Author Topic: Rifling (Read 476 times)

jvs · « **on:** March 07, 2005, 02:13:48 PM »

Can anyone here explain to me the difference, if any, between Marlins Micro-Groove rifling and Button rifling?

Thanks.

John Traveler1 · « **Reply #1 on:** March 07, 2005, 05:02:42 PM »

Marlin's patented "microgroove" rifling consists of 12 equal sized lands and 12 grooves. It is claimed to produce less bullet base distortion and made it reputation for better accuracy in it's rimfire rifles. It may be made by the button rifling process.

Button rifling is made by pressing or pulling a carbide "button" impressed with reverse rifling through a barrel bore. It does not involve cutting metal but rather pushing it aside.

John Traveler1 · « **Reply #2 on:** March 07, 2005, 05:08:46 PM »

Rifling can have any number of lands and grooves, but most makers have settled on 4, 6, or 8 in standard caliber bore and groove dimensions.

The original "microgroove" must have been ben cut or broached, because button rifling did not come into use until after WWII.

jvs · « **Reply #3 on:** March 08, 2005, 12:05:11 AM »

Marlin uses micro-groove on almost all of it's hunting rifles since the late 50's I believe. Only some of the modern Cowboy models offer deep cut rifling.

I knew how button rifling is produced, with metal being pushed aside during the process of a carbide button being forced down the bore. What I don't know is if micro-groove is cut or pushed aside or if 12 lands and grooves, as you have stated, is better for bullet stabilization then 4, 6 or 8 in a .30 or bigger caliber piece, not just .22's.

Somewhere I also read that micro-groove is .004 deep, which I suppose is plenty deep.

gunnut69 · « **Reply #4 on:** March 08, 2005, 04:18:50 AM »

Micro groove rifling was developed to minimized the distortion of the bullet by the rifling. The number of grooves varies with the caliber and some of these number of grooves have changed over the years. It can be formed either with a broach or by using a button, I have never heard of it being hammer formed but assume it probably could be.. The finest target rifle barrel makers don't use this rifling form. I would assume they would were there any major accuracy advantage. I would guess accuracy is more a function of precision than number of grooves.