Number of grooves?

[andym79]

Hi guys I am sure this question has been asked before but are there any advantages or disadvantages between 3, 4, 5 or 6 groove barrels when shooting cast.

My gut says more grooves may improve accuracy but increase fouling, is there any truth in that?

[Larry Gibson]

In my opinion based on experience I prefer 3 or 4 up through 8mm. From 35 through 45 cal I prefer 6. They should provide 35 to 40% bore surface. Groove depth should be minimum of .004 to .005 max.

[jerry6stl]

I've had very good results shooting cast bullets from both 4 and 6 groove barrels.

Also hd one WWI Springfield 03A3 that shot well with a 2 groove barrel.

[Oklahoma Rebel]

what about the 250B and 285C accurate design, they are 9.3 cal and are GCrnfp with one lube groove that's deeper than what you see on multi groove boolits. for 2000-2200fps would a hard lube like carnauba red be best or would their carnauba blue be ok, because I don't have a lube heater. thanks a lot-Travis

[John Boy]

The more GG bands increases bearing surface obturating IMO
200629 Ideal 37584 - note the small base width

[Scharfschuetze]

I've had good accuracy with rifling from two, three, four, five and six groove barrels. I think that the twist rate and the bullet fit and quality (jacketed or cast) is far more important than the number of grooves. Other than in 22 rim fires, I've had no experience with lead bullets with Marlin's Micro Groove rifling, so I can't comment on that genre of barrel.

Over the years I've heard many a discussion over the topic at rifle matches. In summary, winners have used any number of grooves in their barrels to win and it isn't always consistent from match to match or year to year.

[BAGTIC]

How could more GG bands increase obturation when every groove represents less contact between the bullet and the bottom of the groove?

[Oklahoma Rebel]

oh, that's my bad, I rushed through yyour post and thought you were talking about boolits, in gunsmithing there is a special section just for talk about barrels. me, I would prefer 3-4 for cast, but I don't have the gunsmithing knowleddge to back that up! good luck!-Travis

[JasonYbarbo]

I only cast for pistols but have not noticed a difference.

[MyFlatline]

. I've had no experience with lead bullets with Marlin's Micro Groove rifling, so I can't comment on that genre of barrel.



Marlins Micro groove barrels shoot cast just fine, contrary to what is said. I have great success and accuracy with them.

[RU shooter]

A very wise and experienced dearly departed member here named Felix always said go with odd numbered be it 3,5,7 and so on . He was a BR guy , I doubt for regular stuff there's a measurable difference between odd and even

[Scharfschuetze]

It's interesting to look at what the various militaries opted for regarding the number of grooves with the advent of rifled military rifles. The first world armies invested a lot of time and money into adopting accurate rifles.

With the advent of rifled muskets in the US Military, 3 groove barrels were the norm. That remained the standard throughout the Trapdoor series of rifles in both 50/70 and 45/70. A good Trapdoor will shoot very well to very long range. With the adoption of the Krag and the following Springfield, Garand, M14, M16 and the M4, the rifling was/is all even numbered, generally 4 groove. There are exceptions I'm sure, but an even number is the standard. The Model of 1917 (US Enfield) used much of the tooling for the British P14 Rifle and thus had 5 groove Enfield rifling.

If my memory is correct, the British also used 3 groove rifling in their muzzle loading rifles and later a 7 groove "Henry" style of rifling in the Martini Henry. The follow on Lee-Metford in 303 British used a similar 7 groove rifling and that is now well known as "Metford" rifling. As Cordite eroded that form quickly, they adopted the 5 groove Enfield style of rifling and the rifle series became know as the Lee Enfield. With the adoption of the 7.62 NATO and later 5.56 NATO rifles, I believe that they are back to even numbers of grooves and lands.

The Germans? Even numbers of lands and grooves if my Mausers are any indication of Peter and Paul's preference. With the G3, they went with a Polygonal style of rifling, but they are now back to a conventional form with 6 grooves and lands in their G36 rifles.

The Japanese initially had conventional even grooves and lands for their Type 38 rifle's in 6.5 calibre. With the adoption of the Type 99 in 7.7 calibre, they adopted a Metford type rifling with chrome lined bore. I have no idea what they are using in their current rifles, the Type 64 (7.62) and the Type 89 (5.56).