Info. on 6 X 47 Lapua

C

chino69

Guest
Fellow shooters:
I've just purchased a Kreiger 6mm 1 in 7.5" twist LV #18 profile 30" barrel. I was going to have it chambered in .243AI, but after getting opinions from other shooters, I'm considering a 6 X 47 Lapua. I want to shoot everything from 95 grn. up to 115 grn. bullets at 500 meters +. This rig will be used for live varmints and maybe groundhog shoots. I would appreciate any info. shooters have around this cartridge. Specific questions:
1) What reamer maker should I use and what freebore would be right for the above bullet selections? What neck diameter?
2) Who's making dies and what is the best way to go? Wilson, Redding, etc?
3) What kind of velocities and accuracy are you guys getting with the heavier bullets?
4) Just run the brass through a full length die, prior to fireforming?

Any other info. would be greatly appreciated.
Chino69
 
6-6.5x47 info

Chino,

You've probably already this one. Here is an article from 6mmBR.com. http://www.6mmbr.com/gunweek073.html. It gives some reamer specs and turn versus no-turn neck sizes. You can use stock Redding 6.5x47 Lapua bushing dies and just reduce the bushing size to fit the 6. That is what Redding told me. I built a 6mm Rem AI last year. I think the 6-6.5x47 will be my next barrel.

tiny
 
6 x 47 Lapua

tiny68 said:
Chino,

You've probably already this one. Here is an article from 6mmBR.com. http://www.6mmbr.com/gunweek073.html. It gives some reamer specs and turn versus no-turn neck sizes. You can use stock Redding 6.5x47 Lapua bushing dies and just reduce the bushing size to fit the 6. That is what Redding told me. I built a 6mm Rem AI last year. I think the 6-6.5x47 will be my next barrel.

tiny
Click to expand...

Tiny68,
Thanx. I read the thread several months ago and just re-read it. The 6 x 47 has many things to offer as does the 6.5 x 47. The problem, for me, with either of these choices is the additional cost of dies, brass, etc. I have a .243AI reamer, plenty of Lapua fireformed brass, custom dies, etc. If I had an unlimited budget, the 6 X 47 or the 6.5 X 47 would warrant serious consideration.
Chino69
 
As mentioned in your other post, my 6mm project rifle will use a 243AI reamer run short to headspace off 22/250 brass. After fireforming, you get a shorter 243AI or longer 6 Dasher.

I am using Win 22/250 brass as I see no benefit in the much more expensive Euro stuff. I would go with a slight neck turn to clean up.

you can still use your 243AI dies, just shortern appropriately.

My dies will be a shorterned Redding 243AI body die and a custom Lee collet die set for $55.

Performance will be identical to the 6XC and X47L.

Jerry
 
6 X 47 Lapua

mysticplayer said:
As mentioned in your other post, my 6mm project rifle will use a 243AI reamer run short to headspace off 22/250 brass. After fireforming, you get a shorter 243AI or longer 6 Dasher.

I am using Win 22/250 brass as I see no benefit in the much more expensive Euro stuff. I would go with a slight neck turn to clean up.

you can still use your 243AI dies, just shortern appropriately.

My dies will be a shorterned Redding 243AI body die and a custom Lee collet die set for $55.

Performance will be identical to the 6XC and X47L.

Jerry
Click to expand...

Jerry,
If you don't mind, tell me a little more about your set up using existing .243AI dies. I understand the part about shortening the dies but I don't understand the part about the .22-250 brass. Is the brass the same dimensions as the 6 X 47 brass? Would I just enlarge neck on the .22-250 brass to 6mm? If I can keep from investing in new dies and all the trimmings and use my current dies, this approach makes alot of sense.
Chino69
 
When the 22/250 brass is fireformed, it will have the same dimensions as the top 3/4 of a 243AI.

Set up the chamber headspace so that your 22/250 cases are a crush fit. That way you just fireform as the cases come out of the bag and save yourself a bunch of hassle and bullets.

To fireform, just use a small charge of pistol powder under some cream of wheat/cornmeal. The resulting case will have a shoulder that is almost fully formed. Body and neck ready to go.

