resistance. Its just weird (to me) that a new and a once fired case will chamber but until I trim, a resized case won't chamber.
 
Your new cases should not need any body sizing, especially no shoulder work. Most factory chambers are longer than SAAMI so trimming is usually not a issue for me for several firing/sizing cycles.
0.013 case length increase from sizing seems excessive. I see 2.205 max case length for the Swift, so your 2.206 cases may be an issue, I just don't have a factory gun that is that close to specs. Additional notes required in the reloading book for your rifle.
 
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I feel like I'm not explaining whats going on well enough.

New ammo, HSM 220 Swift,Winchester brass, chambers fine in my rifle, shoots OK, bring it home and the fired case will still chamber just fine, run it through my die, it grows .012 and now it won't chamber in my rifle. I can't close the bolt. My die is set to cam over hard, case still won't chamber. Trim the neck, now it chambers but the bolt is a little stiff and I can't set my die to do any more than its doing now.

I don't have a case gauge but I think B23 hit the problem. I think my case is possibly growing in the body and not so much the neck. Can I take a little off the bottom of the die to get a little more bump?
 
Take it off the shell holder, not the die.

Annealing the shoulder/neck might help.

IMO, your chamber might be on the short side, but also oversize in diameter. So the cases expand, when the die resizes it essentially oversizes the body, that brass flows forward and makes the case longer. Basically your die and chamber are quite a bit different dimensions. Not good for brass life.

What I'd do? Get a neck sizer. Or at least try a different fl die.
 
In the mean time, try backing off your die, maybe a full turn, maybe 2. The swift has tons of taper, so backing the die out might allow it to size just the neck, or most of it to hold the bullet without touching the body. Since the cases chamber fine after firing, the shoulder doesn't need pushed back at this point.
 
I have sized almost all my cases with exception to some factory loaded stuff. I'll try backing off the die and just neck size what I have left after shooting them.


Well I forgot I had a box of Hornady that had been fired in my rifle. Measured 2.194 and would chamber easy in my rifle. I set my die to size about 3/4 of the neck. Case grew to 2.205 and was difficult to close the bolt and hard to lift the bolt for extraction.
 
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If you have access to an acetylene torch you can black the case w/acetylene only flame(MT of course
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) , or get a spray can of sight black, spray sized case and attempt to chamber. Tight spots will be obvious.

Regards,
hm
 
Unless there is zero resistance as a case goes up into a FL die, which is nearly never, as the die squeezes down on the body of the case, the brass is going to flow somewhere and it will take the path of least resistance, which is up, causing the base to shoulder datum to grow in length until the shoulder contacts the top of the die at which point it pushes the shoulder back. If a FL die isn't screwed down far enough to contact the shoulder the case will come out of the die longer than it went in.

It may seem odd, but as a piece of brass is FL sized, even new unfired brass, multiple things are happening in that one single stroke of the ram. The body gets sized down in diameter and as this happens it pushes the shoulder forward and if the die isn't screwed down far enough to contact the shoulder, the brass will come out longer. Many reloaders aren't even aware of this because they don't measure their brass and there method of measuring is if it fits in their gun and the bolt closes. For many, this works fine, but when guys encounter a problem like pyscodog has they are left scratching their head thinking what the heck is going on.

 
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+1

In addition, swift necks are thick.

When the expander ball is pulled back through the neck, it can cause growth and crooked necks also.

So, try lubing the inside of the neck...will pull the expander ball through much easier. Lee sizing wax is my favorite for this lube...non petroleum product. You may not feel resistance of the expander ball going through the neck using the lee wax.

For your own mental well being, remove the decapping pin from the die, size down, now mic the neck dia. Now mic the expander ball. There maybe a massive amount of brass movement going on between the sizing and opening up the neck with the expander ball.

In B23's first paragraph, when the die is screwed down, the necks in swifts can grow a tremendous amount in length, constant monitoring of case OAL is a huge consideration when full length sizing every operation, especially with the Swift.
 
I was talking to a friend that shoots a lot of wildcats. He recommended either taking a little metal off the top of the shell holder or getting Redding competition shell holders. The come in a variety of different thickness's. Or a body die for a Swift. I think I may try taking a little metal off the shell holder first. They are cheap and I have several already. Might be an easy solution. Yes?

I have been lubing the necks before running them through the die.
 
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Case's stretch when FL sizing on the down stroke. The sizing plug being pulled back through the neck pulls it and stretch's it some. If it bother's you go to collet die's and the problem goes away!
 
Originally Posted By: pyscodogI was talking to a friend that shoots a lot of wildcats. He recommended either taking a little metal off the top of the shell holder or getting Redding competition shell holders. The come in a variety of different thickness's. Or a body die for a Swift. I think I may try taking a little metal off the shell holder first. They are cheap and I have several already. Might be an easy solution. Yes?

I have been lubing the necks before running them through the die.

You should only take some off the top of the shell holder when you need to push the shoulder back further, this would allow you to close the bolt easier.

If your current die is pushing the shoulder back to where your bolt will close easy, then do not grind the top off the shell holder.

As I said earlier, the expander ball will yank the case to a longer length, and full length sizing makes the cases grow. The answer is not in pushing the shoulder back further to allow for the full length sizing to extend the length, as this method creates excessive headspace and varying case lengths.

Full length size only when necessary for easy chambering of the round
, keep your cases trimmed to length, Lee collet sizers produce an excellent lack of run out. Lee also has mandrels of different sizes which are a lot less expensive than the cost of bushings. Using a redding body die for FL sizing plus the Lee collet sizer for sizing the neck is a good way to go. Having commented on the lee collet sizer, I will add that I have a LOT of bushing Neck and FL sizers from various makers.

Concerning the Swift, brass issues are a constant issue, especially when shooting top end loads as that brass is flowing like the Mississippi river at flood stage.

Again, Lee sizing lube in the tube paste container works wonders in eliminating drag on the expander ball coming through the neck. I put a little bit on a Q tip, and will lube a hand full of brass with that tiny amount. The nice thing about the wax is that the powder will not stick to the wax in the neck like it does with Imperial sizing lube that is a petroleum product.

Around 1995, I bought my 5th swift after not owning one for years, saw it in a gun shop for cheap money, Ruger 77 tang safety. Brass grew .012 in length on the full length sizing with no lube in the neck. I shot a hot load of IMR 4064 with Sierra 55's right at 3900 fps.

I have always wanted a Swift Ackley Improved which would stomp a 22 creed and a 22/250 AI.
 
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Originally Posted By: pyscodogI was talking to a friend that shoots a lot of wildcats. He recommended either taking a little metal off the top of the shell holder or getting Redding competition shell holders.

The Redding comp shell holders are + size only. Exact opposite of what you need. They are for maintaining the consistency of hard cam over while adding shoulder length for normally sloppy factory chambers.

- DAA
 
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