Info. on 6 X 47 Lapua

Chino69, I guess I was putting false trust into the action testing. Wasn't telling me buggerall:eek: Thanks for your insights.

The way it was explained to me was imagine bending a paper clip back and forth. For a while, it keeps bending but eventually it stops bending and breaks. The less you bend it (lower deflection), the longer it takes to break (if ever).

Bend it too far or too fast and it will break sooner or right away.

Once steel gets 'stretched' it changes it's properties in unpredictable ways and is not reversable. You got a time bomb.

Not something I ever want to find out about....

Jerry
 
Failure

Chino69, I guess I was putting false trust into the action testing. Wasn't telling me buggerall:eek: Thanks for your insights.

The way it was explained to me was imagine bending a paper clip back and forth. For a while, it keeps bending but eventually it stops bending and breaks. The less you bend it (lower deflection), the longer it takes to break (if ever).

Bend it too far or too fast and it will break sooner or right away.

Once steel gets 'stretched' it changes it's properties in unpredictable ways and is not reversable. You got a time bomb.

Not something I ever want to find out about....

Jerry

Jerry,
Your paper clip analogy is as deep as you need to go because you understand the concept perfectly.
Chino69
 
Last edited by a moderator:
al, you are right, Brass will fail before the steel action. however, repeated beatings on said action can lead to a structural failure with less load then expected. It's called metal fatigue.

Same idea as commuter jets blowing their tops. Too many compression cycles.

It's back to proof loads. One bang and nothing blows up. Keep banging away and ???????

You are absolutely right that the new 6.5X47L is the super case. it will survive where other cases fail. 110% in agreement.

The issue I have is that conventional brass like Winchester, has no issue surviving continuous beatings at magnum pressures. Magnum pressures is the top that I feel we should be playing at (max 70,000psi).

if you are loading to levels where a conventional case is loosing primers in only a few firings. You have EXCEEDED the yield strength of brass and I bet that pressure level/elastic limit is well above 70,000psi. Did a quick search but couldn't find the chart I saw before.

I am suspecting that is around 90,000 to 95,000psi. From memory, a commercial action is approaching destructive pressures around 110 to 120,000psi. That's getting really close to 'stretching' stuff in ways not friendly to longevity....nor good health.

Using a brass that has a special alloy with a much higher elastic limit simply allows you to start approaching the limits of the action/barrel.

I am sure that modern BR type actions are built very strong. Maybe they have a life cycle much longer and stronger then a conventional action???? Without knowing what that is, we are only ASSUMING that these actions are stronger or when they will fail.

Steel is steel and there are limits no matter how lofty they may be.

Continuous shooting at proof load pressures, or higher, may be fine for a whole bunch of BR actions but it only takes one failure to ruin your day.

For me, it is simply not worth the risks.

Jerry
 
Ok,


First of all, the paper clip analogy is hopelessly flawed. It has no relevance.


"Bending a paper clip" means bending it beyond it's ability to spring back. In other words BENDING it, not just deflecting it like a spring. If EVER an action is "bent" then it may be considered to be irreparably ruined, destroyed. Now if you just set and fiddle with the paper clip, if you pinch it between thumb and forefinger and LICK it, you've bent it about as much as an action is bent when you fire it. You could lick a paper clip for a loooong time before it failed due to fatigue. (No jokes or brags please :D )


FahGIDDA'bout paper clips, think springs..............the springs on your automobile survive millions of cycles, tens of millions if like me you live on the end of a mile of dirt road.


Factory actions FLEX, like springs, they don't "bend". Every time you drive over a bridge, every time you go into the mall, every time you walk on a floor or slam a door or lean against a wall you're deflecting or flexing the structure. The key is that you don't flex it enough to cause permanent damage. There are SOME isolated instances which the shooting/building trades are well aware of where bolt actions of certain heritage are considered "weak".............these actions shouldn't be used, period.