I like to neck size using a Lee collet neck die (or your bushing die), trim, neck turn to clean up about 80% of the circumferance, deburr the flash hole and load'em up.

The first full pressure load will finish the forming process. That first firing is as accurate as the next so you can use it for plinking/hunting. Saves cost and barrel wear.

The dies are cut down to work off this case.... EASY.

Jerry
 
Jerry, please don't make statements like "Performance will be identical to the 6XC and X47L." until you've done it.

I HAVE done it and can tell you that neither the 22-250 case nor the .243 case will make enough pressure to be able to run with either the BR case or the 6.5X47Lapua case.

You're speculating and selling it as experience.


al
 
A few guys in my neighbourhood have been chambering for 6 x 47 L by running a 6BR reamer in deeper.

How acceptable is that?
 
alinwa, I go by case capacity vs case capacity and both of these are near identical.

I also load to pressures that would not be considered proof loads.

If loaded to, dare I say it, sane pressures (no more then 65000psi or magnum pressures), their performance will be identical within the variations in barrels.

If your loads are no more then 65,000psi and velocity greatly exceeds those from similar volumed wildcat made from conventional designed case, then I will become a Lapua convert and never use anything else. I have used lapua brass by the way.

Yes, the Lapua 6.5X47L case is a brute. The case design is well engineered for some very toasty loads. That case is rated, by the factory, to work at 65,000psi (or near this) where other similar cases (22/250) are rated for less at least as defined by SAAMI loads.

We all know that a commercial case like a 308 or 22/250 or modern bottleneck whatever can all easily handle magnum pressures...SAFELY. That's primer pockets staying tight for at least 6 firings (mine are at or beyond 20 reloads and I use Win 308 brass).

The Lapua case, in BR quality actions, are allowing shooters to ramp up pressures to some interesting levels. Are those levels safe?

Put a strain guage on and let me know...

Jerry

PS from the last time I checked. A proof load for ANY modern rifle as defined by SAAMI is 80,000psi or thereabouts. I have proof load cases and there are no seriously flattened primers, leaks and it extracted for the action with little effort.
 
John Kielly said:
A few guys in my neighbourhood have been chambering for 6 x 47 L by running a 6BR reamer in deeper.

How acceptable is that?
Click to expand...

Measure the reamer at the same length as the finished cartridge and see what the diameter is. Hopefully, it will be very close the diameter of your case in the web area.

If so, go for it. If much bigger then you will have to live with case bulge.

Jerry
 
Jerry,


your quote....."If loaded to, dare I say it, sane pressures (no more then 65000psi or magnum pressures), their performance will be identical within the variations in barrels."


I have no idea what you dare say nor what you consider to be sanity but this is a Bench Rest board and I answer as such. While someone like yourself may well be inclined to call a NASCAR racer "insane" even you must admit that he will NOT go out and win with some factory or "sane" motor.



If you want a round to be competitive then you MUST build it as such. The only way to do this is to design a round such that it'll take enough pressure SAFELY so as to be competitive. Neither the 22-250 case nor the .243/308 case fill this bill.


Now Jerry, you're welcome to your opinion that all BR competitors shooting the PPC and BR cases are "insane" but my guess is that Mr Kielly wants him some of this so-called insanity :D


John, running the 6BR reamer in deep is a splendid way to make a 6X47 IMO, and my opinion is pretty picky.


My way involves setting the shoulders back on 5 brand new 6.5X47 cases to use as your initial headspacing tools........you then chamber for crush-fit using a 6BR reamer, send some tightly fired cases around to folks for dies and real headspace gauges and saunter off into the sunset with all your ducks in a row or somesuch......


It's a good way.



al
 
Save yourself some trouble and build a 6xc

I just ordered my 6XC reamer. I've had just about every other mid size 6mm and this looks like the best yet. Great Norma brass, (I have some I formed to 6mm HLS and it is just lovely!). The brass is relatively cheap (55 cents) and its formed ready to load - no screwing around. And you just buy off the shelf dies from David Tubb.

