Not sure when they went from micro-groove to Ballard type but they went to micro-groove rifling around 1954,a 1 in 38 twist is standard for most .44 Magnum &.444 but with some ammo makers making factory loads that use bullets that weigh more then 240grns. in weight buy a Ruger Deerfield simi-auto .44 magnum or their lever action .44 magnums because they have a rifling twist of 1 in 18 that will stabilize the heavier 300grn.plus bullets and don't use the micro-groove rifling,also leading can be a problem in micro-groove barrels if your using soft lead and load them to more then 1200 feet per second so for that reason your better off to stick with jacketed bullets of not more then 240 grains when loading ammo for rifles with micro-groove barrels with the 1-38 twist if your going to be using heavy loads.Hope this info can be of some help to somebody, I have also noticed that the Ruger Deerfield rifle with the faster rifling twist gives a better bullet mushroom as opposed to the old 1-38 twist.If you'd like to learn a little more about this fascinating topic,type rifling characteristics into a search with Google and you will find a lot of interesting information on different types of rifling used by different manufacturers.
New .444's now have a 1 in 20 twist. I hope they do the same in the .44 Mag soon. The 1 in 20 will stabilize 300 grain bullets while the 1 in 38 will not.
1953 Check the article at wikipedia for more.
Marlin switched from Ballard rifling to the newer micro-groove on their 81 DL model in 1954.
It is Ballard style rifling, and should date to 1999. The year of manufacture is 2001. 1st 2 digits of serial # correspond to the year it was made. Ballard rifling is correct.
most likely it is. marlin (glenfield is marlin) began using micro-grove technology in 1953.
the micro groove is button cut and ballard is the lands and grooves are not equally spaced
The rifling is there to spin the bullet, which gives greater accuracy.
No rifling.
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There is a lot less resistance with the polygonal rifling. More over, if the polygonal rifling is chrome lined, the walls of the barrel are completely slick and offer less resistance. The projectile, the bullet, goes way faster. IDPA estimation here in the US are 10-30% faster.
When rifled, the rifling tool cuts the GROOVES. Material left between the grooves is the LANDS.
The rifling in a firearm is designed to cause the project (bullet) to spin, increase stability and accuracy.
Generally a smoothbore weapon, some rifledbore flintlock pistols were produced. The smoothbore were easier to make and mass produce at a faster rate.