What I'm saying is that IMO you can fire loads exhibiting pressures BELOW THE YIELD POINT OF THE CARTRIDGE BRASS in a 700 or a Sav or a modern custom action............you can fire a million rounds and not find any permanent or cumulative damage. No stress cracks. No crystallization. No deformation. No displacement or molecular rearrangement of any sort, just plain old abrasion wear which must me controlled through cleanliness and proper lubrication.


Firing a rifle is kinda' like smacking an anvil with a hammer, only with something softer and more yielding in between to protect the anvil............gener'ly the anvil just shrugs it off. Consider the cartridge case to be your finger between the hammer and the anvil, your finger will "fail" long before you damage the anvil.


Again, I stand to be corrected.........I'm the Original Safety Geek, search "safety geek" and my name will pop up. If someone shows me so much as ONE example, ONE shred of evidence to the contrary, I'll rethink my viewpoint.


Meantime I'm very comfortable using cartridge brass as my "CUP method" of ascertaining safe working pressure.



al
 
Here is a link to Olin Brass for an analysis of the characteristics of the brass they use in cartridges.

Brass type is #260 Yield Strength for various levels of hardness:

Annealed 45 to 61000psi - necks which makes sense
3/4 Hard 64 to 74000psi - guessing this is in the case web area
hard 71 to 81,000psi - guessing this is the case head/primer pocket area

http://www.olinbrass.com/pdf/alloyguide03.pdf

Not sure where Lapua fits in this but if it tolerates pressures above 81,000psi without yielding, that's getting pretty stressful on the action.

YMMV

Jerry

PS the cartridge doesn't not insulate the chamber/action from the pressure at all. The cartridge expands to fill the chamber and becomes a non compressible solid allowing all residual pressure to be applied on the barrel and action.

The cartridge may cry 'ouch' but it will not stop the forces from acting on the steel.

Long term hammering on an anvil will destroy it even though each impact is not enough to destroy it. Surface work hardening leading to brittleness. Why old anvils aren't so popular with metal workers.
 
Last edited by a moderator:
What metallurgcal differences (as compared to lesser brass) are unique to Lapua brass that enable it to tolerate such higher pressures?
 
Magic?

And what is so special about Russian and BR and 6.5X47 Lapua that makes it indestructible? How about Lapua .243 or 6.5X55? Lapua 30-06 or .308 -- is it in the same league?

Its all good stuff but is it really magic?
 
snipped:

I've blown up enough bolt action rifles to have some basis for comparison........believe me, when a bolt action lets go it's as if the brass case didn't even exist. IMO using yield strength of brass as a baseline against which to gauge load pressure is perfectly safe, a valid way to measure safety parameters.

al


You're scaring me now.
 
Ok,


Regarding the relative "hardness" of Lapua brass, I know nothing of brass composition, only how it acts.

You can get .243/308 brass or 22-250 brass from a variety of mfgrs, Rem, Win, Fed, Lapua, Norma, Hornady etc........of all the available brass, Lapua will give you the highest velocity AND good caselife. Winchester runs a close second with all others lagging at least 100fps behind.

For immediate comparison let's just stick with Norma and Lapua since they're manufactured to similar standards of uniformity. Anyone who's taken the time to use them both has found that if you work up a stiff load in Lapua brass and then try to achieve the same velocity/pressure using Norma you're doomed to fail. Same rifle, same everything and you simply cannot get the same performance out of Norma brass. Same with 6BR, Norma makes gorgeous 6BR brass, NOBODY uses it. Why? because you CANNOT compete using Norma brass. Norma brass fails before a usable competitive pressure is achieved. Sure matches have been won with Norma brass.........Matches have been won with Win or any other brass you'd care to name but for pure-dee Benchrest accuracy you will be hard-pressed to find ONE entrant in a field of thousands that isn't Lapua. The only people not using Lapua are those who don't know any better, or who've chosen a design-path which precludes Lapua or those who're still trying to prove something. Or those precious few who've run into a windfall of "something else" and are willing to risk thousands of dollars on the brass they've got. Some like GD Tubb simply took the bull by the horns and MADE something from thin air........in Tubb's case he spent the time and money to develop a case specifically to address these issues, a case which was then eclipsed by the 6.5X47 case, bad timing.


