Forty cal barrel twist

[gonzomann]

Hello, all.

I am interested in building a .40 caliber swamped barrel flinter. I will be shooting a patched round ball. I would like to get input from folks who have experience in shooting a forty, and what twist they prefer. I am looking for optimum accuracy here... barrels are available from 1:48 to 1:66 and maybe more. Can I get some examples of groups shot with specific twists? (say 25,50, and 75 yards or so) Also patch and ball combos. I will be primarily using the rifle for squirrels and other small game. Thanks for the help!

SquirrelHeart

 

[nchawkeye]

I went with the 1-48...Mine has a Rayl barrel, I replaced a 13/16 Douglas in .45 with the .40, after I built a .54, 17 years ago....I have been very pleased, with 40grs FFF it shoots flat out to 50 yards and if my eyes behave it will group inside a squirrel's head at that range...I have tried it with up to 70grs FFF, couldn't see any difference in accuracy.

I ordered a .390 bag mold from Rapine when I ordered the barrel, and use .015 patching, lubed with SnoSeal.

 

[roundball]

Hello, all.

I am interested in building a .40 caliber swamped barrel flinter. I will be shooting a patched round ball. I would like to get input from folks who have experience in shooting a forty, and what twist they prefer. I am looking for optimum accuracy here... barrels are available from 1:48 to 1:66 and maybe more. Can I get some examples of groups shot with specific twists? (say 25,50, and 75 yards or so) Also patch and ball combos. I will be primarily using the rifle for squirrels and other small game. Thanks for the help!

SquirrelHeart

1:48" is the round ball twist for the little .40cal.
I settled on 40grns Goex 3F, .395's, and .015" for general shooting....018" are very acurate as well but were a little firm to start.

 

[captgary]

Have a GM 40 cal swamped barrel with a 1 in 56 twist, it shoots nice and flat out to 50 yds. Goex fffG 40 grains, .395 ball and .018 Wal Mart pillow ticking. Its my favorite target plinker...

 

[shortstring]

I've got one made by Jerry Cunningham in Montana I think. 1 in 72. I use 35 grs 3F for 25 & 50 yds & 45 grs for 100 yds. .395 ball & .017 pocket drill. Back when I shot a lot of offhand it was a tack driver.

 

[Herb]

I have a Rice barrel with a 1-66" twist, I think it is, and it shoots 40 grains well, but I think L.C. Rice told me something about champion shooters using up to 90 grains of powder in this twist. I also have 8 or 10 (I lose track) .40's with 1-48 twists that I have built or still own, and they all shoot well. I also have a .40 Wm Hawken I copied with a Green River barrel and a 1-66 twist (I think it is) that shoots 40 grains well. And I have a 44" Douglas .40 with a 1-66 twist that does very well with 90 grains of Goex 2F, better than light charges.

For squirrel hunting, you probably will want light charges, and the 1-48 twist will do very well.

 

[longrifle78]

The most accurate .40 i had was Rice b swamped 1-66, shot great with anything from 30 to 90 grains of 3f.

 

The old rule of thumb was that the smaller calibers, like the .40, used tighter twists--1:48 is/was considered ~optimum for the .40. However that seems to apply mainly for "reasonable loads" (such as 40 gr fffg). The slower twists seem to allow a wider range of loads and may work better if you choose to shoot "magnum" loads. All that said, my .40 shoots quite well out of its 1:48 barrel with 40 gr fffg.

 

[Java Man]

General reply here....not necessarily Mike

I have two .40's, both 1:48, and shoot well with up to 60gr FFFg. I would say that is close enough to a magnum load with a .40.

 

[bob308]

1-48 is the right twist for a .40.

 

[roundball]

"...my .40 shoots quite well out of its 1:48 barrel with 40 gr fffg..."

Mine as well...and in that tiny bore, 40grns Goex 3F must have some velocity too...a few weekends ago I was playing with it at the range, set up a few empty .12ga hulls and shot them off of a 2x4.

When I went to reset them I was surprised to see that the little ball had cleanly zipped right through both sides of the plastic hulls.

I had assumed the ball would hit and glance the hulls out of the way with one side caved in or something...but never figured the ball would slice through both thicknesses like it was paper...so I assume it must be zipping along pretty good with only 40grns 3F.

 

[George F.]

I have a Green River .40 cal. with a 1 :56 twist. I started shooting with 40 grains of 3f, then I started to drop the load down when shooting at 25 yd. targets with 25 grains, it shot great. no recoil and very accurate, I loved it.

 

[tg]

I had a 1/48 .40 36" barrel that was very accurate with a wide range of loads,

 

[Ohio Rusty]

Mine is 1 in 66 and it shoots dead on at 70 yards with 65 gr. of 3F with a bears oil lubed 10 thou's patch. I prefer the slower twist for round ball as the faster twists can be finicky sometimes. Slower twists I find are a bit more forgiving.
Ohio Rusty

 

[gonzomann]

Thanks for the input guys. Most helpful. :bow: