Improving velocity consistency

[Orchemo]

New to BP shooting. I have a pair of Lyman Deerfield rifles. One in 54 and one in 50.

Been shooting a couple times a week at the range in preparation for an upcoming elk hunt.

Using my Garmin chrono and getting swings in velocity measurements.

My 54 PRB load is 90gr of Triple 7 3F. Gets me right at 1700 + fps.

Between each shot, I run a spit wet patch, then a dry patch.

I took the 90gr of volumetric powder and found it to be 75 gr by weight. Made up 15 tubes of powder at 75gr weight. Comfortable that powder charges are consistent.

CCI caps are new and same tin.

Seems the first 3 or 4 shots are consistent, but then more velocity variation.

What can I improve on?

 

[RobertIN]

What is your SD and ES?

 

[Orchemo]

I think I found my problem. I opened a new box of RB today. They are 0.530
Last week, they were 0.535

Last week,
I was getting 1746 FPS
ES 52
SD 16

Today my WS was closer to 150

Also ran out of 54 cal lubed patches and used 45-50 cal patches today

Will order more patches and RB from the Gun Works in Eugene tomorrow.

Second question: I have an older box of Speer 0.535 RB. Any advantage of Speer vs Hornady TB?

 

[stubshaft]

Keep an eye on your seating pressure.

 

[dave951]

It's all about consistency and variable control. Anything you can think of as a variable, check it, control it. Lots of that is done in modern ammo. Since we literally "hand load" every time, variables are there and quite real.

 

[Uncle Miltie]

Keep an eye on your seating pressure.

Yes, very important.

 

[Grenadier1758]

@Orchemo, I don't trust the store bought patches, especially if they are pre lubed. The pre lubricated patch material deteriorates when stored. Get the unlubricated patches and use your own lubricant. If you feel that you must use a lubricant from the local gun store, then Mr. Flintlock is a good choice. Of course a mix of the dish washing liquid soap at your sink and water is as good. My patches are made from the cotton drill cloth from JoAnn's Fabrics. It is a very consistent tight weave. Holds lubricant well. It is easy to cut squares as they work just about as well as round patches for accuracy or you cut at the muzzle to get a consistent wrap of patch around the ball.

You did right to use the volumetric measure to determine a load and then weigh the Tripple 7 to get a scale weight for your charge.

There is little difference between the performance of a Speer swaged round ball or a Hornady swaged round ball. There may be differences in weight within the box, but often not enough to cause accuracy problems unless going for the tightest group possible.

 

[bigstick6017555]

Wonder if Daniel Boone, Davy Crocket Lewis and Clarke had these problems also

 

[Rifleman1776]

I opened a new box of RB

Manufactured balls may not be consistent. Cast yer own. Consistency is the name of the game.

 

[andy52]

Wonder if Daniel Boone, Davy Crocket Lewis and Clarke had these problems also

Maybe but as long as they hit their target that was good enough.

 

[Freedom]

Order some real Swiss 3fff black powder if you want to see your accuracy and velocity ES at there best.

777 will work in a pinch, but it is no comparison to "real" powder.
If you can afford an elk hunt, you owe it to yourself to enjoy "real" gunpowder.

 

[tallPercshooter]

Manufactured balls may not be consistent. Cast yer own. Consistency is the name of the game.

Manufactured round balls are swaged, I think. Cast might have voids. I would bet factory balls are far more consistent in weight than your cast ones.

 

[Grenadier1758]

Manufactured round balls are swaged, I think. Cast might have voids. I would bet factory balls are far more consistent in weight than your cast ones.

Maybe, but if you get some practice on casting of round ball, you can avoid the voids, and the result is very consistent cast balls.

 

[Boomerang]

Manufactured round balls are swaged, I think. Cast might have voids. I would bet factory balls are far more consistent in weight than your cast ones.

I find quite the opposite.

 

[Pete G]

Manufactured round balls are swaged, I think. Cast might have voids. I would bet factory balls are far more consistent in weight than your cast ones.

You would think so, but experience seems to indicate otherwise.

 

[SeaBee133]

Order some real Swiss 3fff black powder if you want to see your accuracy and velocity ES at there best.

777 will work in a pinch, but it is no comparison to "real" powder.
If you can afford an elk hunt, you owe it to yourself to enjoy "real" gunpowder.

I get the same POI from 3F Swiss and 3F Triple 7. Same setting on the same clear measure, tapped to settle the powder at 30-60-90 marks. .50 TC Hawken and .54 Lyman GPR with Hornady swaged round balls and 100% cotton shirt material. Targets set at 20-40-60-80 yards. Marked lane goes to 160yds, my bifocals do not.