Green Mt barrel 1 in 70 twist

[CAMski64]

Has anyone had any experience with this particular barrel. I have a 1 in 48 lyman trade rifle and with 75 grns of Goex 3fcan keep 5 shots touchibng at 50 yds. Hard to improve on that.

 

[roundball]

I used various calibers in T/C's 28" x 1:48" barrels and always had great accuracy...100yd groups like 1+7/8" - 2+3/4" benched with 90grn Goex 3F hunting loads out of T/C Flintlocks.
I did buy T/C's longer 32" x 1:66" barrels based on what some people advocated on forums like this one but was surprised that I had to really study the targets to detect any minor difference in group size. I also bought a couple of GM 32" x 1:70" barrels in .40cal & .58cal which T/C didn't happen to make, and they were very accurate barrels as well.

I will say that I came to favor the slightly longer barrels for aesthetics...and the longer sighting plane plus increased weight helped minimize muzzle wander for improved accuracy with both T/C and GM barrels from offhand / semi-offhand hunting positions...but I also discovered I could duplicate that in the 28" barrels by simply replacing the light wooden ramrods with heavier solid brass ramrods for more weight out front.

But I never saw any shocking difference in pure barrel accuracy out of the slower twists compared to the 1:48" twist running side x side tests in the matching .45/.50/.54 calibers I had of each to compare them to. In fact, for a few years my signature line was:
"claims that 1:48" barrels are inaccurate are old wives tales".

So I'll bet that you'd "like" the longer barrels for similar reasons I mentioned above...but I'd guard against expecting any "OMG" accuracy differences at the target, particularly with the accuracy you're already getting.

 

[BrownBear]

But I never saw any shocking difference in pure barrel accuracy out of the slower twists compared to the 1:48" twist running side x side tests in the matching .45/.50/.54 calibers I had of each to compare them to. In fact, for a few years my signature line was:
"claims that 1:48" barrels are inaccurate are old wives tales".

So I'll bet that you'd "like" the longer barrels for similar reasons I mentioned above...but I'd guard against expecting any "OMG" accuracy differences at the target, particularly with the accuracy you're already getting.

That nicely sums up my experiences, too.

Claims against 1:48 twists compared to slower with round balls have proven so faulty in my own testing, I've started to suspect other claims made by the slow twist pushers. Such a "religious" fervor about slow twists should reveal it's truth on the target papers, and it just ain't happened for me. :bull:

They can call me a heathen, but my skin is thick.

 

[paulvallandigham]

I think the TRUE test of the difference in " Accuracy" relates to " relative accuracy" defined as follows:

How forgiving is a rifle with faster or slower ROTs when the powder charges vary as much as 5 grains in volume?

Its not the Inherent accuracy of a 1:48 ROT barrel, compared to the same Inherent accuracy of a 1:70 ROT barrel. Its HOW FORGIVING each barrel is to changes in power charge volumes! :hmm: :rotf:

There is some truth to the " OLD WIVES TALE" that the slower ROT barrels are MORE forgiving of changes in powder charges, in my experience, and originally- before I even owned a MLer-- in watching some of my club members shoot various guns. We talk about loading from the "pouch" and some of the older guys I knew years ago not only loaded "from the pouch" but were pretty cavalier about how they measured powder into the antler fixed powder measures, and worse( in my mind at the time) how cavalier they were about pouring the powder in the barrel. I would see variations in the height of the powder in the fixed measures, and I would see these guys miss the muzzle, spilling some few grains of powder on the ground, but still take the shot, and have it hit in their groups at 50 yds.

I don't have the luxury of having different guns, with different ROT barrels, but other wise in the same caliber and barrel length, to test. But friends of mine who do, report that their slow ROT gun barrels are much more forgiving of variations( sloppiness) in measuring a powder charge, than their faster (1:48 ROT) barreled guns.

