Spindrift
Well-Known Member
Even for the non- caster (casteless?), the .358 caliber have a wide offering of commercially available bullets. Light or heavy, different bonding techniques, partitioned bullets, copper bullets in sensible weights. Not to mention the whole menagerie of handgun bullets, offering cheap practice bullets- or bullets that expand at subsonic velocities. On the whole, there are not many rational reasons why you would try to resize 9,3mm (.366) bullets to .358. Unless you just want to try it out! And I did.
I found lots of useful info here.
I got 25 «Geco plus» 9,3mm 255grs bullets cheap. This is a core- bonded bullet, probably advantageous when sizing down.
I worried about springback. It is reasonable to assume the jacket will have more springback than the core. I decided to start with annealing the bullets. I used the same temperature and time I use for curing powder coat. The idea was, maybe the jacket would have less springback, and size easier. Second, this would «reset» the lead core (probably containing some antimon); the following precipitation hardening of the core alloy also cause a little growth, which would reduce core/jacket tension that might otherwise be present after downsizing.
After the annealing, the color of the jacket was lighter. There was a slight extrusion of lead from the «protected point»- type small hollow point.
Bullets were lubed with Lee case lube, as were the insides of Lee .358 and .357 dies. I ran the first bullet through the .358 die, measured .3583. Ran the bullet through the same die again, and measured one more time; same size, no apparent springback. Then through the .357 die, which resulted in a .3572 bullet.
I measured some actual .35 caliber bullets:
Hornady interlock 250 grs: .3575
Nosler accubond 225grs: .3575
Speer hot cor 250 grs: .358
I decided to use the .357 sizer die, as I’d rather use bullets a little small, than a little large. First through the .358 die, then the .357 for final size. Lead extrusion from the tip was a bit more marked after sizing, I simply squeezed it back, forming a neat little FP
The base was originally a little rounded. After sizing, a sharper «flat base». The whole bullet was visibly longer.
Actual weight and bearing surface was very similar to the 250grs interlock, and I simply used the same load of 57grs vihta N150. I got the expected 2450fps from my 20 3/4in barrel (threaded for suppressor). I’ve only shot one group yet, with bullets not fully matured after annealing. This resulted in an unimpressive 50mm 5-shot group at 100m. Still, this group is considerably smaller than the vitals of a moose.
I’ll shoot some more groups, and test penetration/ expansion in a while.
Happy shooting, folks!
I found lots of useful info here.
I got 25 «Geco plus» 9,3mm 255grs bullets cheap. This is a core- bonded bullet, probably advantageous when sizing down.
I worried about springback. It is reasonable to assume the jacket will have more springback than the core. I decided to start with annealing the bullets. I used the same temperature and time I use for curing powder coat. The idea was, maybe the jacket would have less springback, and size easier. Second, this would «reset» the lead core (probably containing some antimon); the following precipitation hardening of the core alloy also cause a little growth, which would reduce core/jacket tension that might otherwise be present after downsizing.
After the annealing, the color of the jacket was lighter. There was a slight extrusion of lead from the «protected point»- type small hollow point.
Bullets were lubed with Lee case lube, as were the insides of Lee .358 and .357 dies. I ran the first bullet through the .358 die, measured .3583. Ran the bullet through the same die again, and measured one more time; same size, no apparent springback. Then through the .357 die, which resulted in a .3572 bullet.
I measured some actual .35 caliber bullets:
Hornady interlock 250 grs: .3575
Nosler accubond 225grs: .3575
Speer hot cor 250 grs: .358
I decided to use the .357 sizer die, as I’d rather use bullets a little small, than a little large. First through the .358 die, then the .357 for final size. Lead extrusion from the tip was a bit more marked after sizing, I simply squeezed it back, forming a neat little FP
The base was originally a little rounded. After sizing, a sharper «flat base». The whole bullet was visibly longer.
Actual weight and bearing surface was very similar to the 250grs interlock, and I simply used the same load of 57grs vihta N150. I got the expected 2450fps from my 20 3/4in barrel (threaded for suppressor). I’ve only shot one group yet, with bullets not fully matured after annealing. This resulted in an unimpressive 50mm 5-shot group at 100m. Still, this group is considerably smaller than the vitals of a moose.
I’ll shoot some more groups, and test penetration/ expansion in a while.
Happy shooting, folks!
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