Lapua makes the toughest brass available, by a wide margin. There are some other exotic European contenders but for currently available and easily obtainable brass Lapua rules the roost. This isn't some "perception" it's simply fact.


BUT.........this isn't ALL of the story.


I realize that this is the factory/hybrid board but it's STILL Bench Rest Central not Grunting Around The Communal Rock Central so my view will be from the standpoint of Extreme Accuracy.


A group of us extremists have been looking for a better 22-250/.308 case for literally years.............12 yrs in my case. You see, for a case to REALLY make pressure it must not only be HARD but it must have a small primer and flashhole.....I've got boxes of URBR brass, the ORIGINAL Bench Rest case......useless junk. I called Kaltron-Pettibone several times over a 5yr period begging them to get Lapua make a run of small-primer .308 or 22-250 brass, preferably with undrilled flashholes. I stayed in contact with GD Tubb from day one with his 6XC case. I got samples and feedback on all of the three runs of brass, all three "generations" so to speak. No dice. I completely shelved my 6MM longrange projects and developed a 30HBR case from Lapua .308 brass which looks pretty weird but shoots well.............but it will NOT make good pressure. About 3250 W/112-118's tops.......


And THEN!!!! HHOOOWWAAUUGGHHHhhhhhhhhHHH!!!! Lapua came out with a BRAND NEW case, the 6.5X47. They did EVERYTHING right on it!.


This new case is the BEANS!


It is the ultimate 22-250/308 size case. AND lapua brought it out in a good necksize at 6.5. I doubt that I'll ever shoot it in 6.5 but that's not the point.


The point is that it's ULTIMATE BRASS.........it's a case from which to build wonderful things. It's what the URBR case SHOULD have been.



To illustrate;

The 6PPC simply IS the Benchrest round of choice for a variety of reasons, IMO the single BIGGEST REASON is that no one makes good factory available 6PPC cases. And every time someone DOES make one the BR community spurns it...........it gets tried, it doesn't agg, it goes away. The REAL reason that the 6PPC is such a world-beater is that making GOOD brass is required. You will not win unless you make your brass, or have it made, from .220 Russian cases. It's that simple. Most folks don't know why.


MAKING brass either in 6X47 or 30X47 from the new Lapua case offers the exact same advantages.............it gives one opportunity to make cases which will agg. It forces people to actually fit their brass to their rifle which is key to accuracy.



Given an accurate platform it's dead easy to test all of this, it just takes time. All you have to do is make brass from several different makers and by several different methods.......


Some loads will be fireformed with some slop, like .002-.005 like any "normal" chamber.

Some will be fireformed with slop but you will "seat the bullets long".

Some brass will be fireformed with grease on them so that they "slide back in the chamber".

Some loads will be tried each way and for each brand of brass.

And SOME loads will be set up to jam against the shoulder for fireforming.

Different methods, different brands of brass.

When the testing is done and the dust settles it will be found that yes! Properly fireformed brass will absolutely agg better than improperly fireformed stuff and YES! Lapua brass is magic! :)


To answer your specific question Henrya, YES Lapua brass will out-perform the others regardless of conditions........but more telling, ONLY Lapua brass will give you that winning edge.



I've spent some time and money testing this.



I've got 5 different 6BR chambers, no not 5 chambers from the same reamer but 5 different reamers. I've also got 5 different 6BR barrels cut with the SAME reamer but all with slightly different headspace. I've got barrels which have been re-chambered 3 times...........same barrel, same rifle, three chambers. And I've spent endless hours actually shooting this stuff head-to-head. I went so far as to order 2 Krieger 6MM barrels from the same production run, tapered the same, identical as they could be. I chambered one in 6BR and one in 6PPC just to see if I could see the difference between a "production cartridge" and the 6PPC. My original intent was to agg them and then switch them around........swap chambers. I never finished the test. I didn't finish the test because I learned what I wanted to know, I'd been chasing the wrong thing. I now apply Benchrest Technique (6PPC brass forming technique) to a wide variety of cases. They SHOOT!


