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Login Name Post: 1:48 Twist        (Topic#260842)
PreserveFreedom 
40 Cal.
Posts: 206
PreserveFreedom
09-02-11 09:13 PM - Post#1039614    


I did a little looking around and found that my .50 Cal T/C Hawken, .50 Cal Traditions Frontier, and both of the .50 Cal project barrels that I bought all have a 1:48 twist rate. I have also been told that this is a great twist rate for either BRP or conicals. Do you agree or disagree with this?

 
GoodCheer 
Cannon
Posts: 6082
GoodCheer
09-02-11 09:25 PM - Post#1039616    

    In response to PreserveFreedom

Indeedy it is a fine twist for a fifty. Works great with patched ball and lots of conical designs.

 
Roundball 
Cannon
Posts: 22964
Roundball
09-02-11 09:37 PM - Post#1039620    

    In response to PreserveFreedom

  • PreserveFreedom Said:

Do you agree or disagree with this?



Completely agree...owned and shot T/C .45/.50/.54cals in 1:48" twist for years...excellent accuracy with PRBs.
Roundball's ML Formula:
"Whompability...Across The Fields and In The Woods"


 
BrownBear 
Cannon
Posts: 14010
BrownBear
09-02-11 10:14 PM - Post#1039635    

    In response to Roundball

The biggest problem I can see with many 1:48's is the comparatively shallow rifling. It forces me to use a little tighter patch than I really like for hunting, in order to bring out the accuracy potential. With deeper rifling they just seem to shoot a little better with my loads, even at the same twist rate. Both 1:48 and slower twists deliver stellar accuracy at big game speeds with the right ball/patch combo.

I've never seen this written up, but I've found something that actually leads me to prefer the 1:48 to slower twists. In my hands anyway, they're more accurate than slow twist barrels with really light loads- the kind I shoot so much for messing around and for mushing bunny heads. My slowest twist barrels just seem to take more powder to deliver small game accuracy. My standard loads for snowshoe hare are in the 20-25 grain range (3f) with 1:48, but with 1:60 and slower I usually have to get up in the 60 grain range.

Maybe my problem and no one else's, but I'm sticking to it with my guns.
"Lay in the weeds and wait, and when you get your chance to say something, say something good."
Merle Haggard


 
Stumpkiller 
Moderator
Posts: 17426
Stumpkiller
09-02-11 10:21 PM - Post#1039636    

    In response to BrownBear

I follow what Brown Bear said.

I like my 1:66" that loads easy, has deep radius grooves that go 5 to 10 shots between spit wipes and shoot well with moderate loads. Though, I must say my T/C rifles do as well accuracy wise with round balls in the conservative loads I use - 85 to 90 gr FFg in .50 and .54 cals.

Years back I used lead conicals in the regular season in cap rifles and there were a few I tried that I never got to shoot well in the 1:48" twist; so I'd say it's a compromise twist that does pretty good but isn't ideal for either round ball or conical - at least in the .50 to .54 calibers.
"Don't take life too serious - it ain't nohow permanent."


 
paulvallandigham 
Passed On
Posts: 17538
paulvallandigham
09-02-11 11:36 PM - Post#1039650    

    In response to PreserveFreedom

The 1:48 ROT works fine with the R.E.A.L. slugs, and other short, lighter weight slugs. It is not fast enough to stabilize longer heavier bullets.

Some shooters never try the right combination of slugs, powder, and make of barrel and therefore never get it right. In the deep grooved barrels with this ROT, you probably need to use a base wad( OP Wad) to seal the gases behind these conicals. Otherwise, gas shoots up those deep grooves, cuts and melts the sides and base of the bullets, and destroys any potential accuracy.

Any wad you choose NEEDS TO BE at least GROOVE Diameter, not the smaller land diameter of the bore. The pre-lubed felt wool "button" wads sold by lots of suppliers can be purchased in the next caliber size( ie. .54 cal. for use in your .50 cal. rifle), and pushed down on the powder to provide the required Groove diameter seal that is needed.

Those who shoot these with conicals all report a great improvement in the groups size a rifle is able to produce.

