Determining barrel Twist
You cannot select the best weight and diameter bullet without knowing your barrel twist.

Having the correct barrel twist is huge when attempting to get accuracy out of any muzzleloader. Knowing what the twist of your barrel is should be your first step in the load development process. I will give you a simple step by step process whereby you can determine the actual twist of your barrel.

How critical is barrel twist? Knight, almost single handed, destroyed the .45 muzzleloader market by introducing the Super .45 disc rifle with a 1:20" twist barrel. They had manufactured and sold thousands of them without doing much testing. Their customers quickly discovered these 1:20" twist barrels would not shoot well as the velocity of 1700 fps and greater was attained. The twist was way, way too fast. Knight proved that to everyone by making a running change from 1:20" twist to a 1:30" twist. That represents a reduction in rotational spin by over 30%.
More recently, Ruger introduced the .204 Ruger cartridge for varmint hunting with a 1:12" twist. Again lack of testing prior to manufacturing and marketing of a product has placed thousands of guns on retailers shelves that will not shoot the most efficient weights of bullets for the caliber. This time the twist is too slow. Experience has proven that a 1:10" twist is a much more versatile and accurate twist for the cartridge.

When it comes to potential accuracy, twist is everything. Bullet length must be matched to actual barrel twist. Don't trust the stamp on the barrel or the writing in the owners manual. Take five minutes and determine the twist of your barrel. Here are the steps:

1. Place your gun in a vice with the muzzle end facing towards you.
2. Get a ramrod that is threaded at both ends to accept accessories.
3. Screw a non rotating cleaning jag tightly onto one end of your ramrod.
4. Screw any other accessory onto the other end of your ramrod but leave several threads exposed to allow the ramrod to rotate.
5. Get a cleaning patch that is a very snug fit in your bore.
6. Wet the cleaning patch, place it on the jag and push it all the way down the barrel until the jag hits the breech plug.
7. Put a wrap of masking tape around the ramrod at the exact muzzle end of the barrel.
8. Use a dark colored marker to make a line on the masking tape where the front sight is located.
9. Now gently withdraw the ramrod, holding onto the accessory screwed onto the end of the ramrod sticking out of your barrel, until the dark mark on the masking tape rotates 1/2 a turn. In other words, if the mark was on the top of the barrel it should now be at the bottom.
10. With a tape measure, measure the distance from the tape back to the muzzle. Take that measurement and double it. In other words, if the mark is 10" from the muzzle your barrel is 1:20"; if it measures 14" from the muzzle, your twist is a 1:28".

Read it over several times. It is quite simple to do and this is critical information to have. I can tell you that I have barrels that are supposed to be 1:28" twist that actually measure 1:26.5" and 1:295". By having this information before you actually start load developing, you can save yourself a ton of time and money by starting with bullets the length that are most likely to perform best in your particular twist.

Cecil Epp

Toll Free Information & Order Line

Posted 1/31/2008

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