Improving velocity consistency

Orchemo · Nov 4, 2024

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 · Nov 4, 2024

What is your SD and ES?

Orchemo · Nov 5, 2024

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 · Nov 5, 2024

Keep an eye on your seating pressure.

dave951 · Nov 5, 2024

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 · Nov 5, 2024

stubshaft said:
Keep an eye on your seating pressure.

Yes, very important.

Grenadier1758 · Nov 5, 2024

@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 · Nov 5, 2024

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

Rifleman1776 · Nov 5, 2024

Orchemo said:
I opened a new box of RB

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

andy52 · Nov 5, 2024

bigstick6017555 said:
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 · Nov 5, 2024

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 · Nov 5, 2024

Rifleman1776 said:
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 · Nov 5, 2024

tallPercshooter said:
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 · Nov 5, 2024

tallPercshooter said:
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 · Nov 5, 2024

tallPercshooter said:
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 · Nov 5, 2024

Freedom said:
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.

longcruise · Nov 5, 2024

Freedom said:
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.

Don't like to overstate this but I'll just about guarantee that BP will give you better ES & SD.

Grenadier1758 said:
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.

The Corbin Brothers, both experts in swaging, say/said that the round ball is the most difficult projectile to swage with consistent weights.

Sam squanch · Nov 5, 2024

Weigh those balls! You may get a shock on how much they vary. I know I did.

Howard Pippin · Nov 6, 2024

Sam squanch said:
Weigh those balls! You may get a shock on how much they vary. I know I did.

Yes, and it was the factory balls that were the most off.

Orchemo · Nov 8, 2024

Howard Pippin said:
Yes, and it was the factory balls that were the most off.

Back at range this morning
54 Speer RB
90gr Triple 7 3F (weighed 75gr)

Velocity settled in at 1705 fps and ES 28 fps

Knocked over a few silhouette pigs at 100 yds. Feeling good with it

Also shot a short barrel 50 cal with Hornady PA conicals.
80 gr by volume Triple 7 3G (65 gr by weight)

Got 1689 fps with consistent velocity.

Impressed for shooting from a 22 inch barrel

Improving velocity consistency

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