Isn't brass supposed to stretch after firing

Uncle nick. I'm setting back shoulders to0.002 on cases fired in my rifle and the once fired brass I got from Hornady in my 308. Just the one gun. The 7 mag in question is cases fired 3 times in husbands gun. The new brass we bought for it doesn't state whether once fired or not. They slip into case guage and chamber quite loose. I imagine they will swell after being fired. I couldn't measure and confirm because when I bought the new brass I had already cleaned and sized the old brass. I will measure after shooting through rifle this time.

I know the 308 new brass said once fired and annealed. I'm not so sure I like the Hornady brass. In my 308 when I'm cleaning primer pockets they seem to shave the outside a little. Makes priming look crooked on some of them.

Primer isn't pushing back as to show any signs of pressure.

The factory Federal and Remington brass in 7 mag doesn't shave off when cleaning pockets. Maybe better brass. Haven't loaded any of the new 7 mag brass yet. Just resized a couple.
 
Again, I have fired cases in chambers with .127" clearance between the case shoulder and chamber shoulder. Had the case stretched it would have experienced case head separation
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People have been doing that since forever . I've watched guys at the range fire form cases with bigger gaps then that for wild cats they made . I believe you have taken that part of the thread out of context . If you were to size that case back down to have that same .127 head clearance each time you fired it . You would get head separation in just a few reloads . It's likely you only did that once for each case to fire form it to your chamber . I see no reason to obtain that .127 clearance again . There would be no reason to over work the brass in that way .

I believe there is a difference between fire forming a case once with a large head clearance and resizing and firing a case multiple times with a head clearance of .008+ each time . The cases that have a head clearance of .008 each time they are fired have a small enough clearance for the case to be pushed all the way forward in the chamber before expanding and sealing the chamber . This will leave that whole .008 gap or close to it between the the head and bolt face . When this happens and you are using a charge with not enough pressure to stretch case body and the head back against the bolt face you get primers that stick out a tad . With a higher pressure load the case body will stretch enough to allow the head to reach the bolt face . do that enough times and you get head separation .
 
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WendyJ, I thought your question was a good one. Anyone reading/learning to reload believes the case length determines stretch.

Isn't brass supposed to stretch after firing
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That leaves no answer for cases that get shorter when fired. The only standard a reloader has for stretch is case length, problem, there are two case lengths. One from the end of the neck to the case head and the other from the shoulder to the case head. The case can stretch and get longer while the case length from the end of the neck to the case head gets shorter.

Then there is trimming. I loaded 150 7mm Remington Mag. All of the cases required trimming .020"+, not because the cases stretched but because of brass flow. .020" stretch would render the case scrap.

Before choosing the 150 cases to reload I rejected as many cases. The cases I decided not to load will work in another chamber that is longer from the shoulder to the bolt face.

Then there is the other problem with learning to reload on the Internet. The press: If I am sizing a case back to minimum length/full length size I can determine if the case was full length sized before lowering the ram. I understand the 'bump the shoulder back .002", what I do not understand is how all Internet reloaders manage a perfect .002" set back:rolleyes: without sorting through the topics being discussed on forums today. If the press is adjusted for .002" bump:eek: how does a reloader determine if the press won or the case won?

F. Guffey
 
Any idea as to what caused these dents in brass? One is 178 grain Hornady Amax .Near Max load. Other is 165 grain Sierra Game King Mid range load. Picked up Hornady 9th edition book today and IMR chart shows mid range load on 178 gr amax. Hornady manual says I'm .5 grains from max. Both were fired from Tikka. Amax 2.80 coal. Sierra Game King 2.75 coal. Both dents in same place on brass.
One at max. One at near minimum. Primers looked ok. Thought I may have over lubed but figured to see marks all the way around the brass or on the body. Run through fls die and marks are still there. By the way, They didn't stretch. These pictures are after resizing again. I'm going to trash them but will leave to experts who I know have seen something like this.
 
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Looks like some sort of ejection dings .Looks like the case is hitting something on it's way out of the receiver on extraction/ejection . The crease in the dent tells me it''s a contact dent and not from lube . There could be something stuck up inside your die causing the dent .

How many cases came out that way and was it there before you sized the cases ?
 
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Die was just cleaned with caseys bore scrubber. Resized another piece that didn't dent. Will fire one or 2 more and eject slow and easy.
 
Just fire these. You can see loaded ones and I tried to post pictures of primers. Just barely pulled bolt back to extract
 
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Metal. I just checked all the cases and none have any dents. Run some patches and fiberglass brush through the rifle. Just looking with light can't see anything. Bolt was a little tight to close before firing. Put 3 rounds in and ejected without firing. No dents on them.
 
