Is there a way to increase case life? Yes there is
03-18-2016, 10:29 AM
#1
Spike
Thread Starter
Join Date: Mar 2016
Location: Aiken, South Carolina
Posts: 55
Is there a way to increase case life? Yes there is
Brass life depends on how you care for it, how it was fabricated and how it was designed and of course how you load it. Commercial brass is generally not designed for long case life.
I had contacts at Remington and Winchester over the years and both considered 5 to 7 rounds to be the life of their center fire rifle brass.
I noted a much shorter life from Federal brass which was confirmed was a result of their fabrications by Federal engineers who stopped by the National High Power Rifle Championships back in the 80s and I learned from them that their case draw procedures present a condition that while safe to fire initially do not lend themselves to sustained reloadings because the primer pockets open quickly which is evidenced when new primers are inserted. My rule on Federal is load it twice and forget it.
Cases fail for three reasons, the necks crack and the primer pockets loosen up and the dimensions of SAAMI chambers allow for expansions that when FL resized shorten your case life which will give you incipient separation failures. You can continue to load loose primer pockets at the expense of sustaining gas leakage around the primers which will flame cut your bolt face.
These failures can be mitigated by mating dies to chambers but the best bet is if you keep a rifle long enough to shoot out the barrel and replace it with a new barrel and have a chamber cut that does not allow a new cartridge case to expand over .002" in any direction on firing. I call this the 222 rule which i.e. the bases do not expand over .002", the necks do not expand over .002" and the rifle is headspaced tightly so the shoulder does not go over .002" forward on firing.
This begs the question why? Cases are expensive these days.
SAAMI specs for 30.06 chambers are allowed to expand outwards and give birth to cases with base dimension of .473 (I have miced fired cases at .475 in factory 30.06 rifles. If you measure the base of a commercial or gov't 30.06 case .200 up from the case rim it should be .465" diameter. Necks have a similar expansion which stretches them way further than needed.
My two custom reamers in 30.06 cut a .4675 base dimension or a .469 base dimension and the necks at .3375. Thus when a new unfired round is inserted and fired the cases expand a tad and spring back to almost unfired conditions. Thus my chambers will accept any commercial ammunition made but are designed to increase its useful life by being able to reload it multiple times.
What does this do? How is it done?
I dedicated 500 cases for my No1 Course Gun (Mod 70 Win Target in 30.06) in 1982 time frame. I shot out the first barrel with them, replaced that barrel and shot out a second barrel and replaced that and it has over 2000 rounds on it now. None of the cases show any signs of starting to fail.
With the cost of ammo these days you need to reload and be aware of how you can increase your brass life. To that end I will post a thread shortly on how to stress relieve necks and shoulders to achieve a much longer life in those areas.
The nicest brass I ever loaded (for a friend) was DWM, the necks were extremely uniform and the primer pockets were very tight on fired cases.
Many highpower competitors use Lapua. I personally do not for the following reasons.
The brass that will hold up the longest are the M72 30.06 Match and the M118/M118LR 7.62 match cases. The heads on the military cases have a hardness gradient callout on the drawings and the heads have to be "hard" to sustain the extraction forces of MGs.
When the gov't arsenals start drawing cases on a production line a case is a case in the beginning stages so it all has hard heads. Thus the ball/tracer/AP/Match all start life equally.
There is a neck wall tolerance on ball brass that is larger than match brass but dimensionally they are equal. One has the primer's crimped in and the MATCH does not.
I have conducted sustained loading tests and I have reloaded M118 Match cases 75 and 90 times. I have one M72 match case I have loaded 157 times and the primer pocket is still snug.
Yogi Berra had a famous quote I like to use, "You don't know what you don't know till you know what you don't know." and Yogi would have been a prime candidate to learn reloading.
Just wondering do any of you guys use a chronograph or have access to one? If so advise and I will post so help for using them as well.
I had contacts at Remington and Winchester over the years and both considered 5 to 7 rounds to be the life of their center fire rifle brass.
