Great article GregLaROCHE. I really enjoyed it. Thanks.
Great article GregLaROCHE. I really enjoyed it. Thanks.
Jevyod
Powder positioning in the 45-70 cartridge case is many times not a problem when testing loads from a bench. The rifle is henerally loaded level and in the same manor so the powder can be, most often, "positioned the same simply from the act of loading the rifle. Field use is another matter though. The rifle is carried or shouldered presented differently thus the powder may be positioned within the case differently. Does this pose problems? Yes it can ond most often does with reduced smokeless loads in the 45-70. I'll present an example with IMR 3031 and a 415 gr cast bullet. However other faster burning powders such as Unique and 2400 can give the same problems when shooting other than at a bench or when positioning the powder (by raising the muzzle prior to shooting) isn't practical.
This target was fired at 100 yards using the tang rear sight on my H&R OM trapdoor. The load was 35 gr IMR 3031 w/o a filler under the 415 gr cast. The first 5 shots were loaded and the rifle was jostled up and down to replicate carrying the rifle. It was then braced on the bench over sand bags and fired. Three of the shots went low out of the bullseye (one was about 1/2" off the bottom of the paper) and two shots went high with another shot off the paper over the top. I then fired 5 shots from the same bench position elevating the muzzle after loading and slowly lowering to the shooting position before firing. The are in the bullseye with four at 3 0'clock and one at 5:30.
The average velocity (24" barrel) was 1080 fps with an extreme spread of 350 fps. The average psi (measured with a M43 Oehler PBL) ran 15,000 with almost 6,000 psi extreme spread.
Attachment 233450
This target was fired right after the above target. The rear sight setting was not changed. Range again was 100 yards. The same load was used except these rounds had a 3/4 gr Dacron filler over the 35 gr of IMR 3031. The rifle was jostled about after loading and turned completely around prior to benching and shooting from the same position as used previously. The average velocity was 1230 fps with an ES of 33 fps. The psi measured 25,500 with an ES of 1,600. Both of those averages are quite good as results on the target demonstrate.
Attachment 233451
Whether or not you want to use a filler is up to you.
Larry Gibson
“Deficient observation is merely a form of ignorance and responsible for the many morbid notions and foolish ideas prevailing.”
― Nikola Tesla
I played around comparing filler vs no filler and didn't find any really practical difference in hunting accuracy with or without their use, except with 3031 powder. Using that powder as described above (tipping and moving it around) allowed the first case of semi-burned powder plugging my barrel on my 1885. I dip all my loads and use a trickler to bring them up to centerline on my scale. For low volume shooting such as the 45-70 in a single shot rifle and load development. Anyway, at the report the gun sounded very odd. Sort of a muffled thump. I looked in the barrel and it was plugged with a "lump" of brown plastic looking stuff. It took a rod to knock it back out of the gun. It was the charge of 3031 fused together and not ignited. Prior to this happening, the POI's were all over the target. I never used 3031 again in that caliber. Even with a filler it didn't group all that well in my guns. Shooting 2400, Rel 7, 4198, and 4227 I get very good accuracy with lighter loads (lighter being a 405g bullet "loafing" along at around 1350-1500 fps). For hunting purposes I just quit using fillers. Note: using 2400 powder my loads were shooting right around 1moa off the bench (scoped) and without filler they were sub 2moa in the worst case scenario. Like stated above, you need to decide if you want to use them. I strongly suggest you use one if you're going to use 3031 powder.
I am using IMR4198,
And shooting around 1600fps.
The deer do not object!
Beer is proof that God loves us and wants us to be happy!
Ben Franklin
Thanks for the replies guys! I loaded up some trapdoor loads according to Lyman 49th edition using 3031 powder. Should get 1200-1300 fps. I assume that should be plenty even for a good size black bear out to 100 yards.
BP | Bronze Point | IMR | Improved Military Rifle | PTD | Pointed |
BR | Bench Rest | M | Magnum | RN | Round Nose |
BT | Boat Tail | PL | Power-Lokt | SP | Soft Point |
C | Compressed Charge | PR | Primer | SPCL | Soft Point "Core-Lokt" |
HP | Hollow Point | PSPCL | Pointed Soft Point "Core Lokt" | C.O.L. | Cartridge Overall Length |
PSP | Pointed Soft Point | Spz | Spitzer Point | SBT | Spitzer Boat Tail |
LRN | Lead Round Nose | LWC | Lead Wad Cutter | LSWC | Lead Semi Wad Cutter |
GC | Gas Check |