Why the huge discrepancy in load data?

[The Wiry Irishman]

I've been using Bullseye for warmish 230 gr LRN .45 ACP loads that replicate the recoil feel of my carry ammo. Since I've killed my 8 pound jug and I'm not 100% satisfied with Bullseye's performance in hotter loads, I just ordered a few pounds of Unique to try out. Lyman's 49th lists the max load for a 225 gr (before lube) LRN as a hair over 7 grains. My Alliant manual lists the max load for a Speer 230 gr LRN as a hair over 5. I don't have my manuals at hand, so I can't quote exact numbers, but this is still a pretty significant difference. Why is that? Are the Speer lead bullets extraordinarily soft, or is it something else?

 

[rcmodel]

Lyman #49 says 7.3 Unique is a max load with the 225 GI profile LRN .

Alliant's 2009 manual shows a 5.8 load with Unique for the 230 LRN Speer.

But, Apples & Oranges:
The Lyman bullet is a #2 alloy cast bullet with a grease groove and two driving bands.
The Speer is soft swaged, dry lubed, and will strip the rifling and lead badly if driven hard in the 1911's shallow rifling.

However, Bullseye WAS the standard powder used by the military for about the first 40+ years of it's life, and the 1911 was designed around it.

A GI equivilent hardball load is 5.2 Bullseye and a 230 FMJ bullet.

rc

 

[Galil5.56]

For perspective, and hard numbers; below is chronograph data from my Sig P220 .45 Auto w/4.4" barrel, using Bullseye and Unique with 225 grain "hardcast" bullets sized .452". Chronograph used was a Competition Electronics ProChrono Digital:

5 grains Bullseye CCI 300 MC 225 TC
783 789 796 781 790 AV 787 ES 15 SD 5

5.8 grains Unique CCI 300 MC 225 TC
782 770 752 750 784 AV 767 ES 34 SD 16

Same gun, same bullet and primers using Power Pistol:

7 grains Power Pistol CCI 300 MC 225 TC
856 877 858 866 877 AV 866 ES 21 SD 10

And WW231:

5.5 grains WW 231 CCI 300 MC 225 TC
776 779 761 775 768 AV 771 ES 18 SD7

Although I cast 95% of my own bullets, I do find Hornady swaged bullets perform better than Speer, and are very accurate. Adding a very light coat of Lee Liquid ALOX to problem swaged/cast bullets can go a long way to making them behave. For really pushing performance to the max with 230 grain jacketed/cast bullets, I have always found HS-6, and AA#5 really hard to beat. I'm starting to warm to Power Pistol, and I like older recommended max charges of WW231 very well too for very good velocity. Lots-o-choices out there, and it's harder to find a fastish/medium burn rate propellant that won't work at least decently.

 

[Steve C]

Alliants listing their top load at 5.8grs of Unique for the Speer 230gr LRN for a velocity of 848 fps for a typical GI ball equivalent. Lyman ilists 7.3grs wit their cast bullet for another 57 fps (905fps).

My experience with Unique is loading jacketed bullets and 6.2grs will push a 230gr jacketed bullet to just the + side of 850 fps from a Sig, 1911 Gov or Commander. Since lead usually shoots a bit faster than jacketed I'd say Alliants velocity estimate is very close while I'd expect a bit faster numbers from the Lyman max data.