Even the .243AI will shoot pretty good for a round or two but then, just as you've formed a good case you run into problems maintaining it.........the long 40* shoulder doesn't respond well to FL sizing.


FIRST one must fireform a case to perfect fit, THEN one must devise a way to MAINTAIN that perfect fit.


Much easier said than done.


But when it's done it's a marvelous thing. A perfect case will last literally forever. I've fired 6BR cases until the flashholes were burnt out into weird shapes and the necks were wearing thin from abrasion. IMO a case doesn't even start to shoot right until it's been "seasoned" by about three firings.


But hey........these last are just MY OPINIONS.

The part about the Lapua brass being more durable is FACT.

The part about the 6BR/PPC cases with their small flashholes and small primer pockets performing 'WAYYY beyond their size is FACT.

The part about the new 6.5X47 case being a world-beater is IMO FACT!! :D:D:D


LOL


Time will tell, it's still in its infancy.





Ohhh, yeahh and Henrya, that part about blowing up actions :) I was in gunsmithing school when I met a gentleman who was really interested in the 6.5 Arisaka's. Julian hatcher or PO Ackley or one of those Giants had made the statement that two of the strongest bolt actions on the planet were the much maligned Krag-Jorgensen and the Arisaka. This fellow proceeded to blow some stuff up! I thought at the time that it was insane. I then met another guy who'd done the same thing.............then I ended up building a rifle on a Rock Island Arsenal Springfield by accident........and then I got wind of a couple of actions that had been destroyed cosmetically........and then I got curious about just how much pressure WAS built into a small ring action that had been chambered to a magnum.......and then I got ahold of some actions that had been through a fire........one thing led to another and I've been around some pressure and destruction.


Right now I've got a sporterized Springfield 30-06 in one of my vises just waiting to be blown apart...........problem is, I've been instructed to blow it up in such a way that I can use it as a demonstration piece in our Hunter Safety class...... Really, a fellow donated it to the class and has asked me to show what a blown up action looks like. It's got a bulged barrel from some earlier mishap and instead of re barreling it he's asked me to blow it apart. We've got broken shotguns and pistols, we've got the pictures of the defective Sako's that are floating around. We've even got access to one of them, one with the classic curled out fluted pattern barrel rupture. We've got examples of magazine detonations and loaded guns that have been through fires.....but real honest-to-goodness pressure failures of bolt-actioned rifles are few and far between.



I've learned one thing from being around (controlled) action failures........it takes one hellacious amount of pressure and only one out of twenty actually LOOKS impressive. I'm stymied as to exactly HOW to get this one to where I want it. I want it ruptured, most of them just crack and bulge. I'm probably going to drive a bullet about 3" down the bore and then fire another one onto it using Bullseye........this will all happen down on the HE testing range under an explosive mat of course.


See, the thing is, speculation on "safety" just isn't in me.........The Good Lord only gifted me with two eyes and ears and at 45yrs I've still got perfect hearing and 20-20 vision..........I don't MESS with that! I wear sunglasses and earmuffs while I mow my lawn. My dad thinks I'm crazy but then he don't hear so well :)


I DO NOT take the prospect of action failure or brass failure lightly.


I believe that Lapua brass will allow you to SAFELY go where you will not go with another brand..............just like race cars are built safe, so are BR chamberings, done right.



Whewww my fingers are sore :eek: All that and the steenking post is so long nobody will prolly even GET this far......:rolleyes:


Ohh well, I mean well.


LOL



al
 
Well that went on for a while but.....

Al, You're pretty entertaining but I'm pretty hard to convince. And I give you high marks for consistency of your viewpoint - it doesn't change. But saying it over and over again does not make it right.

I don't see that the only way to get accuracy is to "make pressure". I don't see that in what the competition people here report. The other thing I don't see is the quoting of pressure figures as if you have a strain gage built in your trigger finger. The pressure numbers getting bounced around here are pure speculation about something that simply is not to be guessed at.

