Old Coot wrote: I think that Mtngun us just running his own set of experiments or trials and is giving us the benefit of his work. He is not apparently interested in suggestions because he just wants to run his trials and see for himself what happens and what conclusions can be drawn from them. He (and he has told us so) is not so much interested in help or suggestions as he just wants to share his findings.
I beg to differ, Old Coot.
Yes, there are one or two self-appointed experts that I have kinda sorta told that I am not interested in their “help." Not everyone on the internet is worth listening to. :D
But I would not post here if I did not respect the CBA and at least some of its members. I'm glad that LMG took an interest in my post. I wish more people would.
What I would like to see happen from my posts is for other people to become interested in high velocity cast, if they aren't already, and join in the game, and post their results. Similar to how John Alexander's ongoing posts on 22 caliber finally interested me in 22 caliber.
Over the years I have bumped into various people who claimed to have had success with high velocity cast. I read Veral's book shortly after it came out and he made it sound like there was nothing to it (as long as you bought his stuff).:D In the early 80's a local shooter told me he was getting 1 MOA at 3000 fps from a 7 mag, using Veral's methods. Of course I suspected he was BSing or at least exaggerating, but nonetheless it piqued my interest and I've been interested ever since.
One of my customers shared my interest in hi-velocity and liked to tease me with “snippets” of his lucky high-velocity targets. But never more than a single target, and he was evasive on load details, and when pressed he sometimes admitted that some days his load didn't shoot all that well.
The same customer was quite sure that there was something wrong with my bullets so he generously sent me some of his bullets to try, with his alloy, his lube, and sized to his recommended diameter. I loaded them over his recommended primer and his recommended powder charge and proceeded to shoot a shotgun pattern. :D :D :D
To sum things up, I've been interested in full throttle cast loads for what -- 33 years -- and in that time I've have heard a lot of claims and have been given a lot of advice. What has been lacking, until recently, is real data that you can sink your teeth into, and real targets. Good on LMG and Goodsteel for posting some of their results ! :dude: Good on Paul Pollard and that other competitor for winning matches with hi-velocity cast. Finally we have something more than rumors and claims! At last, we have undeniable proof it can be done and we have a pretty good idea of how to go about it.
Sure, there are disagreements on some of the fine points -- name one aspect of shooting where there are zero disagreements? -- but as I see it we agree more than we disagree.
LMG, as I tried to explain by PM, I appreciate your comments and I hope that you continue commenting. I did, as you suggested, re-read yours and Goodsteel's excellent posts on recovered bullets that appeared to have been “swaged down." I'm not going to hijack my own thread by dwelling on that subject here, but this is my quick and dirty take:
First I would say, as others have already said, that interpreting damage to recovered bullets is always a judgment call. Was the damage done in the barrel, or upon impact? I'm not sure.
That said, let's assume for the sake of discussion that the damage was done in the barrel. Let's even assume for the sake of discussion that lube, being an incompressible fluid, may have played a role in swaging down the bullet.
Even if we assume all those things, it does not automatically follow that lube was the root cause.
Similar bullet deformation, except far more severe, has been reported by http://www.mountainmolds.com/phpBB3/viewtopic.php?f=11&t=509>Ross Seyfried. Now maybe Seyfried's swaged-down bullets are a completely different phenomena that has nothing to do with your swaged down bullets, but it makes you wonder. What is undeniable is that all bullets are deformed by the rifling. The metal displaced by the rifling has to go somewhere. There are only two places it can go 1) into the grooves or 2) the entire bullet gets squeezed like a tube of toothpaste.
The grooves are full of an incompressible fluid so that may present a problem. Maybe some lube can squirt out, or maybe not?
If the entire bullet gets squeezed like a tube of toothpaste, funny things can happen to the bullet. The physics are mindboggling, but the results that Seyfried posted are undeniable. Other experimenters, including myself and dating at least as far back as Colonel Harrison's book, have verified that grooves play a vital role -- more so at higher velocities --besides providing a convenient place to put lube. That what my TFS article discusses, and I wonder if it may be relevant to your bullet with its teeny weeny grooves?
So that's my off-the-cuff reaction to your “swaged down” bullets, assuming they were really swaged down in the barrel.
No I have not yet recovered bullets fired at 2900 fps. My water trap is torn apart for maintenance so it will be a while before I'm back in the bullet recovery business. I dunno if a bullet fired at 2900 fps will survive the water trap in good enough shape to provide useful information.
I have, over the years, dug the occasional bullet out of the berm that was in good enough shape to measure the bottom portion just as you did with your recovered bullets. I recall at least one such bullet fired at 2700 fps that showed obturation just as you would expect.
A more detailed discussion of the subject deserves its own thread and I would want to try to duplicate your 2900 fps tests before I jumped to any firm conclusions.
 bullets were cast with wheelweight alloy and quenched at the 400F curing temperature, making them approximately 18 BHN. The OBPU (oil based polyurethane plus mica) bullets were oven treated at 470F, making them approximately 25 BHN.</p>
<p>The WC844 powder burned very well in this cartridge, with the velocity standard deviation running from 0.38% to 0.53%. This load runs around 45 ksi whereas my 6BR loads run around 25 - 30 ksi and WC844 doesn't burn so well at those lower pressures.</p>
<p>The TPCF coating seemed to be slightly more accurate than OBPU, so TPCF will be my standard coating for GC bullets until something better comes along.
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-- apply self-adhesive teflon or UHMW tape to the toe of the stock to reduce friction
-- place a microfiber cloth between the stock and the bag to reduce friction</p>
<p>I debated whether to order a custom bag to fit my chubby stock, or to reshape the stock to fit my bag. Custom bags are expensive and this stock is cheap as benchrest stocks go, so I decided to modify the stock.
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, I tried gripping the rifle instead of “free recoil.)
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