Whats the Hodgdon equivalent of AA3100?. Pat
Whats the Hodgdon equivalent of AA3100?. Pat
O.S.O.K., I said before, I have full confidence that you will get your Swede to shoot cast!
One little trick you might try. Load up one or two squib loads and catch the boolit undamaged to see what it's doing. Of course that is not the same as what will be happening at full tilt but it will show flame cutting and entering the bore at an angle and things like that. If it's not behaving properly with squib loads it won't behave well with full loads.
This boolit shows no defect and indeed, it shoots well.
This one shows base deformation and it shoots very poorly in that gun.
This one shows some 'shearing' in the rifling. That would cause leading and it did.
Flame cutting.
This was caused by the condition of the bore. Fire-lapping sorted it out.
The middle one shows good fit in the throat.
It took several attemps to get the shape right!
Last edited by 303Guy; 09-01-2009 at 02:13 AM.
Rest In Peace My Son (01/06/1986 - 14/01/2014)
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303 you have certainly come a long way in a short time...
and 3100 is on the slow side of the 4831 family.
aa 2700 is not a happy player in the cast world as it likes to be compressed some to burn completely. and consistently.
whereas 3100 is slower yet and has the same compression likes but burns more progressively [completely]at lower pressures.
kind of like 7828 in an 0-6 holds great accuracy till the bbl heats up,and lube is a major player there too. gonna give the castor oil swab a try here shortly.to see if 5 shots will hold the tight group that 3 does.3/4" at 2700. with a bore rider no less.
303guy,
I feel you're off on this one. The 6.5 Swede does behave with what you call squib loads. It's not flaming cutting ether at high velocity. You can't compare the Swede to your 303's..different everything in that barrel.
I've recovered high velocity bullets that didn't shoot good and the rifling on them show nothing...no flame cutting, no stripping or shearing.
The trick to the Swede, or any very fast twist rifle, is how you launch the bullet....and I don't mean from the muzzle. That is only one step to the equation.
Joe
Well, one thing that I'm suspect of with my boolits is the sizing. I thought I had the right nose punch but it did not center the nose... I had to carefully center it and hope for the best...
Now, I did roll the loaded cartridges to check for run-out (you can see run-out by doing this) and they looked true.
But I'll be glad when my Lee custom sizer arrives - I really prefer the bottom push method of sizing... I've never had an out of kilter boolit come out of my Lee sizers...
Again, thanks for the additional information and advice!
Oh and I just thought of something else. I shot some rounds into the 50 round target too and there was no evidence of keyholing at that distance. So, they were destabalizing between 50 and 100 yards...
And I have to say again that this just kinda blows my mind - I mean, too fast a twist that causes destablizing? That doesn't seem logical. I've always understood that too slow a twist has that effect.... and that too fast either strips the alloy or blows the bullet apart.
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Buckshot made me a push sizing die in .268 and I've enjoyed shooting my 6.5 Jap ever since. My Lyman 266469 bullets would sometimes bend as I was sizing them to .264 (nominal 6.5) and the accuracy was horrible.
Now, the bullets come out at .266 and the checks get crimped on and the bullets fly straight.
Lee-Style Push sizing dies are the bomb for these long for diameter bullets.
Bruce
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The fast twist isn't destabilizing them, if anything it's helping them. If it were a 10 or 12 twist, whatever you're doing with you loads, it would be worse and keyhole totally sideways. The fast twist does put more stress on the alloy and does require that the bullet is centered and doesn't have defects such as voids, because the faster spin will accentuate those two things.
Joe
I was basing my comment on the Don Miller bullet twist ballistics calculator that suggests that a slower twist would produce accuracy in this caliber/weight... but if I'm getting wobbly boolits with the fast twist, then that doesn't make sense.... as you point out...
And you make me realize that even the slightest varience in concentricity will throw a monkey wrench in this.
I think I'll just put the current batch of boolits into the melting pot and cast another batch and wait for the Lee sizer to show.
Last edited by O.S.O.K.; 09-01-2009 at 02:27 PM.
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StarMetal, what I meant was that at squib load velocity one can catch a boolit intact and examine it. It doesn't tell the whole story but if it's not behaving at low velocity it won't behave at high velocity. But a boolit seriously deformed on impact (or lost) doesn't yield much info. Unless one has a serious boolit trap! (That's what I would like).
As an example, I could not get my paper patched boolits to perform in my two-groove Brit and had no idea why. The low speed captured boolits revealed what was happening. I needed to use a rebated boolit to avoid base deformation. Although I was able to capture a high speed boolit, the base deformation was hidden by the general deformation. That's not the only problem though.
Capturing low speed boolits has another important benefit - it's fun! (Especially when one isn't having success initially).
O.S.O.K. A consideration with long cast boolits is that they can bend (iether in the mold or as they come out - not sure). I have found one or two castings really banana shaped. I have also sized a few long boolits in a push through and those really bent! Such long boolits can also bend on firing while the boolit transits from case mouth to bore. That won't necessarily show up in a low speed test and at higher speed it could be impact induced bending. But when the recovered boolit is bent and the rifling marks match the bend, then one wonders.
Last edited by 303Guy; 09-02-2009 at 01:33 AM.
Rest In Peace My Son (01/06/1986 - 14/01/2014)
''Assume everything that moves is a human before identifying as otherwise''
I actually saw my bends in a Lyman 45. The Push through die I think supports them better as the force is directed in one direction. My Lyman sometimes tilts those longer ones also.
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Mine sized easy enough in my RCBS lubersizer but I didn't have the right top punch. After looking for it again and finding it at Midway - but not in stock, I put it on backorder - figure I might polish the die open some more to .268" and see if that helps. Then I'll have the Lee at .266" and this one...
I remember trying to find the top punch way back when I bought the sizer die - and it was out of stock then. I guess this is one of those cast calibers that's just marginal in sales?
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You are "seriously" correct. Welcome to the world of "myths, secrets, old wife's tales and witchcraft" regarding cast bullets at high velocity. Go ahead and cast some of 50/50 alloy, HT or WQ them, let them age, slap some LBT Blue on 'em and fill the case up with a slow powder.....go test them and then come back ans some of us will tell you point blank why the accuracy still sucks.
Did I tell you of shooting a 10 shot group at high velocity with cast bullets out of my 6.5 Swede? Well 3 of those shots were within MOA so it's an MOA load! All I've got to do is pay attention to the "masters" and figure out what made those 3 shots land within an MOA of each other! As to the other 7 shots? Obviously they landed upards of 8" from the "group" so I must have "torn the rice paper".........
I've got an email from 45 2.1 where in he "reveals" the true secret to his "high velocity" 6.5 Swede loads. The secret is he uses that Lovern bullet over 2400 loaded to around 1800 fps. He also does the usual other case prep and loading techniques we all use or soon learn to use. Perhaps therein lies the secret to learn from the "masters"; call 1800 fps from a 6.5 Swede with a cast bullet a "high velocity" load. It also helps too, as did all old good witchdoctors, to scare the hell out of those inquiring with things like; "It is not a recipe and experimenting without knowing what your doing can get you hurt. NOT for general dispensation at all." That's about all for now as I don't think 45 2.1 really wants me to tell all his "secrets" here or he couldn't have so much fun spinning the yarns he does.
You might wonder why I don't mention Starmetla? Joe and I are good friends but we have been over this numerous times on this forum and others. We have repeatidly asked him to show us 3 five shot groups or 1 10 shot group fired with his high velocity load out of his ARs, .223 or 6.5 and he has failed to do so giving numerous excuses why not. ( a simple "search" of this forum will result in numerous threads where this has been discussed) No need to take him seriously until he posts the actual data and sufficient test groups to demonstrate some consistency of accuracy.
One can shoot a good group simply due to random dispersion. The key to accuracy is not just one group but the ability to consistently reproduce that accuracy without excuses such as different lots of powder, primers, GCs, ambiant temperature, nodes, lubes, etc.
So go ahead and shoot those bullets faster as you want to, we'll be waiting for your results.
Larry Gibson
I'll admit and I think 45 2.1 will agree that it's hard to shoot HV with a very fast twist. Let me clarify the word "hard". By that I mean you have to do lot's of work and testing to find that "pressure" sweet spot.
I also think that 45 2.1 can shoot. I got some reports from eye witnesses to his shooting. Of course he and I talk at length about that. I believe he can do what he says about 99 percent of the things he says he does. We all say we can do things that is hard for other's to swallow unless we were there to actually see it. I can say this (gulp) I haven't been able to prove him wrong on the things he told me do that I didn't think would work.
There's a loading technique that if done incorrectly can be dangerous and it has to do with controlling the pressure of the powder burn. Yes there are ways to do that without physically making the case smaller or seating the bullet deeper and deeper. No not as simple as changing the amount of the powder charge either.
Larry I'm closing in your rpm threshold with some more of my rifles. By now you know I call the one the "6.5 secret rifle".
Joe
Compressing powder before seating the boolit, as the BP guys do?
"A cheerful heart is good medicine."
ball powder like W760 and W748 doesn't usually do well in reduced charge loads.....
keyholing could also be caused by a boolit that is not sized correctly for the groove dia.
That's not much of a reduced charge for 760. On the Hodgdon data site they list minimum for a 140 jacketed at 39 grs and 160 jacketed at 37.5 grs. It's probably just too slow for the application here.
Or it pushed the bullet too fast, as the velocities listed for the jacketed were 2300 to 2400 fps.
Joe
Slow it down to 1500 and use the gas check. If this produces a decent group, and I bet it will, it suggests slippage on the lands at high velocity. Not uncommon to get big time, group ruining slippage without getting leading.
dac
I just built a bullet recovery system using a big water tank. I shot both the 55 grain (spoke of here) and 70 grain 22 caliber bullets into it at 2300 fps with my Colt HBAR with 7 twist. The alloy was 50/50 wheelweights/lead water dropped. The 55 grain bullet was ages quite some time. The 70 grain was less then a week. Calling this a recovery system might be wrong because it depends what you shoot into it and at what velocity. The 22's a HV get pretty well destroyed. At any rate there was enough bullet to examine the the rifling quite well. I can tell you that there was no slippage. Further more the rifling is very shallow in this barrel, especially when compared to a 6.5 Swede. I can't see him stripping through the rifling, but anything is possible. The only way to know is to recover a pretty intact bullet.
Joe
Joe when you get that 6.5x47 lapua wrung out give us a report with pictures.
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