3 vs 6 vs 8 groove barrels?

[FOTIS]

Why the difference in grooves in barrel making. What are positives and negatives please?

 

[DrMike]

It is my understanding that three groove fouls somewhat less (provided land/groove ratio is maintained) than six or eight groove barrels, without sacrificing accuracy. Also, a smaller number of grooves may be advantageous in maintaining barrel life.

 

[FOTIS]

So just barrel life (less friction) and a cleaner tube huh?

 

[DrMike]

That is my understanding. I know that a lot of the long-range shooters gravitate to three-groove barrels. When questioned, most will state their opinion that they have better barrel life and less fouling. I suspect that for the average shooter, it wouldn't make much difference. However, fellows that shoot competition and put a lot of rounds downstream are the ones who are able to witness the benefits and costs of such changes.

 

[FOTIS]

Thank you!

 

[SJB358]

Didn't the old Springfields have 2 grooves? Was it to save work?

Great question though.. I always wondered the same thing. What about 5R? Whats the big deal?

 

[DrMike]

There appears to have been no significant difference in accuracy in the '03 Springfields regardless of whether the barrels had two grooves or four grooves.

 

[Ridgerunner665]

Been curious about this too...my M70 is 4 groove.

 

[FOTIS]

My buddy's 308 Norma mag was built on a 2 groove '03. What a shooter man!

 

[.300winmag]

5R is a big deal supposedly because with five grooves, the land is opposite of a groove, if it were an even number of grooves, the grooves would be opposite of another groove. Supposedly having a land opposite of a groove exerts less stress on the bullet. Krieger published they haven't noticed any difference in their 5R barrels over their standard barrels however.

 

[Desert Fox]

I have Pac-Nor 3 grove that is very accurate and foul less. But then again, it's 308.

I have 4 grove Krieger on my 6.5-47 Lapua that is equally accurate and foul less also.

I have canted 5 grove Broughton on my 338 Lapua Ackley and 7WSM which is very accurate and doesn't foul much.

I have 6 grove Shilen on my 6MM Remington that is very accurate but foul a bit more than all of the above.

I don't own 8 grove barrel but I have one Polygonal barrel on my 300 Win Mag.

So what's this all means?

The number of groves the barrel has doesn't matter much... They all can be very accurate. The bottom line is, it all boils down to the quality of the barrel, the skill of the smith and nothing else.

 

[Ridgerunner665]

My 4 groove fouls some, but my sons doesn't....both are new M70 Ultimate Shadows...mine is slightly more accurate but that could be because its been shot more.

Mine is beginning to foul less though...took about 200 rounds to get there.

 

[usmc 89]

I have had success with 3 groove barrels from lilja, my lilja 1-8 6.5-284 barrel.has 1100+ plus rounds through it and won the sage flats steel match two weeks ago. the throat is a bit of a mess but is still shooting well. as far as lasting longer?,I don't know for sure but this barrel has been used in several matches where 10-15 shot strings of timed fire were used. I was told when I bought the 5r Krieger for my 300 Norma build that it would clean.up a bit easier but there were no differences in the accuracy department. I am not sure what the differences will be between the 4,5,6, or 8 groove barrels other than marketing advantages. I think it is similar to the debate between cut rifled or button rifled barrels, I have had both.and they both worked well. I think desert Fox hit the nail on the head with his post in regards to buying premium barrels.

 

[jason miller]

I have been told by one person that his 3 groove barrels have been "fast". Take small samples with a grain of salt, but I would be interested enough in giving one a try if I ordered a custom barrel.

 

[Desert Fox]

I have been told by one person that his 3 groove barrels have been "fast". Take small samples with a grain of salt, but I would be interested enough in giving one a try if I ordered a custom barrel.

Jason, My Pac-Nor 3 grove in my 308 seems to support that theory. Case in point, I can push the 155 grain bullet at 2900+ fps with only 43 grain of Varget, whereas I've seen others does it using 45 to 46 grain to get the same velocity.

 

[257 Ackley]

Most of my rifles being built have cut rifling from either Brux or Bartlein. The Bartlein barrel for the 6BR being built will have 5R rifling. There is a plan in place to try a different barrel break-in for the Brux on the 6.5X47 to see how burnishing in a new barrel works without the "one and clean" method of barrel break-in used in the past for a new barrel. This doesn't mean I'm going to rapid rifle 10 shots through a new barrel, just not going to clean after every shot for the first 20. The good thing about trying this will be to see how my velocities compare to Jeff's rifle in the same caliber with a few rounds through it.

There should be less drag on a bullet with fewer grooves (physics is not a strong suit of mine), so I'll leave the scientific stuff to you other brilliant minds to discuss. :wink: DF and Jeff are correct in stating that quality barrels usually equal great results if the gunsmith knows what they are doing. Next week can't get here fast enough for me. New brass is loaded with their pet load for the 6.5X47 (40.5 grains of H4350) with the 130 VLD's. We will be mounting the scope and doing initial shooting from Jeff's deck to see how it shoots. If that load works, we will have a little session at 1000 plus yards to test the LR accuracy.

 

[Ridgerunner665]

Sounds like you're going to break in like I do...similar anyway .

I just shoot it however many rounds (usually around 20 per session) then clean to the metal .

I keep doing that until the barrel settles down (fouling and accuracy)...generally takes 100-200 rounds for a factory barrel.

The Shilens settled down much quicker...

 

[onesonek]

I will agree that less grooves have less angles/corners for fouling to collect. And also that there a a whole host of factors regarding accuracy that don't necessarily relate to groove count. Powder charges being equal, more grooves create more pressure, just as a faster twist will also. I will add, that lapped barrels foul far less from the start most often. But,,,, nothing cleans as easy as a lapped Polygonal Rifled barrel, and I have been getting excellent accuracy with them as well.

 

[IdahoCTD]

I asked Bartlein and Kreiger about the number of grooves they use. Both said 4 was the least they would cut and have it shoot every bullet well. Cut rifled barrels take about 45 minutes to rifle in 4 groove, as opposed to button rifling that takes about a minute. So obviously they want to use the least they can to speed up the process as long as it doesn't affect the accuracy. The 5R barrels are a Boots Obermeyer thing to a large degree. They sometimes are faster and clean easier but you can't really prove that they shoot better. They don't tend to shoot light weight short range BR bullets well.

One thing with button rifling is that not all buttons are created equal. Some will produce super accurate barrels and others will be just so so. Obviously the quality of the steel dictates the quality of the barrel as well but that is the same weather it be button or cut.

 

[Desert Fox]

I think what Fotis was asking was if there are significance differences between barrels with different number of groves. Methods of rifling are another matter all together.