 
Trench 
62 Cal.
Posts: 2989
Trench
09-03-11 06:22 AM - Post#1039679    

    In response to PreserveFreedom

Agreed here as well. Although, my .50 didn't like anything over 70gr of 2F, it grouped 2in at 70 yards.

 
Rifleman1776 
Cannon
Posts: 14194
Rifleman1776
09-03-11 07:27 AM - Post#1039695    

    In response to PreserveFreedom

  • PreserveFreedom Said:
I did a little looking around and found that my .50 Cal T/C Hawken, .50 Cal Traditions Frontier, and both of the .50 Cal project barrels that I bought all have a 1:48 twist rate. I have also been told that this is a great twist rate for either BRP or conicals. Do you agree or disagree with this?



I wouldn't call the 1:48 twist "great". It works. But in cals of .50 and larger working up a patched round ball load for accuracy is tricky. You will be limited to lighter loads. If you want to use conicals it is pretty much needed. Call it a comprimise twist. FWIW, in my Jaeger .54 I have a 1:72.

 
ohio ramrod 
75 Cal.
Posts: 5779
09-03-11 08:03 AM - Post#1039703    

    In response to BrownBear

It is just simple mathmatics. The round ball gets its stability in flight by rpm. The faster twists give you more rpm for velocity. If you want maximum energy which increases as the velocity squared, the slower twists requires you to get more velocity to obtain the desired rpm.

 
Roundball 
Cannon
Posts: 22964
Roundball
09-03-11 08:11 AM - Post#1039705    

    In response to Roundball

GENERAL OBSERVATION AND COMMENT:

That 1:48" barrels using near-max/max published powder charge are inaccurate is an unfounded old wives tale.
It keeps getting repeated year after year on forums like this, and 99% of the readers just blindly accept it and then worse...they start repeating it themselves with zero hands on experience running detailed range tests to back it up.
There are too many posters...and one or two in particular...who do that constantly...simply plagiarizing what they've seen in other members posts and reposting it as if it’s their idea and a well established fact, when in reality they don't have a clue.

Here are some facts on this particular subject, which depending on the age of he MLF archive files, might be searched for as I posted these test results here on the MLF several years ago.
Side by side test results with:
3 TC 28" x 1:48" Flint barrels in .45/.50/.54cal
3 TC 32" x 1:66" Flint barrels in .45/.50/.54cal
I used the following loads in all of them:
90grns Goex 3F
Oxyoke OP wad
TC .018" precut/prelubed pillow ticking
Hornady .440" / .490" / .530" respectively

Shot the pair of .45s one Sunday, the pair of .50s the next Sunday, the pair of .54's the next Sunday...so all other conditions would be equal on each caliber's given day.
I even swapped each pair of barrels in/out of the same stock at the range to keep the locks, stocks, and triggers as a constant.

I used Stumpkiller's suggestion for precise long range shooting of placing an inverted sheet of gaudy bright colored notebook paper cut in the shape of a large triangle, with the bottom point in the center of the bull...a very effective high visibility aim point allowing the tiny bottom point to be set right on the front bead.

All test groups were shot at 100yds benched, and fell into a range of 1+7/8" to 2+3/4", regardless of twist or caliber.

If people get worse results than that in T/C 1:48" x .006" groove barrels, they need to look elsewhere for the cause because it definitely isn't caused by high power loads in that barrel twist and groove depth.
Roundball's ML Formula:
"Whompability...Across The Fields and In The Woods"


 
flehto 
Cannon
Posts: 7751
09-03-11 09:53 AM - Post#1039746    

    In response to PreserveFreedom

In my TC Hawken .50 I've settled on 2 loads...one a 410 gr Buffalo Bullet ahead of 100 grs. 2f and a PRB ahead of 90 grs 3f and a .018 patch. Both loads have accuracy sufficient for deer and elk. The Buffalo Bullet load is used now because the rifle is only used to hunt elk.....Fred

 
bull3540 
54 Cal.
Posts: 1958
bull3540
09-03-11 10:25 PM - Post#1039973    

    In response to PreserveFreedom

  • PreserveFreedom Said:
I did a little looking around and found that my .50 Cal T/C Hawken, .50 Cal Traditions Frontier, and both of the .50 Cal project barrels that I bought all have a 1:48 twist rate. I have also been told that this is a great twist rate for either BRP or conicals. Do you agree or disagree with this?