The reamer for current Norma brass is known at Pacific Tool as revision C. This has Tubb's 3/4 degree and long freebore which is made to shoot the long bullets you are writing about. I ordered a 1 1/2 degree and .045 freebore for lighter bullets. I'd order the standard Tubb reamer for long bullets. If you have doubts about the throat Dave Kiff at Pacific can set you straight if you tell him what bullets you will shoot.

Now about this pressure thing. I don't see any big push to shoot those long pencil bullets loaded to the gills like some PPC shooters do with their little pills. What you do want is consistent velocity and consistent bullet performance to give consistent time of flight to long range. David Tubb has a new 111 gr. plastic pointed bullets he's shooting right now with excellent results. No meplat trimming with the plastic point. He's shooting 3050 f.p.s. with the 111 gr. and H4350 at comfortable pressure. There is no point in pushing your luck with marginal high pressure loads that kill your brass in a couple of firings.
 
Again, the 6.5X47 case will simply do things that Tubb's case cannot, safely.


And it is actually LESS hassle than using 6XC brass.


My definition of "good case life" is 50 firings.


al
 
alinwa said:
Jerry,
I have no idea what you dare say nor what you consider to be sanity but this is a Bench Rest board and I answer as such. While someone like yourself may well be inclined to call a NASCAR racer "insane" even you must admit that he will NOT go out and win with some factory or "sane" motor.

If you want a round to be competitive then you MUST build it as such. The only way to do this is to design a round such that it'll take enough pressure SAFELY so as to be competitive. Neither the 22-250 case nor the .243/308 case fill this bill.

Now Jerry, you're welcome to your opinion that all BR competitors shooting the PPC and BR cases are "insane" but my guess is that Mr Kielly wants him some of this so-called insanity
al
Click to expand...

Interesting you bring up race cars as it is one of my other loves. I can say with certainty, that race cars are the safest vehicles on four wheels. The sanctioning bodies do everything in their power to ensure that the equipment lives up to the task while minimizing risks to the driver.

The sanctioning body rarely ever wants the cars to go slow!

The question above has little to do with pressure signs or stiff bolt lift - there will not be any. It has to do with chamber pressure and its relation to action/barrel - strength/fatigue/wear.

A very dangerous pressured load can still be operate with one finger lift on a BR quality action. It does not change the value of the pressure and its affect on the steel surrounding it.

Are the steels/materials used in BR actions that much stronger then commercial actions?

Is the fatigue life of the BR action substantially higher/longer then a commercial action?

These questions I have no idea on and have seen no info on the topic. Essentially in the BR world, it is a non issue.

That's DANGEROUS!!!!

IPSC has seen this problem after decades of high major load ratings. They saw how shooters would work all manner of engineering to meet that requirement and provide some shooting advantage. Absolutely cutting edge but riding the razors edge of disaster. After a number of guns failed, the rating have been lowered, guns no longer blow up, scores are still excellent and the top shooters still kick everyones butt.

We have not seen any mechanical failures in match rifles to this point (certainly none I have seen in the last 12yrs of shooting/wildcatting). Cartridge pressures continue to rise as shooters continue to push more velocity out of smaller cases. Tighter tolerances and stronger brass keep this trend going without pressures signs, but NOT WITHOUT ELEVATED PRESSURES.

SAAMI proof load pressures are there for a reason. They are not levels to be used on an ongoing basis due to the concern of increased material fatigue.

A cartridge fired at 80,000psi in a BR tight action WILL NOT SHOW ANY PRESSURE SIGNS but that much pressure does put strain on materials. Maybe these BR actions are that much stronger then conventional products? Maybe the actions are still too new to show the signs of fatigue?

Some feedback from custom BR action makers might be interesting. Wonder what they rate their actions for? Duty cycle at what operating pressures.

Yes, every action has a lifespan and will wear out.

Put a strain guage on these BR loads/rifles and see what pressure rating it gives you. If they are within the very safe magnum pressures levels of 65000, even a bit hot at 70,000psi, AWESOME. However, I suspect that shooters are treading much higher.

Safe???? I guess that depends on what you consider safe.

Personally, if I can't reach a velocity goal with a particular case at magnum pressures or a bit over, I simply go to the next larger case. Thus I have skipped over the 6BR and moved to a 22/250 variant.

