I have heard of several types of rifling but can't seem to really get a grasp on how it is performed or what advantages there may be from one to the other. I understand how button, cut, and hammer forged rifling is done. What is ratchet rifling and polygonal rifling and micro groove? Are their any real advantages or disadvantages such as production time, accuracy, barrel life...etc between the many types?

Andy B

Just making what people ask for and that is about it.
Butch

Most "production" rifles have forged barrels because they are cheaper and faster to make, in the long run.

Ratchet, polygonal and microgroove are terms that describe the shape of the rifling grooves rather than the method of forming them. There are many other rifling groove shapes such as Boots Obermeyer's famous 5R form as well as Harry Pope's original wide shallow grooves with narrow lands. Some unique forms such as the polygonal were originally created as an aid to cleaning and barrel life, while others like Marlin's MicroGroove were apparently done as a manufacturing shortcut to speed production.

IMO the rifling form and the method of creating it are largely immaterial; all the makers will claim their method is better or cheaper or more elegant or whatever, but all their verbiage is basically horsefeathers.

What really matters is the performance and the barrel's performance is determined largely by the care and expertise used in its manufacture, regardless of the rifling shape or forming method. Use a barrel from a maker of known quality with a history of good performance if you want good results, and don't worry too much about the details of manufacture.
Regards, Joe

On that a said, Just going to change lanes for one sec.
Someone once told me that you cannot use lead bullets in the "micro grove".
"Because it is micro cut and will foul the groves quickly filling them with lead soon there after acting like a smooth bore."

But I now have come to know of that guy full of crap. But it dose make one wonder. How much truth is there in that if any at all?

Now back to the Rifling methods, Steele, that's wicked, because I was unaware of how much of that was hype and what was not.
It would be interesting to know or learn the method(s) of rifling. If I ever try it, well I doubt it. I will be starting a machining course come this fall. I would like to be a hobbiest smithy at best. Possibly make my own lead bullet molds.

quote:

Someone once told me that you cannot use lead bullets in the "micro grove".

Mmmm... I have come across that too! Can someone explain why? What about paper patched boolits? I have read that micro-groove 22rf's can be sensitive to ammo brands. Why would that be?

Most all RF rifles have a preference for one certain lot of ammo. Just ask the RF BR crowd.
I beat myself groggy trying to get real world accuracy out of hard cast bullets and micro-groove barrels. I sure was glad to see Marlin re-introduce "Ballard" style rifling.

There is a gun shop about 20 to 30 min drive from my place. One of his racks is full of those Marlen Micro Grove lever actions. This rack is about 12' long and just jam packed with them. They don't seem to sell. At least out here they don't.

quote:

quote:
Someone once told me that you cannot use lead bullets in the "micro grove".

Mmmm... I have come across that too! Can someone explain why? What about paper patched boolits? I have read that micro-groove 22rf's can be sensitive to ammo brands. Why would that be?

Regards
303Guy

I think it might be because the micro groove rifling is very shallow, about half the depth of regular rifling, and that is the reason that they use lots of grooves in the 22rf barrels. The shallow depth of the grooves in a .30 caliber may not be enough to grab hold of a lead bullet without shearing a little bit thus causing a drop in accuracy. My thought anyway!

quote:

Originally posted by clowdis:

quote:

quote:
Someone once told me that you cannot use lead bullets in the "micro grove".

Mmmm... I have come across that too! Can someone explain why? What about paper patched boolits? I have read that micro-groove 22rf's can be sensitive to ammo brands. Why would that be?

Regards
303Guy

I think it might be because the micro groove rifling is very shallow, about half the depth of regular rifling, and that is the reason that they use lots of grooves in the 22rf barrels. The shallow depth of the grooves in a .30 caliber may not be enough to grab hold of a lead bullet without shearing a little bit thus causing a drop in accuracy. My thought anyway!

That is only part of the reason. The bore and groove dimensions are different from say cut rifling or button rifling, etc... With that said most people try to fit the bullet for the other types of riflings. For example if you have Model 700 Remington in .308 the bore is usually .300 and the groove diameter is .308...make that about the same for a Win Model 94 30-30. So if you pick up a Marlin 30-30 with micro groove and fit the cast bullet as you would for the two mentioned rifles you won't have any success.

To really learn about this you need to go over the Castboolets forum and sign up and ask your Marlin micro groove questions there. There are members there shooting Marlins with great accuracy. Here's the link: http://castboolits.gunloads.com/