Looking for 5.56 lands and groove specs

[Mars attacks...]

Hi, I'm looking for a 5 groove pattern with the lands and grooves dimensions. If someone has something I can use as reference, or a formula to start with I'd appreciate it very much! Thank you!

[lysander]

Hi, I'm looking for a 5 groove pattern with the lands and grooves dimensions. If someone has something I can use as reference, or a formula to start with I'd appreciate it very much! Thank you!

Five groove rifling is 'non-standard', and there may be more than one type. You will probably have to go the specific manufacturer to get exact dimensions.

[Mars attacks...]

I am aware of it being non standard. I need some kind of starting point to work from.

[lysander]

The best starting point is the particular barrel maker those 5-groove rifling you are interested in...

The only generalization one can make is the groove diameter will be around .2235" to .2245", and that's not necessarily guaranteed.

If you want to learn about 5-R, talk to Obermeyer....

If you want to learn about 5 groove polygonal rifling talk to someone that makes it...

etc...

etc...

[Clint]

Start with this

http://www.saami.org/pubresources/cc_drawings/Rifle/223%20Remington.pdf

It gives the basic bore and groove dimensions along with the minimum bore area.

At a constant bore area, the reference of 6 grooves at .074" width translates to 5 grooves at .089" width.

The minimum bore area is important because it relates to the land-groove width ratio.

[Mars attacks...]

Thank you gentlemen, I now have some data to work with.