What kind of rifling do you have in your most accurate rifle?

[zimmerstutzen]

Really, describe the caliber, configuration, twist, number of grooves, shape of grooves, and width of grooves compared to the lands. 


Just saying you have a brand x barrel is worthless.  Some makers have their general rifling and then for their select customers, their special rifling.   

I have a 42 inch 45 caliber barrel with 8 grooves,  The grooves are approximately 7 times wider than the lands.  Grooves are .012 deep at their deepest.   The grooves are not round bottom as in circular, they are more like an oval laid on it side.  Twist is one in 66.  it also has a choked bore.  It is an H&H barrel, but was specially cut for me

[Rasch Chronicles]

Zim,

Great follow up to the powder thread. I was just about to ask the same or similar question.

In your example, the bottom of the groove has a larger radius than half the groove's diameter.  What might you guesstimate the radius to be? Maybe closer to the bore's?

(Now you guys have me wondering if the barrel I am thinking of getting for that 36 has round, square, or maybe even with my luck triangular grooves...)

Best regards,
Albert “Afghanus” Rasch   
The Rasch Outdoor Chronicles’ Top Ten!

[ironwolf]

  Any barrel can be made to shoot well. It's all in the testing to find that perfect combination of ball, patch, charge and lube.  The big difference in barrels is the ease/difficulty of cleaning and loading. We have a match the first weekend of each month at my home club, we'd love to have you and your H&H barrel come and participate.

  K
              www.floridafrontiesmen.org

[smylee grouch]

Square cut rifling, groves 70% of circumfrence of bore, lands 30%. 58 cal. shoots 575 ball into one hole at 50 yds., 1 turn in 75, cuts I think are 14/1000 deep, need a short starter to load with 20/1000 patch, 110 gr. 2f swiss. Hope I didnt get too far off topic  by adding load data.

[D. Taylor Sapergia]

Smylee, the description of your barrel and load makes the outcome predictable.  Those specifications/relationships are common to superb accuracy.

[smylee grouch]

Taylor, I forgot to mention that the barrel has been tapper laped also, tappering more tightly from the breech to muzzle. I told Jim what I wanted for the specs. on the rifling and he told me thats what he always did anyway.

[hanshi]

ROT ranges from 1-48" (.32) to 1-66" (.54).  Flint gun grooves are about twice the width of the lands at least.  Depth?  Appears around .010" to .012" but mostly a guess.

[Daryl]

I find I can make just about any barrel group well - as long as the grooves aren't excessively deep.  I kinda have a thing about WAYYYY undersized balls and sail canvas heavy for patching as would be needed in rifling much over .020" deep.  The deep grooved Bauska I had (the machine didn't turn off or they forgot about it working away.) ight have been an annolly, but I didn't have to use an undersized ball - I used a ball that was .009" larger than the bore and a .022" denim patch.

 Black Hand (Hugh T.) though, seems to achieve good results on paper with his hand rifled barrels out to .036" deep when using a scoped machine rest for testing accuracy - that's prior to the barrels being mounted on rifles.  If that changes things I don't know. It's possible as I haven't seen any targets nor heard of any groups matching his scoped  machine rest groups, which run moa at 100yds. Since some people are capable of shooting an inch with open sights and finished rifles, perhaps that says something about the 'hunting' rifle barrels out there.

[northmn]

Accuracy is a matter of load in any barrel.  While I think bore condition is a factor and likely a bore depth of 010, I wonder if there really is much difference in accuracy.  Many of the ideas are for handling fouling more than accuracy.  Also when one considers all the combinations it can take to make a barrel shoot, its a wonder we ever find the sweet spot.  I still think the the load is 99% of the accuracy issue in any quality barrel.

DP

[BrownBear]

I don't know where this fits in anyone's preconceived notions about accuracy, but my most accurate uses a ball that's undersize and a patch that is patently "too thin" for the bore.

The rifle is a GRRW 58 cal Hawken and when the moons align It can virtually touch shots at 100 yards from a rest.  The bore is "choked" however, getting smaller progressively toward the muzzle.  A bare .575 ball will rest on the muzzle without dropping, and if there's the slightest irregularity in a .570 it won't drop either.  To load it I have to use .562 balls and ticking, and that's a bit of a grunt.  But it gets so loose about 2/3 of the way down the bore that rod weight alone is enough to seat the ball in a clean bore.  

