The load for these older 38 Specials is a 158 lead RN or LSWC with 3.5 grs Bullseye. As best I can tell, over the chronograph, this is a factory equivalent, standard pressure load, and it shoots to point of aim in these older fixed sight revolvers.
I have shot thousands upon thousands of 38 Special rounds using 3.5 grains of Bullseye with LSWC, JHP, LRN, LBBFPRN, etc. Point of aim between the bullets type is close enough that I cannot tell a difference between bullets. I truly think that my flinch causes more variation in impact than bullet configuration. Velocities are so similar it would take a statistical analysis, (perhaps Students T test?) to see if there is a velocity difference between a LSWC and a LRN of the same alloy. I have shot that load in many revolvers, some I still own, some I do not. I have shot that load in 38 Snubbies, four inch barreled 38’s, and 357 Revolvers. It shoots very well. This is real world data, not shot from pressure barrels.
The dumped charges are as similar as I can make them, given a Dillion progressive, there are variations due to which primers I used. Primer use is based on who was making the cheapest primer at the time of loading. Winchester has been the consistently low cost primer maker for a while, most loads are WSP. I have never found a need to use the same case, so I am using brass that has been fired God Knows how many times and a rainbow of headstamps. All of which shoot fine.
I have shot other powders and other loads, but Bullseye is so constantly accurate and shoots to Point of Aim in the fixed sight revolvers, that I have standardized on that load and powder and see no reason to chase the “
Powder de jour” . It also is close to the non +P factory ammunition I have shot in terms of velocity. So I consider this load equivalent to factory ammunition.
Taurus M85 B2UL 2" Barrel
158 LSWC
3.5 grs Bullseye thrown, Mixed Brass WSP 11-Dec-04 T = 54 F
Ave Vel = 686.3
Std Dev = 13.63
ES 58.48
High 718.8
Low 660.3
N = 30
shot little high and centered
158 LRN Master Factory Ammo 30-Dec-04 T = 56 F
Ave Vel = 698.2
Std Dev = 20.56
ES 105.8
High 753.5
Low 647.6
N = 32
shot 6" high centered,until barrel leaded
158 LSWC
3.5 grs Bullseye Mixed brass Fed 100 30-Dec-04 T = 56 F
Ave Vel = 706.2
Std Dev = 23.45
ES 81.94
High 748
Low 666.1
N = 48
Colt Detective Special mfgr 1963 24-Jul-99 T = 100 F !
158 gr LRN
3.5 grs Bullseye thrown, CCI primers mixed cases
Average 751 fps
Standard Deviation 32 fps
Extreme Spread 90 fps
High 805
Low 715
Recorded shots 22
158 LRN
3.5 grs Bullseye WSP Mixed cases 8-Jan-06 T = 52 F
Ave Vel = 675.9
Std Dev = 18.6
ES 96.18
High 723.9
Low 627.7
N = 32
158 LSWC
3.5 grs Bullseye WSP Mixed cases 8-Jan-06 T = 58 F
Ave Vel = 706.8
Std Dev = 15.55
ES 65.87
High 742.9
Low 677
N = 32
Colt Cobra 2" barrel 30-Jan-05 T = 42 F
158 gr LRN
3.5 grs Bullseye thrown, Fed 100 primers mixed cases
Average 696.6
Std Dev 20.49
Extreme Spread 72.93
High 745.5
Low 672.6
13 recorded shots
shoots point of aim
Colt Police Positive Special 4" Barrel mfgr 1930
158 LRN
3.5grs Bullseye Mixed cases Fed 100
4-Sep-05 T = 72 F
Ave Vel = 759.2
Std Dev = 36
ES 104.8
High 813
Low 709
N = 32
158 LRN
3.5grs Bullseye Mixed cases WSP
29-Jan-06 T = 68 F
Ave Vel = 760.3
Std Dev = 27.53
ES 111.4
High 814.1
Low 702.6
N = 29
158 JHP
3.5grs Bullseye Mixed cases WSP
29-Jan-06 T = 68 F
Ave Vel = 633.1
Std Dev = 41.32
ES 113.2
High 706.7
Low 593.5
N = 6
