The Firing Line Forums

Go Back   The Firing Line Forums > The Skunkworks > Handloading, Reloading, and Bullet Casting

Reply
 
Thread Tools
Old June 19, 2007, 09:48 PM   #1
Glennster
Senior Member
 
Join Date: July 31, 2005
Location: Northern Indiana
Posts: 226
.308 Brass- use it how many times?

I've got some Lapua (.308) brass I've loaded 5 times. How many times can I load it and maintain safety and accuracy?
Glennster is offline  
Old June 19, 2007, 10:05 PM   #2
T-Bear
Senior Member
 
Join Date: November 23, 2005
Posts: 119
It all depends on the rifle chamber, wieght of charge's, FL or Neck sized only.
You can get anywhere from 3-10 times out of brass.
Give us some history of the brass so we can a better idea.
T-Bear is offline  
Old June 20, 2007, 05:37 AM   #3
Glennster
Senior Member
 
Join Date: July 31, 2005
Location: Northern Indiana
Posts: 226
The load I'm using is : 43.5 gr. of BL-C2, with a 168 gr. Berger VLD. It's a Remington action with a Krieger 1:13 twist barrel.
I only neck sized the first few times. The last three times I ran them through the full length die because they where chambering a little hard. The accuracy has been 1/2 MOA or better.
Glennster is offline  
Old June 20, 2007, 09:50 AM   #4
Tanzer
Senior Member
 
Join Date: February 18, 2007
Posts: 884
How are the primer pockets holding out? Rifle brass tends to "flow" forward. be wary of this as they get used. Don't just ram 'em in when they chamber poorly, they may be getting thick up front.
__________________
Only the ignorant find ignorance to be bliss. Only those of us who know better will suffer from it.
Tanzer is offline  
Old June 21, 2007, 04:34 PM   #5
Slamfire
Senior Member
 
Join Date: May 27, 2007
Posts: 4,079
That is a very interesting question. I will give my opinion.

Case life depends on the tightness of the primer pocket and when the case necks split.

Assuming that your resizing process does not cause case head separations by setting the case shoulders back more than .003" or so.

I took brass, in a M1a, shot it in Highpower rifle matches, and took the stuff about 22 or 24 reloads. I lubricated the outside of the cases with Johnson Paste Wax. M1a's extract when there is still pressure in the barrel and that stretches the cases. Without that frictional stress I never had a case head separation or any indication of case head separation in any case at any time. I did get case splits from brass flaws.

I sectioned cases that had body splits, neck cracks, to see what was going on inside. What I noticed was that as the number of reloads increased, brass was being washed out near the case head. The brass had a “spongy’ appearance.

The last I shot it was at Rattle Battle at Camp Perry. Still I picked up some of my cases. Don’t plan to reload it anymore, the pockets won’t hold primers very tightly, and I think with the spongy internal appearance, maybe 20 times is prudent limit. I would not argue if the limit was less.
Slamfire is offline  
Old June 21, 2007, 04:59 PM   #6
W.E.G.
Senior Member
 
Join Date: March 11, 2007
Location: all over Virginia
Posts: 266
I know I'm pretty new on this board, so I don't want to sound argumentative.

But, paste wax on the exterior of the case?

That's a new one to me. You got by with it 20 times (on each case no less!) by your account. It must not be overly dangerous, since your post does not appear to be typed in braille.

I still gotta wonder whether defeating the system that causes the brass to grip the inside of the chamber might allow the bolt to move back with greater force than normal. Maybe peen the inside of the receiver when the bolt strikes it harder than usual.

When I was shooting the M14 (without paste wax on the cartridge cases), I would get three or four loads out of a batch of Lake City Match brass before I would start to see signs of the brass weakening (stretch-rings or outright head separations). And I was using an RCBS precision mic to be sure I was not setting-back the shoulder too far on resizing. Loads were usually 41.5 grains IMR 4895 and a 168 grain Matchking bullet.

