More Tales from the Back Creek Diary
100-Yard Accuracy Results of Selected .38 and .357 Magnum
Cast Loads in a BSA Single-Shot and Marlin Cowboy Rifle
The proof of the pudding in any long gun is it will do at 100 yards. Not all handgun loads provide linear dispersion in proportion to the range, when fired from rifles, you need to test. Wad cutters do well at 50 yards, but not at 100.
I tested ordinary .38 and .357 handgun ammunition for which I had previous data. These included match-grade Norma 158-gr. lead round nose factory ammo, hand loads with Speer swaged lead round nose and semi-wad cutters and hand loads with cast lead, flat nosed cowboy slugs. All were standard velocity loads fired from my BSA Martini with 6X Unertl small game scope for five consecutive 5-shot groups at 100 yards. The best loads in the Martini were tested again in a Marlin 1894 with 2.5X Weaver scope.
Results are summarized in the accompanying table.
Norma 158-gr. LRN factory loads averaged just less than 3” at 100 yards from the BSA. Hand loads with swaged lead round nose and semi-wad cutter ammo in .38 Special cases didn’t shoot quite as well, but did stay under 4 minutes of angle, having useful field utility.
The most accurate 100 yard cast loads used the Hunter’s Supply cast 190 LFN of 92-6-2 alloy, sized .358 from Midway, with 4.3 grains of Bullseye in .357 cases. They averaged 2.18” in the BSA and 2.36” in the Marlin. This is the same bullet as NEI #191A. I cast some of those also from wheel weights tested them, getting comparable results as long as velocities with softer wheel weight alloy were subsonic. I normally use 3.5 grains of Bullseye in .38 cases and from 4.0 (if low noise is important) up to a maximum of 4.3 grains in .357 cases based upon accuracy results. Supersonic loads do not group as well at 100 yards as the slower ones, due to transonic buffeting as projectile velocity decays below the speed of sound.
My advice is not to magnum-ize it, but keep it handgun-caliber lead loads for rifles slow, accurate and quiet. A good working velocity range is from 950 to 1050 f.p.s. In a 24” barrel this gives a peak decibel noise level of less than 90dB, so there is no crack to disturb the neighbors. A big flat-nosed bullet is effective on groundhogs, wild turkey and larger edible critters raiding your garden. Bon appettit!
Sidebar to accompany .38 Special Test results
The accompanying test
data were fired from sandbags at 25 yards using my .357 BSA
Martini. I started this project simply
because I wanted to know if my own cast bullets shot as well as “bought ones”
and whether it was worth the money to buy commercial soft-swaged wad cutters or
good quality commercial cast bullets, or to cast my own.
The accompanying test data were fired from sandbags at 25 yards using my .357 BSA Martini. I started this project simply because I wanted to know if my own cast bullets shot as well as “bought ones” and whether it was worth the money to buy commercial soft-swaged wad cutters or good quality commercial cast bullets, or to cast my own.
I was very pleased that my own wheel weight metal, cast Saeco #348 wad cutters, loaded as-cast, unsized, lubed either with Lee Liquid Alox (LLQ) or Rooster Jacket tumble-on lube (RJTL), in unsized fired cases, decapped and flared only, with my standard charge of 3.5 grains of Bullseye, crimped in the revolver crimp groove and profiled in the Lee Factory Crimp Die shot equal to factory loaded Winchester wad cutter ammunition. The results also indicate that using the same simplified loading, method with soft-swaged Remington factory wad cutter bullets, enables you to assemble your own accurate match ammunition to equal or exceeding the grouping of factory wad cutters now available.
Commercial hard cast bullets of 92-6-2 alloy, sized, to .357” or 358” diameters did not shoot as well as my own unsized wheel weight cast bullets lubed with LLQ or RJTL. The Remington soft swaged HBWC bullets shot wonderfully when flush seated, using the black dry lube which came on them. None of the cast double-enders grouped as well when flush seated as they did when seated out and crimped in the crimping groove.
I believe that this is attributable to two causes. First, flush seating results in increased free bullet travel of the wad cutter bullet during initial acceleration, when fired in the .357 chamber. Also, when the top driving band is seated below the case mouth, crimping and profiling in the Lee Factory Crimp Die results in a slight reduction in its diameter. When bullets are seated out and crimped in the crimp groove with the top band exposed, its diameter remains as cast, or as-sized.
I believe that either an enlarged front band, or an expanding hollow base, as in the Remington HBWC bullet, aid in providing a positive gas seal, which reduces leading and bullet deformation, which hurt accuracy. There was no leading whatever with the factory HCWB bullets or the unsized cast bullets lubricated with either LLQ or RJTL.
I did some limited firings of my .38 Special Colt Officer’s model from sandbags to check each load. The loads which shot well in the Martini also shot well in the Colt. All of the cast wad cutters were tested with the same 3.5 grain charge of Alliant Bullseye, because this is proven reliable in past experience. The results would indicate this is the case.
The soft-swaged Remington hollow-based wad cutters shot consistently well, even with somewhat lighter and heavier charges than those usually recommended. I found that a somewhat heavier charge of Alliant Bullseye, than the often recommended 2.7-2.8 grains was needed with the HBWC bullets to approximate the velocity of factory wad cutter loads and that whether firing in the Martini Cadet rifle or the 6” Colt revolver that a charge in the range of 3.0 to 3.2 grains was correct.
When Spring weather permits, I hope to do some confirmation firings outdoors at 50 yards and also shoot some lead round nose and SWC bullets from the rifle at 100 yards to see how well a .38 Special rifle fares as a mild and quiet small game rifle. So stay tuned!