Deviation in FPS

[Tennessee Snuffy]

Folks

 

I have been loading 100 g of 1 1/2 F  for a 45-120.  Over a 10 shot average, I am getting a 50 fps spread (from the highest to the lowest).  Average FPS = 1450.  Since I am new to the black powder world, is that pretty good, ok or stinks like a dead skunk?

 

Thanks 

 

Tennessee Snuffy

[Dilli GaHoot Galoot]

If I read that correctly your fps run from (roughley) 1425 to 1475? 

Is that the average, as in you added up all the velocities and divided by 10 or is it the median, the halfway point between your lowest and highest velocities? 

Either way I think you should be fine

I stand corrected 

Edited February 2 by Dilli GaHoot Galoot

[The Original Lumpy Gritz]

Fouling out.

For match grade loads you want maybe 10fps ES.

Make sure your crono has fresh batteries. 

Edited February 2 by The Original Lumpy Gritz

[SHOOTIN FOX]

Cold barrel to hot barrel. Ladder check your velocities.

[The Original Lumpy Gritz]

What are you doing for fouling control after each shot?

Have you annealed the case necks?

How do you measure your powder out?

[Cholla]

I don’t think 50 is good. Anything over 20 is considered bad in long range smokeless. My latest 45-70 testing was 7. 

[Dilli GaHoot Galoot]

5 minutes ago, Cholla said:

I don’t think 50 is good. Anything over 20 is considered bad in long range smokeless. My latest 45-70 testing was 7. 

 

They way he wrote it it sounds more like 25fps 

[Lead Monger]

You made no mention of bullet weight along with other variables like wiping the bore between shots, primer used or powder compression. I have found my 45-120 Pedersoli much prefers 500 to 550 grain billets and compressed powder charges. If I throw 400 g or lighter bullets my ES opens up. Adding powder helps a bit but heavier bullets are more accurate for me. Another thing easy to overlook is the condition of the brass. My best accuracy has been with  once fired cases, run only about 30% into sizing die and then into a .459 expander. 120 grains of GOEX 2F are compressed enough to allow a 535g Lyman to be seated without distortion and a light crimp just to smooth the case walls and keep the bullet from moving. I always use a Fed 215 primer with this rifle. ES is less than 20 if I wipe between shots.

[Dilli GaHoot Galoot]

I recall reading an article by Mike “Duke” Venturino back in the 80's (+/- 10 years) where he said he got better, more consistent results when he loaded with a drop tube.  

 

I don't know if this is a real thing or not, just throwing it out there in the hopes it might jog someone's memory 

[Buckshot Sheridan]

50 is a pretty wide spread. Single digit extreme spreads are attainable, certainly under 20. Which powder are you specifically using. I know when I switched from Old Einsford to Swiss my velocities went up substantially, and the velocity spread dropped by 90%. Your amount of compression can make a big difference here as well. 

[The Loose Moose]

Best I’ve gotten is 7fps standard deviation on my match loads. The single best thing I did to improve that was compression, but wad type, powder brand, and neck tension also played a big role too. The velocities tightened up and scores improved. 

[Tennessee Snuffy]

Thanks for all the advice. 

 

Let me add a bit more information.

 

Velocity running from 1425 to 1475

New batteries installed with  same results

blow tube between ever shot then clean after 5th  shot

Using SPG lube with 530 gr postel bullets

Powder measured by weight -- 100 grains and dropped via drop tube

Federal match grade rifle primers

I use 0.030 veg wad and ox yoke wad on top of powder;

Compression is light about 0.030" -- what is considered excessive?

Bullet is seat into rifling and no crimp

Cases have not been annealed

Using Old Einsford 1 1/2 F

Do not full length size case

 

 

Ok now that I have provided a lot more information on what I am doing, what do I need to change or  modify or start doing in order to obtain a more consistent fps?

 

thanks for all your help

 

Tennessee Snuffy

[Buckshot Sheridan]

I start using more compression and see what it gives you. I’m loading 112gr of Swiss 1 1/2 in a 50-90 with .200 compression.   Also be interested if you are seeing any correlation between your cleaning, and velocity changes. 

[Tennessee Snuffy]

Buckshot

no correlation between cleaning and velocity

 

how do you obtain your compression— searing bullet deeper or adding more veg wads

 

it seems bay rifle  does not like bullet jump but like the bullet to be on the rifling 

[Jasper Agate]

2 hours ago, Tennessee Snuffy said:

Thanks for all the advice. 

 

Let me add a bit more information.

