I'm trying to help my father in law determine why he is getting split necks in his savage lrpv in 260 rem with a 28" shilen barrel. Does it have to do with a loose chamber? I measured his brass after being resized, loaded, and after being fired. I don't remember the measurements off hand but the resized brass was .002" smaller before being loaded, and grew to .010" bigger than the loaded round after being fired. He's loading a pretty stiff load of varget (40.5 grains) in rem brass, cci br2 primers, behind a 123 A-max, about .020" off the lands. Is it from working the brass too much or? We begin finding split cases after the third firing on the brass. Any help would be greatly appreciated.
What causes split necks? help please
- Thread starter bjordan
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Re: What causes split necks? help please
Make sure to trim and chamfer your brass. If you have more than a few reloads in this brass you need to anneal the case mouths. Try annealing a few and compare to ones not annealed.
Not sure if you have done it before, but a google search can get you a step by step. I do it in low light to make sure my case mouth never gets past a very very dim red. Cherry and you ruin the brass.
Make sure to trim and chamfer your brass. If you have more than a few reloads in this brass you need to anneal the case mouths. Try annealing a few and compare to ones not annealed.
Not sure if you have done it before, but a google search can get you a step by step. I do it in low light to make sure my case mouth never gets past a very very dim red. Cherry and you ruin the brass.
Re: What causes split necks? help please
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Shiredude</div><div class="ubbcode-body">what kind of brass?
I used to have splitting problems after 2 firings on a 7 STW, but that was with much more pressure than you're dealing with, and crappy brass. </div></div>
remington brass
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Shiredude</div><div class="ubbcode-body">what kind of brass?
I used to have splitting problems after 2 firings on a 7 STW, but that was with much more pressure than you're dealing with, and crappy brass. </div></div>
remington brass
Re: What causes split necks? help please
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: roggom</div><div class="ubbcode-body">Make sure to trim and chamfer your brass. If you have more than a few reloads in this brass you need to anneal the case mouths. Try annealing a few and compare to ones not annealed.
Not sure if you have done it before, but a google search can get you a step by step. I do it in low light to make sure my case mouth never gets past a very very dim red. Cherry and you ruin the brass.
</div></div>
He hasn't ever tried annealing, but he does prep his brass, trim, chamfer, debur, whole nine yards. He's waiting on Lapua brass but I wondered if the neck was to loose if it would even help anything.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: roggom</div><div class="ubbcode-body">Make sure to trim and chamfer your brass. If you have more than a few reloads in this brass you need to anneal the case mouths. Try annealing a few and compare to ones not annealed.
Not sure if you have done it before, but a google search can get you a step by step. I do it in low light to make sure my case mouth never gets past a very very dim red. Cherry and you ruin the brass.
</div></div>
He hasn't ever tried annealing, but he does prep his brass, trim, chamfer, debur, whole nine yards. He's waiting on Lapua brass but I wondered if the neck was to loose if it would even help anything.
Re: What causes split necks? help please
http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=1269188#Post1269188
First page about 1/3rd way down posts by suasponte gives very clear and proper directions.
This most closely duplicates how it is done in the arsenals.
The arsenals do not set cases in water, they don't quench them in water, they don't heat them red hot.
http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=1269188#Post1269188
First page about 1/3rd way down posts by suasponte gives very clear and proper directions.
This most closely duplicates how it is done in the arsenals.
The arsenals do not set cases in water, they don't quench them in water, they don't heat them red hot.
Re: What causes split necks? help please
Check the chamber.....Sounds to be on the big side to me.
LG
Check the chamber.....Sounds to be on the big side to me.
LG
Re: What causes split necks? help please
Since you have measured the brass to compare loaded vs fired, just set up the sizing die to bump the shoulder.002-.003 back from the fired dimension. Granted, since this chamber does seem a tad large, using a standard sizing die set up to just bump the shoulder may not come close to sizing the body.
But for sure, setting the shoulder back each time by .010" is certainly working the brass.
Since you have measured the brass to compare loaded vs fired, just set up the sizing die to bump the shoulder.002-.003 back from the fired dimension. Granted, since this chamber does seem a tad large, using a standard sizing die set up to just bump the shoulder may not come close to sizing the body.
But for sure, setting the shoulder back each time by .010" is certainly working the brass.