:hmm: :surrender: :thumbsup: I am shooting a .50 cal. rifle with a 1:48 ROT, from Green Mountain. Its shoots fine. But, I also take care in how I load my adjustable powder measure, and in how I pour the powder down the barrel. The few times I have shot the gun over a rest with quickly thrown and badly measured powder charges, groups opened up at 50 yds- not enough to miss a deer at that range-- but something to worry me if I were trying to take a deer at 100 yds. and beyond. :hmm: :thumbsup:

 

[Trench]

I never saw any OMG accuracy with my 1:70 green mountain. I had to build up an "accurate for me" load like any other barrel regardless of the twist. That turned out to be 90gr of 2F, a .570 ball, and a .025 patch.

For my caliber, it seemed to want a thicker patch and heavier charges in the 90gr-100gr range.

 

[Golfswithwolves]

I am developing an impression in my mind that slow twist barrels shoot better with healthy powder charges than they do with light charges. (Or maybe this is only in my own rifle). :hmm:

 

[George]

Its not the Inherent accuracy of a 1:48 ROT barrel, compared to the same Inherent accuracy of a 1:70 ROT barrel. Its HOW FORGIVING each barrel is to changes in power charge volumes!

That has been my experience with slow twist barrels. I don't own any barrels with 1:48" twist, because I shoot only round ball, and I was taught early on that slow twist barrels do that best. My barrels are a .54 in 1:70", a .40 in 1:66", and a .30 in 1:56". I think of all of them as very accurate barrels, but I understand my definition of that will not suit everyone. They are all more accurate than I need as a hunter.

The thing I've been aware of for all of my shooting career is that I have never had the troubles with changes in accuracy and consistency when I change loads that I see described all the time by many shooters. Each of my barrels accepts a wide range of charges without any problems. I shoot Goex FFFg in all these rifles. I shoot 80 gr.-110 gr. in the 1:70" barrel, 35 gr.-70 gr. in the 1:66" barrel and 15 gr.-25 gr. in the 1:56" barrel. I never really have had a problem losing accuracy through the entire range of charges for any of these barrels. At 100 yards with the .54 and .40 I may... may... see a shift in point of impact up or down, but even that is minimal. If they do shoot higher or lower, because of the simple physics involved, they shoot acceptable groups higher or lower.

My .40 is a good example. It's a Douglas barrel, 8 lands and grooves, land diameter .403", groove depth .012", 1:66" twist. I shoot .395" or .390" balls with .015" pillow ticking patch, beeswax-tallow lube. I have shot 55-60-65-70 grains FFFg as hunting charges with no degradation of accuracy. When I decided I wanted to use it for squirrel hunting I shot 30-35-40 grains and found the gun to shoot very nicely with all three, I couldn't tell a difference, all three loads shot better than "minute of squirrel noggin". So, I can just stuff whatever charge I want in this gun, depending on whether I'm after grizzlies or chipmunks, and it shoots them all very well. This is the way a gun should work, I think, and I've generally found all three of these guns to do that. Is it the slow twist? I don't know. Am I just lucky to have wound up with these three particular rifles? I'll never believe that.

I've never been a big fan of the concept that each gun has one particular load that it likes best and won't shoot others acceptably. That has not been my experience.

One other thing I've noticed over the years is that a minor change in powder charge has absolutely no discernible effect on my accuracy. I'm firmly convinced that I can't spot any effect of a change of as much as 5 gr. of powder. I've always believed the idea that a small variation in charge makes a difference may be a notion carried into the black powder shooting sport by converted smokeless shooters, especially handloaders. It doesn't happen for me, never has. Maybe that's because of the slow twist barrels I shoot, but I really doubt it.

Your milage may vary.

Spence

 

[roundball]

The thing I've been aware of for all of my shooting career is that I have never had the troubles with changes in accuracy and consistency when I change loads that I see described all the time by many shooters. Each of my barrels accepts a wide range of charges without any problems. I shoot Goex FFFg in all these rifles. I shoot 80 gr.-110 gr. in the 1:70" barrel, 35 gr.-70 gr. in the 1:66" barrel and 15 gr.-25 gr. in the 1:56" barrel. I never really have had a problem losing accuracy through the entire range of charges for any of these barrels. At 100 yards with the .54 and .40 I may... may... see a shift in point of impact up or down, but even that is minimal. If they do shoot higher or lower, because of the simple physics involved, they shoot acceptable groups higher or lower.