Yes, I agree with this. However my 54 caliber, 1:48 ROT rifle shoots RB somewhat better than conicals and certainly with less recoil. 85 grains of 2f pushing a PRB is plenty accurate for my needs, but I know that the Hornady Great Plains bullet is capable of getting about a 2 inch larger group.


 
Rifleman1776 
Cannon
Posts: 14194
Rifleman1776
09-04-11 08:15 AM - Post#1040039    

    In response to Roundball

  • Quote:
That 1:48" barrels using near-max/max published powder charge are inaccurate is an unfounded old wives tale.




Roundball, I have to disagree with you. From experience and shared experience of some of the finest 'X' hunters in the country. A 1:48 twist in larger calibers (.45 and up) is generally very finicky in what it will shoot accurately with. Ask any serious Buffalo match or bench rest shooter what the twist is in their rifles. Invariably they will be 1:66; 1:72 or even 1:144. That allows them to load heavily for stability and wind bucking velocities.
My own experience has been a 1:66 is the best, most versitile, most accurate twist for almost all kinds of shooting, including heavier hunting loads.
OTOH, confession time in some museums where good specs. are posted with each rifle, the 1:48 twist is the overwhelmingly most common ROT found on sporting rifles of all types. Somebody musta liked it.

 
MSW 
Cannon
Posts: 6921
MSW
09-04-11 08:29 AM - Post#1040044    

    In response to Rifleman1776

Rifleman, thanks for the post- i was unaware of the prevalence of 1:48 twist in antique barrels. As a practical matter, I get acceptable accuracy out of my T/C .50 cal flint. The .45 Green Mountain i used to build my wife's flinter has deeper grooves, and it shoots a little better, but then again, she shoots a little better than I do.

Just my two cents worth.

 
Roundball 
Cannon
Posts: 22964
Roundball
09-04-11 08:41 AM - Post#1040050    

    In response to Rifleman1776

  • Rifleman1776 Said:
  • Quote:
That 1:48" barrels using near-max/max published powder charge are inaccurate is an unfounded old wives tale.




Roundball, I have to disagree with you.





You can disagree all you want...doesn't change the facts...they are not inaccurate.
Roundball's ML Formula:
"Whompability...Across The Fields and In The Woods"


 
paulvallandigham 
Passed On
Posts: 17538
paulvallandigham
09-04-11 09:21 AM - Post#1040067    

    In response to Rifleman1776

I think the two of you are talking circles around each other, referring to different definitions of the word "Accurate".

Remember that in old days, powder was even more difficult to obtain than it is now. People "husbanded" powder, by using lighter charges in their guns, and relying on their tracking skills to find game they had shot but did not drop dead within sight of the shooter. The fact that a particular ROT shows up more in guns surviving in museums may only reflect that reality, and not that this was the "Best" ROT.

There are "games" we play where different kinds of barrels are used. For instance, it was After the Civil War, and well into the cartridge era, that long bullets, and various ROT barrels, and groove depths were tried out for long range shooting contests. Some of this work had been done before the war, as evidenced by some of the Sniper rifles used by both sides during that sad affair. But, most people had never seen such rifles before the war ended. As better rifling machines were made, and sold at prices people could afford, better barrels were made, and sold to the public.

With a Round Ball, and any ROT, a gun can shoot accurately PROVIDED that the patch is thick enough to seal the bore, and hold onto the ball to impart the fast ROT spin.

With conicals, You can go a bit slower than 1:48 and still stabilize some longer bullets. But, either paper patched bullets in shallow grooves must be used, nor a good base wad to seal the gases behind the bullet needs to be used so that you can get the velocity needed to stabilize these longer bullets in flight.

Round balls in slow twist barrels may require more powder-- MAY--- not "must have". It all depends on barrel harmonics.

