I just picked up a little Redolfi double in .444Marlin, it's quite well made but they told me it was regulated with Remington 240gnfactory ammo.

I'd like to use it with a hard cast bullet in the 325 - 405 grain range, and the guys at the Redolfi workshop said they could regulate it with whatever ammunition I provided them with, for what I thought seems like a ridiculously low price.

Anyways, my main question is; normally, how finicky are doubles with different bullets of the same or similar weight weight? How much of an improvment can youy get though load development?

See, I need to get the hard cast from the states, but I can use some 300gn jacketed pistol bullets that I already have here to see if it even needs regulation with the heavier bullets.

My point being, if I find that it shoots ok with the 300gn jacketed pistol bullets, and try a 325gn hard cast, is it likely to shoot askew? And would trials with a 300gn pistol bullet be meaningless with regards to how the 405gn cast might behave?

Just curious, tomorrow I'll load up some 300gn bullets and see how they shoot, then I'll get back on here.
Cheers.

I have found that I can generally "re-regulate" a properly-made double rifle when I change bullet weights by varying the powder charge behind the new bullet type until the guns shoots both barrels together. This is done by changing the MV as needed.

MOST doubles have their barrels joined so that the axes of the barrels converge. When fired, if the shots for the two barrels go wide of one another, (left bbl shoots left of the sights, right bbl shoots to the right of the sights), it is because the barrel time is too slow, allowing recoil to rotate them away from one another. This gives wide shots. To bring the shots closer to the sights, you need to increase the MV by adding powder until the shots are as close together as you want them at a given range. Conversely, if the shots are crossing, left barrel shoots to the right of the sights, right barrel shoots to the left of the sights, the MV is too high. To make the barrels both shoot cl;oser to the sights, you must reduce the powder charge/MV until both barrels shoot as close to the sights as you want them at that range.

I personally like my doubles to shoot both barrels between 2.5"-3" of one another at 100 yards. My theory is that if they will do this, they are close enough together at all shorter ranges.....

This is my old J.P. Sauer 8X60RS double at 100 yards with either Speer or Nosler Partition 200-grain bullets at 2420 FPS MV:

Here's a .54-cal. Pedersoli Kodiak ML shooting .535" round balls at 100 yards...


BOTH of these rifles were "regulated" by working with the powder charges using the above information to adjust the powder charges to get the regulation desired. You can do the sam with yours.

My double rifle is a .408 caliber 450/400 3 inch. It was regulated for 400 grain bullets at about 1950 FPS with Cordite (55 grains).

I have had good luck in loading 300 grain Hawk Bullets over the same load I use for my 400 grain Woodleighs. That load uses 62 grains of RL-15.

I presume that working in reverse a 300 grain bullet over your 240 load might do the same thing. The factory has already told you that they could regulate it for the load, right?

quote:

Originally posted by EXPRESS:
I just picked up a little Redolfi double in .444Marlin, it's quite well made but they told me it was regulated with Remington 240gnfactory ammo.

I'd like to use it with a hard cast bullet in the 325 - 405 grain range, and the guys at the Redolfi workshop said they could regulate it with whatever ammunition I provided them with, for what I thought seems like a ridiculously low price.

Anyways, my main question is; normally, how finicky are doubles with different bullets of the same or similar weight weight? How much of an improvment can youy get though load development?

See, I need to get the hard cast from the states, but I can use some 300gn jacketed pistol bullets that I already have here to see if it even needs regulation with the heavier bullets.

My point being, if I find that it shoots ok with the 300gn jacketed pistol bullets, and try a 325gn hard cast, is it likely to shoot askew? And would trials with a 300gn pistol bullet be meaningless with regards to how the 405gn cast might behave?

Just curious, tomorrow I'll load up some 300gn bullets and see how they shoot, then I'll get back on here.
Cheers.

Realley the best thing is try it and if you can't make it shoot then think about having it re regulated.
Bill

Today I tested some 300gn Sierra jacketed soft points that I jimmy rigged with .44magnum dies as I'm waiting on the .444 Marlin dies.

The surprising thing was that they shot closer together than the Remington Factory 240's the gun is supposed to be regulated for.

At 50 meters rested off my patio table the 300 grain bullets were about 1.5" apart while the Remington 240's were a terrible 4.5" apart, each barrel shooting into less than one inch.

The 300's shot 3" low with the lower, wide express sight, and about 5.5" high with the finer sencond sight. This might work out to be ok if I try the loads closer and further away.
Another funny thing was that the 300's remained the same distance apart with all three powder does - 48gn H4895, 50gn H4895 & 52gn H4895, just going up in height by about 1.5" with each step.

Obviously some tuning is needed, but I feel confident I can get it right with a few more tests.

quote:

Originally posted by EXPRESS:
Today I tested some 300gn Sierra jacketed soft points that I jimmy rigged with .44magnum dies as I'm waiting on the .444 Marlin dies.

The surprising thing was that they shot closer together than the Remington Factory 240's the gun is supposed to be regulated for.

At 50 meters rested off my patio table the 300 grain bullets were about 1.5" apart while the Remington 240's were a terrible 4.5" apart, each barrel shooting into less than one inch.

The 300's shot 3" low with the lower, wide express sight, and about 5.5" high with the finer sencond sight. This might work out to be ok if I try the loads closer and further away.
Another funny thing was that the 300's remained the same distance apart with all three powder does - 48gn H4895, 50gn H4895 & 52gn H4895, just going up in height by about 1.5" with each step.

Obviously some tuning is needed, but I feel confident I can get it right with a few more tests.

You are in luck then since the 300's are a much better RIFLE BULLET than the 240's!