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The number of lands and grooves in a weapon's barrel vary by manufacturer.

Could it be possible that EACH gunmaker could have a unique set of these?

Is there any kind of firearms standards bureau that assigns these numbers to the
various gun makers?

Will a firearm that has a higher number of lands and grooves be more accurate than
the same caliber in a brand with fewer lands and grooves?

These questions are kind of "inside baseball" items, but if anyone knows, please share.

The floor is open.

SIA

It's questions like these that make me wish I would have pursued a career in gunsmithing.

I'm skating on the edge of the envelope of my knowledge here, but I'll give it a shot.

Lands & grooves are caliber specific. It has nothing to do with manufacturers being assigned specific numbers.
Lands & grooves determine the rate of spin for a bullet as it travels down the barrel, and controls the trajectory of the bullet as it exits the barrel. It also controls accuracy.

And it's not a more or less thing. It's more of how many lands and grooves are the best for that certain caliber, in order for the bullet to achieve its maximum efficiency(trajectory, accuracy, speed).

I know that doesn't help much, but if I say anything more I'll probably get it wrong. But for a more detailed look at lands & grooves and rifling, here's a pretty interesting website you might enjoy:

http://www.firearmsid.com/A_bulletIDrifling.htm" onclick="window.open(this.href);return false;

Hope that helps

What about H&K and Glock pistol barrels without lands & grooves?

As long as the barrel is made properly the number of Lands and Grooves have little effect on accuracy. The M1903-A3 Springfield rifle that was the substitute standard rifle in World War II had two grove barrels as a production expedient. These rifles were exceptionaly accurate, so much so the M1903-A4 sniper rifle used the same barrel, the barrel life was just shorter.

Some guns with more than six grooves in the barrel will only shoot ammunition with specific bullets at very limited velocity ranges. The "Micro Groove" barrel is an example of a barrel of this type - - - very accurate limited usage. Most barrels made nowadays are four to six groove barrels with the hammer forged type being the most durable and accurate. The H&K and Glock barrels are a hammer forged barrel that produces a pentagonal shaped bore that substitutes for lands and grooves.

I hope this answers the question.

boomerang wrote:What about H&K and Glock pistol barrels without lands & grooves?

They do....it's just not the "square" land that is common on all other guns like Colt, S&W, Remington, Ruger, etc. Those 2 use a unique type of rifling called "polygonal" rifling. More of a ridges and valleys than the standard square land and groove that's most common.

joe817, et al:

Thanks for the website and the other responses.

SIA

joe817 wrote:Those 2 use a unique type of rifling called "polygonal" rifling.

Correct. No lands and grooves.