Joined
·
3,367 Posts
I've fired LOTS of 250g LFNGC's from my Marlin .375's, both of whjch sport MicroGroove rifling. Best performance from both rifles was obtained with .377" diameter bullets, BHN 21, and contrary to popular thought regarding cast in MicroGroove barrels, at velocities over 1650 fps.
Many of our customers report excellent accuracy out of their Marlin .375 Winchesters using the above mentioned bullet, and a starting load of 32.0g AA 1680 with a Winchester LR primer.
Other powders that have given excellent performance with this bullet at near factory velocities are RL-7, H322 and H335.
Oddly, my guns haven't liked the Lyman #375244 bullet at all! I've tried different bullet hardness, sizing diameters and a variety of powders/velocity combinations with no gratifying results.... mediocre being the best performance I've obtained.
Too, I've found it essential to seat the bullet out of the case as far as the action will cycle the round, then crimp with a Lee Factory Crimp Die, regardless of where the case mouth falls in relation to the crimp groove. The die will tuck the case mouth into the bullet sufficiently and not allow it to set back in the case under recoil. Marlin, when they chambered these rifles used a reamer that cut ENORMOUSLY LONG throats of relatively generous diameters, and aloy bullets as a general rule don't like a long jump into the lands... the .375's are no exception to this rule as far as my experience bears out.
Lastly, my particular guns have an annoying tendency to throw their projectiles sideways at the target if velocities are under about 1500 fps. This I really can't explain, as the twist is tighter than nearly all standard twist 38-55's, and should stabilize the bullets with surety.... however, the targets remain to bear witness that sometimes logic doesn't always prevail!
I've had many reports back from customers using my above recommended loads and acheiving very satisfactory, to excellent accuracy. Especially in those barrels that have been fire-lapped to releive the constrictions where the dovetails are cut for the rear sight and forend hanger. Fire lapping the MicroGroove barrels (especially those that look like they were rifled by a blind Girl Scout with a cold chisel), enhances the ease by which superb cast bullet load development is accomplished.
Just my 2 Cents worth!
God Bless,
Marshall Stanton
Many of our customers report excellent accuracy out of their Marlin .375 Winchesters using the above mentioned bullet, and a starting load of 32.0g AA 1680 with a Winchester LR primer.
Other powders that have given excellent performance with this bullet at near factory velocities are RL-7, H322 and H335.
Oddly, my guns haven't liked the Lyman #375244 bullet at all! I've tried different bullet hardness, sizing diameters and a variety of powders/velocity combinations with no gratifying results.... mediocre being the best performance I've obtained.
Too, I've found it essential to seat the bullet out of the case as far as the action will cycle the round, then crimp with a Lee Factory Crimp Die, regardless of where the case mouth falls in relation to the crimp groove. The die will tuck the case mouth into the bullet sufficiently and not allow it to set back in the case under recoil. Marlin, when they chambered these rifles used a reamer that cut ENORMOUSLY LONG throats of relatively generous diameters, and aloy bullets as a general rule don't like a long jump into the lands... the .375's are no exception to this rule as far as my experience bears out.
Lastly, my particular guns have an annoying tendency to throw their projectiles sideways at the target if velocities are under about 1500 fps. This I really can't explain, as the twist is tighter than nearly all standard twist 38-55's, and should stabilize the bullets with surety.... however, the targets remain to bear witness that sometimes logic doesn't always prevail!
I've had many reports back from customers using my above recommended loads and acheiving very satisfactory, to excellent accuracy. Especially in those barrels that have been fire-lapped to releive the constrictions where the dovetails are cut for the rear sight and forend hanger. Fire lapping the MicroGroove barrels (especially those that look like they were rifled by a blind Girl Scout with a cold chisel), enhances the ease by which superb cast bullet load development is accomplished.
Just my 2 Cents worth!
God Bless,
Marshall Stanton
