Al's 6x47L

[steveinflag]

Thanks Al,

Great groups by the way!

I shot one five shot group yesterday at 400 yards with my 6x47/115's, making sure that they were under the 3100fps imposed limit for a Tactical match I'm going to next weekend and 3 shots were almost touching at .3 inch and the wind took the other two shots 1.5 inches away.The vertical was still only an inch.

Thanks for the info about the reamer.

Got's to love this cartridge!

Steve

 

[alinwa]

I hear ya' Steve,

Right now I've got my range set up at 100yds, fully flagged and with a Wind Probe, but from there on out to my next 350yd butt, no flags....... So shooting beyond 100yds for testing is pretty much a waste of time unless it flattens right out. What I'm saying is, shooting 350 or 400 WITHOUT BEING ABLE TO SEE THE WIND is just a waste of barrel because random shots go out for "no reason" that I can see.

I find that at 100yds I just drive the 6X47L like a PPC....... AFTER 100yds is where the big bullets really take over. What I do when I'm shooting the 350 is keep a PPC right handy and use it to test the wind If the PPC is drilling dots then I can shoot the 6X47L with confidence. If the PPC is getting blown around 4"-5" (or more) then I just stay at 100 where I can keep some coherency. I'm daily just AMAZED at the accuracy level of a PPC even at 350yds IN THE CALM..... the little bullets walk all over in the slightest wind but when it flattens off the silly things will just rip a hole. More than once I've been tempted to take a tuned PPC to a 600yd match.

But then the trees start to twitch.. bullets scattered all acros't creation.

Plus, my first 100yds is pretty much out in the open across my yard. The remaining 250yds is through a slot in the trees which is both a blessing and a curse! When it's "calm" it's REALLY calm but the minute the trees start shaking the swirling vortex is un-shootable. Currently my best "windflags" for the 350 are a light misting rain or a gentle snow....... anything heavier and I can no longer see my bullet holes.

al

 

[milanuk]

Waaay back around post #54...

In the post above I've tried to explain how a "normal person" can make good brass with only one barrel!

Just fwiw, Al, that is mucho appreciated. Interesting reading, even if it's not exactly a direction I'm headed. It does give me an idea or two to mull over...

Good stuff, man. Keep it comin'

Monte

 

[alinwa]

perfect case forming

MY DIES FINALLY CAME IN!!!!!

So here are some shots of the cases I'm making up using the stepped neck die.

PERFECT!

Every case is necking down concentric and clean, going down now to crank on a barrel and set the headspace for final necking, initial turn/fireform.

The first picture shows the problem, the others show well prep'd brass, ready for final neckdown and headspace bump.

AWESOME......

al

 

[alinwa]

misfires, hangfires

Today while fireforming for another chamber and barrel I tried CCI BR-4's, CCI 400's and Rem 7 1/2's with a compressed load of H4350 and got some hangs and one missfire. 1 Hang w/7 1/2, 1 miss & 1 hang w/BR'4's and 1 hang w/CCI 400.

All at 65degrees.

I've got just over 1000rds through this barrel using Federal 205M's and no hangs/misses yet.

Fingers crossed

al

 

[alinwa]

Problem solved.

I'm a slob and was using a very sticky assembly lube for neckturning lube and left some in the cases. Killed the primers dead. I pulled down the powder, reprimed and k'BOOM.

(I was fireforming)

al

 

[alinwa]

OK,

So here are some more pix.

I finished necking down using the Neil Jones die with a smooth bushing, suh'wheeet, no step, clean and concentric. Note that the necks are FLAT! No ugly twisted taper like before.......

First neckturn is to .267 the loaded round to be fireformed (hammered out) in a .268nk chamber. This chamber was cut using a 6BR reamer so the throat area is wicked long..... I've got 50thou of extra room beyond the end of the case.

Next is to SLAPPP them out.....

al

 

[alinwa]

Next step.

Fireformed prior to final neckturn...... gotta' SLAPPP that case out to shape and iron the dings out of the neck. Next phase will include necking BACK DOWN and then running an expander ball through the neck five times. I'm trying this in lieu of reaming.

Works well. A nice tight run with 0000 and the insides of the necks are like freshly honed Harley cylinders...

The first pix are of the fireformed cases, then the brass after having been worked once to check for final tension/diameter and the last thou turned off....


These cases are now turned to have .0012 total neck clearance. I was shooting for .001 but missed. They all turned off identical which indicates that my first turning was good too.

