# of lands-grooves...what is the deal?

My logic is telling me three grooves, for instance must create less resistance=more fps

really wondering what the concepts or opinions are around 3, 4, 5, and six or more?

Thank you for any insight you can give on this!

I do know that 3 grooves place more stress on bullet jackets, they dig into the jackets deeper.
From hwat I been told speed comes from resistance and pressure, this is why a 1 in 8 twist barrel will be faster than a 1 in 14 twist, both barrels sharing the same amount of grooves, bore size, and length, shooting the same load.

sooo....do the grooves get lower profile as the number increases?

Quite a large question.

Depends on the barrel maker. Ever hear of two identical barrels...but one is faster than the other? Can be many differences in the machining, but, more than likely, it depends on what the actual bore and land diameter is.

Three groove can be wide or medium narrow. Same as 4, 5, 6, etc groove barrels.

I built two 6.5x55 AI's at the same time. One barrel is 50 fps faster and, in my opinion, a touch more accurate. Of course, my barrel is the slower of the two! ...go figure.

Guess I was thinking/hoping for some solid constants to help make a decision

I have noticed artillery barrels with quite a large number

and thought accuracy must have been the only consideration

I remember when..............................

[img width=363 height=450]http://i122.photobucket.com/albums/o254/bigedp51/SAID2058-1.jpg[/img]

The above photo is for the No.1 Enfield rifle that fired "HOT" Cordite powder with 23% Nitroglycerin, the British preferred five groove barrels for longer barrel life and accuracy. Having said that one of my most accurate Enfields has a two groove war time production barrel.

Check out Krieger barrels and their 5-R Rifling below

http://www.kriegerbarrels.com/5_R_Ri...246-wp6676.htm

Without exception, since I went to a three groove Benchmark barrel my velocities are definitely faster. I have a friend with a bunch of fast twist Benchmark 3 grooves. At hyper velocity some bullets like berger with not make it to a 100 yard target. Only brass bullets turned on a lathe will actually stay together. We are talking 3600fps from a 7MM X 378 Weatherby Improved shooting 180 and above weight bullets.

The Old M1 Grand barrels had two grooves and these guns were highly accurate.

The lands on a three groove are wider than a 4-5-6 groove barrel. Calibers being the same mathematically speaking, the sum of the lands of the various grooved barrels should be close to the same area. Depth of groove is each manufacturers from what I have seen. SHilen in my experience has the shallowest rifling I have seen. Its been a couple decades though since seeing a Shilen so haven't any idea what they look like today.

so the Berger's not making it caused by the fast twist?

or from the deep cuts in the jacket from the 3 groove setup?

combination of both?

Velocity + 3 groove + fast twist+ LONG barrel!

He has gone to Titanium Nitride to see if that will help. It gave him more velocity ( Lots)and the last I heard the jury was out on bullet preformance.

Neal

358Hammer, just a quick question about your Benchmark barrels, do they make a pre-fit chambered drop in Savage barrel?

Yes

I have six now. In fact I have one action set up and indexed for a 6.5 WSM, 338WSM and a 458 Lott.

Neal

Quote:

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Originally Posted by 358Hammer

The Old M1 Grand barrels had two grooves and these guns were highly accurate.

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Nope - Many 1903a3 and war time production replacement 1903 barrels had two grooves and were known for their accuracy with cast bullets. If you find an M1 with a two groove barrel it is probably an 03a3 barrel turned down and fit into a demilled M1 "stub" - run away!

Of course the custom barrel makers will make you whatever you want.

Folks have used all combintations of profiles and numbers of lands/grooves over the years. The "ratchet rifling" isn't new either - check out the bore of a trapdoor Springfield. If there was a clear "best choice", everyone would be using it.

I'm not one to push bullets as fast as I can get them, so the 3 land barrel works great for me. I think if your going with a really fast twist, having more lands is a good thing.

There is a new process out that's kind of like the Tritanium Nitride process, but is different. The guy who developed it took two years in doing so for the military. The concern was the fast burning up of the throats of the barrel. He claims 40,000 rounds from an AR-15 with no wear at the throat and about 150 FPS more velocity.
Scott Null, owner of Savagegunsmithing just got back about 20 customer barrels from customers who want to test the process. It makes the barels punch about 100 on the Brinal scale and any mods to the barrel such as cutting for a muzzle brake have to be done prior to the treatment.
If it works as advertised, it will be a major break through for all shooters, especially the BR shooters who change barrels once a year due to wear in the throat. Right now, Scott is the only one the guy is doing barrels for other than the military. If you want more info on the process, call Scott at 208-313-1570, he knows far more about it than I do.

I'm waiting to see the results before I get my barrel treated and will most likely start out with a new barrel.
It costs $240.00 per barrel for the treatment, so it's not something I want to jump right into. The guy has the barrels and test results to back up his claims, but I want to see what kind of results the people who Scott had the process done for get.

I'll try to keep you all posted on the results. Scott will be checking the barrels with a bore scope as they are shot to see how the throat wear if any is going.

Back to the original post, I think in the slower twist barrels, shot at reasonable velocities, the 3 grove barrels are the best things going. If I was to go with a fast twist and pushing the bullets at high FPS, I'd want more grooves. Those old 2 groove barrels sure shot excellent, but they were not a real fast twist and not shooting the new fast cartridges.

John K