Ball size for GM .40

[fitter]

What is the best ball size for a .40 cal. GM barrel? I use wally world red ticking in my other guns. I'm thinking .390. How about powder charge?

 

[Gemoke]

Before I was dumb enough to sell my 40cal. I used a 395rb with a 18th patch. mine had a 42 gm barrel

 

[roundball]

I recently had GM make a Flint version of a .40cal drop-in barrel for a TC Hawken stock...15/16" x 33" x 1:48".

I stocked up on .395's and will be using the same .018" TC prelubed pillow ticking patches I use for my .45cal...test-started one in the garage and it seems like / feels like an excellent fit...planning to use 40grns Goex 3F.

 

[Patricknwohio]

I shoot .395 RB with a .015 patch.

 

[paulvallandigham]

Saying something is .40 caliber is not going to be definite enough to give you an exact recommendation. You have to actually measure the bore( land to land) and groove diameters to help in deciding which diameter ball to use. .40 caliber rifles used both .390" and .395" balls, commonly, but there are others who require balls of smaller or larger diameter. As for powder loads, generally start at the same amount of powder as the caliber if the barrel is( 40 grains of Goex FFFg powder). YOu can usually work up to 1.5 calibers in these small caliber guns ( ie. 60 grains of Goex FFFg powder) without causing any safety issues. If you have a longer barrel, you may even have to use more powder to keep crud from caking in the last few inches before the muzzle with each shot.

For short range shooting, plinking sessions, and even for hunting squirrels, you can reduce that powder charge down to 30 and even 20 grains, and still get amazing accuracy.

 

[bob308]

my hoyt .40 uses a .395 ball .18-.20 patch 40gr 3f to 100 yd. after that i add another 5.

i always start with the cal being the gr load.
.40 cal 40 gr.
another way the old timers did it was hold the ball in their hand and pour powder till it was covered. and that was their starting load.

 

[bwhoffman]

Welcome to the .40 group!
I put a GM 32x .40 on a TC hawken stock.
I'm shooting .395 homecast with a .015 patch.
.018 ticking starts a little harder than I like, really have to whack the short starter.
Shooting 40gr 3F goex and dang, it groups well!

share your results with us!

Brett

 

[Java Man]

I've had and have several GM barrels, including two .40's. All of them like a .005" under "caliber" size ball, with .015"-.018" patch. I've had excellent accuracy with 50gr FFFg, and trying 30gr in my offhand rifle. That's a sweet load in an almost 8# rifle. Like shooting a .22, only a little louder.

 

[silverfox]

Got a TVA .40 and use the red wally world for patches. Both .390 and .395 and haven't blown a patch yet. Accuracy with either is far better that I can hold.
Fox

 

[fho]

I just finished a 40 caliber half stock rifle. I am shooting .400 round balls but think that they are too tight, so I am going to try .395 balls. Right now I am tring to get a load worked up for this rifle.

The barrel is a GM 15/16 x 36 inch 40 caliber. It is a little heavy but it hold very nice for off-hand shooting.

Olie

 

[CrackStock]

Best is a relative term. I have a mould that throws a ball of just over .400. It is extremely accurate, but beating them into the bore caused my stock to finally crack at the wrist. This convinced me to return to my old .395 mould for future shooting with my .40s and accept a slightly decreased accuracy level.

CS