carpal tunnel..... I really do care about this
Dunno how I could take it any further.....??
I don't have anywhere to go!
You make a vid mebbeso Wilbur will put it in FAQ
al
Controlling Runnout?
- Thread starter JDBraddy
- Start date
carpal tunnel..... I really do care about this
Dunno how I could take it any further.....??
I don't have anywhere to go!
You make a vid mebbeso Wilbur will put it in FAQ
al
Joe Woosman
Member
Al,
In general, your observations are spot on IME and maybe there is no further practical ground to be had. But to your following statement:
This is not entirely correct. By conventional means it probably is. I can straighten cases as well as change the hardness at various areas of a case so that the die sizing effect takes place at targeted areas. If you had the ability to point at different areas of a case and say I want this a little harder and this a little softer with a little more metal added here, all while IMPROVING concentricity,.... Would you change anything?
Boyd Allen
Active member
Al,
We all want straight brass, and somehow, without getting exotic, I have managed to do that. When I make PPC cases, I take extra time, and use methods that do this very well. I guess that my point is that looking at the accuracy that the OP reported, I do not think that concentricity is his main issue, because I know how crooked even the best factory ammo is, and I have had a Savage that shot that ammo into an honest half inch, properly measured.
Back in the day, when I went through several Remington sporter barreled .222s and .223s, that I did my own bedding work on, in every case, I was able to tune them to shoot reliably under 1/2", with the best five shot groups being under 3/8. Later on I came across one that a friend had that was one of the ones with an HS precision stock, and fluted stainless barrel (I forget the model designation) that was over headspace (The bolt would close on a NOGO gauge.) and which had a throat so long that one could not load to touch the rifling. For that one, the barrel needed to be set back to get it to shoot, but it did. Some time later, I ran across a different problem on a factory rifle, where the guy was very meticulous and was cleaning his stainless Ruger .270 too so often that he never got to see what it would do because the barrel never got fouled enough to settle in. He had worked long and hard, very carefully without much luck. I suggested that he just keep shooting, instead of cleaning every dozen or less rounds, because that rough barrel was never going to break in like a custom one, and after he took my advice, before he got to 20 rounds from his last cleaning, the groups tightened up to something that he could live with for a factory big game caliber. I don't know how many shooters I have helped with things like bag position on the forend and butt stock, with rather dramatic results. The point is that before we start getting too far into the minutiae, we need to make sure that the big stuff is taken care of. When we were working with my friend's custom magnum rifles, we were able to quite handily hit his accuracy goals by simply loading new brass and doing our workups from that point, using off the shelf bushing FL dies, and doing careful load workups, loading at the range, shooting over flags. The concentricity of his loaded ammo was quite acceptable as was his accuracy. Getting back to the basics, I don't know how many fellows that I have met that were struggling with a rifle that had not been bedded, because they did not know how important it was to get that out of the way first thing. None of this is rocket science, or requires anything out of the ordinary. Now when you are trying to work down under a quarter inch, that is when more advance methods may show up, if the caliber and rifle are capable, but above that more ordinary methods will generally get you there.
We all want straight brass, and somehow, without getting exotic, I have managed to do that. When I make PPC cases, I take extra time, and use methods that do this very well. I guess that my point is that looking at the accuracy that the OP reported, I do not think that concentricity is his main issue, because I know how crooked even the best factory ammo is, and I have had a Savage that shot that ammo into an honest half inch, properly measured.
Back in the day, when I went through several Remington sporter barreled .222s and .223s, that I did my own bedding work on, in every case, I was able to tune them to shoot reliably under 1/2", with the best five shot groups being under 3/8. Later on I came across one that a friend had that was one of the ones with an HS precision stock, and fluted stainless barrel (I forget the model designation) that was over headspace (The bolt would close on a NOGO gauge.) and which had a throat so long that one could not load to touch the rifling. For that one, the barrel needed to be set back to get it to shoot, but it did. Some time later, I ran across a different problem on a factory rifle, where the guy was very meticulous and was cleaning his stainless Ruger .270 too so often that he never got to see what it would do because the barrel never got fouled enough to settle in. He had worked long and hard, very carefully without much luck. I suggested that he just keep shooting, instead of cleaning every dozen or less rounds, because that rough barrel was never going to break in like a custom one, and after he took my advice, before he got to 20 rounds from his last cleaning, the groups tightened up to something that he could live with for a factory big game caliber. I don't know how many shooters I have helped with things like bag position on the forend and butt stock, with rather dramatic results. The point is that before we start getting too far into the minutiae, we need to make sure that the big stuff is taken care of. When we were working with my friend's custom magnum rifles, we were able to quite handily hit his accuracy goals by simply loading new brass and doing our workups from that point, using off the shelf bushing FL dies, and doing careful load workups, loading at the range, shooting over flags. The concentricity of his loaded ammo was quite acceptable as was his accuracy. Getting back to the basics, I don't know how many fellows that I have met that were struggling with a rifle that had not been bedded, because they did not know how important it was to get that out of the way first thing. None of this is rocket science, or requires anything out of the ordinary. Now when you are trying to work down under a quarter inch, that is when more advance methods may show up, if the caliber and rifle are capable, but above that more ordinary methods will generally get you there.