Just so I understand , the fired/empty cases in the pic with the loaded rounds . did NOT have those marks on the neck before you fired them ??? I want to make sure I have the order right as to what I'm looking at .

oh and how I wish I could just load up a few cases , fire them and post pick in a matter of minutes . Man that would take me 4hr to do that . what ever time it took me to load the rounds . load the truck up . Drive 45min each way to the range not to mention the time at the range .
 
Yes. Thanks for replying. I had ten of each loaded. I fired one of each. One sgk and one Hornady Amax. The same dents same spot. These I didn't resize as earlier pictures. The live round is one that was loaded and has no dents in brass at all.
Put one of each live round in chamber and just ejected. Didn't fire. No marks on brass. Silver cci primer looks kind of funny but not cratered or backed out as I can see. Tried to see if anything funny in rifling or throat as it just had a thorough cleaning from range last week. Run some patches down but with light can't see anything out of ordinary.
Cleaned dies last week with gun scrubber and put a little lube on neck opener. Last time I cleaned with the gun scrubber got my first stuck brass. Not all that lucky. Just live in the county. I just fired at 10 yards. I'm like you. 40 minutes to firing range.
I think shoulders are set back right. 0.1785 if I'm correct. That's 1/8 turn more on my fls die.
 
Alright IMO the dents are coming from when the ejector tries to fling the case out but the neck and shoulder have not cleared the lugs/receiver . As you slowly extract the case the ejector is putting force on the head causing the case to drag along the chamber wall at about 1:30 /2 o-clock . When the neck clears the chamber the ejector tries to flick the case out . Problem is the case has not cleared the lugs or the rest of the receiver yet . So it flips out of the chamber and smacks up against the lugs or a part of the receiver before it gets completely to the ejection port to be thrown free . that's where you are hitting something that is causing the dents .

I'm not sure if i"m using the term lugs right . I'm referring to the area of the receiver the bolt lugs lock into when the bolt is fully closed .

Try extracting the case after firing a little faster . so that area of the neck clears the lugs a little quicker . No need to yank it back just faster then you have been . or extract the case slowly while not letting it flick off the bolt by holding it straight on the bolt face with a finger till it clears the lugs
 
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I'll try that next time. I just fired a 168 Sierra game King using IMR 3031 at 39 grains of powder. Ejected super slow and no dents. Brass looked good. Could you see any pressure signs on picture of primers.
 
The heads are a little blurry . looks like the camera focused on case holder . From what I see as far as the primers they look fine but I do see an extra ding/dent on the one on the right . It also looks like they are two different primers . One gold the other silver is that accurate or is that just the lighting ? The heads are to blurry to see if you have any extractor marks on them .
 
Yes sir. One is a cci, the other Winchester. These are pictures I just took of 2 rounds fired with IMR 3031 at 39 grains. No dents. However I did run some patches and brush through the chamber before. Done what you said and ejected a little quicker. Instead of catching in my hand just let them hit the floor. Maybe overpressure? As stated IMR site showed mid range load. Hornady 9th edition said .5 under max. Although this is same load with the sgk I've been using. Maybe I had something in barrel after thorough cleaning. Won't let me upload pictures of this brass.
 
My Sierra manual shows minimum 36.3gr @ 2400fps / maximum 41.1gr @ 2700fps .

Hodgden website shows http://www.hodgdonreloading.com/
168gr smk minimum 39gr @ 2507fps / maximum 42gr @ 2710fps

168gr barns ttsx-bt minimum 38gr @ 2493fps / maximum 41.5c @ 2693fps

Lyman manual
168gr HPBT minimum 37gr @ 2336fps / maximum 42gr @ 2645fps

My Hornady 9th manual does not even have IMR 3031 listed for the 165/168 bullets

All rifles are different but 39gr should be good .
 
Sierra loads are good. Hornady was using IMR 4064 at 41.5 grains per Hodgdon website for 180 grain since I was shooting 178 Amax. Hornadys 9th edition shows 178-180 grain Amax using 4064 starting 34 gr max 41.3. I was using 41.5 per IMR site. Was using 40 grains of 4064 with 165 Sgk. Should have been able to push that one to 45 compressed load Hodgdon per online powder usage. I have shot the 165-168 with that powder combo before. First try with Hornady Amax. Got more books to buy looks like.

Really why I like Nosler on line data. It's been excellent so far. I use way more Nosler bullets. They are ordered and in the mail. Either way both loads put dent in brass. The 39 grains of IMR 3031 with 165 Sgk came out clean. Maybe when I gave thorough cleaning left piece of cloth hung in chamber or something. I'm lost on this one for now. Used page 418 of Hornady book to see my load was too hot on Amax.
 
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Hornady loads too hot but before I pulled them and reloaded shot one more after cleaning bore and throat. No dents. Maybe a piece of loose poder or something left behind from cleaning. All is well. Need new bore guide.
 
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