ATH
Well-Known Member
Months ago we had a thread about long range muzzleloading. I'd hoped to have my rig tuned up and tweaked by now, but since I don't, I thought I'd start the discussion without the data.
Anyone who has done serious ML shooting knows that it is a whole different ballgame than centerfire. This becomes all the more true as distance increases. This is true for several reasons.
1) Muzzle velocity. MLs, excluding the smokeless Savage 10-ML-II, run at a maximum velocity of about 2400 fps with a 190-200 grain bullet and 2200 with a 240-250 grain bullet. Some people get around this by going with tiny (180 grain) bullets, but these have tiny BCs as well. A few guns out there (Ultimate Firearms has one) shoot up to 200 grains of powder to get the velocity up there. But in the end, we're still left short of centerfire by a wide margin.
2) Twist/sabot. These are interlinked. The fastest ML twists are 1:20. Most are 1:28. The 1:28s are too slow to stabilize really long bullets, but the 1:20s were soon pulled from the market because they were very fussy and stripped sabots. So, in the end, we are stuck with a maximum twist of around 1:24 until the technology of the sabot is improved.
3) Sabot itself. In addition to its limitations on twist, a ML sabot must be soft enough to ram down the barrel yet tough enough to take the rifling and pressure without letting the bullet drill backwards. Currently, shooters of the smokeless Savage are suffering from the weakness of ML sabots in their efforts to push 3000 fps. While they have found some useful tricks, this limitation remains.
4) Low BC bullets. This is one of the most severe limitation. A quick survey of most available ML bullets will find BCs averaging around .15. The highest currently marketed are the 200 grain T/C Shockwave and the Dead Center line by Precision Rifle. The Shockwave is advertised around .24, and the Dead Centers vary up to an advertised .375 (though the real value is regarded as under .3). Due to the bore, twist, and velocity restrictions, it is a battle getting a higher BC bullet to fly. The high BC Dead Centers are also pure lead, which is fussy in some guns and will not fly fast. So until someone duplicates them in a copper jacketed version, they cannot be pushed to the max in most cases.
With these limitations in mind, I have set about working up a gun to hunt deer to 400 yards and punch paper to 500 yards. Last year with my old gun I shot the 195 grain Duplex Dead Center over 100 grains 777 powder at 1998 fps. This load was 4" high at 100, 0 at 200, and 17" low at 300. Group size at 300 was just over MOA. However I suffered from a cheap gun with an unsafe trigger, so I upgraded.
I currently have a T/C thumbhole stock Omega with a Leatherwood In-Liner 3-9X scope. It wouldn't shoot the Dead Centers (MLs are MUCH more bullet fussy than centerfires), but I could push the 200 grain Shockwave to 2100+ fps with sub-MOA accuracy.
I have since upgraded the gun from 209 primer ignition to the .25 ACP conversion to use small rifle primers. This should help accuracy some.
Hopefully I'll get to finish choosing the flatest-shooting accurate load this weekend so I can move on to long range work.
Anyone else done some work on this subject?
Anyone who has done serious ML shooting knows that it is a whole different ballgame than centerfire. This becomes all the more true as distance increases. This is true for several reasons.
1) Muzzle velocity. MLs, excluding the smokeless Savage 10-ML-II, run at a maximum velocity of about 2400 fps with a 190-200 grain bullet and 2200 with a 240-250 grain bullet. Some people get around this by going with tiny (180 grain) bullets, but these have tiny BCs as well. A few guns out there (Ultimate Firearms has one) shoot up to 200 grains of powder to get the velocity up there. But in the end, we're still left short of centerfire by a wide margin.
2) Twist/sabot. These are interlinked. The fastest ML twists are 1:20. Most are 1:28. The 1:28s are too slow to stabilize really long bullets, but the 1:20s were soon pulled from the market because they were very fussy and stripped sabots. So, in the end, we are stuck with a maximum twist of around 1:24 until the technology of the sabot is improved.
3) Sabot itself. In addition to its limitations on twist, a ML sabot must be soft enough to ram down the barrel yet tough enough to take the rifling and pressure without letting the bullet drill backwards. Currently, shooters of the smokeless Savage are suffering from the weakness of ML sabots in their efforts to push 3000 fps. While they have found some useful tricks, this limitation remains.
4) Low BC bullets. This is one of the most severe limitation. A quick survey of most available ML bullets will find BCs averaging around .15. The highest currently marketed are the 200 grain T/C Shockwave and the Dead Center line by Precision Rifle. The Shockwave is advertised around .24, and the Dead Centers vary up to an advertised .375 (though the real value is regarded as under .3). Due to the bore, twist, and velocity restrictions, it is a battle getting a higher BC bullet to fly. The high BC Dead Centers are also pure lead, which is fussy in some guns and will not fly fast. So until someone duplicates them in a copper jacketed version, they cannot be pushed to the max in most cases.
With these limitations in mind, I have set about working up a gun to hunt deer to 400 yards and punch paper to 500 yards. Last year with my old gun I shot the 195 grain Duplex Dead Center over 100 grains 777 powder at 1998 fps. This load was 4" high at 100, 0 at 200, and 17" low at 300. Group size at 300 was just over MOA. However I suffered from a cheap gun with an unsafe trigger, so I upgraded.
I currently have a T/C thumbhole stock Omega with a Leatherwood In-Liner 3-9X scope. It wouldn't shoot the Dead Centers (MLs are MUCH more bullet fussy than centerfires), but I could push the 200 grain Shockwave to 2100+ fps with sub-MOA accuracy.
I have since upgraded the gun from 209 primer ignition to the .25 ACP conversion to use small rifle primers. This should help accuracy some.
Hopefully I'll get to finish choosing the flatest-shooting accurate load this weekend so I can move on to long range work.
Anyone else done some work on this subject?