M
mks
Guest
Joe,
Now this discussion is getting interesting. I would like to hear/see your case preparation methods.
Regarding the question above, isn't varying hardness around the circumference of the case self-defeating? It will work once for a particular distribution of case crookedness, but after the case is plastically deformed to the chamber dimensions during firing, which induces work hardening of different amounts based on the initial hardness levels, it elastically recoils to a different banana shape and a different hardness distribution. So you have to start over again, and recalculate how much and where to harden to get a straight case during sizing. Much more practical to select straight cases and recycle the crooked ones. Maybe this is the point of your question?
Cheers,
Keith
Boyd Allen
Active member
Let me see if I remember this correctly. Joe, are you using cnc metal spinning (without a form) to reshape cases, and varying the hardness by feed rate and dwell time?
Joe Woosman
Member
Joe,
Now this discussion is getting interesting. I would like to hear/see your case preparation methods.
Regarding the question above, isn't varying hardness around the circumference of the case self-defeating? It will work once for a particular distribution of case crookedness, but after the case is plastically deformed to the chamber dimensions during firing, which induces work hardening of different amounts based on the initial hardness levels, it elastically recoils to a different banana shape and a different hardness distribution. So you have to start over again, and recalculate how much and where to harden to get a straight case during sizing. Much more practical to select straight cases and recycle the crooked ones. Maybe this is the point of your question?
Cheers,
Keith
Keith,
It's hard to say when I might get to the video so I'll try to explain. I use a technique from the "metal spinning" industry. Here is a youtube link to a crude spinning setup that shows you how a roller can manipulate thin materials.
http://www.youtube.com/watch?v=l2Gm3q0WMaQ
I developed tooling used in a CNC lathe and can form/reform cartridge brass to about any shape desired. The roller can push the material where you want it depending on the tool motions. The longer you work the brass, the harder it becomes. Instead of lines of stresses formed along the length of the case as a die would cause, the spinning action strengthens and uniforms the material diametrically. I stumbled across my method in search for a way to locate a case in a CNC spindle and make the neck round and concentric to the case body so I could bore the neck ID and turn the OD in the free state. Once I saw what was happening it lead me into exploring other possibilities. I found that forming the shoulders to a near spring temper virtually eliminated brass flowing into the neck and the OAL growth during resizing.
My current approach is based on the fact that the closer to full annealed brass you get, the further and quicker the brass strength properties can change. In example, the need to adjust a shoulder bump or neck bushing size throughout subsequent loadings. I first design a case around the available brass. Then the chamber using the predicted elasticity limits of the brass. Then the dies, again using the predicted limits. When all is well, the chamber, brass and dies should work together as a designed system where the firing or sizing isn't working the brass much, if at all, past its strength limits causing change.
M
mks
Guest
Joe,
Very impressive! The barrel, receiver and bolt deformation also factor into whether the brass exceeds the elastic limit. Do you think it would be possible to design a system that fired a high pressure case like a PPC so that brass never needed resizing, i.e., never passed the elastic limit?
Keith
Very impressive! The barrel, receiver and bolt deformation also factor into whether the brass exceeds the elastic limit. Do you think it would be possible to design a system that fired a high pressure case like a PPC so that brass never needed resizing, i.e., never passed the elastic limit?
