Powder Charges

[ShawnAgne]

I have 3 rifled muskets. 2 are .58 cals (1855/1863) with Bobby Hoyt barrels on them and the other is a 1816 that also has a rifled Bobby Hoyt barrel on it. I'm shooting the Lyman 530gr Minnie Ball in the .58's and the Lyman 730gr on the .69cal. My question is how do you go about finding the correct charge accuracy wise to put behind them? I have been using a charge of 60gr FFg on the 58's, but I haven't shot the .69 yet as I wasn't sure where to start as I've only found charges for .69's shooting round ball. Any help on developing the correct load charge would be greatly appreciated. Thanks in advance.

[Muley Gil]

Most folks that shoot .58 rifle muskets use loads in the 40-50 grain range and I would say most use FFFg powder. Minie balls should be at the most .002" smaller than actual bore size and cast of PURE, SOFT LEAD.

[ShawnAgne]

How do they go about determining their exact charge in the 40-50gr range? Thank you for the reply.

[Lou Lou Lou]

How do they go about determining their exact charge in the 40-50gr range? Thank you for the reply.
Load up 5-10 rounds of the following charges
35 grain, 40 grain, 45 grain, 50 grains
shoot from the bench.
Which ever group, shoots the smallest group, try 2 grains on either side of that amount.

that is how you work up to a load. Trial and error, empirical testing

[ShawnAgne]

Ok thanks that is what I figured but was just going to check. I've been doing Audette Ladder tests for my 1000yd prone and Palma rifles. I was going to do the varried charge for group method but just wanted to check just to see if BP did it any different.

[ian45662]

you ever try the 315 grain semi wadcutter in your 58? What is their rate of twist?

[Mike w/ 34th]

A good starting point is to use the 10:1 lead to powder ratio. If you have a 425-grain bullet, use 42.5 grains of FFFg. If you're using FFg, add 10%, so 48 grains of FFg.

I make up 5 rounds at 2-grain increments on either side of the 10:1. If something seems to group better, then I make up 5 rounds each at 1/2 grain increments.

Brush the bore after every 5 shots, so you're starting with basically the same conditions, and shoot from a good rest.

[Maillemaker]

Also, if you are going for accuracy, you might consider weighing your bullets and rejecting anything outside of +/- .5% of average.

I was astonished how many bullets with mild wrinkles that I previously would have accepted as good turned out to be substantially lighter than average.

Steve

[hobbler]

you ever try the 315 grain semi wadcutter in your 58? What is their rate of twist?

Recently obtained the 575494 315 SWC mold. And quickly discovered that the 575213 and 577611 mold plugs would fit it interchangeably. Just more options to try out.:rolleyes:

[ian45662]

AWESOME!!! I really like the 575213 also.

[ShawnAgne]

Thank you for the advice. No I have not tried the 315gr semi-wadcutter. The only mold I have for the .58 is the 530gr Lyman. I really appreciate the 1:10 advice as this will give me a place to start on the 69 also.