Case stretching during re-sizing question...

2bad4u2

2bad4u2

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I'm using Hornady New Dimension rifle dies and I'm getting between 5-6 thousandths case stretching after sizing. How much is normal? With this much stretch, I'm frequently trimming cases and that's a major pain in the ass.

I'm setting the dies up as per the instructions, with no camming over as listed. I've tried camming down some but it doesn't have an effect on the stretching.

I even put a little bit of powdered graphite on the inside and outside of the case necks to reduce the working of the brass. It maks life easier but doesn't have much of an effect regarding the issue at hand.

Any suggestions? Are there dies out there that you would recommend that don't stretch as much?
 
I guess it depends what is actually causing the case lengthening. Could be similar to a problem I had a number of years ago, that being an oversized chamber. Another possible cause could be 'give' in the action, similar to what is sometimes experienced with 303 British in SMLE actions.
What are you shooting and in what firearm? One 'possible' solution may be neck sizing. Even if your chamber is a little on the big side, once you shoot a round, you've fireformed it and by neck sizing, you're not 'working' the brass back to a standard.
 
Hi,

Any full length case resizing die will cause this. When you run a spent (expanded) casing thru the die - you restore the OUTSIDE diameters and knock the spent primer out. You do nothing as to restoring the original wall thickness. As such, when you re-work the material, "excess" has no choice but to extrude up through you die and appear as a lengthened neck - as nominal as it may be.

I never use the same casing more that three loadings. Others may beg to differ.

Hope this helps.
 
hakx said:
Hi,

Any full length case resizing die will cause this. When you run a spent (expanded) casing thru the die - you restore the OUTSIDE diameters and knock the spent primer out. You do nothing as to restoring the original wall thickness. As such, when you re-work the material, "excess" has no choice but to extrude up through you die and appear as a lengthened neck - as nominal as it may be.

I never use the same casing more that three loadings. Others may beg to differ.

Hope this helps.
Click to expand...

Thank you. I've considered that. Does the amount of stretch seem excessive to you from your own personal observations?
 
Case stretch varies greatly with the load,the brass,the chamber dimensions and the dies that are used.My own cases do not stretch nearly as much as yours appear to.
 
2bad4u2 said:
Thank you. I've considered that. Does the amount of stretch seem excessive to you from your own personal observations?
Click to expand...
Seems a little high, but then again, it depends on a few variables. The difference between your chamber & resizing die dimensions, the loads used and case shape, ie; bottle neck or straight wall.
 
I'm not worried about case stretch during the firing process as it doesn't appear to be an issue with no more than 1-2 thousandths growth after firing.

Just to be totally clear so I'm not misunderstanding or leading you guys down the wrong path, I'm talking about the case length measurement after firing and then comparing it to the length after full length re-sizing.
 
As you cycle the round into the die at the bottom of the stroke the die squeezes the neck smaller then it should be. As the round is pulled out of the die this is when the expander button is pulled through forming the proper diameter so the neck will hold the bullet. This is where the stretching happens, the brass has to go someway.
If you are full length re-sizing, this is when you should be trimming.
The way to avoid all this trimming is to neck size only, with say a Redding neck size die that does not have the expander button.
As the brass is worked and sometimes over-work with full length resizing, brass with different neck/wall thickness may stretch at different rates. As will brass that may be a but harder or softer.
If you can avoid overworking the brass (neck size most of the time, and only full length resize every 4th of 5th time you fire it) it can last a long time. If the brass becomes too brittle and you start to get split necks or the primers start to go in too easy, it is time for new brass.
I have had some rifle brass (Remington)that was reloaded 10-15 times. The brass I am using now (Lapua) is on it's 4-5 trip and still going strong.
 
Best thing to do is to Back your sizing die out a couple turns, resize a case, put it in the rifle and try to close the bolt. Normaly you would only want to push the sholder back/reduce fattness of the brass enough for easy chambering in the rifle you are loading for. The less you resize the less the case grows.

What caliber is it?
 
Well, I just tried backing off the sizing die in 1/2 turn increments to see the affect on stretching. It took 2 full turns to keep the stretching within 1 thousandsth.

Loaded up a dummy round and it seemed to chamber in the rifle though it was slightly on the tight side closing the bolt. Firing live rounds will be the real test.

I've been recommended to try Lee collet dies. They sound like a smart investment. I do believe I'll be ordering myself a couple of sets in .223 and .308 Win. if the Hornady dies don't pan out after this.
 
2bad4u2 said:
Well, I just tried backing off the sizing die in 1/2 turn increments to see the affect on stretching. It took 2 full turns to keep the stretching within 1 thousandsth.

Loaded up a dummy round and it seemed to chamber in the rifle though it was slightly on the tight side closing the bolt. Firing live rounds will be the real test.

I've been recommended to try Lee collet dies. They sound like a smart investment. I do believe I'll be ordering myself a couple of sets in .223 and .308 Win. if the Hornady dies don't pan out after this.
Click to expand...

this is how I resize my cases all the time, it's sort of quasy neck sizing. If they will chamber than they are no problem firing. In fact this method generaly produces excellent accuracy and very good case life. In my son's 30-06 with pretty strong loads I recently threw out brass that I had shoot at least 10 times for no real reason other than the number of loadings. My 300 win mag gets 5-6 loads before they ar done. All this time I haven't had to retrim the cases after the first time they were fired.
 
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