The traditional teaching about slow ROT barrels is that they are more "forgiving" of changes in the amount of powder used, and will still shoot their balls to the same POI. That is NOT THE SAME THING as NEEDING more powder to achieve the same degree of tight groups( One definition of accuracy), as you may get from a barrel with a slightly faster( ie. 1:48") ROT.

Run The Greenhill formula( which is intended for Conicals, but will still give you a good idea of what works well for round balls) and you find that 1:48 ROT is terrific for .32, .36, .40 and .45 caliber guns. When you get to .50 and .54, that 1:66 begins to be less " finicky" with powder charges. Go on up to .58, .66, .69, and .72 calibers, and you find an even slower ROT will probably be more forgiving on variations of powder charges. ( ie. 1:70, 1:72, etc.)

IN those same museums, you will find guns with a ROT being 1:100" or slower! You have to question the quality control on the powders and the other components used in those guns.

I believe, from my own testing, that Roundball is right about the 1:48 ROT. It shoots ROUND BALLS as accurately as any slower ROT will, Provided, the right charge is found. But, that is true of all barrels. Barrel harmonics control that degree of accuracy. You do seem to have to be fairly exact in measuring that powder charge, to get small groups, compared to shooting RBs out of slower ROT barrels.

When it comes to shooting conicals, you are talking different considerations, shallower grooves, and the Greenhill formula dictates the use of even faster Rates of Twist in the rifling as the length of the bullet increases, to stabilize the bullets in air.

If you like FAST ROTs, the current US military battle rifle now comes rifled with a 1:7" ROT. Its also spitting long, 70+ grain bullets out at over 3000 fps. MV.

50 years ago, when that gun was first introduced, it had a 1:10" ROT, shooting a shorter, 55 grain bullet at over 3300 fps. MV.



Edited by paulvallandigham on 09-04-11 09:33 AM. Reason for edit: No reason given.

 
Dan Phariss 
70 Cal.
Posts: 4622
Dan Phariss
09-04-11 10:43 AM - Post#1040081    

    In response to Roundball

All known original Hawken rifles are 48 twist.
One of the most accurate rifles I ever owned had a 48 twist Douglas 50 caliber barrel, yes, Douglas made 48 twist both for their own "Hawken" barrels and the seven groove barrels they made for Golden Age Arms. This barrel shot 90 grains of FFF Goex wonderfully, 495 ball ticking patch.
The Myth of the 48 twist being inaccurate with the PRB came from the TC Hawken being used by people who either failed to use the proper ball/patch fit OR the grooves were far too shallow the barrels being made for the MAxi-Ball. Probably to force people to buy TCs ammo or one of their moulds. This was not an issue until the TC "Hawken" "graced" the ML world.
Unless the caliber exceeds 54 or 58 I would PREFER a 48 twist.
The PRB will shoot well with grooves as shallow as .008. But less than this may cause trouble unless the fit is very tight.

Dan

 
ericb 
45 Cal.
Posts: 639
ericb
09-04-11 01:24 PM - Post#1040124    

    In response to Dan Phariss

FWIW - John Getz told me that years ago they had made some Barrels for Hershel House, who used them in traditional Rifles he used for doing 300yd demos. Target was a half silhoutte (from the chest up), which he would hit every shot. Barrels were 1:48 twist, and large caliber; .62 if I recall correctly. I don't remember the load, but I remember recalling it sounded pretty darn stiff. He also said (as has already been mentioned here) that many of the original barrels he has seen were 1:48.

My Harper's Ferry has a Getz tube; 1:66 - .54 cal. It does seem extremely forgiving, almost boring in fact, regarding the loads I use. It's a shooter, with very little difference in group size whether I use 70, 80, 90, or 100 grs. The trajectory is of course a different matter.

The subject is fascinating, and good campfire conversation. I come away thinking, as I usually do, that there's more than one way to skin a Cat.

FWIW -

Eric

 
Roundball 
Cannon
Posts: 22964
Roundball
09-04-11 02:58 PM - Post#1040151    

    In response to ericb

Actually, articles I've read, corroborated by DaveK and a couple others, show that the myth started back in the 60s when some very shallow 3 land / 3 groove 1:48" military imports began finding their way into the US, designed for a form of minnie ball with a skirt to flare, etc.
Then as people began experimenting with PRBs, the word started spreading that heavy powder charges caused the PRBs to "skip the rifling".