I've been around and seen blown up guns too. I consider my experience there to be mere conjecture just like yours.

I give now - you've worn me out.

Best,
 
Lapua Brass

I have absolutely no issue with Al's statements about Lapua brass being the toughest and best commonly available to reloaders. As reloaders we control the working pressures of our ammo. What does the manufacturer recommend in the way of pressures? The preface to the Lapua load data states that pressures are limited to the lesser of CIP/SAAMI specs. The Lapua.com website doesn't currently list the 6X47 L in their load tables, but does list the 6BR Norma. The max loads shown are quite a lot lower than many BR shooters routinely use. Why? I don't know, probably to placate the lawyers. However, since I'm rather attached to my fingers and eyesight, I'll stick to the manufacturers recommendations. Vic
 
Henry,


I don't have to convince you...........just go to a BR match and see for yourself.


Even the 1K crowd is coming around. High pressure = consistency.


al
 
Safety factor

The max loads shown are quite a lot lower than many BR shooters routinely use. Why? I don't know, probably to placate the lawyers. However, since I'm rather attached to my fingers and eyesight, I'll stick to the manufacturers recommendations. Vic

The reasons the max loads are lower than most BR shooters routinely use are, as you pointed out, lawyers as well as a safety factor. A safety factor takes into consideration the premise that people will make mistakes, differences in brass, chambers, powder lots, etc. The max loads are lower so that this safety factor is built in and on the conservative side. A beginner is best to adhere to the published loads until they firmly have their feet on the ground, have experience and knowledge and the confidence in their skills before they venture out of the safety zone.
Chino69
 
alinwa -

I recently finished building my 2nd 6x47L - this one on a BAT 3L. The one issue I have with this case is that - at least in colder temps (28F-45F) - it's not unusual to get fairly high ES & SD numbers relative to what I typically see out of my Dashers (have four of them, and use nothing but Lapua cases in all). I saw the same thing with my 1st 6x47, which I built on a SA 700, and which, coincidentally, was also finished just in time to break in the barrel and do initial testing in cold temps. I've used Fed 205Ms, CCI BR4s & 450s, R 7-1/2s, and even old nickel-plated WSRs, and all gave velocity spreads of 30-50fps with slow powders typically used (N160 is my favorite) with 105-115gr. bullets for LR prone shooting. Let the temperatures warm up into the 50-60F range, and things begin to improve.

At this point, I'm not sure whether it's the small primer or .060" flashhole, or the combination. However, when David Tubb wrote the specs for his custom made 6XC brass, he went with a large primer when it would've been just as easy for him to specify a small primer pocket. Granted, most of us won't be shooting BR or LR prone in sub-freezing temps, but it's still something worth mentioning. I'm not complaining about the 600yd. accuracy I'm getting out of the BAT with its 7.5-twist Krieger & DTAC 115s, but I'm somewhat concerned about the ES when we move back to 1000.
 
Flatlander,


So how do you make your "DAsher" brass to avoid the "problem" of small primer and flashhole?


al
 
I recently finished building my 2nd 6x47L - this one on a BAT 3L. The one issue I have with this case is that - at least in colder temps (28F-45F) - it's not unusual to get fairly high ES & SD numbers relative to what I typically see out of my Dashers (have four of them, and use nothing but Lapua cases in all). I saw the same thing with my 1st 6x47, which I built on a SA 700, and which, coincidentally, was also finished just in time to break in the barrel and do initial testing in cold temps. I've used Fed 205Ms, CCI BR4s & 450s, R 7-1/2s, and even old nickel-plated WSRs, and all gave velocity spreads of 30-50fps with slow powders typically used (N160 is my favorite) with 105-115gr. bullets for LR prone shooting. Let the temperatures warm up into the 50-60F range, and things begin to improve.

At this point, I'm not sure whether it's the small primer or .060" flashhole, or the combination. However, when David Tubb wrote the specs for his custom made 6XC brass, he went with a large primer when it would've been just as easy for him to specify a small primer pocket. Granted, most of us won't be shooting BR or LR prone in sub-freezing temps, but it's still something worth mentioning. I'm not complaining about the 600yd. accuracy I'm getting out of the BAT with its 7.5-twist Krieger & DTAC 115s, but I'm somewhat concerned about the ES when we move back to 1000.