I hear of the bolt-gun crowd getting many more loads by just neck-sizing. If you stick with mild loads in a bolt gun, I think you might get an impressive number of reloads from a single case.
W.E.G. is offline  
Old June 21, 2007, 06:39 PM   #7
Slamfire
Senior Member
 
Join Date: May 27, 2007
Posts: 4,079
What you are repeating is the echo created by the shill gunwriters of the 70’s and the 80’s. It kind of evolved from Hatcher’s Notebook. Remember in that book the 1921 tin can ammo? The bullet cold soldered itself to the case neck. The Ordnance Department did a CYA and blamed civilians for the rifle blow ups instead of acknowledging the bore obstruction they created. It was a common practice at the time to grease bullets to reduce jacket fouling. The Ordnance Department “proved” that greased bullets were dangerous. According to the book, you are putting your life in risk every time you shoot a moly lube bullet. Which I suspect would be a total surprise to all of those who have fired ten of thousands of moly lubed bullets.

Shill gunwriters took the lubricated bullet idea further and claimed that any grease or oil on cases was dangerous. They claimed the case needed to cling to the microscopic pores of the chamber or the gun would blow up.

Which in fact is rubbish. The structural design of a rifle bolt does not assume any load reduction through case friction. You just cannot assume the case takes any loads. Imagine you reduced the lug thickness because you assumed a certain friction reduction from the case. One sneeze, one gob of snot on a case, and the fragile action you designed would shed its lugs.

To push this further, friction is bad. Case friction requires extra force to peal the case off the chamber walls. So you need, in the real world, heavier extractors, more gas going through the mechanism, heavier springs, etc. Life would be much easier for a designer if the case was frictionless.

Blowback actions need lubricated cases, or they won’t function. Lacquer on steel cases provide dual functions of rust protection and a lubrication barrier to prevent steel on steel contact. And then there is the Peterson Rifle which used wax on the cases. Examine the G3 rifle. The chambers are fluted to float the upper 2/3rds of the case off the chamber walls.

And in fact, case life in the M1 and M1a is reduced because the front of the case is sticking to the chamber during unlock. That's the major cause of case head separation in those rifles. Eliminate the friction and you lose the stretch line.

As long as the ammunition is within spec for pressure, you won’t overload the bolt. If the ammunition is overpressure, well cut your loads, overpressure is bad regardless of case condition.
Slamfire is offline  
Old June 22, 2007, 09:33 AM   #8
L Puckett
Senior Member
 
Join Date: March 2, 2002
Location: Mid-Tennessee
Posts: 150
Glennster,

In your bolt rifle, if you try to maintain no more than .002 shoulder setback and anneal the necks every 3-5 firing you should see 20 reloads in Lapua.

I have found that neck splits from no annealing and head seperation (thining) from excessive setback are the limiting factors in Lapua brass. Primer pocket stretch has been a non-issue with Lapua.

These tests were conducted using relatively hot loads for 1000 yrd shooting in several different bolt rifles. Your mileage may vary dependent on your procedures.

LP
L Puckett is offline  
Old June 22, 2007, 05:11 PM   #9
dutchy
Senior Member
 
Join Date: May 30, 2005
Location: Holland
Posts: 196
About 25 years ago, I bought a very nice swedish mauser.
With the rifle I bought Lapua match ammo, berdan primed.
I used these cases all those years, in the beginning fl resizing, later neck sizing.
Yes, I've lost some due to split necks, but still use the remaining.
Must have reloaded them at least 20 times, probably more.
I once stress relieved them by heating, but that was too much work for me.
Important: my loads are not for hunting, but for target, and I consider them to be moderate.
dutchy is offline  
Old June 22, 2007, 05:56 PM   #10
Glennster
Senior Member
 
Join Date: July 31, 2005
Location: Northern Indiana
Posts: 226
dutchy,
How do you get the berdan primers out of the case?
Glennster is offline  
Old June 22, 2007, 06:25 PM   #11
dgc940
Senior Member
 
Join Date: September 15, 2005
Location: Graham Texas
Posts: 258
did yall also read where he has a Krieger barrel? I also bet his smith didnt make his chamber as loose as the factorys do! so this meens his brass dosent get the work over that factory rifle brass gets. and if he uses bushing dies and controls the neck exspansion to a degree well you get the picture!
I guess I should tell my lapua brass it needs to die! they have about 20-25 reloads on them. but Im not trying to set fps records either!
__________________
Some people say what they think!
Some say what they know!
Then there's those that think they know what they are saying!
dgc940 is offline  
Old June 23, 2007, 02:53 AM   #12
k Squared
Senior Member
 
Join Date: June 10, 2007
Location: Albuquerque, NM
Posts: 223
Johnson Paste Wax

SlamFire1,

Your Johnson Paste Wax technique caught my attention.