YMMV.

Jerry
 
Last edited by a moderator:
Pressure and fatigue

mysticplayer said:
A very dangerous pressured load can still be operate with one finger lift on a BR quality action. It does not change the value of the pressure and its affect on the steel surrounding it.

Are the steels/materials used in BR actions that much stronger then commercial actions?

Is the fatigue life of the BR action substantially higher/longer then a commercial action?

These questions I have no idea on and have seen no info on the topic. Essentially in the BR world, it is a non issue.

That's DANGEROUS!!!!

SAAMI proof load pressures are there for a reason. They are not levels to be used on an ongoing basis unless the desire for material fatigue is desired.

A cartridge fired at 80,000psi in a BR tight action WILL NOT SHOW ANY PRESSURE SIGNS but that much pressure does put strain on materials. Maybe these BR actions are that much stronger then conventional products? Maybe the actions are still too new to show the signs of fatigue?

Some feedback from custom BR action makers might be interesting. Wonder what they rate their actions for? Duty cycle at what operating pressures.

Yes, every action has a lifespan and will wear out.

Put a strain guage on these BR loads/rifles and see what pressure rating it gives you. If they are within the very safe magnum pressures levels of 65000, even a bit hot at 70,000psi, AWESOME. However, I suspect that shooters are treading much higher.

Safe???? I guess that depends on what you consider safe.

Personally, if I can't reach a velocity goal with a particular case at magnum pressures or a bit over, I simply go to the next larger case. Thus I have skipped over the 6BR and moved to a 22/250 variant.

YMMV.

Jerry
Click to expand...

Jerry,
You bring up some very valid points that many never consider. A rifle chamber, for a split second, is a pressure chamber. Any pressure vessel or chamber expands, within the elastic range of the material, and returns to the former dimensions when the pressure goes away. Any material, particularly steel, is subjected to cyclical stresses. These stresses can be cumulative, and if the material is subjected to overpressure, the material can fail without warning. How do you know?

In the nuclear industry, we subject our vessels and critical equipment to non destructive examinations (NDE). This can be mag particle, liquid dye penetrant, eddy current, ultra sonic, or radiography depending on the material, stresses, and wear of the material being tested. Our steel also meets strict specifications followed by certified certificates of conformance that attest to the pedigree and certification testing of the material. Our continued operation depends on our ability to prove to ourselves and regulatory agencies, that our equipment is safe to run and perform it's intended function. This process also allows us to make accurate predictions with regards to when a component is likely to fail and implement the necessary precautions and preventive maintenance to preclude failure.

How does this tie in with shooting? Many shooters routinely run higher than normal pressures. Yes, custom actions are stronger and are made with better materials than factory. Most experienced shooters are knowledgeable enough to stay out of trouble. To make a long story even longer; impending failure may not be apparent to the naked eye. Just something to ponder.
Chino69
 
chino69 said:
To make a long story even longer; impending failure may not be apparent to the naked eye. Just something to ponder.
Chino69
Click to expand...

So how do we test our actions to ensure that all is well??

I have magnafluxed some WWI/WWII actions to look for cracks. Is that enough/the correct procedure?

I have also seen a dye product but have heard the magnets are better ? Any thoughts?

Do we just assume so many firings and the action gets parked?

I have heard that a life cycle of a bolt action is 100,000 firings (anecdotal). Does it drop off exponentially if fired at high pressures?

Any thoughts would be appreciated as we all want to have fun and be safe.

Jerry
 
Action life

mysticplayer said:
So how do we test our actions to ensure that all is well??
Any thoughts would be appreciated as we all want to have fun and be safe.

Jerry
Click to expand...

Jerry,
The point I was trying to make is that if you stay with reasonable pressures and within the safety window (SAAMI specs.) that you'll probably never have to consider material failure as a result of fatigue. Those that push the envelope, are not really aware of what area they are operating in. The stress/strain curve shows the dimensional change in steel for a given amount of force. Within a certain range the steel will return to it's former dimension once the force is removed. Go beyond this point and you may have subjected the steel to internal stresses that will not be visible.

