.40 cal ball size.

[Scoper05]

So I'm getting a 40 caliber Kibler SMR and I was wondering what size round ball you guys with 40 caliber rifles are having the best of luck with? .390 or .395? Thanks in advance for any feedback you can give me.

 

[Kansas Kid]

It’s gonna be one or the other. No trying to be funny but it’s going to depend on your barrel. I use .395 in both my .40s one has square rifling and one has round. .015 patch and .020 respectively.

 

[Flintleather]

I use a .395 Hornady ball with .018 pillow tick in my Rice barrel

 

[Don Steele]

I believe it's fair to say that most 40 cal rifle shooters are using the .395. Start with the .395. You gotta start somewhere. Play with patch material and lube until you have arrived at the very best, consistent group the .395 will provide. The radius ( "roundbottom" ) rifling will generally require thicker patch material, all other things being equal.
THEN...take a look at .390, .400 in small quantities, with various patch choices to see if you can do better. Some folks report best results with the .400, some like the .390 with thick path...the options available will keep you busy for as long as you want to keep trying different combinations. Eventually...settle on ONE combination for that rifle. THEN...and only then...make the adjustments necessary to your rifle's sights to center the group where you want it at whatever range you're comfortable with.

 

[Loyalist Dave]

Would you believe....389 Round Ball ? ☺
.389 Round Ball
Track isn't the only place that offers them that size.

LD

 

[Grenadier1758]

I am back to suggest that rather than ask about ball size in a 40 caliber rifle, measure the bore diameter and the depth of the grooves. Are the grooves radiused or flat bottomed? Are the lands and grooves about the same width? What is the twist rate? There will still be load development. However it may narrow the starting choices for ball size, patch thickness, patch lubricant, and powder charge. Then when all is said and done, someone will have a different load in the same rifle that outperforms your best group. We missed the April "Pink Super Moon" to make incantations in the middle of a country crossroads with the rifle pointed at the moon at midnight.

Practice and consistency in loading do more to optimize accuracy than we realize. Load development gets us out to practice. Thinking about what we are doing as we analyze the results takes us along the path to improved consistency. Yup, Dave's 0.389" ball seems like just the ticket.

 

[Buckskinn]

I just finished my 40 and got some Hornady 390's and first batch down the pipe were cutting one hole at 25 yards. Seems to be a very easy caliber to get to shoot compared to the 54 that I have anyway. Played around with different patch thickness and really didn't seem to matter much so I'm going with the thinner (.015) easier push for now unless it opens up at further distance. Problem is my eyes may not be a good indicator of that!!!

 

[Scoper05]

Thanks for all the input guys.i realize the I'm going to have to do some trial and error but i just want to see what everyone else was using.thanks again all.

 

[sawyer04]

Would you believe....389 Round Ball

Early last fall I cherried a mold that proved to be .387 for a 40 caliber custom build. with pillow ticking it glided down the barrel without much effort. Owner was happy.

 

[Smokey Plainsman]

.395s and .018” ticking

 

[Smokey Plainsman]

I was using .400 with .018 ticking at the range with excellent results,

But in the field, it was tricky to start due to shooting in the dirt. I have since switched to .395s and a coned muzzle. Works great and loads much smoother.

 

[Mulebrain]

My .40 likes .389, but .390 puts the ball in the same hole at 25yds from bench. I have settled on .390
I like to use the same size patch and lube, and change ball sizes only.

 

[jlatz]

In the .40 I use a .395 ball and a .15 patch and around 40 grains of fff for target work.

 

[Scoper05]

I just wanted to thank everybody for all their feedback on my question here. That's awesome having a forum like this to answer my dumb questions. LOL

 

[Griz44Mag]

I just wanted to thank everybody for all their feedback on my question here. That's awesome having a forum like this to answer my dumb questions. LOL

No such thing. Every question is valid. We all learned from someone else by asking questions.
Thanks to the help and advice I got here when I got my first one, I am now a dedicated enthusiast.