two groove Bbl's

[runfiverun]

allright:
most of us have one of these, either in a 303 or in a 30-06.
let's see what has worked.
and what hasn't worked well, or at what level it quit working.
and if there is any consistency in bore to groove relationships.

[W.R.Buchanan]

Most get good accuracy between 16-1800 fps. Some load faster with good results.

No appreciable difference in accuracy between 2 and 4 groove barrels.

Loads vary greatly,,, see "favorite loads" section and "military rifle" section for more info. I use 25 gr of XMR 5744, but there is a bunch of other powders that work well in this application.

Good boolits are Lyman or clone 311299, 311041, Lee 308-190,and RCBS 308200-SIL.

The longer ones seem to work the best in Springfield rifles.

Randy

[uscra112]

Long boolits with parallel-sided noses that fit the bore and short ogives do best, according to Col.Harrison. If the nose is the least bit undersize, or has a long ogive, (i.e. spitzers) they don't do as well. The canonical test was to insert the nose section into the muzzle. If it went in with a wee bit of resistance, it would be good, if it fell in with no resistance, it was too small. Not much personal experience to report - I had reasonably good results with a 311284GC in straight wheelweights and 4198, sometime around 1997, but never followed it very far. Someday I'll get back to it.

I recall that Mike Venturino recently published a piece. He was set on 5744 as the only powder to use.

[zomby woof]

311284, my best load so far has been 32 grains of 3031 with Dacron filler

[1Shirt]

My Springfield 2 land loves anything above 170, and really loves 311284's.
1Shirt!:coffeecom

[45 2.1]

let's see what has worked.
and what hasn't worked well, or at what level it quit working.
and if there is any consistency in bore to groove relationships.

You would be better off asking what size the groups were along with the comparison. The two groove Springfields always outshot the four grooves for me, but I use something that fits those two grooves quite well.

[44man]

Long boolits with parallel-sided noses that fit the bore and short ogives do best, according to Col.Harrison. If the nose is the least bit undersize, or has a long ogive, (i.e. spitzers) they don't do as well. The canonical test was to insert the nose section into the muzzle. If it went in with a wee bit of resistance, it would be good, if it fell in with no resistance, it was too small. Not much personal experience to report - I had reasonably good results with a 311284GC in straight wheelweights and 4198, sometime around 1997, but never followed it very far. Someday I'll get back to it.

I recall that Mike Venturino recently published a piece. He was set on 5744 as the only powder to use.
That is exactly what is wrong with a Keith boolit in the revolver. Funny how the rifle stuff applies.
I have shot many rifles with 2 grooves and they work just fine. Fit is king every time.
I have the hardest time with shallow rifling with many grooves. All lead needs is deeper grooves. The best ML barrels have rifling .010" deep.

[Finnmike]

Two-grooves are the huckleberry for cast boolit shooting. I use 16-17 gr of 2400 and a Lee 309-180R WWAC. Now experimenting with the 185R. Use a bore-riding boolit and seat into the lands, about 3.30".

[Larry Gibson]

Two groove barrels will shoot cast pretty much as well as 4 or 6 groove barrels with many cast bullets out to 200 - 300 yards with regular loads. However, I've found that with the higher end loads the 4 groove barrels will most often five better accuracy at 300+ yards. With most M1903A3s and their sights you won't notice any difference at the closer ranges. The cast bullets are not round/concentric on exit from a 2 groove barrel and will be more adversely affected as the range increases.

The answer to the question lies in this; 2 groove barrels are quicker and cheaper to produce than barrels with 4 or more grooves and were produced as a wartime measure. Thus if they were just as accurate or more accurate they would be made today and used on hunting and match rifles but they aren't.........

Larry Gibson

[milprileb]

2 groove was just fine for Angle of Kraut Tunic
and 4 Groove is better for accuracy groups on the range.

[303Guy]

2 groove barrels ...... Thus if they were just as accurate or more accurate they would be made today and used on hunting and match rifles but they aren't......... Well almost. There is a three-groove target barrel out there. I don't know whether it uses narrow grooves like the two-groove barrels. My rust 'textured' two-groove seems pretty accurate with j-words. Hopeless with cast. I haven't tried my mint bore two-groove yet. I do have a boolit for it but it's a paper patched boolit.

I've found with two-grooves that the boolit trailing edge gets distorted unevenly. That can't be good for accuracy.