Post by Bullshop on Sept 7, 2020 16:57:45 GMT -7
Until recently I had not actually worked at developing a cast bullet load for our Marlin micro groove 30-30. I have loaded ammo for it but just that ammo without any effort working for accuracy. This was our daughter Joy's rifle and she recently expressed that she was not real happy with it shooting what we will call deer loads. She liked it with the light loads with light bullets just for fun shooting but as we worked her up to full power loads lost interest in the gun She recently asked if I would trade her for a 25-20 built on an 1898 Springfield that she likes to shoot with the full spectrum of loads so the 25-20 is now hers and the 30-30 mine , until she changes her mind again.
Thinking I might want to use it for early season coyote hunting I set to developing an accurate load.
With the ammo I had been loading it was just an average shooter grouping 4" to 5" at 100 yards. I think that is what most folks expect from any 30-30 carbine but experience has shown that with adjusted loads they can do much better. I had been as standard procedure sizing bullets to .310" diameter and as stated they gave so so accuracy. The Ranch Dog bullets always seem to be a perfect fit in Marlin chambers but in this case not so. The 170gn RD bullet in this gun is being heavily engraved for about .050" when crimped into the crimp groove of the bullet. With fairly hard in this case BHN-20 alloy that .050" engraving requires quite a tight squeeze on the lever to fully chamber. I dont care for having to squeeze the lever that hard so decided to seat past the crimp groove and crimp into the nose section ahead of the crimp groove. This made cartridges chamber freely with just barely a trace of engraving.
This alone did seem to help accuracy but not enough to matter. The next thing was to see if it had a preferred bullet diameter that shot best. From previous experience with micro groove barrels I learned that fat and hard usually worked best and this carbine was true to form. Going from 5" 100 yard groups with the .310" bullets I sized some to .308" to see if there would be any change, and there was. At 100 yards with the .308" bullets only one of several hit the target and it had a serious wobble oblong entry hole.
OK so 308" is out so what is the largest diameter that will freely chamber in this gun? Since the Ranch Dog bullets drop from the mold at .314" I tried some at as cast diameter. With a .314" diameter bullet and in the PMC brass I was using the ammo will chamber freely but shows a very slight drag mark on the case neck so this is as larg a diameter bullet that will freely chamber in this gun. The very noticeable difference was that groups were nearly cut in half from the .310" diameter bullets.
Finally a tweek in the powder charge has this short rifle a solid 2" shooter at 100 yards. The powder I was using was IMR 4895 partly because it was already in my powder drop and partly because we just recently bought four kegs of it. Of all the load data I looked through 4895 was a solid 200 fps slower that the powders giving the highest velocities. Often time different books show different results but in this case they were unanimous in that 4895 was just a slower powder in the 30-30. Thats fine though because a 170gn bullet at 2000 fps is fast enough for my purpose.
Because I did want the highest velocity possible with this powder and a 170gn cast bullet I used the max charge shown of 31gn for a 170gn jacketed bullet. This load shot fair but not as good as I hoped. It seemed to not be making round holes on paper so I reduced it to 30gn and the groups tightened nicely and holes on target were round.
So the load I have settled on is with the Ranch Dog bullet at BHN-20 sized to .314" loaded over 30 gn IMR 4895 with a WW LR primer and a moderate crimp in the bullet nose using a Lee factory crimp die. That load makes this gun a solid 2'' shooter at 100 yards. If other brass that may have slightly thicker necks is used I think that bullet diameter could be reduced to .313" and accuracy retained but so far that is only theory. If need be .0005" could be turned from each side of case necks giving a total reduction in case neck diameter of .001" and that would also eliminate the very slight drag marks I get on the necks of the PMC brass.
So success has been realized with this Marlin micro groove 30-30 with cast bullets delivering top level accuracy with full power loads. Thank for following my ramblings!
Thinking I might want to use it for early season coyote hunting I set to developing an accurate load.
With the ammo I had been loading it was just an average shooter grouping 4" to 5" at 100 yards. I think that is what most folks expect from any 30-30 carbine but experience has shown that with adjusted loads they can do much better. I had been as standard procedure sizing bullets to .310" diameter and as stated they gave so so accuracy. The Ranch Dog bullets always seem to be a perfect fit in Marlin chambers but in this case not so. The 170gn RD bullet in this gun is being heavily engraved for about .050" when crimped into the crimp groove of the bullet. With fairly hard in this case BHN-20 alloy that .050" engraving requires quite a tight squeeze on the lever to fully chamber. I dont care for having to squeeze the lever that hard so decided to seat past the crimp groove and crimp into the nose section ahead of the crimp groove. This made cartridges chamber freely with just barely a trace of engraving.
This alone did seem to help accuracy but not enough to matter. The next thing was to see if it had a preferred bullet diameter that shot best. From previous experience with micro groove barrels I learned that fat and hard usually worked best and this carbine was true to form. Going from 5" 100 yard groups with the .310" bullets I sized some to .308" to see if there would be any change, and there was. At 100 yards with the .308" bullets only one of several hit the target and it had a serious wobble oblong entry hole.
OK so 308" is out so what is the largest diameter that will freely chamber in this gun? Since the Ranch Dog bullets drop from the mold at .314" I tried some at as cast diameter. With a .314" diameter bullet and in the PMC brass I was using the ammo will chamber freely but shows a very slight drag mark on the case neck so this is as larg a diameter bullet that will freely chamber in this gun. The very noticeable difference was that groups were nearly cut in half from the .310" diameter bullets.
Finally a tweek in the powder charge has this short rifle a solid 2" shooter at 100 yards. The powder I was using was IMR 4895 partly because it was already in my powder drop and partly because we just recently bought four kegs of it. Of all the load data I looked through 4895 was a solid 200 fps slower that the powders giving the highest velocities. Often time different books show different results but in this case they were unanimous in that 4895 was just a slower powder in the 30-30. Thats fine though because a 170gn bullet at 2000 fps is fast enough for my purpose.
Because I did want the highest velocity possible with this powder and a 170gn cast bullet I used the max charge shown of 31gn for a 170gn jacketed bullet. This load shot fair but not as good as I hoped. It seemed to not be making round holes on paper so I reduced it to 30gn and the groups tightened nicely and holes on target were round.
So the load I have settled on is with the Ranch Dog bullet at BHN-20 sized to .314" loaded over 30 gn IMR 4895 with a WW LR primer and a moderate crimp in the bullet nose using a Lee factory crimp die. That load makes this gun a solid 2'' shooter at 100 yards. If other brass that may have slightly thicker necks is used I think that bullet diameter could be reduced to .313" and accuracy retained but so far that is only theory. If need be .0005" could be turned from each side of case necks giving a total reduction in case neck diameter of .001" and that would also eliminate the very slight drag marks I get on the necks of the PMC brass.
So success has been realized with this Marlin micro groove 30-30 with cast bullets delivering top level accuracy with full power loads. Thank for following my ramblings!
!!!!! i hate recoil!!!!!!!!