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  • Thor™ Hammer Bullet Sizing Pack - .500 to .503 DiameterThor™ Hammer Bullet Sizing Pack - .500 to .503 Diameter

Thor™ Hammer Bullet Sizing Pack - .500 to .503 Diameter


4 Pack - Model THOR-SAMPLE
.50 Caliber, .500 to .503 Diameter


Availability: In Stock

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The Thor™ Bullet produced by OPG Gun Ventures is a patented, full bore diameter, bullet conical that is bore size specific. Being 100% copper, the Thor™ Bullet is not soft like lead, and will not size to the bore like lead bullets when loading. As a result, these bullets require sizing to ensure a perfect fit to your bore. The Thor™ Muzzleloader Bullet sizing pack comes in .50 caliber with 4 diameters of .500", .501", .502" and .503". 

Before purchasing your first pack of Thor™ Bullets, you first need to order this test sizing pack which will allow you to correctly size your bore. It is important that you start with the smallest diameter Thor™ Bullet, and work your way up in diameter size until you find the proper fitting Thor™ Bullet for your muzzleloader.

To determine which bullet is best for your muzzleloader, start with an empty rifle, remove the breechplug and slide in the .500 bullet. If it slips easily down the bore, you then try the .501 and so on.  When you find the diameter that requires about 20/30 ft./lbs. of force to push down the barrel (that is comparable to the resistance you get loading a standard sabot bullet), then that’s the correct size for your rifle. While manufacturers have similar bore diameters, they will vary .001”-.002" from gun to gun, so it is extremely important to correctly size your bore to determine which diameter works best for you. 

The Thor™ Bullets are a premium Barnes bullet with proven technology. The bullet’s hollow base expands when the powder goes off, both gripping the rifling and sealing the bore. If it is a quality conical you are looking for that won’t fragment into a million pieces, the conical Thor™ Bullet is the way to go.

Package Quantity
Bullet Diameters
.500" TO .503"
Thor™ Hammer Bullet Sizing Pack - .500 to .503 Diameter

Thor™ Hammer Bullet Sizing Pack - .500 to .503 Diameter.

Rating: 4.7/5 based on 8 review(s)
  • Price: 5.00 - In stock
    Sold by
  1. Didn't work review by Doug N on 8/26/2019

    "Wanted to try these real bad but the smallest bullet wouldn't fit down the barrel of my CVA Optima."

  2. THOR BULLET SIZING PACK review by Greg on 3/6/2019

    "Great service and fast delivery from! Sizing pack was easy to use, the .501 fits perfectly in my CVA Optima Nitride. I have heard so many good things about THOR (Barnes) bullets, I can't wait to try them out on the range. "

  3. Thor Bullet Sizing Kit review by Gregory on 2/5/2019

    "Fast delivery; easy to use sizing bullets. My Traditions StrikerFire LDR barrel measures .502. "

  4. Measurements are accurate and easy to determine review by Joe America on 9/16/2018

    "I re-measured each bullet and they all were right on. Took a couple of minutes to determine I needed a 0.502, 0.503 wouldn’t even fit. "

  5. Sizing Pack review by Russell H. on 12/12/2016

    "The bullets arrived with instructions on how to determine what diameter Thor should work best in my rifle. It'll save time and money over buying bullets that don't fit the barrel's inside diameter."

  6. Thor bore size sample kit review by Gregory W. on 3/22/2016

    "I like the sample pack they send, it makes it simple."

  7. Great fit. review by Joe on 8/26/2015

    "With the different sizes I was able to find the size that fits my Knight perfect. Good accuracy too."

  8. Great bullet! review by Sam L. on 8/20/2015

    "Great sample pack to determine what Thor bullet is the right one for my rifle.....the .501 works best for me. If you are looking for a quality conical that seals both the rifling and the bore, plus won’t fragment into a zillion pieces, this bullet is definitely the way to go!

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If you are not 100% satisfied with your order, you can return it to us for a refund or exchange within 30 days of delivery. We accept returns on all products that have not been used or registered, no questions asked. All returns are subject to a 5% Re-Stocking Fee. To make returning an item easy, contact our friendly customer service representatives toll free 1-855-236-5000.


Most items ship within 1 business day! We ship orders from our warehouse Monday through Friday. If an in-stock order is placed on Friday evening, Saturday or Sunday, it may not ship out until the following Monday.

We rush-ship directly to customer's doors throughout the United States. Depending on the shipping method and area of the country, orders can arrive in 1-5 business days. Our policy as an organization is to successfully deliver on all orders, regardless of the chosen shipment method.


Standard Ground $20.00 4-7 Business Days
Three-Day $40.00 3 Business Days
Two-Day $60.00 2 Business Days
Overnight $90.00 1 Business Day


Standard Ground $6 to $12 3-5 Business Days
Three-Day $25.00 3 Business Days
Two-Day $30.00 2 Business Days
Overnight $50.00 1 Business Day

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