Muzzleloader Accuracy: Find The Right Bullet for Your Rifle

tc encore barrel

Clean Thompson Center Encore Barrel

Accuracy with a modern Muzzleloader is dependent upon consistent cleaning, lubricating and loading.

It is simple, but time consuming to clean and lube consistently.

It is also simple to load consistently, but we still may not get the accuracy we want until we find the right combination of components (bullet/sabot/powder/primer) that shoot consistently from each particular barrel.

After consistent cleaning and lubricating, finding the right bullet or bullet/sabot combination is the next most important thing to improve the accuracy of modern muzzleloaders. But finding an accurate bullet is only part of the problem.

When hunting, if we can put it on target, it is the bullet that closes the deal. So for hunting, we should choose bullets based upon their terminal performance and then learn how to shoot them accurately.

All Muzzleloader Barrels are Not Created Equal

According to several sources, Thompson Center Barrels consistently measure 0.500 inches. Savage Muzzleloader Barrels are consistently 0.501 inches and Knight barrels are consistently 0.502 inches.

Other muzzleloader barrels can range from 0.497 to 0.508 inches and some manufacturers are not even consistent among barrels of the same design.

That should convince you that different guns will shoot the same bullet and powder combination differently.

The Muzzleloader Component Equation

When we load a bullet (or bullet with sabot) with powder and a primer, we use only three or four components. But bullets are made from different materials and come in different shapes and weights. We can also use different brands of powder or pellets in a range of loads from 70 to 150 grains, so there are no less than six variables that make up every load.

Six variables that affect the load and accuracy of a muzzleloader.

  1. Bullet Brand, Make & Type
  2. Bullet Weight
  3. Sabot Brand & Size
  4. Powder Brand & Type (powder or pellet)
  5. Powder Weight
  6. Primer Brand & Type

Testing Protocol for Muzzleloader Components

So, how do we find the best combination from all these possibilities?

Before I started systematic testing, my best accuracy was 6 inch groups using Power Belt 245 grain Aero Tip Bullets and 120 grains of Pyrodex Pellets. I was not consistently cleaning the barrel after each shot. Since I didn’t know better at the time, I listened to people that didn’t know better. Power Belt bullets were the only bullets I could push into a dirty barrel and that is a bad reason to choose a bullet (more on that later).

I had four types of bullets I wanted to test, each in two different weights, I had two types of sabots, two types of powder and two brands of 209 primers. I considered using different loads in 5 grain increments, so there were 17 different loads between 70 and 150 grains. That is 1,088 different load combinations. There is no way I could do all those different tests, especially if a three-shot group would be the minimum test for each combination.

barnes 250g T-EZ muzzleloader bullet

Barnes 250 grain T-EZ muzzleloader bullet in Thompson Center Encore Barrel.

So, I started by choosing one brand of bullet based on the terminal performance. Originally, I chose Barnes TMZ bullets and sabots because they have excellent weight retention and controlled expansion. I tested two weights of the Barnes TMZ bullet (250 grain for deer and 290 grain for elk) using the sabots that came with them.

After other testing showed me the Pyrodex Powder was more accurate than the Pyrodex pellets, I used Pyrodex (RS Select) powder and Winchester 209 primers. Nothing fancy here.

And by reducing load increments from 5 to 10 grains, this reduced the total number of load combinations to be tested to 18, which was manageable. There was no guarantee that I would find an accurate load among these combinations, but I had a plan.

My Bullet Testing Protocol

My plan was to start with three shot groups using 70 grains of powder. I would increase the loads in 10 grain increments for each successive shot group until I found the load that produced the tightest groups or until I reached the maximum 150 grain load.

With 70 grains of powder, I immediately got better results using the Barnes bullets than I ever had with Power Belt bullets. I cleaned and lubricating the barrel and cleaned and dried the breech plug after each shot.

Note – when practicing and testing at the range, I always shoot second shots at a separate targets. The second shots replicate a hunting situation where a follow up shot would be taken with a dirty barrel. For second shots, I use 100 grains of Pyrodex Pellets with Barnes 250 grain T-EZ bullets (for mule deer) and 110 or 120 grains of pellets with 290 grain T-EZ bullets (for elk). These groups are not usually as good as the clean barrel first shot groups, but are usually less than three inch groups, which gives me a fair amount of confidence with either load.

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To make a long story short, the groups continued to improve with 80, 90 and 100 grains of powder, but at 110 grains, the groups started to open up again. I shot a second group at 110 grains of powder and confirmed that accuracy was decreasing.

I decreased the load back to 100 grains and the groups improved again. I shot one more test group with 95 grains, which was about the same at 100 grains, so I use 100 grains when shooting 250 gran TMZ bullets.

I followed the same procedure with the 290 grain TMZ bullet and found that it shoots best from my gun at 120 grains of powder. Since that time, I have also tested the 250 and 290 grain versions of the Barnes T-EZ bullets.

Most Accurate loads with Barnes Bullets in my Thompson Center Encore

  • 250 grain TMZ – 100 grains Pyrodex Powder
  • 290 grain TMZ – 120 grains Pyrodex Powder
  • 250 grain T-EZ – 95 grains Pyrodex Powder
  • 290 grain T-EZ – 120 grains Pyrodex Powder

With my 1 power (non-magnifying) scope, I can consistently shoot 1-2 inch groups at 100 yards using these loads and have shot 1 inch groups with each of these loads when I used a 3-9x scope.

Could I improve my shot groups with different bullets, powders and primers? Maybe, but I am probably as good as I can be for hunting since I have to use a non-magnifying scope. I may try a different powder in the future, but why fix something that ain’t broke? I am extremely satisfied with the Barnes Bullets and don’t plan to use anything else.

Other Variables that Affect Shot Groups

Remember that the shooter, air temperature, humidity, wind speed, consistent cleaning, lubricating and the temperature of the rifle barrel are also variables that affect your shot groups . A gun vice can be used to make the shooter less of a factor, but the temperature, wind and humidity will change and there is nothing we can do about it unless we have access to a climate controlled indoor range. By cleaning and lubricating the rifle after every shot, the condition and temperature of the barrel will be more consistent.

Anyway, we do the best we can to remove ourselves from the equation and pay attention to the weather. If the wind picks up significantly while running a test, that has to be taken into consideration or the test has to be postponed. Otherwise, we learn nothing from the test no matter how much fun we have. There was no guarantee that the Barnes Bullets would shoot well from my gun, so perhaps I got lucky. Since Thompson Center Barrels are consistent in size, I believe that most Thompson Center muzzleloaders will also consistently shoot the Barnes TMZ & T-EZ bullets. But remember for best accuracy, you have to be disciplined enough to clean the barrel and breech plug after each shot. At least shoot clean barrel shots at one target and 2nd shots from a dirty barrel at a different target.

modern muzzleloader guide


  1. Denis Roussel says

    If you are interested in muzzleloading rifles, you might like to look at this book. I have a hard copy, but it can be found online here:;view=1up;seq=9

    Ned Roberts is the Roberts of 257 Roberts fame.

  2. My gun does better with 2nd and 3rd shots but I like everything about what you said

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