I noted a much shorter life from Federal brass which was confirmed was a result of their fabrications by Federal engineers who stopped by the National High Power Rifle Championships back in the 80s and I learned from them that their case draw procedures present a condition that while safe to fire initially do not lend themselves to sustained reloadings because the primer pockets open quickly which is evidenced when new primers are inserted. My rule on Federal is load it twice and forget it.
Cases fail for three reasons, the necks crack and the primer pockets loosen up and the dimensions of SAAMI chambers allow for expansions that when FL resized shorten your case life which will give you incipient separation failures. You can continue to load loose primer pockets at the expense of sustaining gas leakage around the primers which will flame cut your bolt face.
These failures can be mitigated by mating dies to chambers but the best bet is if you keep a rifle long enough to shoot out the barrel and replace it with a new barrel and have a chamber cut that does not allow a new cartridge case to expand over .002" in any direction on firing. I call this the 222 rule which i.e. the bases do not expand over .002", the necks do not expand over .002" and the rifle is headspaced tightly so the shoulder does not go over .002" forward on firing.
This begs the question why? Cases are expensive these days.
SAAMI specs for 30.06 chambers are allowed to expand outwards and give birth to cases with base dimension of .473 (I have miced fired cases at .475 in factory 30.06 rifles. If you measure the base of a commercial or gov't 30.06 case .200 up from the case rim it should be .465" diameter. Necks have a similar expansion which stretches them way further than needed.
My two custom reamers in 30.06 cut a .4675 base dimension or a .469 base dimension and the necks at .3375. Thus when a new unfired round is inserted and fired the cases expand a tad and spring back to almost unfired conditions. Thus my chambers will accept any commercial ammunition made but are designed to increase its useful life by being able to reload it multiple times.
What does this do? How is it done?
I dedicated 500 cases for my No1 Course Gun (Mod 70 Win Target in 30.06) in 1982 time frame. I shot out the first barrel with them, replaced that barrel and shot out a second barrel and replaced that and it has over 2000 rounds on it now. None of the cases show any signs of starting to fail.
With the cost of ammo these days you need to reload and be aware of how you can increase your brass life. To that end I will post a thread shortly on how to stress relieve necks and shoulders to achieve a much longer life in those areas.
The nicest brass I ever loaded (for a friend) was DWM, the necks were extremely uniform and the primer pockets were very tight on fired cases.
Many highpower competitors use Lapua. I personally do not for the following reasons.
The brass that will hold up the longest are the M72 30.06 Match and the M118/M118LR 7.62 match cases. The heads on the military cases have a hardness gradient callout on the drawings and the heads have to be "hard" to sustain the extraction forces of MGs.
When the gov't arsenals start drawing cases on a production line a case is a case in the beginning stages so it all has hard heads. Thus the ball/tracer/AP/Match all start life equally.
There is a neck wall tolerance on ball brass that is larger than match brass but dimensionally they are equal. One has the primer's crimped in and the MATCH does not.
I have conducted sustained loading tests and I have reloaded M118 Match cases 75 and 90 times. I have one M72 match case I have loaded 157 times and the primer pocket is still snug.
Yogi Berra had a famous quote I like to use, "You don't know what you don't know till you know what you don't know." and Yogi would have been a prime candidate to learn reloading.
Just wondering do any of you guys use a chronograph or have access to one? If so advise and I will post so help for using them as well.
03-18-2016, 02:44 PM
#2
Nontypical Buck
Join Date: Feb 2003
Location: Eastern wv
Posts: 3,648
brass is a mixture of copper and tin, tin makes it harder copper makes it softer, the exact mixture, combined with chamber size, and how much pressure you load them with is the key to brass life, if not given room to stretch in the chamber, it won't until your pressures exceed what the brass itself can withstand, this is why custom chambers will exceed factory ones in MV but not show signs of higher pressure. your chambers actual size compared to your die setting has more to do with pressure than anything when your looking at case life. seating depth is also a major culprit, you can be shooting under max velocity loads but still over pressure due to pressure spikes from seating too long.
RR
RR
03-18-2016, 07:05 PM
#3
Spike
Thread Starter
Join Date: Mar 2016
Location: Aiken, South Carolina
Posts: 55
As well brass work hardens when it is reshaped and goes through the forming operations.
