# Heavy or light bullets for best accuracy???



## Watcher (Dec 31, 2008)

When I was dialing in my 300 WSM, the range master suggested I try larger weight bullet. This made some sense: longer bullet means better BC, bigger bullet means a little slower. Results - a more stable and consistent bullet in flight. I’ve been reading about getting the best accuracy out of your 50 cal muzzle loader, shooting sabots, and it appears the guidance for getting stable flight is opposite: if you’re not getting good groups go to a smaller bullet weight. The discussions also imply 45 cal bullets are better than 44 cal. I know muzzle loaders are particular and need to be dialed in at the range. But as a paper exercise before the range: generally is this advice correct and if so help me understand why?


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## CROC (Sep 12, 2007)

Muzzleloaders are picky, you can find someone with the same gun and you won't like how their tried and true favorite bullet patterns out of your gun. I have always done better with the heavier bullet, I mostly like that every deer I have hit with a bigger bullet didn't go very far. I tried 3 different styles in my inline, and at least 6 in my traditional before I found what I can make a good pattern with at 100 yds. You will have to spend some time seeing what works for you. I found shooting "ladykillers"(bullets with a plastic skirt) were not as accurate for me don't know if it was the way that the skirt was seated or not but I get a tighter group using a bullet that is the actual size of my barrel. Another factor for me is yardage, I won't shoot over 150 yards and so I am not looking for the long range bullet that some do either.


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## colorcountrygunner (Oct 6, 2009)

CROC said:


> Muzzleloaders are picky, you can find someone with the same gun and you won't like how their tried and true favorite bullet patterns out of your gun. I have always done better with the heavier bullet, I mostly like that every deer I have hit with a bigger bullet didn't go very far. I tried 3 different styles in my inline, and at least 6 in my traditional before I found what I can make a good pattern with at 100 yds. You will have to spend some time seeing what works for you. I found shooting "ladykillers"(bullets with a plastic skirt) were not as accurate for me don't know if it was the way that the skirt was seated or not but I get a tighter group using a bullet that is the actual size of my barrel. Another factor for me is yardage, I won't shoot over 150 yards and so I am not looking for the long range bullet that some do either.


I've found the same thing in my old school .54 cal Knight inline. I shoot a 425 grain Great Plains Hornady conical out of it and it shoots awesome. The many saboted bullets I shot out of it didn't work nearly as good. Plus, you gotta love a bullet that as soon as it hits hair is already the diameter of a .30 caliber bullet if/when it expands to 1.8 X its original diameter. Not many game animals are gonna argue with a hole that big.


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## DallanC (Jan 13, 2009)

It all comes down to barrel twist, bullet lengths and tolerances. Longer bullets stabilize in different twists than short bullets. There are barrel twists that fit a wider range of bullets, but no 1 size fits all. 

So the whole "longer bullet will stabilize better" can be generally true, but most definitely not in all cases. I cannot for example, shoot a 65grn bullet out of my 22-250 with its 1/14" twist barrel with any hope of good accuracy. That same 65grn bullet will shoot .4" out of my 1/8" twist barrel though.

Muzzleloaders are odd beasts, barrel tolerances are all over the place. Is your barrel bore .499"? .501"? .502"? What twist does it have? 1/48? 1/38? 1/32? 1/28? 1/24?

The best place to start is find someone with the same model muzzleloader as you and see what they use, otherwise you need to start trying alot of different components to see what it likes. 

-DallanC


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## Critter (Mar 20, 2010)

I have found with my metallic cartridge firearms that the heaver bullets will give you better accuracy especally in the magnums. But if the firearm is a smaller caliber then you are going to have to find a happy medium since a lot of them will not stabilize the heaver bullets due to their rate of twist. 

On my smoke poles I like to slug the bore to find out just what the diameter is and then find a bullet that matches it. My .54 T/C Renegade loves 430 grain T/C maxi balls that I hand cast but my .50 caliber barrel on the same action has problems with 370 grain maxi balls but likes maxi hunters. 

DallanC is right about finding what your ML likes but if you can pull the breach plug and push a lead bullet down the bore and then measure it you will be money ahead in finding what it likes to shoot.