Tomorrow I will trim to 1.835 because my chamber is set to 1.840 OAL. This all leaves 5 thou clear at the mouth of the case. I'd go closer but I've never used this new Jones die, I'd better leave some room. This die is tapered differently than the chamber. JUST IN CASE I've mis-figgered and get some case growth over the first 6-8 firings this leaves some slop. I've got 10 cases from my old chamber that have now been FL sized 42 times and show zero dimensional change.

Final chamfers in and out, buff with steel wool and my guts tell me that I won't have to fine tune more than a couple cases.

I've got three long afternoons into these cases at this point. And just last week Jim Borden told me "I over-engineer this stuff..." how can he SAY stuff like that??? A hunnerd cases in what 18-20 hours??

c'MON!



LOL

al



BTW, my initial FIREFORM groups were in the twos....... wicked tight jam-fit. 'bout scored the lugs eh....

 

[JRinCo]

Any updates?

Just wondering if you have had a chance to shoot this creation at a longer distance yet.

 

[alinwa]

Just wondering if you have had a chance to shoot this creation at a longer distance yet.

Not yet using the latest tuner'd barrel. The gun weighs 17lb with the old barrel and I'll have to do some weight adjusting to use the new barrel in competition. It's been "ready" for quite some time but for the local 600yd comp the old barrel is sufficient. I've managed to get small group/small agg type plaques for shooting in the 2"+ area at every match which means the gun (even with the old barrel) is shooting OK. (I can't shoot for @#$% but the gun's OK!) The rifle will hold about 1.5"@600yds consistently with the old barrel.

Note that the basic case-forming methods are essentially the same. I form cases for everything "Jim Borden PPC style" which means jam-fit. IMO this jam-fit fireforming step is essential to good aggs. The rest of the silliness just makes all of the cases identical, my seating pressure is smooth as silk and consistent case-to-case. I don't anneal. I don't know if this is important but it eases my mind and my ES is so incredibly low that I believe I can see the difference between kernels of powder. I feel that one kernel of H3540 is worth about 5fps, maybe 8fps. I do load to the kernel of powder, .02 gr. My current load is 40.04gr +- nothing.

My loaded rounds exhibit less than .001 runout, all of them.

al

 

[JRinCo]

Keep us posted

I'm trying to make up my mind wether to chamber a 6x47 or an improved 6br barrel for next year!

 

[alinwa]

I'm trying to make up my mind wether to chamber a 6x47 or an improved 6br barrel for next year!

I guess I have to wonder why anyone would continue to improve 6BR's when this case is available. It's the same case, only longer.

al

 

[Rick B]

Lynn,

Because no resizer can resize the casehead.

It's the casehead expanding that loosens the pocket. A casehead can expand as much as .004-005 above the web before the primer gets loose.

Here's my full reason...... .005 over will reliably work to eliminate the click (I THINK) but I go even larger because this allows me to cull my cases for eccentricity simply by looking at them. Cases which expand evenly are "Match", those which scrub down one side are "Foulers" and the ones in between are "Sighters."......

See pix, case on right is "scrubbed" and case on left is evenly expanded.


edit... I just realized something. The case on the left IS NOT "evenly expanded" that's the back side of a "scrubbed" case to show how big the bulge is. An evenly expanded one doesn't show as abrupt nor as large a swelling.


al

I think I understand why you want the area above the (solid) case head to expand, but I am not sure that I understand just why the result should tell you anything. Unless there is a very tight "fitted neck" to the case it is almost certain to be laying down in the chamber and so even a "perfect" case would probably have at least some degree of uneven expansion.

Could you please explain this to me? Obviously you have not experienced irregular expansion on all of the cases.

Thanks,

Rick

 

[DirkTejan]

Couple a questions....

I have a little benchrest experience. Not much.

I have been following this thread with great interest. I have a 6XC and I am trying to perform some of these procedures to enhance accuracy. So far on a really good day I will get groups in the 3s. Unfortunately my reamer is cut the standard way - therefore I am opening up the necks to .264 or so and then necking back down only part way with my standard die to provide something for the bolt face to crush against. Another thing is that I am stuck with Norma brass.

I like the idea of using 0000 steel wool to polish inside the necks- I am wrapping it around a nylon brush and running it into the neck with a drill. It doesn't seem to work very well. Is this the right approach?

When you guys are talking about "clicking" - are you talking about the bolt clicking after firing a hot load? I always thought that the load was too hot when I heard that click - so I always backed off. I was afraid that I would hurt the rifle. Not true?

Al - I am curious- when you are talking about "tight" neck tension what do you consider "tight". .003"? .004?

I am thinking about having a custom die made from Hornady without an interchangeable neck bushing because the total runout is supposed to be better.