Per the Federal engineers they explained why theirs was on the soft side as they figured out a way to skip one of the normal draw operations in forming the brass.
When I was at Aberdeen PG we did a Rockwell Test on a S&W Revolver and a LC M118 MATCH case and the LC case was harder than the S&W revolver frame which surprised all of us. Both were on B scale.
Per the Federal engineers they explained why theirs was on the soft side as they figured out a way to skip one of the normal draw operations in forming the brass.
When I was at Aberdeen PG we did a Rockwell Test on a S&W Revolver and a LC M118 MATCH case and the LC case was harder than the S&W revolver frame which surprised all of us. Both were on B scale.
Last edited by Hummer70; 03-19-2016 at 04:40 AM.
03-19-2016, 07:24 AM
#5
Spike
Thread Starter
Join Date: Mar 2016
Location: Aiken, South Carolina
Posts: 55
I use Lake City Match cases to form other cartridges. The 7.62 I make 7/08 with and 260 and 358 Win.
The 30.06 I make 6.5X06, and 35 Whelen.
I generally try to only buy rifles I can make cases for from the above "standards".
I have one 308 Win custom reamer that requires loaded ammo to have the necks turned and be no larger than .335" as the reamer cuts a .336 throat. That insures the bullet eases into the throat on firing dead center because the case neck is the same thickness all the way around.
It is not uncommon to find case neck variations of 7.62/308 cases as much as .007" which means your bullet is way off center before it starts to move.
Years ago the military teams would leave it laying for us and I was a human vacuum cleaner ! ! ! !
The 30.06 I make 6.5X06, and 35 Whelen.
I generally try to only buy rifles I can make cases for from the above "standards".
I have one 308 Win custom reamer that requires loaded ammo to have the necks turned and be no larger than .335" as the reamer cuts a .336 throat. That insures the bullet eases into the throat on firing dead center because the case neck is the same thickness all the way around.
It is not uncommon to find case neck variations of 7.62/308 cases as much as .007" which means your bullet is way off center before it starts to move.
Years ago the military teams would leave it laying for us and I was a human vacuum cleaner ! ! ! !
Last edited by Hummer70; 03-19-2016 at 07:31 AM.
03-19-2016, 08:54 AM
#6
Nontypical Buck
Join Date: Oct 2009
Location: Kansas
Posts: 3,903
Hummer70 - and anyone looking to follow this kind of case annealing or stress relieving process.
One good thing to come out of Lee is their case cutter lock stud - but not for what it was meant to be used. I used to use the lock stud and the case holder from their case length gauges to hold cases for annealing.
Use the lock stud from this set ($8):
And the case holder "nut" from this set ($6 per cartridge head size):
One good thing to come out of Lee is their case cutter lock stud - but not for what it was meant to be used. I used to use the lock stud and the case holder from their case length gauges to hold cases for annealing.
Use the lock stud from this set ($8):
And the case holder "nut" from this set ($6 per cartridge head size):
04-09-2016, 07:15 AM
#9
Nontypical Buck
Join Date: Feb 2003
Location: Eastern wv
Posts: 3,648
the less you work your brass, the longer it will last, I shoot a high intensity cartridge called the 7MM Allen Mag, basically a 7mm/338 Lapua AI, it will run a 160 accubond at 3575 fps with a top level load, I have 3.00 in each case when I load it the first time so I take care of them. I load them with 110 gr of a very slow burning powder that is designed for the 50 BMG and the 20MM Vulcan cannon called WC872, I anneal my cases every other
loading and I get 5-6 loadings from each case before I notice the pocket getting loose. the guy who designed the cartridge and built the rifle recommends loading them to 3700 fps and trash them after the pocket gets loose after the third loading, I've killed deer with this combo at 3575 fps way beyond 1000 yards so I want all the life I can get from them.
RR
loading and I get 5-6 loadings from each case before I notice the pocket getting loose. the guy who designed the cartridge and built the rifle recommends loading them to 3700 fps and trash them after the pocket gets loose after the third loading, I've killed deer with this combo at 3575 fps way beyond 1000 yards so I want all the life I can get from them.
RR