T/C brought out its 1:48" x .006" standard barrel in the next decade of the 70's and people immediately...and incorrectly...spread the word that T/C 1:48" standard barrels would "skip the rifling" with heavy powder charges...better just use conicals and get GM barrels for PRBs.

What further falsely supported the myth was when people would buy / try "deep groove" GM drop-in barrels...which also happened to have a slightly slower twist...(hardly any difference between 48" and 66", think about it)...they would get good accuracy of course...BUT...a number of things contributed to that:

Instead of going back up and trying 110-120grn powder charges, most people continued to use the same mild powder charges they used just fine in T/C's standard barrels to begin with...just as most people even today continue to use mild powder charges regardless of the barrel.
In addition, GM's barrels had much deeper grooves so the continued use of moderate size patching which allowed people to thumb start...and caused engagement problems in T/Cs shallow grooves...still produced good accuracy in the deep groove GM barrels. Instead of recognizing that, they simply accepted that 1:48" barrels are inaccurate with PRBs...ie: most people don't think independently, they just follow.

All that helped perpetuate the myth that 1:48" twists were inaccurate with PRBs...helped perpetuate the myth that T/C's 1:48" x .006" barrels were inaccurate with PRBs, etc...when in reality as Dan correctly pointed out, people in general simply were not using the correct PRB combo that was required to get good accuracy out of T/Cs standard 1:48" / shallow groove combination.

To repeat, anyone who can't get 2.xx" accuracy at 100yds out of a T/C 1:48" x .006" barrel needs to look elsewhere for the cause...not at the barrel.
Roundball's ML Formula:
"Whompability...Across The Fields and In The Woods"


 
necchi 
Cannon
Posts: 12202
necchi
09-04-11 03:16 PM - Post#1040163    

    In response to Roundball

  • roundball Said:
To repeat, anyone who can't get 2.xx" accuracy at 100yds out of a T/C 1:48" x .006" barrel needs to look elsewhere for the cause...not at the barrel.



2.xx" accuracy at 100??.
That's pushin the envelope really tight and you know it.

I am a proponant of all the 1-48 twist out there currently being able of some supurb accuracy with the PRB.
But I can't sit back and watch the accuracy curve grow smaller and smaller every year and every time it's disscussed.
Bill, you really need to shoot with other people.

Whaompability or what ever it is for deer size game is worlds away from some glorious 2" group from every gun,,
JohnT
Molon Labe~


 
Dan Phariss 
70 Cal.
Posts: 4622
Dan Phariss
09-04-11 08:15 PM - Post#1040260    

    In response to necchi

  • necchi Said:
  • roundball Said:
To repeat, anyone who can't get 2.xx" accuracy at 100yds out of a T/C 1:48" x .006" barrel needs to look elsewhere for the cause...not at the barrel.



2.xx" accuracy at 100??.
That's pushin the envelope really tight and you know it.

I am a proponant of all the 1-48 twist out there currently being able of some supurb accuracy with the PRB.
But I can't sit back and watch the accuracy curve grow smaller and smaller every year and every time it's disscussed.
Bill, you really need to shoot with other people.

Whaompability or what ever it is for deer size game is worlds away from some glorious 2" group from every gun,,




A good barrel in good conditions should shoot under 2" at 100.

Dan




 
necchi 
Cannon
Posts: 12202
necchi
09-04-11 08:42 PM - Post#1040271    

    In response to Dan Phariss

With peep sights, a bench, and the eyes of a 20yr old thats had 10yrs training.
My point is to keep it real for new ml prb shooters that pick up a TC hawkin or other with open sights.
Just randomly tossing out that these guns should shoot 2" groups or your a failure is not a point that'll keep folks in the game.
4-5" is very good with 6" average and a well trained good shooter getting 3".
2" with TC or you got a problem,,fooey!

