cayugad

70 grains of Triple Se7en 3f and a 410 gr Hornady Conical with a wad is rated at 1383 fps. So a 460 gr would not be too far behind that. This information is taken out of Hodgdon's Basic Muzzleloading Manual. If that's any help.

Pglasgow

Thats 1741 ft-lbs at the muzzle. The same muzzle energy for the 460 would be a little less than 1310 fps. One trick I use for predictingmuzzle energies for two projectiles using the same chargeis to take a ratio of the projectile weights. eg 460/410 = 1.12.

So the 460 weighs about 12% more. Now you can multiply the percentage increase in projectileweightby .45 to get the percentage increase in muzzleenergy, which is .45 x12% = 5.4%.

Then just multiply 1.054 x 1741 ft-lbs = 1835 ft lbs. After one has the muzzle energy, one can use a formula or a ballistics program to calculate the muzzle velocity. Given to the task of predicting velocity for the 460 in the barrel hodgdon tested the 410 with, I would predict a muzzle velocity of 1340 fps with 70 grains 3f 777.

cayugad

That's pretty interesting how you figured that Pglasgow... Then I remembered that Sabotloader shot some 70 gr T-7 3g 460 No Excuse over a chronograph and reported the results. 1390 fps. So you are right on the money there. I have to remember that trick.

Pglasgow

I figure that Sabotloader would do better than Hodgdon with the 410. I have found hodgdon's data somewhat conservative, but then every rifle is different and I suspect powders vary a little by batch (mostly in weight per volume)

Since you liked that one cayugad. Here is another trick. Say you want to increase or decrease the charge and want to know how that will affect muzzle velocity.This works especially well with black powder, but as works fairly well for subs.

Say Sabotloader gets1390 with 70 grains.How much with 80 grains? Just think of powder as energy. The muzzle energy per unit volume of powderwill depend on the projectile chosen. The greater the weight of the projectile the more energy one gets at the muzzle for a unit volume (grain) of powder.

One just takes the ratio of charge volumes. Or 80/70 = 1.143. There is 14.3 % more powder in the 80 grain charge. This means there is14.3 % more energy in an 80 grain charge. Since Sabotloader gets1974 ft-lbs at the muzzle with 70 grains, he should get 14.3% more muzzle energy with 80 grains or 1.143 * 1974 = 2256 ft lbs.

This corresponds to a muzzle velocity of 1486 fps in Sabotloader's rifle. I figure thats pretty close.

eldeguello

"I had to walk about a half mile to the nearest house to call someone to come pull me out. Since I am now typing this you cansee they were able to get me unstuck. He had chains on his 4x4 that I didn't have and he just barely got me out."

Half a mile in New Mexico is NOT BAD! You're li=ucky you weren't in Ojo Feliz........

dmurphy317

Pglasgow,
You may be correct, I just went by the shooting results of about 1" high at 25 and dead on at 75 and threw in velocity numbers in my ballistics calculator till I came close to those results. It could very well be off since I didn't do an exact measurement of the bullet impacts. The good news is, my chonograph arrived today so I'll be ready the next time out to verify the velocities. If it is around 1300 to 1350 it will mean I can use an 8" PBR and shoot to 150 and be within +/-4" with that load and still have around 1300fpe at 150 and 1200fpe at 200. Drop at 200 would be around 28" so, if the distance is known, an elk would be big enough to shoot at that range by holding just about a foot over the top of the back.

Eldequello,
I'm not sure where Ojo Feliz is but I do think I was lucky. The house I used the phone at was the only house occupied within about 2 miles and I would have had to climb over at least 1 hill to reach the next nearest house.