Thanks a whole bunch to anyone willing to answer these questions!

Dirk

 

[alinwa]

I think I understand why you want the area above the (solid) case head to expand, but I am not sure that I understand just why the result should tell you anything. Unless there is a very tight "fitted neck" to the case it is almost certain to be laying down in the chamber and so even a "perfect" case would probably have at least some degree of uneven expansion.

Could you please explain this to me? Obviously you have not experienced irregular expansion on all of the cases.

Thanks,

Rick

The case always blows out further on the softer or thinner side. Contrary to popular opinion, orientation in the chamber has nothing to do with it.

This is easy to test, just mark (index) your cases with a Sharpie and fire factory rounds in a factory chamber to see that they don't blow out to the high side.

al

 

[alinwa]

I have a little benchrest experience. Not much.

I have been following this thread with great interest. I have a 6XC and I am trying to perform some of these procedures to enhance accuracy. So far on a really good day I will get groups in the 3s. Unfortunately my reamer is cut the standard way - therefore I am opening up the necks to .264 or so and then necking back down only part way with my standard die to provide something for the bolt face to crush against. Another thing is that I am stuck with Norma brass.

Norma brass won't allow you to run very hot but you're doing the right thing in necking up/down. Strive for a tight crush on your bolt.

I like the idea of using 0000 steel wool to polish inside the necks- I am wrapping it around a nylon brush and running it into the neck with a drill. It doesn't seem to work very well. Is this the right approach?

I strongly prefer spinning the case. The little drill press in the pictures cost me less than 50bucks. I wrap around a brass brush.


When you guys are talking about "clicking" - are you talking about the bolt clicking after firing a hot load? I always thought that the load was too hot when I heard that click - so I always backed off. I was afraid that I would hurt the rifle. Not true?

Clicking is the result of your case expanding to beyond it's ability to spring back. It's the result of the case sticking in the chamber either from a hot load or from a too-tight chamber. It won't really hurt the rifle but it's a pita. Backing off cures it, mostly. Keep your primary extractor cam greased. (Find this cam at the root of the bolt handle, front and top corner.

Al - I am curious- when you are talking about "tight" neck tension what do you consider "tight". .003"? .004?

Yes, .003 or .004 would be fairly "tight" for me. Beyond .003 it gets really hard to maintain linearity. I've run as tight as one can get, sizing as much as ten thou, collapsing bullets etc..... can't see any reason to go beyond .003 myself.

I am thinking about having a custom die made from Hornady without an interchangeable neck bushing because the total runout is supposed to be better.

IME runout is best controlled by minimal sizing. Size very far and nothing can help you. Don't get hung up on "straight dies" or "beefy presses" or "align-bored gobbledygook" cuz in the end the brass WILL bend to the soft/thin side you push it very far..... and there ain't NO die so far out of line so as to bend your cases...

IMO

Thanks a whole bunch to anyone willing to answer these questions!

Dirk

Dirk, I hope this helps

al

 

[Rick B]

The case always blows out further on the softer or thinner side. Contrary to popular opinion, orientation in the chamber has nothing to do with it.

This is easy to test, just mark (index) your cases with a Sharpie and fire factory rounds in a factory chamber to see that they don't blow out to the high side.

al

Thanks, Al.

I guess the short answer is that 60K (+) PSI overcomes whatever small "misalignment" there may be in the chamber. (I note that you used the expression "SLAPPP them out" several times.)

The late T.J. Jackson used to bore the inside of 6 BR cases as a part of his rather extensive case preparation, but that was back in the era of really tight neck cases...0.0007" Total neck clearance was popular back then (that is not a typo, seven tenths total or three and one half tenths per side).

"Why would anyone bother improving the BR case with these (6x47 cases) available?" Apparently someone is trying to get Lapua to make a run of 6 BRX cases (with a normal length neck). Even so, it would still fall short of the velocity you have been achieving, unless they went and "improved" the improved case to get the capacity closer to your 6 BR long.

Cheers!

Rick

 

[DirkTejan]

Ahhhh so!

So that's why you guys want to get rid of the "clicking"- so you can run your fireforming loads hotter.

Thank you Al !! Awesome !

 

[alinwa]

Ahhhh so!

So that's why you guys want to get rid of the "clicking"- so you can run your fireforming loads hotter.

Thank you Al !! Awesome !

Welll, no.......

I want to get rid of the clicking on every shot. Clicking upsets the sandbags, annoys the neighbors and attracts bushmen which all in all destroys aggs.

al

 

[DirkTejan]

Thanks again Al.

Dirk