Re: What causes split necks? help please
Annealing usually sorts it out but if it keeps on happening could be another issue at play
Annealing usually sorts it out but if it keeps on happening could be another issue at play
Re: What causes split necks? help please
Brass work hardens. That means that when you deform it permanently (by sizing it or by firing it), it gets harder, stronger, and more brittle. The effect of work hardening is cumulative. So eventually, you get a a very hard neck that splits on firing (or during sizing).
Work hardening can be reversed by annealing. Just make sure you know what your'e doing when you anneal brass, because if you do it wrong, you can soften the wrong parts of the brass, which can be problematic at best, dangerous at worst.
Work hardening can be mitigated by minimizing the amount of sizing you do, and also by tight clearances between the loaded round and the chamber. Benchrest brass, where they keep clearances down to as little as 0.001" on the neck and often size only the neck, will last many times longer than regular brass in factory chambers.
BUT - Keeping those tolerances requires diligence, knowledge, and the proper tools. Unless it's done properly, you're asking for trouble in the form of stuck cases and/or spiking pressures. That .001" clearance I mentioned above is not normal, and is not something that should be done without knowing EXACTLY what is going on. A more reasonable match clearance is more like .004-.005" (on the diameter). Factory will be higher than that.
Brass work hardens. That means that when you deform it permanently (by sizing it or by firing it), it gets harder, stronger, and more brittle. The effect of work hardening is cumulative. So eventually, you get a a very hard neck that splits on firing (or during sizing).
Work hardening can be reversed by annealing. Just make sure you know what your'e doing when you anneal brass, because if you do it wrong, you can soften the wrong parts of the brass, which can be problematic at best, dangerous at worst.
Work hardening can be mitigated by minimizing the amount of sizing you do, and also by tight clearances between the loaded round and the chamber. Benchrest brass, where they keep clearances down to as little as 0.001" on the neck and often size only the neck, will last many times longer than regular brass in factory chambers.
BUT - Keeping those tolerances requires diligence, knowledge, and the proper tools. Unless it's done properly, you're asking for trouble in the form of stuck cases and/or spiking pressures. That .001" clearance I mentioned above is not normal, and is not something that should be done without knowing EXACTLY what is going on. A more reasonable match clearance is more like .004-.005" (on the diameter). Factory will be higher than that.
Re: What causes split necks? help please
I happen to have a lot (100 count) of brass with 30 reload cycles on them. The rifle they are fired in has a large diameter neck (Remmy) and the brass comes out obturated to 0.3445". I size this down in two steps with a 0.338 bushing and a second bushing at 0.332. In between the two bushings I do my length trim, chamfer, and deburr. After Neck-Only sizing most of the time, the brass spend 2-6 hours in the tumbler (I like shiny brass).
This brass has never been annealed*. {I have nothing against annealing, this just happens to be an ongoing experiment I am running.}
All 30 reload cycles have use 47.8 gr Varget and push 155 Scenars to 2925-2950 fps--so you can't say it is NOT a stiff load.
After 30 reload cycle (and on the 29 cycle) I lost 2 cases due to a body crack and culled out 2 more for inisipient case head separation. The other 96 remain in circulation. I am yet to loose a neck or a primer pocket.
{Winchester Brass.}
I happen to have a lot (100 count) of brass with 30 reload cycles on them. The rifle they are fired in has a large diameter neck (Remmy) and the brass comes out obturated to 0.3445". I size this down in two steps with a 0.338 bushing and a second bushing at 0.332. In between the two bushings I do my length trim, chamfer, and deburr. After Neck-Only sizing most of the time, the brass spend 2-6 hours in the tumbler (I like shiny brass).
This brass has never been annealed*. {I have nothing against annealing, this just happens to be an ongoing experiment I am running.}
All 30 reload cycles have use 47.8 gr Varget and push 155 Scenars to 2925-2950 fps--so you can't say it is NOT a stiff load.
After 30 reload cycle (and on the 29 cycle) I lost 2 cases due to a body crack and culled out 2 more for inisipient case head separation. The other 96 remain in circulation. I am yet to loose a neck or a primer pocket.
{Winchester Brass.}
Re: What causes split necks? help please
It sounds to me like he may have neck trimmed the neck wall too thin for the chamber neck size. If that is the case then the neck is expanding and contracting too much, quickly work hardening the brass.
Check one of his prepped cases neck wall thickness.
