brandoninaz
(.224 member)
09/10/15 12:03 PM
Re: Husqvarna Mod 4 RB 20 ga

Quote:

If - if the groups are good with either, then I'd simply replace the front sight, keeping the rear as an original piece of the rifle.

-----if the grouping is not good, I'd work up a good load, then 'adjust' the sights to accomodate the point of impact.

-----if I demanded to get the gun to shoot to the sights on the rifle, I'd reduce the ball weight- ie; size, to reduce the impact height. The heavier the projectile, the higher it is going to strike as the muzzle will be higher when it departs.

I would try sucessively smaller balls, starting at a .648" ball with wads, ie; cushion and hard overpowder wad. Because the ball is larger than the bore size & will be engraved, it will pretty much centre in the bore and should also have a 'wash' of lubricant on it, ie: beeswax/Vaseline, beeswax/Neetsfoot oil, beeswax/roo grease/comercial BP lube - not ALOX. Alox lubes are smokeless lubes and do not mix with nor soften BP fouling.

You can also try increasing the charge weight to reduce the impact height.

75gr. is a pipsqueak load and might be the reason it is shooting so high. Even 90gr. to 120gr. 2f in a 20 or 16 bore rifle produces low pressure, when fired with a round ball. A Flintlock or caplock rifle or 20 or 16 bore will easily shoot 150gr. of 2F with a round ball without stressing anything - except perhaps the shooter's shoulder & not much at that. Your Rolling block is considerably stronger than the 'system' used in a muzzleloading rifle, therefore prudent increases in powder charge can help 'regulate' the load to it's sights.

The .020" deep rifling is quite interesting. It is very deep and might be meant for a smaller ball, not a full sized one. In the 70's, it was felt the rifling needed to be deeper than the projectile's size, to accomodate fouling. That is the reason the M71 Mauser had a .457" groove diameter and shot a .446" bullet. By 1884, that thinking had changed for most. Perhaps not all. Your rifle is just over 20 bore (20 bore is .615") on the bore size, and 16 bore in the grooves. That's .040" total rifling depth, .020" per side.

My own Husky 16 bore double-gun, has a 13 bore rifled barrel with .015" rifling depth, yet takes brass 16 bore cases (brass or paper originally, and now plastic. The thin brass case perfectly fits a .705" ball, yet I use a .662" ball in .030" denim patching, or a .690" ball bare. They both shoot well or about s well as straight rifling will shoot.

I really like the looks of your 20's action - supurb! Fantastic? Any 'full-rifle' pictures?




Daryl,

Would you recommend going up to 150gr of 2F in a Model 17 Husqvarna? I just acquired one, and took a chamber casting to figure out what I was working with. Chamber seems to be the standard 50mm case. Rifling starts at about 2.315" deep. Bore groove diameter is .635", 8 lands. Are there any resources for smokeless loads, or is black powder the only way to go in a case like this?

A sidenote. I also bought a Model 17 with a 12.7x44R barrel. I was shocked at how deep the rifling was when I slugged the barrel. Ended up with a .5105" groove and .476" land diameter. I could not believe how deep the rifling was.


Spud303,

Any updates on load development?

Edit: I also found the 20 ga rims on the CBC brass to be too large in diameter for my rifle. Going to have to turn them in the lathe.

Thank you,
Brandon



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