My .40 is a good example. It's a Douglas barrel, 8 lands and grooves, land diameter .403", groove depth .012", 1:66" twist. I shoot .395" or .390" balls with .015" pillow ticking patch, beeswax-tallow lube. I have shot 55-60-65-70 grains FFFg as hunting charges with no degradation of accuracy. When I decided I wanted to use it for squirrel hunting I shot 30-35-40 grains and found the gun to shoot very nicely with all three, I couldn't tell a difference, all three loads shot better than "minute of squirrel noggin". So, I can just stuff whatever charge I want in this gun, depending on whether I'm after grizzlies or chipmunks, and it shoots them all very well. This is the way a gun should work, I think, and I've generally found all three of these guns to do that. Is it the slow twist? I don't know. Am I just lucky to have wound up with these three particular rifles? I'll never believe that.

I've never been a big fan of the concept that each gun has one particular load that it likes best and won't shoot others acceptably. That has not been my experience.

One other thing I've noticed over the years is that a minor change in powder charge has absolutely no discernible effect on my accuracy. I'm firmly convinced that I can't spot any effect of a change of as much as 5 gr. of powder. I've always believed the idea that a small variation in charge makes a difference may be a notion carried into the black powder shooting sport by converted smokeless shooters, especially handloaders. It doesn't happen for me, never has. Maybe that's because of the slow twist barrels I shoot, but I really doubt it.
Your milage may vary.
Spence

All perfectly well said and I couldn't agree more.
And that understanding only comes from years of range trips and thousands of shots to build the first hand experience base...not from repeating what's been read in other posts on a forum somewhere.
:thumbsup:

 

[BrownBear]

Its not the Inherent accuracy of a 1:48 ROT barrel, compared to the same Inherent accuracy of a 1:70 ROT barrel. Its HOW FORGIVING each barrel is to changes in power charge volumes!

That has been my experience with slow twist barrels. I don't own any barrels with 1:48" twist, because I shoot only round ball, and I was taught early on that slow twist barrels do that best. My barrels are a .54 in 1:70", a .40 in 1:66", and a .30 in 1:56". I think of all of them as very accurate barrels, but I understand my definition of that will not suit everyone. They are all more accurate than I need as a hunter.

The thing I've been aware of for all of my shooting career is that I have never had the troubles with changes in accuracy and consistency when I change loads that I see described all the time by many shooters. Each of my barrels accepts a wide range of charges without any problems. I shoot Goex FFFg in all these rifles. I shoot 80 gr.-110 gr. in the 1:70" barrel, 35 gr.-70 gr. in the 1:66" barrel and 15 gr.-25 gr. in the 1:56" barrel. I never really have had a problem losing accuracy through the entire range of charges for any of these barrels. At 100 yards with the .54 and .40 I may... may... see a shift in point of impact up or down, but even that is minimal. If they do shoot higher or lower, because of the simple physics involved, they shoot acceptable groups higher or lower.

My .40 is a good example. It's a Douglas barrel, 8 lands and grooves, land diameter .403", groove depth .012", 1:66" twist. I shoot .395" or .390" balls with .015" pillow ticking patch, beeswax-tallow lube. I have shot 55-60-65-70 grains FFFg as hunting charges with no degradation of accuracy. When I decided I wanted to use it for squirrel hunting I shot 30-35-40 grains and found the gun to shoot very nicely with all three, I couldn't tell a difference, all three loads shot better than "minute of squirrel noggin". So, I can just stuff whatever charge I want in this gun, depending on whether I'm after grizzlies or chipmunks, and it shoots them all very well. This is the way a gun should work, I think, and I've generally found all three of these guns to do that. Is it the slow twist? I don't know. Am I just lucky to have wound up with these three particular rifles? I'll never believe that.

I've never been a big fan of the concept that each gun has one particular load that it likes best and won't shoot others acceptably. That has not been my experience.

