Glad to see you here though I was thinking you were already a long time member. I sure do want a whiz-bang little cast bullet load using Unique for the .41 Magnum. I've had the bullets now for some months but need to actually poke them into some cases. I intend to run the whole gamut with Unique and cast 210 grain SWCs from mild to wild just for the education of it all. What a great revolver cartridge the .41 Magnum is. Why did I go so long without one?
Unique is the staple handgun powder around here. I use others but load more Unique than anything else.
One thing that I'd like to add is that according to a long time user of the .41 once you get up to 9.0gr of Unique it is best to turn to another powder for more performance. His point was that he started running into diminishing returns much beyond that, the pressure wasn't woth the small gain in performance. I can't comment on his advice but I worked up to 8.7gr and decided to stop there since recoil was getting to be more than I wanted for a general purpose/plinking load in the BH. The 8.5gr load was more accurate too so that was why I settled on it. I plan on turning this load loose on some piggies this fall:biggrin2:
Originally Posted by bmcgilvray
sorry for resurrecting this old post but I thought this was interesting.
Last night I made a spreadsheet using calculations from the chapter on reduced loads in the lee reloading manual. I've been punching numbers into it all morning from hodgdons website and my lyman handgun manual. using powder/bullet combinations with 3 charges/pressures listed (starting, max and +p) I've been getting pressure estimates out of the spreadsheet that are within 100-700psi when staying within 38spl and within 1000-3000 psi when entering 357mag loads into the spreadsheet and reducing to 38spl charge weights.
not knowing what bullet or OAL was used in these tests makes it possible to only give a rough estimate, but I have made estimates from several different loads, both working up from 38spl data and down from 357 data (which seems to work especially well for the lyman 170gr SWC, btw). I have rounded these numbers out for convenience.
first lets go with "The Load"
8.0 grains of 4756 should give you somewhere around 42,000psi depending on the bullet its used with and assuming you keep the OAL as close to max as you can. this figure comes from 357mag data because "The Load" was 1.5grains higher than the max charge for 357. when working from 38spl data I projected the pressure to be closer to 30,000 psi, but this number is most likely very low. as you add powder to a case it takes up volume which by itself causes pressure to increase further, basically each .1grain gets you a little more pressure than the last. because Richard lee's calculations are based on 2 points of data and I'm bad at math, these calculations become more and more inaccurate as you move farther outside the 2 points your using. hence the calculations based of 357mag data are probably closest to the truth
next lets talk about the 11.5 grain charge of 2400
this ones not so bad. depending on the bullet your using and the OAL, your looking at somewhere between 21,000 and 29,000psi. I personally have worked up to 10.5 grains with 2400 and the speer 158g LWSC-HP and all cases dribbled out of my S&W 15-3. with that bullet/charge I estimate I was at 22,000-25,000psi. this one worked out different than the 4756 load in that the 38spl data yielded the higher estimates while the 357mag data yield the lower estimates. this is consistant with 2400 being a slower powder, giving the pressure increases a less pronounced curve as powder is added because the powder takes longer to burn.
well that's what I have to offer. I didn't bother with the other loads because 5.4g of unique is still max for lyman in my handgun manual and is of course a high end but saami approved load. ditto 5.0 of herco. for pressures on those loads see a load manual, not a madman with a spreadsheet. if anyone is interested in hosting the file for the spreadsheet I made to do these calculations I will be happy to share. honestly i'd like to see it stickied for use estimating reduced charge pressures, which is its intended purpose.
"The Load" is what it is. It is nothing more than an actual published load found in an older manual. It is the starting load listed for IMR 4756 with a cast lead 158 grain semi-wadcutter bullet as found in the .38 Special chapter of the Speer No. 8 manual which has a publication date of 1970. Some later printings of the Speer No. 8 don't show it and neither does the Speer No. 9. "The Load" is the result of a bunch of friends' discussion on a private firearms forum over several years time. We all worked it up and conducted various tests with it using revolvers as small as a steel J-Frame Smith & Wesson up to as large as a N-Frame Smith & Wesson .38 Special Heavy Duty. Colt Detective Special and Official Police models saw some use by members of this group. For my own 6-inch barrel chronograph tests I employed a .357 Magnum revolver. I'm not aware that it was tested in any other brands of .38 Special revolver. It is very heavy and would not be recommended for extended use, even in quality .38 Special revolvers of steel construction. It would be completely unsuitable for use in alloy-framed revolvers or cheapo revolvers. No prudent person should take any load data at face value whether it is a shooting bud's pet favorite, or found on the internet, or even found in loading manuals, old and new. Always work loads up for one's own gun.
You mention pressure estimates and pressure estimates would be fun to calculate but it is hard to say how accurate they truly are. One out of the group owns a commercial bullet casting operation and went to the trouble to pay to have "The Load" tested by SAAMI. I didn't know this was possible and don't know the cost. He apparently prepared the ammunition and sent it to them. He says that SAAMI tests showed "The Load" returned an average pressure in the range of 26,000 psi. This is still above all SAAMI .38 Special +P specifications, a figure which has been a moving target over the years. It's been variously set at 18,500, 20,000, and 21,500 psi.
We had a good time seeing what could be accomplished with the .38 Special cartridge and published data from days gone by. I was willing to work up to the minimum listed charge weight of IMR 4766 but personally saw no future in striving to go any higher. Given the outstanding velocity performance with the minimum charge of IMR 4756 there is no need.
Practically speaking, there is no real need to use such heavy handloads at all since revolvers chambered for the excellent .357 Magnum are readily available. I have several .357 Magnum revolvers on hand if truly increased performance is required. For the avid handloader though, who only possesses a .38 Special revolver, such heavy loadings could find a niche. Playing with the .38 Special has been a lifetime academic exercise that I enjoy. It's an underdog cartridge that has been severely underrated. Despite current conventional wisdom, the .38 Special and the 9mm are two peas in a pod yet the 9mm enjoys an unfair measure of performance respect that the .38 Special doesn't enjoy. I place the .38 Special ahead of the 9mm simply because the .38 Special handles heavier bullets more capably. The .38 Special revolver can be far more than just a small, light 5-shot snub and .38 Special factory loads can be far more than lightweight jacketed hollow points at 800-900 fps. In the not too distant past, accepted and published .38 Special handloads could be even more potent. Some of us ol' geezers have long memories.
The data and results for the four loads mentioned in this thread were presented for interest to avid handloaders, not as a suggestion to attempt them. They happened to work out for me and my guns.