Compare that to an unaltered / untrimmed case.
It sounds to me like he may have neck trimmed the neck wall too thin for the chamber neck size. If that is the case then the neck is expanding and contracting too much, quickly work hardening the brass.
Check one of his prepped cases neck wall thickness.
Compare that to an unaltered / untrimmed case.
Re: What causes split necks? help please
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: WARDOG</div><div class="ubbcode-body">It sounds to me like he may have neck trimmed the neck wall too thin for the chamber neck size. If that is the case then the neck is expanding and contracting too much, quickly work hardening the brass.
Check one of his prepped cases neck wall thickness.
Compare that to an unaltered / untrimmed case. </div></div>
Sorry for any confusion but he doesn't trim the necks at all, he just trims the brass length, and chamfers it.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: WARDOG</div><div class="ubbcode-body">It sounds to me like he may have neck trimmed the neck wall too thin for the chamber neck size. If that is the case then the neck is expanding and contracting too much, quickly work hardening the brass.
Check one of his prepped cases neck wall thickness.
Compare that to an unaltered / untrimmed case. </div></div>
Sorry for any confusion but he doesn't trim the necks at all, he just trims the brass length, and chamfers it.
Re: What causes split necks? help please
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MitchAlsup</div><div class="ubbcode-body">I happen to have a lot (100 count) of brass with 30 reload cycles on them. The rifle they are fired in has a large diameter neck (Remmy) and the brass comes out obturated to 0.3445". I size this down in two steps with a 0.338 bushing and a second bushing at 0.332. In between the two bushings I do my length trim, chamfer, and deburr. After Neck-Only sizing most of the time, the brass spend 2-6 hours in the tumbler (I like shiny brass).
This brass has never been annealed*. {I have nothing against annealing, this just happens to be an ongoing experiment I am running.}
All 30 reload cycles have use 47.8 gr Varget and push 155 Scenars to 2925-2950 fps--so you can't say it is NOT a stiff load.
After 30 reload cycle (and on the 29 cycle) I lost 2 cases due to a body crack and culled out 2 more for inisipient case head separation. The other 96 remain in circulation. I am yet to loose a neck or a primer pocket.
{Winchester Brass.} </div></div>
Shit dude... 30 loads and no annealing. Thats heresy!
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MitchAlsup</div><div class="ubbcode-body">I happen to have a lot (100 count) of brass with 30 reload cycles on them. The rifle they are fired in has a large diameter neck (Remmy) and the brass comes out obturated to 0.3445". I size this down in two steps with a 0.338 bushing and a second bushing at 0.332. In between the two bushings I do my length trim, chamfer, and deburr. After Neck-Only sizing most of the time, the brass spend 2-6 hours in the tumbler (I like shiny brass).
This brass has never been annealed*. {I have nothing against annealing, this just happens to be an ongoing experiment I am running.}
All 30 reload cycles have use 47.8 gr Varget and push 155 Scenars to 2925-2950 fps--so you can't say it is NOT a stiff load.
After 30 reload cycle (and on the 29 cycle) I lost 2 cases due to a body crack and culled out 2 more for inisipient case head separation. The other 96 remain in circulation. I am yet to loose a neck or a primer pocket.
{Winchester Brass.} </div></div>
Shit dude... 30 loads and no annealing. Thats heresy!
Re: What causes split necks? help please
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: vman</div><div class="ubbcode-body">Shit dude... 30 loads and no annealing. Thats heresy!
</div></div>
I understand the heretical nature of the ongoing experiment. But the experiment (show) must go on.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: vman</div><div class="ubbcode-body">Shit dude... 30 loads and no annealing. Thats heresy!
I understand the heretical nature of the ongoing experiment. But the experiment (show) must go on.
Re: What causes split necks? help please
I've seen some dies that *really* work the brass. Take the expander ball out of the die, size a case and see what you get. The brass could be going from fired condition, to (say for example) 0.015" under in the die, then back out (say for example) 0.010" under from the expander ball, then maybe 0.007" under with a bullet seated, then back to fired condition.
I've seen some dies that *really* work the brass. Take the expander ball out of the die, size a case and see what you get. The brass could be going from fired condition, to (say for example) 0.015" under in the die, then back out (say for example) 0.010" under from the expander ball, then maybe 0.007" under with a bullet seated, then back to fired condition.