Go figger and splain as you want, but I'd almost guess that the first half of the bore could be smooth and the rifle might still shoot as well.

[Daryl]

BrownBear - Interesting point - brings up the question of obturation again - how much, when, or even if it happens?

My Musketoon has a .574" bore, .577" groove at the muzzle & .585" to .588" groove depth at the breech, yet a .565" RB loaded and drawn/sized into that tight muzzle with a .0215" patch is not burnt at all and reusable, even though it is roughly .005" undersized at the point of ignition - ie: .0025" per side-   yet no burns by the powder gasses that should be going by in each of the 5 grooves. There is no fouling buildup at all and it remains easy loading & accurate from start of the shooting until the shooting is done.  With the issure sights only about 18" apart, I've only been able to get a 2 1/2" group at 100 meters off a single rest.  It appears the ball is obturating upon ignition, just as a slug would, yet my .69's .012" deep rifling will not handle a .020" patch with it's pure lead ball only .007" under bore size - go figure. Sometimes it just doesn't make sense.

[BrownBear]

... a .0215" patch is not burnt at all and reusable, even though it is roughly .005" undersized at the point of ignition - ie: .0025" per side-   yet no burns by the powder gasses that should be going by in each of the 5 grooves.

Forgot to mention it, but my fired patches (cut at the muzzle) are virtually pristine, too.

[Daryl]

What gets me - is that if there is no choke of any sort for the length of the bore, ie: the ball and patch is less than compressed in the bottom of the grooves full length when loaded at the muzzle, the patch will burn and the bore will build up fouling even in .58 or larger bores. Those for sure, should be showing this obtruation effect regardless of any choke or taper inside the bore or groove - yet the evidence of no obturation is substancial.
It does not make sense at times.

[Daryl]

Most shooters are aware of the rifling that is inside an 1855 through 1858 Enflied's bore, I believe. The bore is supposed to be .577" with 48" twist, hand having .003" depth of rifling at the muzzle, progressing (increasing in depth) and extra .008" to the breech face. About equal width, grooves and lands.  Thus, the bore is even - straight, while the grooves increase in depth to the breech. My Musketon noted above and made in Italy on the Confederate pattern with brass furniture, has this style of rifling. The 1853 3-band had a 78" twist, 3 grooves and progressive depth rifling. They also were very good shooters with round balls.

 The US pattern replical rifles of the Civil War are also supposed to have this style of preogressive depth rifling, but they don't seem to.  As far as I know, of the Italian made rifles, only the Enfields, like mine, have the progressive depth rifling.

Now, the point is - I have shot more than 1, 1 1/2" groups at 100 meters with one of these rifles - a Parker Hale 2-band rifle, 32" bl., with a .022" denim patched (as measured in 1975) with .575" ball and a mere 85gr. (or was it 95gr.?) 2f powder (C&H) using the issue, military sights. Given good sights, I am quite positive this rifle would have shot an inch or even better.  Round ball, loose in the grooves at the breech, tight only at the muzzle when loading. It did not build fouling as it should, due to no blowby - it seems, & like all my shooting was done 'dirty' - obturation? Sounds like it.

Is the semingly obturation of the ball due to the ball being converted into a very short slug, rounded on both ends? My rods and starter have cups to prevent ball damage.

[BrownBear]

It does not make sense at times.

Ain't that the truth.  Come to think on it, neither do I!  My wife swears she's going to put it on my headstone.  

[Mike R]

for what it is worth, I have rifles with barrels from nearly all the best barrel companies, both in round and square botom rifling. My best shooter [most accurate] remains my old .45 I built with the now defunct Green River barrel with square bottom rifling--but I admit to still be tinkering with a couple of rifles....the fact is that the old Green River barrel [ca. 1978] has always shot tight groups at 50 yds with any reasonable load I tried.  Unfortunately, 40+ days and counting of over 100 deg weather here and relatively high humidity, too have kept me off the range all summer....too busy trying to keep my yard alive...

Couple weeks ago up in Oklahoma, where it hit 115, I saw a church with a sign out front that read:  We got a note from Satan; he wants his weather back.   