One other thing I've noticed over the years is that a minor change in powder charge has absolutely no discernible effect on my accuracy. I'm firmly convinced that I can't spot any effect of a change of as much as 5 gr. of powder. I've always believed the idea that a small variation in charge makes a difference may be a notion carried into the black powder shooting sport by converted smokeless shooters, especially handloaders. It doesn't happen for me, never has. Maybe that's because of the slow twist barrels I shoot, but I really doubt it.

Your milage may vary.

Spence

I've always honored and valued experience over theory. Many thanks for the feedback and insights! :hatsoff:

 

[MikeChapin]

That has been my experience with slow twist barrels. I don't own any barrels with 1:48" twist, because I shoot only round ball, and I was taught early on that slow twist barrels do that best. My barrels are a .54 in 1:70", a .40 in 1:66", and a .30 in 1:56". I think of all of them as very accurate barrels, but I understand my definition of that will not suit everyone. They are all more accurate than I need as a hunter.
...

Long twist barrels are more forgiving that tighter twist. Over the years I have worked up loads for my muzzleloaders and for many other people. Over the years I have seen some barrels that could give a rip what powder charge you have, others that are sensitive to it.

I do all load workup at 50 yards. I have found at 25 yards it is difficult to see any spread in groups. Almost all rifles will print nice groups at 25 yards with most any load. At 50 yards a tight 25 yards will spread to 2 or 3 inches. At 50 yards you can see the effects of changing the load where you can't at 25.

With long twist barrels even at 50 yards you don't see a lot change. A three inch group will go to two inches and then start opening up a little when you go to different charges. On a 1:48 twist you will generally see more change in the group from load to load.

I have found over the years that the powder charge is the least component in barrel accuracy. When I find the charge that gives the smallest group, be it 1" or 4", I then start messing with the patch/ball combination. I work with these until I can get the group to less than an inch at 50 yards. This is usually just one ragged hole with a five shot group with a .45 or above.

After that I raise the charge until I am hitting with the same POA/POI that I used at 50 yards. Back when my eyes were better, I could keep the 100 yard group at 2 to 2.5 inches. A 1:48 twist may take a little tinkering with the powder charge to get this but most long twist barrels have no problems.

Over the years all of the patch/ball combinations have one thing in common. They start with a slap on short starter to start but go down easily after starting. A wet lube patch will usually allow these rifles to shoot all day without cleaning.

This is just stuff I have found over the years. As Spence said "your mileage may vary".

 

[ebiggs1]

“I've never been a big fan of the concept that each gun has one particular load that it likes best and won't shoot others acceptably. That has not been my experience."

"One other thing I've noticed over the years is that a minor change in powder charge has absolutely no discernible effect on my accuracy. I'm firmly convinced that I can't spot any effect of a change of as much as 5 gr. of powder. I've always believed the idea that a small variation in charge makes a difference may be a notion carried into the black powder shooting sport by converted smokeless shooters, especially handloaders. It doesn't happen for me, never has. Maybe that's because of the slow twist barrels I shoot, but I really doubt it.”


This is exactly what I have seen. Actual shooting is the best teacher, you can read and theorize all you want but doing is best. I have purposely tried to make a difference by loading each shot of a five shot group differently and have not seen the accuracy suffer greatly. My GM barrels digests just about whatever I put in them and shoot wonderfully. It is probably the fact that black powder muzzleloading has been around for such a long time that so many myths exist about them. The best teacher in any case is the go shoot.

 

[paulvallandigham]

I agree. Its when the ROT is faster that barrels seem to have problems shooting good groups with a variety of load. They may shoot well with one load, but not with other loads- often only 10 grains or more/less different. Drives me NUTS when working up loads.

FWIW, I believe that the fast ROT barrel suffer greater variations in vibrations( harmonics) due to the change in Torque forces applied as a result of the fast ROT, and different velocities. You will see small changes in group sizes with very thick barrels, compared to bore size, but if the barrels are the same diameter, The Fast 1:32-to-1:48 ROT barrels will give you more problems, than the slower 1:56-to-1:70 ROT barrels, when shooting the PRB.

When shooting Conical bullets in any barrel, you need to match the weight and length of the bullet to the ROT chosen, with faster ROTs needed to stabilize the heavier bullets.( Per the Greenhill Formula.) Depth of rifling also becomes much more critical when shooting conicals, along with matching the diameter of the bullet closely to the bore diameter.

I am of the same mind that if you need, or "want," more power down range, then use a larger caliber ball/gun, rather than expect better performance by using more powder. You can flatten trajectory only so much adding more powder, shooting round balls, and that generally still restricts your ability to hit game accurately with open sights to less than 150 yards.

Part of Traditional MLing hunting is all about getting in closer to game, and passing on shots that are beyond YOUR chosen Maximum range. Moving quietly, determined scouting before the season, placing blinds and stands to maximize your chance of seeing and intercepting game-- whether in trees or on the ground-- are all necessary parts to Traditional hunting with these guns, and add to the immense satisfaction one gets from such hunts. :thumbsup:

 

[nkbj]

I am developing an impression in my mind that slow twist barrels shoot better with healthy powder charges than they do with light charges. (Or maybe this is only in my own rifle). :hmm:

Yep, you hit on something there as a general rule. Everybody has a different barrel, loading technique and a variety of factors influencing their experiences but me thinks you are correct.

 

[CAMski64]

Thanks guys, I think I just savded myself some money and will shoot more instead.

 

[ldykeman]

Just wanted to comment on my own experience and to reinforce what others have said. In my younger days, when I first got into muzzleloading with my .50 cal Renegade 1 in 48" twist stock barrel, I assumed you had to work up the most powerful load you could, based on the table supplied in the T/C book that came with my rifle. At that time, in NYS, the law required the use of a patched round ball for muzzleloading season. And, Faster is better, right? I found that as I approached the max loads listed, my accuracy suffered. I was not content with the muzzle velocity of my most accurate loads (around 70 - 80 grs. of FFg). So I gave in and bought a T/C 1 in 66" barrel, and things really started cooking with that one at 100 grs. of FFg. For some reason, accuracy was better with the higher charges, and all was happiness. After more years than I care to admit to, I found that these really heavy charges are not necessary for whitetail deer hunting. Those 70 - 80 gr. loads in my original barrel passed completely through deer just as well as my max loads with the long barrel, and without the cheekbone bruising kick. So, it turns out that I really did not need to buy that 1 in 66" barrel after all. But I will say, I like the longer sighting plane as well as the looks of the longer barrel.
Larry

 

[nkbj]

You know, I've been working around a GM .58 1:70" twist perc barrel for the better part of a year now, threatening to break it in. This thread makes me wonder just how much powder that thing is gonna be happy with. Perhaps more than am I!

 

[BrownBear]

The two I know are equally happy with 80 grains of 3f or 90-100 grains of 2f. You can certainly go higher, but for deer anyway, I'm not inclined.

A load of 50-60 grains of 3f is a mild and accurate plinking load in both.

Recoil with 100 grains of 2f is a lot like my 54 cals. That 80 grain 3f load is mild, not unlike my 50 cal hunting load.

Once you start shooting it, you'll be surprised by the moderate recoil. I'm sure you can "find" all the recoil you want as you pass beyond 100 grains, but that's not me.

 

[nkbj]

Hey BrownBear.
Sounds like more fun than dusting the exterior.

 

[BrownBear]

Now you got it! :thumbsup:

 

[rmonday2]

I only wish I had the good fortion with my Thompson that others have had. My Hawken likes nothing above 50gr 3f with PRB and i have fed it everything emaginable. It will however shoot a maxi balls with exellent results at 50 yards .8" group but thats it!
I was told that its not the ROT as much as depth of riffeling that Thompson lacked.
Dont get me wrong I Love my rifle and i think Thompson has some of the best looking wood and craftsmanship for a factory built rifle but my relults are limited. I have taken several deer over the years with no probems but when i visit Friendship to shoot silouet they require a little more UMP out past 100yrd's.