Earlier this year I was running a test on some .38 Special loads using Rim Rock 158 gr. SWC-HP with gas check bullets. These bullets being known as the old "FBI" load are not a hardcast but in the 7-10 BHN range.
Shooting them through my 4 inch S&W M 66 of 1976 issue they shot very well at +P levels with 6.3 gr. of Power Pistol at speeds in 1060 FPS range. No leading at all after 12 shots.
When shot through my LCR with 1.875 barrel speeds were checked at 924-940 range but barrel was leaded a good bit after 5 shots.
Just got around to measuring cylinder throats and slugging barrel on the LCR...
Cylinder Throats check at .358 measured and .358 RR bullet slides in with a push.
Barrel slug shows a .356 diameter.
The SW M66 cylinder throats measured a tighter .357
Haven't slugged the barrel yet.
Could the .356 size be at the threaded fire cone area but be .357 further down causing the leading?
Didn't notice the slug tighten up when exiting barrel/cone area.
Shooting them through my 4 inch S&W M 66 of 1976 issue they shot very well at +P levels with 6.3 gr. of Power Pistol at speeds in 1060 FPS range. No leading at all after 12 shots.
When shot through my LCR with 1.875 barrel speeds were checked at 924-940 range but barrel was leaded a good bit after 5 shots.
Just got around to measuring cylinder throats and slugging barrel on the LCR...
Cylinder Throats check at .358 measured and .358 RR bullet slides in with a push.
Barrel slug shows a .356 diameter.
The SW M66 cylinder throats measured a tighter .357
Haven't slugged the barrel yet.
Could the .356 size be at the threaded fire cone area but be .357 further down causing the leading?
Didn't notice the slug tighten up when exiting barrel/cone area.