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Removed20090331
Advanced Member
USA
550 Posts |
 Posted - Oct 16 2008 : 14:36:12
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I loaded 5 rounds of .375-338 last night with the .265 gr. gas checked lead ahead of 70.0grs of IMR7828 and will try them out on Saturday. This should give me 2000fps and maybe a little more stability. I've been using the SR powder for an 1844fps load, but the accuracy is about 2" at 100yards.
Pressure should be low for this load in the .375, but I would like to know if there are any observed cast bullet failures at this speed? The bullets are #2 Lyman stock with a bh of 15. |
"The best defense against usurpatory government is an assertive citizenry.” William F.Buckley, Jr. |
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IraqVet2003
Advanced Member
USA
1338 Posts |
Posted - Oct 16 2008 : 16:03:08
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| Normal cast bullet speed for rifles to obtain the best results is to my knowledge around 1000-1800 FPS. Normaly what happens pushing them any faster you run out of lube before the bullet gets to the end of the tube which causes sever leading. This can turn a rifle into a smooth bore quick, which I'm sure if you were to shoot an extended session you might experience and your groups would open up even more. This is my limited knowledge shooting led bullets in rifles, hope it helps. |
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Evad
Advanced Member
USA
1322 Posts |
Posted - Oct 18 2008 : 01:33:43
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Some cast bullet loads go as high as 2800 fps. It depends on the alloy, abd the lube. Also a smooth barrel does better than a rough one. You just have to experement with your gun.
Dave  |
I never met a gun I didn't like. |
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k-townman
Advanced Member
USA
517 Posts |
Posted - Oct 18 2008 : 10:29:14
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| My rule of thumb has always been that cast bullets are kept under 2000 FPS. |
If all else fails; LOAD THE GUNS!!! |
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oneokie
Advanced Member
USA
908 Posts |
Posted - Oct 18 2008 : 12:23:25
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Which 265 gr. gc bullet are you using? The Lyman 375449?
Which SR powder are you using? There are several. Something similar to one of the 4895 powders would be more appropriate. The IMR7828 will be very dirty. I suggest you try different powders to improve accuracy. Burn rate and pressure curve can make a big difference.
What is the twist rate for your barrel? 1-18" or faster?
What "failure" are you concerned about? Disintergration or barrel leading?
If your bullets are groove diameter + .002", and you are using the correct lube, leading should not be a problem. Two excellent lubes are Speed Green and Felix lube. |
Dumb can be overcome, but Stupid goes on forever. |
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Removed20090331
Advanced Member
USA
550 Posts |
Posted - Oct 18 2008 : 17:44:39
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Well, the 6 rounds were hotter to say the least. There wasn't any sign of fouling the lands, but the group went from 2" to 6". I ran a 270 grainer through after the cast to check the rifle out and, other than my hearing protecters falling off with the recoil, it was 3" high at 100 yds like I ordered. I'm sticking with the SR4759 for this hunt.
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"The best defense against usurpatory government is an assertive citizenry.” William F.Buckley, Jr. |
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leadburner
Starting Member
USA
2 Posts |
Posted - Oct 04 2009 : 02:03:54
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| I run a 220 grn. Lee gas checked boolit through my 338 win mag at 2050 fps. The load is 55 grns. H-4350,CCI LRM primers,3.34 OAL. Shoots 1.5 in.@ 100 yds,and also shoots close to point of aim with 225 grn. jacketed bullets. My alloy is around 16 bnh.If your groups open up like that,you are probably exceeding the pressure that your alloy can take.I figure my load is right in the 30,000 psi range,which I found my alloy could stand.In Lee's book,"Modern Reloading", you can find many loads that you can reduce to a certain pressure,and pressure verses alloy streghth is what it takes to get accuracy.I really recommend that book,I've learned a lot more about casting since I've owned it.Keep trying,thats the fun of it! |
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Onondaga
Advanced Member
USA
1378 Posts |
Posted - Mar 13 2010 : 10:06:57
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Cast lead bullet failure above certain speeds took me a lot of study to understand. I have finally come to agree with Richard Lee in his Second Edition Modern Reloading manual. His lengthy dissertation on cast bullet performance relating to chamber pressure in PSI and lead alloy deformation in PSI has made sense to me and I have repeated his testing method again and again verifying my agreement with him every time. Following his method, I can find a sweet spot of accuracy for a particular alloy that I have tested the hardness of with the Lee lead hardness testing tool. When Load pressures in PSI approach the deformation PSI of the alloy, a certain point nearby is the sweet spot of accuracy. Manipulating the alloy strength to allow higher and higher pressures of course allows higher velocities too. I even developed what I thought was impossible before. A .223 Rem. load that will equal factory velocities with a cast bullet. It is just a matter of manipulation of the alloy. A very hard alloy like good Linotype can be cast then heat treated then quick cooled in ice water and will have the strength to withstand the pressure to be driven over 3100 fps. They shoot well, but at that hardness are pretty brittle and border on frangible. The price, however, is well worth the effort.
Studying the Lee book has also helped me develop wonderful loads in .308 Winchester, .458 Win Mag and .500 S&W Mag. Each of my loads has used the Lee method and I manipulated the alloy hardness to approach the sweet spot of accuracy at the velocities I was trying to achieve.
Getting great cast bullet performance is a matter of determination, science and art. Quick easy trials rarely have excellent results. |
Fine rifles are never really owned. |
Edited by - Onondaga on Mar 13 2010 10:11:21 |
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Cast Bullet max speed?