I know full well what these are capable of, I've placed in plenty of matches across the state with Renegades and even Jukars.
It just galls me when people streatch the truth to blindly prove a point.
All Hail T/C,,
JohnT
Molon Labe~


 
Dan Phariss 
70 Cal.
Posts: 4622
Dan Phariss
09-04-11 09:26 PM - Post#1040291    

    In response to Roundball

  • roundball Said:
Actually, articles I've read, corroborated by DaveK and a couple others, show that the myth started back in the 60s when some very shallow 3 land / 3 groove 1:48" military imports began finding their way into the US, designed for a form of minnie ball with a skirt to flare, etc.
Then as people began experimenting with PRBs, the word started spreading that heavy powder charges caused the PRBs to "skip the rifling".

T/C brought out its 1:48" x .006" standard barrel in the next decade of the 70's and people immediately...and incorrectly...spread the word that T/C 1:48" standard barrels would "skip the rifling" with heavy powder charges...better just use conicals and get GM barrels for PRBs.

What further falsely supported the myth was when people would buy / try "deep groove" GM drop-in barrels...which also happened to have a slightly slower twist...(hardly any difference between 48" and 66", think about it)...they would get good accuracy of course...BUT...a number of things contributed to that:

Instead of going back up and trying 110-120grn powder charges, most people continued to use the same mild powder charges they used just fine in T/C's standard barrels to begin with...just as most people even today continue to use mild powder charges regardless of the barrel.
In addition, GM's barrels had much deeper grooves so the continued use of moderate size patching which allowed people to thumb start...and caused engagement problems in T/Cs shallow grooves...still produced good accuracy in the deep groove GM barrels. Instead of recognizing that, they simply accepted that 1:48" barrels are inaccurate with PRBs...ie: most people don't think independently, they just follow.

All that helped perpetuate the myth that 1:48" twists were inaccurate with PRBs...helped perpetuate the myth that T/C's 1:48" x .006" barrels were inaccurate with PRBs, etc...when in reality as Dan correctly pointed out, people in general simply were not using the correct PRB combo that was required to get good accuracy out of T/Cs standard 1:48" / shallow groove combination.

To repeat, anyone who can't get 2.xx" accuracy at 100yds out of a T/C 1:48" x .006" barrel needs to look elsewhere for the cause...not at the barrel.



Val Forgett imported a bunch of rifles such as the 1803 Harpers Ferry copies that had 58 caliber barrels with 3 groove minie ball rifling. I can't recall the twist right now. In any case Val Forgett was enamored with the Minie ball and made a hunting style rifle for it and even a pistol. The old ads I found don't list a twist.

The 48 twist shallow groove TCs had some problems as well. But nobody I associated with at the time owned one so all I know is what I heard and read. Its possible that some barrels slipped out that were a little too shallow since not everyone had problems.
In some cases even a deep groove barrel like a Douglas will blow patches but there are variables. I had a batch of heavy ticking a few years back that produced a rash of blown patches. Some even on fire. But I have never had that problem before or since. So maybe the cotton was rotten
When using the dried water soluble oil patch lube my 70 twist 50 will blow patches unless I put a patch over the powder ?? Never blows a patch with a lubricated patch, tallow or animal oil.
Dan

 
paulvallandigham 
Passed On
Posts: 17538
paulvallandigham
09-05-11 12:26 AM - Post#1040361    

    In response to necchi

I agree. The big Bead front sights on many of these "hawken" style "Mountain rifles" covers either 6" or 8" at 100 yards. You are not going to tell me the average shooter is going to shoot 5 or 10-shot groups at 100 yds., even off a bench rest, into a 2" group, using those factory iron sights.

I will concede that the Barrel MAY BE capable of that kind of accuracy, FROM A MACHINE REST, or in the hands of an experience Target shooting a scope sight. He might be able to do it using a tang Peep Sight, and a Globe Front sight.

 
Roundball 
Cannon
Posts: 22964
Roundball
09-05-11 06:17 AM - Post#1040384    

    In response to Dan Phariss

  • Dan Phariss Said:

Val Forgett imported a bunch of rifles such as the 1803 Harpers Ferry copies that had 58 caliber barrels with 3 groove minie ball rifling.



That's it exactly...
Roundball's ML Formula:
"Whompability...Across The Fields and In The Woods"


 
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