How do you apply the wax and how often do you do it?
__________________
K Squared
k Squared is offline  
Old June 23, 2007, 08:01 AM   #13
Slamfire
Senior Member
 
Join Date: May 27, 2007
Posts: 4,079
Quote:
Your Johnson Paste Wax technique caught my attention.

How do you apply the wax and how often do you do it?
I paste wax all my match M1a and M1 Garand ammunition. Each and every reload. I have a bean bag chair in front of the TV and I lay down, propped up by the chair, and with my fingers and a felt shirt patch apply the paste.

I have a cake pan with loaded rounds, and I will pick up a round, rotate it in my fingers with paste wax on the patch, and coat the entire case. I make sure that the shoulder has a good coating. Then I toss the coated case in a plastic dishwashing pan.

I let the stuff dry.

I used to leave the cases as is, but I found at Camp Perry on a unusually cold day, that gobs of paste wax will slow the rise of the cartridges from the magazine. So I had an alibi due to the bolt closing on an empty chamber. Since then I have polished my rapid fire rounds. Just takes a couple of swipes with a clean felt rag or shop rag.

The Distinguished HM Gunsmith I got the idea from simply left RCBS case lube on the outside of his cases. His cases felt slightly greasy. I tried this, worked well, but I did not like the fact they would pick up dirt/dust, so I tried paste wax.

You do not need much of a lubricant layer to get the benefits of lubrication. I suspect the RCBS lube thickness or even the paste wax layer is in the order of thousands or tens of thousands of an inch.

I am of the opinion that most store bought factory rounds are coated with an invisible wax coating to keep them shiny. This is based on examination of corrosion patterns of cases; some of them look like the corrosion is going under something.

Lubricating cases is absolutely unnecessary for bolt guns or my AR's. There is no pressure to stretch the case when your hand reaches the bolt handle, and the pressure curve in the AR is such that case life is quite good. I am up to five reloads without the slightest sign of case head separations.
Slamfire is offline  
Old June 23, 2007, 10:07 AM   #14
Unclenick
Staff
 
Join Date: March 4, 2005
Location: Ohio
Posts: 10,247
The Pederson rifle did indeed lube the cases, but not with wax, IIRC. It had oiler pads built into the magazines.

Varmint Al has a finite element model showing case stress and boltface thrust on firing on his web site. It shows that within the coefficient of friction of common petroleum-based lubes, the brass still sticks to the chamber wall, just not as well.

You can test this very simply. During normal firing of a FL resized case, the firing pin pushes the whole cartridge forward against the headspace stop (shoulder, for most of us, but rim or belt in cartridges with those features). As the powder starts to burn, the cartridge is in this forward position. In a high power rifle, the pressure builds far enough to expand the case web (walls) and by simple friction will stick them to the chamber walls before the bullet is released from the neck. Only after the bullet is released by the neck does the pressure try to push the case rearward. At this point, if the case has stuck to the chamber wall, the casehead can move rearward only by stretching the web where it meets the casehead. This is the cause of the thinned ring of brass that eventually results in casehead separation.

If cases didn't stick, thinning and casehead separation would not occur. It is why you don't see the problem in most pistol and lower pressure chambering that do not have enough pressure to stick to the chamber wall. The threshold is usually in loads with around 30,000 PSI peak pressure, but also depends on the case geometry. It is also why lower pressure pistol rounds never needing the cases trimmed. They can actually shorten with resizing, which flows the brass rearward.