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## redleg (Dec 5, 2007)

The classic Greenhill equation is 
T' = 150 / L' 
where the twist and the bullet length are in calibers. Removing bullet diameter from twist and length gives the equation often found: 
T = 150 * D^2 / L 
The Greenhill equation includes no term for muzzle velocity, and several sources suggest replacing the 150 with 180 for muzzle velocities over 2800 fps. Increasing muzzle velocity increases bullet spin, and spin provides the stability. An article in the 11/2001 _Single Shot Exchange_ cites an article by Les Bowman in the 1962 _Gun Digest_ offering an equation which includes muzzle velocity (in fps): 
T = 3.5 * V^0.5 * D^2 / L 
At 2800 fps, this equation is equivalent to using 185 in the Greenhill equation, and at 1840 fps, this equation is the same as Greenhill's.


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## Watcher (Dec 31, 2008)

*The Greenhill Equation*

That's what I was looking for - thanks!
The Greenhill Equation appears to be a basic model for calculating ideal barrel twist and requires a limited number of input variables. I found a calculator on the Interweb that needs: bullet length, bullet diameter, muzzle velocity, and bullet specific gravity. It did shed some light on my question. 
All theoretical but running a few numbers (data from Barnes web site):

250 gr/0.451 caliber Barnes Copper TMZ (1.102 inches long)
90gr Triple Seven, 1952 ft/sec muzzle velocity : ideal barrel twist - 1:26
150gr Triple Seven, 2242 ft/sec muzzle velocity: ideal barrel twist - 1:28

290 gr/0.451 caliber Barnes Copper TMZ (1.218 inches long)
90 gr Triple Seven, 1808 Ft/sec muzzle velocity: ideal barrel twist - 1:22
150 gr Triple Seven, 2047 ft/sec muzzle velocity: ideal barrel twist - 1:24

My interpretation:
1) For a given bullet, as you increase the velocity, the ideal barrel twist increases.
I guess this means it takes less bullet spin to stabilize a bullet moving faster.
2) For a given bullet, as you decrease the bullet length (and weight), the ideal barrel twist increases.
I guess this means it takes less spin to stabilize a shorter (lighter) bullet.


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## taxidermist (Sep 11, 2007)

As a norm, the longer the bullet, the tighter twist you need in your barrel. Look into the evolution of the modern muzzeloader. The side lock guns were normally a 1in 60 twist. Try to shoot anything other than a round ball through it, and your going to get frustrated. 

Now, we have modern jacketed bullets for a ML. If you can get a 1 in 22 twist, with a 30in. or longer barrel, and a mag rifle primer for ignition, you could load it with a 1.50 in. Bullet, and 200 gr. of powder. Your muzzle velocity would be about 2400 fps. And, all your powder would ignite within the first 10 in. of the barrel.


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## derekp1999 (Nov 17, 2011)

Watcher said:


> ...getting the best accuracy out of your 50 cal muzzle loader, shooting sabots...


With bullet length being the key in all these equations how would you account for a sabotted bullet?

I use the same sabot for two different weight bullets (250gr and 300gr). Clearly the 300gr bullet is longer... but it's not the bullet that is contacting the rifling, it's the sabot. Wouldn't the length of the bullet be irrelevant itself and the length of the sabot be the critical measurement? The sabot contacts the rifling the same (at least in my observation) regardless of whether I use the 250gr or 300gr bullet.


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## Watcher (Dec 31, 2008)

derekp1999 said:


> With bullet length being the key in all these equations how would you account for a sabotted bullet?
> 
> I use the same sabot for two different weight bullets (250gr and 300gr). Clearly the 300gr bullet is longer... but it's not the bullet that is contacting the rifling, it's the sabot. Wouldn't the length of the bullet be irrelevant itself and the length of the sabot be the critical measurement? The sabot contacts the rifling the same (at least in my observation) regardless of whether I use the 250gr or 300gr bullet.


No expert but the calculator I used ( http://kwk.us/twist.html ) required four inputs:
1) Bullet diameter
2) Bullet length
3) Muzzle velocity
4) Bullet Specific Gravity (given length, diameter, and specific gravity this somewhat factors bullet weight).

It's obviously not very sophisticated as ballistic coefficients, etc. are not considered. However, it gave the insight I was looking for.

The way I would interpret your question is that the sabot performs two primary functions: making a good tight gas seal behind the projectile and making good tight contact with the barrel's rifling to impart the spin. Because the sabot (theoretically) separates quickly after leaving the barrel, you've got your bullet at velocity with imparted spin so the effects of the sabot should not play a role in the calculation.

Once again, this stuff is all theoretical and based on pretty simple assumptions. 
Twice again, I'm no expert.

Two words - field testing.


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