What size round ball and what powder load?

[Rolf]

Soon finished With the marman underhammer I've been building from scratch. Only thing left is rust bluing the barrel. The barrel is 32" long, Caliber 0.54.
Never worked up a load for a rifle. How should I proceed?

Best regards
Rolf

[wattlebuster]

I would start with 70 grains of ffg with a .530 ball an a .015 patch. See what it does an try different powder charges an patch thickness an lubes. Keep your targets an write on the target itself the load an then stick with the tightest group combo. With shooting an patience your gun will let you know what it like to digest

[bob in the woods]

What barrel ?  What rifling depth ?   I have seen .54 cal barrels with grooves from 8 thou to 16 thou. I shoot .527 to .540 balls in my .54 cal rifles . Finding out what you are dealing with will give you an idea where to start.

[hanshi]

What wattle says. 

[Rolf]

What barrel ?  What rifling depth ?   I have seen .54 cal barrels with grooves from 8 thou to 16 thou. I shoot .527 to .540 balls in my .54 cal rifles . Finding out what you are dealing with will give you an idea where to start.

Don't know. I hand rifled the barrel myself. Lokks a little deeper the the standard Rice barrel.

Best regards
Rolf

[D. Taylor Sapergia]

You will have the best luck discovering what the rifle likes if you know a little more about it.  What size is the bore and the groove depth in thousandths?
What twist rifling?

[Standing Bear]

Rate of twist and depth of rifling.  My .54 GM has a 1:70 twist and .012 rifling. Using .535 ball and .018 patch with 60gr and found it likes 90 gr.  Works well w 120 gr for 130 yards w/o changing sight picture.
TC

[Daryl]

Soon finished With the marman underhammer I've been building from scratch. Only thing left is rust bluing the barrel. The barrel is 32" long, Caliber 0.54.
Never worked up a load for a rifle. How should I proceed?

Best regards
Rolf

Hi Rolf - knowing what the rifle will be used for, is also important.  By this I mean most or many of us use a water based lube for target shooting, but switch out of necessity to an oil or grease for hunting.

Hunting type loads are usually, but not always larger charges than match or accuracy loads, however if switching lube types, one must test to ensure little or no point of impact change, which can be quite dramatic. Too - further load development might have to be undertaken. 

This means, that while your rifle might like 3 drams or 82gr. 2f for plinking and targets shooting with a water-based lube, if switching to a slippery oil or grease, it might require 110gr. to shoot well.  We must try these methods to find what our guns demand from us, in the way of loading.

[Rolf]

You will have the best luck discovering what the rifle likes if you know a little more about it.  What size is the bore and the groove depth in thousandths?
What twist rifling?

Twist is 1:70, bore 0,54".  the grove Depth 0,3-0,4 mm = 0.015"-0.016"

Best regards
Rolf

[Daryl]

I personally would make sure the muzzle has a nice crown.  I would then use a .530" ball with 10 ounce or thicker denim - that is .025" or up to 12 ounce at .028-30"(depending on measuring tool)
I would not shoot less than 3 drams- ie: 82gr. 2F, and would expect best accuracy at 50 to 150yards to be with 110ger. to 130gr. 2F. The lubricant is your choice, water based for target, oil or grease for hunting, such as NeetsFoot Oil.

I suspect your best results will be with a .535" ball and the 10 ounce or thicker,  (.0225"- .025" mattress ticking or maybe canvas) denim for patch and up to 130gr. 2f for hunting, or down to 82gr. for plinking with water based lubes.

My .016" deep rifled .50 is shooting quite well with 82gr. 2F, a .495" ball and that same .0225" denim patching. For hunting, I suspect I'll have to use 110gr. 2f and perhaps a thicker patch.