Al's analysis shows that some old beliefs about case sticking are false. Increased boltface thrust does occur, but it isn't terribly significant until the coefficient of friction is greatly reduced. Merely polishing a chamber does not reduce friction enough to make serious trouble. In his modeling, a normal chamber boltface thrust of around 4500 pounds is increased to about 7600 pounds when the coefficient of fricition is reduced to 0.01. That is the half the coefficient of friction of molybdenum disulfide (moly). By comparison, a greased chamber COF is about 0.11. That only raises boltface thrust about 8%. If your bolt lugs are not lapped or are otherwise uneven. that can increase stringing along the closed lug axis. With a blueprinted gun, it shouldn't matter much, as long as it is uniform.

As with the Pederson design, a lubed case will help extraction in a self-loader because the pressure drops enough for the lube to break friction with the chamber by the time extraction occurs. I am more inclined to try polishing the chamber first, and see whether that doesn't helps enough? I have a new M1A barrel, and I will try this when I chamber it. All lists COF for very rough down to polished chambers as going from about 0.55 down to 0.19.

I have heard of benchrest shooters getting 50 reloads from a case. These would be cases neck-sized only until they get too hard to fit. At that point the benchresters use a special die called a bump die. It pushes the shoulder back without narrowing the web.

The forward flow of brass mentioned earlier accumulates where the shoulder and neck meet. The effect is to narrow the base of the neck by forming a thickened brass ring inside it. This is commonly called, "the dreaded donut." It must be removed with an inside neck reamer. That becomes a regular step for benchresters, done when they trim a case.
__________________
Gunsite Orange Hat Family Member
CMP Certified GSM Master Instructor
NRA Certified Rifle Instructor
NRA Benefactor Member
Unclenick is offline  
Old June 23, 2007, 11:36 AM   #15
Slamfire
Senior Member
 
Join Date: May 27, 2007
Posts: 4,079
Quote:
“Al's analysis shows that some old beliefs about case sticking are false. Increased boltface thrust does occur, but it isn't terribly significant until the coefficient of friction is greatly reduced. Merely polishing a chamber does not reduce friction enough to make serious trouble. In his modeling, a normal chamber boltface thrust of around 4500 pounds is increased to about 7600 pounds when the coefficient of fricition is reduced to 0.01. That is the half the coefficient of friction of molybdenum disulfide (moly). By comparison, a greased chamber COF is about 0.11. That only raises boltface thrust about 8%.”

What an excellent reply. Previously I have visited Varmit Al’s web page and examined the simulation and found it fascinating. If you notice, as the friction between the case and the chamber is reduced, so is the strain on the case. That is reducing case friction reduces material damage to the case. Which is all to the good because it is the case that is the weakest link in the system, not the bolt lugs.

Quote:
"If your bolt lugs are not lapped or are otherwise uneven. that can increase stringing along the closed lug axis. With a blueprinted gun, it shouldn't matter much, as long as it is uniform.”
That is probably a true statement, but I doubt it is a significant error contributor for a sport like highpower shooting, where the human error is the dominant factor. I tell the gunsmith not to lap the lugs as long as I have close to 70% lug contact. Whatever accuracy is gained is not worth the function problems when any case or surface finish hardening is removed. I had a stainless steel Winchester just gall and gall after lug truing. I believe Winchester had some surface finish, and truing did not help things. Indeed talking to Gunsmith and Long Range Champion Randy Gregory of Medford WI, lugs may set themselves in. Randy used a old model Ruger M77 for 10 years and 45,000 rounds. Had 11 barrels on rifle. Measured set-back from receiver ring to bolt face. Said that around barrel 5 or 6 the set back was 7 thousand of inch. (.007”). No more increase after that.

Quote:
“The Pederson rifle did indeed lube the cases, but not with wax, IIRC. It had oiler pads built into the magazines.”
I am certain your memory is a bit fuzzy on this. There absolutely were mechanisms in the early days of automatic weapons that used oilers. Indeed, Col Chin’s Vol IV Book of the Machine Gun shows all sorts of variations, but according to Hatcher, Pederson used a wax coating. And the criticism of the coating must have irritated Hatcher as “much ado about nothing”. He was so understated and never expressed a strong negative opinion in his writing, but he mentioned this in his discussion of the Peterson rifle. I think that is one of the few times you see the curtain slip, and detect in him a level of frustration with the unfairness in the behind the scenes politicking that occurs with all procurements.
Slamfire is offline  
Old June 26, 2007, 11:07 AM   #16
Unclenick
Staff
 