Liquid dye penetrant or mag. particle will migrate and identify an existing crack or cracks. Liquid dye penetrant takes more prep than mag. particle. Some of the more exotic testing is used for identifying bad welds, etc.

I'm not a metallurgist but have enough understanding of materials to know why specs. exist and how they were determined.

From an action standpoint, a magnaflux will show whether there are any surface cracks but will do nothing to show what is happening inside. Stay inside the safety zone and shoot without worry. If you do go beyond established safety standards, know what the hell you are doing and realize you are in a 'grey' zone.
Chino69
 
Last edited by a moderator:
A seldom heard voice of reason....

"Personally, if I can't reach a velocity goal with a particular case at magnum pressures or a bit over, I simply go to the next larger case. Thus I have skipped over the 6BR and moved to a 22/250 variant."

I'm glad to read the last few posts. Its good to hear an intelligent discussion of pressure and safety. I find nothing macho about wrecking an action for a few feet per seconds velocity. But at times that what seems to motivate the "load it 'til it nearly pops" crowd.
 
Last edited by a moderator:
Jerry, good point about the race cars being SAFE.

To answer your question in real-world terms.............to the best of my knowledge NO ONE has EVER blown up an action used for Benchrest shooting except by using the wrong powder or something. These actions have redundancy built into them.


Now on the subject of BR chamberings in factory actions...........again NONE have ever been blown as far as I know. The actions will tell you when they're being over-stressed. The symptom is hard bolt lift coupled with sticky extraction. The cause is action flexure, the chamber/action ring, lugs expand just a little further than they should and when they collapse back they trap the case. On this note, these signs show up long before catastrophic failure is imminent. It would take a lot of work to flex an action long enough or cycle it enough times for it to show signs of fatigue.



I do NOT advocate anything but Rem 700 or Savage "110" series factory actions for building for pressure. I also note that factory actions WILL often get sticky before a custom will. If you search my posts you'll find me to be one of those who DOES NOT advocate the use of factory actions for magnum builds. My 300WSM project uses a BAT with the large threaded tenon JUST for this reason.


A properly modified 700 or Sav will allow you to run pressure/velocity up SAFELY using Lapua small flashhole brass, pressure that will destroy any other case like the 22-250 or .308-based variants.


If your method worked then you would see folks running other cases for BR accuracy, it doesn't. I happen to be one of those who've spent the money to prove this to my satisfaction. I've had dozens of barrels/chambers cut to "BR Spec" using full-on BR platforms and shot them extensively head-to-head with BR stuff.


Henrya makes a point about 1000yd stuff not needing to be run at the higher pressures...........While this has been true, 1000yd shooting is evolving rapidly. What was considered to be cutting edge accuracy as little as 6-8yrs ago wouldn't even make a showing today. High pressure and FB bullets are making inroads. Current accuracy levels for VLD's is "in the 2's" at 100yds.......G D Tubb's stuff doesn't meet this accuracy standard, it's used for a different game requiring less in the way of inherent accuracy and more about function from a mag.


Your points about building IPSC and race pistols is well taken, here we agree, BUT, I see no valid comparison between a racegun and a BR rifle.


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.


Now the DAY someone pops an action open from pressure while working under the yield strength of the brass will be the day that I change my methods!!!


Meantime, Lapua BR, PPC and 6.5X47 cases will SAFELY do things that no other easily available line of cases will do.


Just try them.............make up an un-modified 6.5X47 barrel for your platform and see if it doesn't eat your mystic up, with less powder and commensurately longer barrel life. I've just taken the time to completely scrap my 10yr-long .308HBR project (based on modified .308 Lapua brass) and am changing it all over to 30X47 at great expense. The new brass opens a door which didn't even exist 5yrs ago, it's revolutionary.


quote - "Yes, every action has a lifespan and will wear out."


Don't know that I can agree with this..........there are BR actions out there with hundreds of thousands of cycles on them that are still capable of winning, safely.


IPSC guns wear out, shottyguns wear out. BR actions? Not really, and if they do, guys just bore them out BIGGER (less strength?) and bush or replace the bolts to tighten them back up.




al
 
You must log in or register to reply here.
Back
Top