Keith
Boyd Allen
Active member
It was done, and passed out of use, a long time ago. With something like a .262 neck 6PPC chamber, you turn the necks so that the loaded round clearance, measured over the largest diameter of the seated bullet is something like a half thousandth. The flies in the ointment are that the best in the game have gone to some where between .002 and .003 (which require neck sizing) because it gives a cleaner bullet release, and improved accuracy, that is particularly noticeable at 200 yards. If you want to hear more about this, take a look at the six video segments on Youtube of Jack Neary's presentation about tuning, and related matters. The other fly, as it were, is that one can only refrain from sizing if cases are not loaded to what we now consider normal pressures, otherwise the bolt will become difficult to operate. You see, not only does the case swell under pressure, but the chamber around it does as well, and that works the brass as they enlarge and snap back repeatedly. So there you have it, the purpose of match rifles is accuracy, and if the requirements of obtaining it mean that cases must be sized, then they will be, but of course you have all of the tools to try the older system by simply turning your necks to a suitable thickness.
Joe Woosman
Member
Yep. Sure can. I achieved that with common cartridge brass. Then it opened the window to running higher pressures. Then we exceeded the strength limits of cartridge brass again and I had to search for an alternative. I began development of a case based on a phosphor bronze material. That case most definitely was going to raise the limits. Which prompts the question what are we trying to achieve here?
I came to the conclusion we can maintain a good working system with common cartridge brass and I feel gains in accuracy are not going to be found in extra FPS or funky case designs. Being I can cut chambers and dies without special tooling, I tried a number of different case configurations. I found that, (similar to Al's findings), if the precision is maintained between the chamber, brass, and dies..... It can be made to shoot. I've made PPC capacity cases on shorter-fatter designs and they shot the same. I've made 30BR capacity cases on 284 and even WSM cases. They all shot. I made a HBR min case capacity 30 on a 284 case and it shot every bit as good as my 30BRs. Now I see 30PPC type cases, the 220 and 6 Beggs, they all seem to shoot.
Regarding neck hardness, I found that increasing the thickness and hardness allowed much greater neck tension than people have probably played with and my cartridges seemed to LOVE it. The drawback was increased carbon on the outside of the necks and chamber.
Joe Woosman
Member
Boyd,
With harder, more elastic necks you can run greater neck clearance with full springback. But as I said earlier, you'll have greater carbon flow.
M
mks
Guest
Agree on cartridge design. It has been demonstrated that a 30-30 can be accurate!
I am curious what action you used to avoid resizing? VarmintAl calculated axial bolt head movement at 0.007", which seems like a lot to get under the elastic limit. That was for 60ksi in a big Chey-Tac BAT, but the 6PPC in a smaller action is probably in the same ballpark.
Thanks,
Keith
Joe Woosman
Member
Wow! .007" is a lot longer than anything I recall. It's been 8+ years now so I'm stretching the memory but I seem to remember a BR type case could stretch about .003" and return. But even that's not accurate to say because the case body grips the chamber wall and depending on the surface finish, lubricity, etc. the case could stretch over different distances. Most of what I paid attention to was the case measurements before and after firing. If it didn't grow, I assumed I was within its elasticity limits. I can tell you as the case head diameter increased, the more the brass moved and the lower the operating pressure became before the brass would yield. I attributed this added movement to the thinner barrel material in the tenon. I suppose the action contributed too since the larger surface area of a larger case would convert PSI into greater axial force. All testing was with BAT actions of 1.350 diameter.
I must also note I didn't spend much time trying to move away from resizing and exclusively reloaded using FL dies. I found with running high chamber pressures, the wall just in front of the solid case head did not behave like the rest of the body and would creep larger if it wasn't kept in check. The FL dies did that.
OK..... it must be noted here that Varmint Al's simulations are just that, simulations........
Varmint Al left this site specifically because lots of people are daily DOING what his simulations showed to be impossible.
It's called GIGO
There is nowhere near .007 of axial bolthead deflection, NOWHERE NEAR!
FACT
I do shoot cartridges up to large magnums at very high pressures (75,000psi+) and achieve long (50-100 reloads) brass life.
DO SHOOT.....
This isn't speculation.
IT'S FACT.
Facts suck when you're a speculator but this doesn't disallow them, facts just ARE, they exist on their own, they don't need the "support" of mobs or opinions.....
"The truth is out there"
Carl Fredricksen, 'UP'
Varmint Al left this site specifically because lots of people are daily DOING what his simulations showed to be impossible.
It's called GIGO
There is nowhere near .007 of axial bolthead deflection, NOWHERE NEAR!
FACT
I do shoot cartridges up to large magnums at very high pressures (75,000psi+) and achieve long (50-100 reloads) brass life.
DO SHOOT.....
This isn't speculation.
IT'S FACT.
Facts suck when you're a speculator but this doesn't disallow them, facts just ARE, they exist on their own, they don't need the "support" of mobs or opinions.....
"The truth is out there"
Carl Fredricksen, 'UP'