Join Date: March 4, 2005
Location: Ohio
Posts: 10,247
On J.D. Pederson's rifle, you are correct. I was remembering Hatcher's description of the Thompson Caliber .30 Autorifle. On page 62 of The Book of the Garand, Hatcher says of it, "this system functions quite satisfactorily, providing the cartridge cases are lubricated with a thin film of sperm oil which is placed on the cases by means of a double set of oil pads located on each side of the interior of the magazine."

Regarding lug lapping, you need to know the heat treating method applied to the steel. Locally carburized (case-hardened) steel, or locally flame hardened and lightly drawn back surfaces may have a hardened skin that is just a few thousandths thick. If you don't lap below the hardened surface thickness, you should be OK, but you need some idea of what it is? You may not get much over 50-70% coverage on some guns with light lapping, but 100% is far from required. You are just trying to reduce elastic flow enough to prevent the bolt from tipping under peak pressure.

Harold Vaughn's, Rifle Accuracy Facts (Precision Shooting publisher, 2000), contains a good discussion quantifying of the effects of receiver pressure asymmetries on group sizes. I have to agree with you that this can get well beyond requirements for service rifle match shooting, but isn't always so. I find a lot of people blow-off gun accuracy errors, claiming "it shoots better than I do," only to find their scores go up when they get their hands on a better rifle. I rebuilt some of our club's old DCM Garands decades ago, and users of these loaner rifles were amazed by how much better they could shoot than they had previously believed. We had to pull bullets on a lot of our Lake City M2 ball and replace them with 150 grain SMK's to see the effect, but it did work.

Stainless is famous for gauling. I would not lap stainless before checking with the action maker to see how far it can safely be taken and to learn what kind of surface finish it requires? The radial ridges raised in normal lapping are unacceptable with some S.S. alloy/heat treatment combinations. The only way around it, if the bolt doesn't have enough side play to work them out, is to work only with extremely fine near-finish-grade abrasives, and just expect to spend a long time getting it done.

Are you making it up to Perry this year? I am hoping to, at least hit the EIC and the John C. Garand matches, but may have to be out of town to participate in testing some equipment during that period.
__________________
Gunsite Orange Hat Family Member
CMP Certified GSM Master Instructor
NRA Certified Rifle Instructor
NRA Benefactor Member

Last edited by Unclenick; June 27, 2007 at 09:33 AM.
Unclenick is offline  
Old June 27, 2007, 01:10 PM   #17
Wild Bill Bucks
Senior Member
 
Join Date: December 28, 2005
Location: Southeastern Oklahoma, Next door to Sasquatch
Posts: 1,264
I don't overly load my cartridges, and shoot mostly rounds that I have worked up for hunting. I can load them about 10 times before I start noticing any real wear on them. I inspect them carefully before I re-load them each time, and I could probably load them several more times if I wanted to, but I buy them new for $17.00 per 50 which after loading them 10 times apeice breaks down to about 3.4 cents per round, so I chunk them and buy new brass just to be safe.
Wild Bill Bucks is offline  
Old June 27, 2007, 02:28 PM   #18
crowbeaner
Senior Member
 
Join Date: June 4, 2007
Location: Upstate SC
Posts: 1,938
Just my .02 worth. How about the chrome chamber problem with the M 16, and the malfunctions that occurred when McNamara's whiz kids decided that the plating was too expensive therefore unnecessary? Due to the asinine myth that the rifle was self cleaning and the loss of life resultant, change from stick to ball powder, and all the other bad PR the rifle got, do you think if the chambers had all been chromed that many malfunctions could have been prevented? Or were the MFs all ammo related?
crowbeaner is offline  
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 07:31 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
This site and contents, including all posts, Copyright © 1998-2014 S.W.A.T. Magazine
Copyright Complaints: Please direct DMCA Takedown Notices to the registered agent: thefiringline.com
Contact Us
Page generated in 0.11881 seconds with 9 queries