 

Velocity running from 1425 to 1475

New batteries installed with  same results

blow tube between ever shot then clean after 5th  shot

Using SPG lube with 530 gr postel bullets

Powder measured by weight -- 100 grains and dropped via drop tube

Federal match grade rifle primers

I use 0.030 veg wad and ox yoke wad on top of powder;

Compression is light about 0.030" -- what is considered excessive?

Bullet is seat into rifling and no crimp

Cases have not been annealed

Using Old Einsford 1 1/2 F

Do not full length size case

 

 

Ok now that I have provided a lot more information on what I am doing, what do I need to change or  modify or start doing in order to obtain a more consistent fps?

 

thanks for all your help

 

Tennessee Snuffy

You should be getting less than 10 fps DS. Are you casting your own bullets? Do they all weigh within a grain difference? What alloy are you using?

[Lead Monger]

3 hours ago, Tennessee Snuffy said:

Buckshot

no correlation between cleaning and velocity

 

how do you obtain your compression— searing bullet deeper or adding more veg wads

 

it seems bay rifle  does not like bullet jump but like the bullet to be on the rifling 

I would loose the Ox yoke wad and add at least 10 more grains of powder. Set the card wad on the powder and compress it with a compression die as much as you need to, to set the bullet on the powder where you want it. I size the neck a little bit so I can control neck tension and use just a hint of crimp to keep the bullet in place. Do not compress the powder charge with the bullet. The 120 is a long powder column so you might compress a full charge as much as 3 tenths of an inch depending on powder and bullet choice.

[Tennessee Snuffy]

Lead Monger

 

Thanks for the information.  For my education, why to you suggest to not utilize the ox yoke wad?  How much is too much powder compression?

 

Thanks

[The Original Lumpy Gritz]

12 hours ago, Tennessee Snuffy said:

Thanks for all the advice. 

 

Let me add a bit more information.

 

Velocity running from 1425 to 1475

New batteries installed with  same results

blow tube between ever shot then clean after 5th  shot

Using SPG lube with 530 gr postel bullets

Powder measured by weight -- 100 grains and dropped via drop tube

Federal match grade rifle primers

I use 0.030 veg wad and ox yoke wad on top of powder;

Compression is light about 0.030" -- what is considered excessive?

Bullet is seat into rifling and no crimp

Cases have not been annealed

Using Old Einsford 1 1/2 F

Do not full length size case

 

 

Ok now that I have provided a lot more information on what I am doing, what do I need to change or  modify or start doing in order to obtain a more consistent fps?

 

thanks for all your help

 

Tennessee Snuffy

Up the compression. 

I compress Old E about .350.

 

Edited February 5 by The Original Lumpy Gritz

[Old Man Graybeard]

OLG...top of post says 45-120

[The Original Lumpy Gritz]

Just now, Old Man Graybeard said:

OLG...top of post says 45-120

Just saw that 

[Tennessee Snuffy]

1 hour ago, The Original Lumpy Gritz said:

Up the compression. 

I compress Old E about .350.

 

OLG

 

Since I am new to the black powder world, if I add more compression and I want the bullet to be long and touch the rifling, do I add veg wads to take up the extra space?

[Buckshot Sheridan]

Adding Wads or increasing powder charge. Either will work just have to see how the rifle responds to it. 
 

I drop tube my powder, add a .030 fiber wad and compress .200 with a compression die, then seat a .030 poly wad. Paper patch bullet patched to bore diameter is then slip fit into the case. My bullet is well beyond the start of the rifling.  At some point I’d like to be able to recover a few fires bullets from this combo to see if there is any finning happening which would indicate I should make a taller wad stack. 

[Lead Monger]

6 hours ago, Tennessee Snuffy said:

Lead Monger

 

Thanks for the information.  For my education, why to you suggest to not utilize the ox yoke wad?  How much is too much powder compression?

 

Thanks

I use grooved bullets and try to select bullets that carry enough SPG to keep fouling soft. I have not found grease cookies or lube wads to be helpful. I still have to blow tube or wipe between shots so why risk powder contamination from putting lube in the cartridge. Some of my ammo is stored for many months or even years (bullet nose down) and with no lube wads there is no worry of lube weeping into the powder. 
For compression; if you are set on the powder charge and overall length then you can add wads too very the compression until you find what the rifle likes. 2,3 or 4 tenths of an inch! I don’t know that there is a compression rule beyond what the rifle tells you it likes.

[The Original Lumpy Gritz]

8 hours ago, Tennessee Snuffy said:

OLG

 

Since I am new to the black powder world, if I add more compression and I want the bullet to be long and touch the rifling, do I add veg wads to take up the extra space?

Use a compression die.

Increase powder charge to increase compression.