It's the small primer and how much flash they have. Been working with a 223 and even with so much less powder, I had to switch from a BR4 to a 450 for cold weather shooting (right around to below freezing). Stringing and flyers with the BR4 in the cold were very obvious.

Had the same issue with a 6BR. The BR4 is just fine in the warmer temps.

I do compete in the cold so having reliable ignition in the cold is very important to me. That is why my next 6mm will have a LR primer. I can tailor from a very soft BR2 to a 210M or even a 215M mag primer depending on the temp. I will always have enough brisance for ignition.

The use of a small rifle primer is really to help with limiting pressure signs like cratering and flattening. Will show up much sooner using a LR primer. However, that level is still at or over 70,000psi so we are already in the toasty range.

I know, I know, there is 'lots of evidence that small primers are more accurate'. Will I have seen lots of very accurate LR primer cases too.

Many modern powders burn their best at magnum pressures. I have tested lots of the Hodgdon Extreme line and ALL have burnt cleaner with less velocity variations when pressures reached magnum levels. Accuracy tailed off quickly beyond that though.

I have never seen any testing to show a duty cycle for a commercial/custom action at/near/over proof load pressures (80 to 85000psi). We know that at magnum pressures, the actions pretty much live forever. We know that metal fatigue grows exponentially with pressure. We just don't know to what extent (if some engineer has that data, please post).

The trend is for higher and higher pressures because the actions are built to such low tolerances. There are simply no warning signs. As I have said before, that is leading us down a very dangerous path.

I bet alot of shooters would back off their loads/change cartridges if they found out what pressures they were running.

Until there is a body of proper testing to show we can do it, I lean towards safety and will burn a few more grains of powder in a slightly larger case to reach the same velocity. Barrel wear will be no different and arguably better then a small case run at 125%.

Jerry
 
I've never had a problem with ES/SD in the Dasher - cold weather or hot -which is the point of my post. It looks to me as though the 6x47L's extra case capacity relative to the BR or Dasher is the reason for the higher ES/SD numbers. What else could it be? As has been pointed out, the 6x47 is just a longer 6BR - nothing else is changed. The only way to take advantage of the extra case capacity without running excessive pressure is to fill it with slower powders than we use in the BR & Dasher cases. The slower the burn rate, the heavier the deterrent coating. The heavier the coating, the more effect the primer is going to have on consistent ignition.

I'm not about to give up on my 6x47s, and in fact am really looking forward to shooting the new BAT at 1000 out at Byers. I just felt the experience I've had in colder temps was worth mentioning.
 
Dennis that makes perfect sense......I'm still in the process of just getting the basic 6X47 up and running and I expect that within a short time folks will be pushing the shoulders back for exactly the reason you've stated........but that isn't a bad thing, at least with the new case one has the neck to work with and it's dead easy to SHORTEN cases :)


Keep us posted please, I'm sucking up any and all info on this new case.


Thank you.


al
 
As has been pointed out, the 6x47 is just a longer 6BR - nothing else is changed. The only way to take advantage of the extra case capacity without running excessive pressure is to fill it with slower powders than we use in the BR & Dasher cases. The slower the burn rate, the heavier the deterrent coating. The heavier the coating, the more effect the primer is going to have on consistent ignition.

YEP, why my wildcat will use a LR primer. ZERO chance of an ignition problem.

Jerry
 
6 X 47 Lapua vs. 6.5 X 47 Lapua

Anyone have experience enough to comment on the 6 X 47 Lapua vs. the
6.5 X 47 Lapua? I've read about the differences but would like to hear from those who can tell me if one is better than the other. What I'm looking for is performance at 600 meters, load info., bullet selection, etc. I'm trying to make a decision to go with one over the other. Any experience would be appreciated.
Thanx in advance,
Chino69
 
Back
Top