I think we need a little more information on your loading methods. Are your bullets pan lubed or sized (to what?). What is your alloy? What are you using to compress the powder? Are you using a drop tube? My standard loading for my 40-65 is 53 grains of 1 1/2 Swiss with no compression. What is your fouling control method? Is your barrel leaded? You should be getting groups no larger than 4.5 inches at 300 yards.

Hi thanks for the replies,
Bullets are 20-1 sized .409 SPG lube.
Using drop tube.
Blow tube between shots.
Cleaning after shot string with peroxide, murphys oil soap, alcohol mix.
Thank you,
Bill

I shoot that bullet in two Shiloh Sharps 1874's, one in 1:14 twist and the other in 1:16 twist.    I use a lot more powder ( 58gr of Swiss 1.5, or 58gr of Goex FFFg Express ).  It shoots extremely well at 200 & 300.   

I've never tried it with plain Goex as I've never had good luck with plain Goex.

I generally use 20:1 lead/tin and SPG lube, with a 0.060" LDPE wad underneath.   Wiping between shots and getting the bore condition just right each time is key. 

Chris.

I agree on a longer bullet for a 14 twist 40 caliber. My 14 twist 40-60 Maynard likes the BACO 400 and 420 money bullet. Not so much the saeco 740,use if in 16 twist.

I just bought a 1/16 Pedersoli Sharps 40-65 and came across this thread looking for load data.  I notice I'm a bit behind.

I'm not sure there is such a thing a over-spinning a bullet.  That has been bandied about for many years, but excess bullet spin CAN cause instability if the bullets imperfections, either through the casting process, loading process or travel through the barrel causes the bullet to become deformed or dinged.

I'm also not sure why the Saeco 740 bullets work well in some rifles and not in others, there are a ton of reasons that can happen.

Following the "longer is better trend" you would need a bullet in excess of 1.6" and 500+ gr weight to get the 1/14 to shoot supposedly, but in my experience with smoke/smokeless for 17 to 54 cal, long range/benchrest etc., there is usually something other than twist causing problems.

12" at 300 yds means ≈4" at 100 so I would look at the rifle/shooter/casting/loading process as a system and work through each to reduce variables.  Depending on the original MV, the BC and the ending velo, the "wobblies" could be the bullet falling through the sound barrier and getting a kick that way.   

I have 3 cartridge BP's and 3 Muzzle loading BP's and just like smokeless cartridges each rifle decides what components it likes...even a change in primer can cause a 1.5" variation in accuracy.

I've tried several bullets in the 210-265 gr range, and have looked at the 740 plus ordered a couple of molds from Accurate Molds in 350-420 gr to try...one that mimics the 740 closely. 

Something to think about.

Good Luck

While bullet dynamics and CG are all well known factors in this process, we are talking about a bullet that is already proven to be accurate so all the minutia should be left for talking over a barley pop.  

I ran the 5477 numbers through QL and QT just to see whatthehey...all numbers being rough and no chrono numbers to verify.  BC is ≈0.490, 21 gr 5477 gave 1445 fs and QT indicated ≈1041 fs at 300 yds very close to dropping thru the S.B.  It would be nice for Bill(FLINTLOCK) to chime in here with more information.

I have some 400 gr Lyman 410663 Snover's and 385 gr 410660 spritzers I'm itching to try as soon as the rain stops and the ground dries out a bit...my range is a muddy mess and I don't dare walk out to hang a target...at least the pine cones are still available.

I also want to try some Triple 7, Buckhorn 209, 5477 and smokeless along with my Goex BP, but I 'm guessing them's dust-up words on this forum.  

I need to post a pic of my 700 gr 50-70, 50-90, 50 cal wildcat WFNGC...didn't think the 600-650 grainers were big enough. 

Luck in Battle.

If it's going through the target looking like it's tipping heavily or keyholing then something is happening to that bullet between the cartridge case and the muzzle while it's being fired.  It's no longer symmetric so it's wobbling.   I've shot that bullet on paper at 600 yards a number of times in a 1:16 twist Shiloh with no tipping at all.   By the time I'd switched to my 1:14 twist rifle I'd already switched to the Money bullet for 600.

I imagine either the bullet does not seal the chamber well and it's gas cutting.

Chris.