[BrownBear]

That appears to be the case for many of us with GRRW barrels, doesn't it?

I didn't dig far enough to find it, but I have a letter from the GRRW smith who built my rifle, in which he explains their rifling process resulting in that choked bore.  Interesting read, and I have to dig a little further because I surely don't want to lose track of it.

[Daryl]

My .69 barrel, easily my most accurate - to date, is also a GRRW barrel. Best group so far, is 6 shots into 1 1/4" wide X 3 1/2" long - 200yards, single rest - ie: bag under my left hand, no rear bag.  It has shot many groups of 1" to 1.5" at 100 yards, same type of rest- single bag under my left hand.

Also - it is the roughest barrel (inside) that I have, or perhaps tied with the Italian Musketoon & the .58 Kodiak for reaming marks, yet none of them retains fouling & accuracy is uneffected by the number of rounds fired.  It shot that well right from day 3 of testing - when I got the charges up to where it 'shined'- (shone?) HA! Grooves about 40% wider than the lands & .012" deep - 66" Twist.  Maybe it isn't as bad as it looks.
The rod wear on that land in the groove at 11:00 oclock in the picture doesn't seem to be effecting it's shooting ability, as 1" at 100 meters and the above group at 200yards were shot after this picture was taken. there are benefits to larger bore sizes, other than having the welcoming "thump" to the body upon ignition.  Last time out, my first three went into 2 1/2" at 200 yards. Maybe it needs more powder or a tighter combination - or a new barrel?

[BrownBear]

.... - or a new barrel?

Wash your mouth out with soap, young man!!!!!   

[Daryl]

Well?- got this one pretty much figured out. About time to work on another. That's about the way I do it with modern stuff - friends of mine own or have owned 20 or more of my 'old' rifles, after I get bored with them.

Just kidding I won't part with the 14 bore - it staggers moose.

[northmn]

I had a GRRW 58 barrel that did not impress me all that much.  A Numrich 58 I shot with had two "sweet spots" .  One with about 70 grains 3f and aother with about 100.  The 58 Green river did not start shooting until about 140 grains.  It was a 1" 36" barrel and I did not like 140 grains.  I now have a Green Mountain 58 that shoots at least as well and I have not really done a lot of load work.  Green Mountain has been doing fairly well on the BPC circuit also.

DP

[axelp]

I am only a mediocre shooter, so I wont even begin to brag on anything remotely close to them fellers in Canada but the barrel I own that is the best shooter is on my newest rifle---Chambers Isaac Haines. 38" .50 cal swamped Rice Barrel. The specs are .008" shallow groove 1:80" twist. Square groove. I have just started playing with it, but it comes closer to hitting what I am aiming at than any flint rifle I own.

So far, I shoot a .018 cloth patch (spit or bear oil and beeswax) and a .490 roundball with about 85-90 gr of FF.

Ken

[Daryl]

My GRRW (or Large) .58 also needed 140gr. to 'start' shooting well - 1 1/2" to 2" at 100 yards.  Due to it being a Hawken, I didn't like tht much either & sold it. I did experiment with slugs up to 675gr. as well and those needed just as much powder as round balls. My Zouaves & the Numrich or H&A underhammer also shot well with the same heavy charges with round balls. None of those were built for the recoil, either. If it's going to kick, it should be an English gun or early Amercian style. 2" + butts and proper geometry to handle recoil. Then, what Fun!

[BrownBear]

My GRRW (or Large) .58 also needed 140gr. to 'start' shooting well - 1 1/2" to 2" at 100 yards.  Due to it being a Hawken, I didn't like tht much...

Popped out of the same "mold" as mine I think.  But mine settles in to my satisfaction at 120 grains and is quite comfortable due largely to the weight (12 pounds) I suspect.  Come to think of it I've never explored larger charges, which could well bring our opinions right in line on the stock style.   

A year of shooting a 62 cal that has a hooked butt and is a little short for me, I'm certainly drawing up plans for a replacement in English style!

[Daryl]

A year of shooting a 62 cal that has a hooked butt and is a little short for me, I'm certainly drawing up plans for a replacement in English style!

It's not much fun when they hurt every shot. THIS is fun! Just a big old lazy push.   It would not be fun, from prone. The 'push' works out to 67 pounds but I think the formula lies?