Two Groove Rifling

[Aragorn243]

I have a 1917 that has 2 groove rifling. I'm never sure what I'm looking at when I check the bore. I've read on the CMP site that most of the rifles they are selling now don't have much if any rifling.

I have distinct rifling in the barrel. A bullet also does not go very deep into the muzzle which is one of the tests I've seen a few guys here recommend. The bore does have some pitting but it is not what I would call a dark bore, but by the same token it's not a bright bore either.

What I'm wondering is if the rifling in these 2 groove barrels just is not as deep as what you find in a 4 or 6 groove barrel. The rifling is pretty wide and if it were as deep as other types, it would seem it might bind. So what should I be looking for here. I know the final test is shooting it which I still have not gotten around to doing so that's still the final determination.

Information

Warning: This is a relatively older thread This discussion is older than 360 days. Some information contained in it may no longer be current.

[mike16]

typicaly a 2 groove barrel is a replacement barrel circa wwII. while generally its suposedly not as desirable as a 4 groove barrel 1903a4's came from Remington with both 2 and 4 groove barrels. The best advice I have been given and pass on is to simply shoot it and see what it does. and remember that m2 ball was 150 grain. I have an M1 with a muzzle and a chamber that rates about a 6 in terms of wear yet it will shoot about 2 MOA at 100 yards. 2 groove rifleing looks kinda funny until you recognise what you are looking at. the depth is the same as 4 groove too so thats not a factor either.

[us019255]

I re-barreled one of my M1917's with a WWII two groove barrel. It shoots as well as any rifle I have. Qualified with it during the old DCM days.

By the way this was one of the one's that came back from some Arabic country many years ago. At the time new old stock stocks and barrels were readily available and cheap. Aside from the lack of rebuild stamps, after a park job it looks like it just came from a rebuild.

[Calif-Steve]

My 2 groove would heat up and at about 25 rounds would lose its bedding. I then began over-shooting the target by 1-2 feet. I sold the gun.

[mike16]

when the barrel is streight if you crygenically temper treat the barrel it will usually hold its zero

[Paul1807]

I have a two groove on mine and it is ok with flat based bullets boatails are another story, but that is typical with two grooves

[Chuckindenver]

Rock Island and Johnson Automatics made 2 grooves,,they shoot just fine.

[45B20]

Chuck is right that two groove barrel shoot very well, some two grooves shoot better than four grooves and visa versa. I have heard that after four to five thousand rounds the grouping ability of the two grooves drops off quicker than the four grooves. I do not know for sure as I only shoot cast bullets thru mine.

To correct Chuck a bit, Rock Island never made barrels for the M17 and except for small experiments,, never made anything but four groove barrels.

The WWII spare barrels for the M1917 were made by Hi-Standard and Johnson Automatics. Ferris states the Hi-Standards had four grooves and Hatcher wrote that 81,570 Johnsons were two grooves. Johnson may have made some four grooves, I don’t remember. However, all Hi-Standards I have seen had four grooves and all Johnsons I have see have had two grooves.

45B20

[Calif-Steve]

I swapped stocks on my 2 groove '17. Didn't help Once the barrel hit 25 rounds it would start over-shooting the target. A nice barrel, as well. I took that rifle to Perry, long drive to make a fool of myself. I sold the rifle.

[Chuckindenver]

RIA made many many replacement barrels for the 1917...iv installed a few. they are only marked RIA with no date no ord, bomb..and are also 2 groove.. LA also made unmarked barrels for the 1917,, actually for the 1941 johnson. if you remove a barrel from a johnson. you can see the extractor cut for the 1917.. if you remove the receiver ring from a johnson barrel, it will fit the 1917. and vise versa..