American Long Rifles Welcome, Guest. Please login or register.
July 22, 2014, 09:23:06 AM
Home Help Login Register
News:

View the Most Recent Posts
View the ALR Mission Statement
View ALR Rules and Policies
Donate to ALR via US Mail or PayPal

+  AmericanLongRifles Forums
|-+  General discussion
| |-+  Gun Building
| | |-+  Forsyth rifling and Rice Barrel Co
« previous next »
Pages: [1] 2 Go Down Print
Author Topic: Forsyth rifling and Rice Barrel Co  (Read 3556 times)
Kermit
Hero Member
*****
Posts: 2127


« on: September 25, 2011, 10:57:41 AM »

Renner's underhammer blog ( http://underhammers.blogspot.com/ ) has a discussion worth reading re Forsyth rifling. He says Rice is going to do a run of .62cal barrels so rifled. Get on the list early if you want one, I 'spect. I can see one of these on an English sporting rifle or maybe even a jaeger. Not for me, but makes hunting sense.
Logged

"Anything worth doing is worth doing slowly." Mae West
Daryl
Guest
« Reply #1 on: September 25, 2011, 11:42:17 AM »

That will be great.

I spoke with the boys from Rice a couple years ago at Dixon's about making some barrels with Forsyth-style rifling - extra slow, shallow and wide grooves.  In a .62, that would be about 80" to 85" and about .007" deep.  In calibres this small, it's all guess work.
Logged
smylee grouch
Hero Member
*****
Posts: 1812


« Reply #2 on: September 25, 2011, 11:57:34 AM »

This sounds like a great express rifle barrel, smaller bore needing larger charges to shoot fast lightweight bullets, in the round ball world anyway.   Smylee
Logged
Daryl
Guest
« Reply #3 on: September 25, 2011, 01:17:47 PM »

The whole idea, is that a larger diameter, almost bore size ball can be loaded with a thinner patch, say .015"patch for example, yet fill the grooves & give good accuracy yet load easily and allow heavier loads for flatter trajectories over hunting ranges and not build fouling shot to shot. That's a tall bill.

This type of rifling might have a definite use in areas that have to use non-lead balls.  Due to being non-compressible, these balls literally cry out for shallow rifling so that the patch can provide the fit and spin to the ball, where the ball's circumference in not 'disturbed' by the lands.  The rifling will have to be slow, to allow the shallow grooves and high velocity with good accuracy.  The shallow grooves also allow the thinner patch for easier loading.

The idea, of course, was developed/designed by Lt. James Forsyth in the mid 1800's. Today, we and our modern barrel makers are still re-learning what was proven to be 'best' way back then.  Forsyth-style rifling was designed for large bore hunting rifles, to produce the highest speeds for flattest trajectories with them, when at that time, the normal gun maker's push was for faster and faster twists which they thought made guns shoot harder - black magic/voodoo or whatever - it's BS.

 Thankfully, a 'forward thinking' person, namely Forsyth though out and  brought forth the truth in the matter and actually published it so we could re-learn as well.  How it will work in small bores, I'm not positive, but it shows promise under some circumstances.

The reason for this type of rifling is quite  simple.  In Forsyth's day, barrel makers were running twists in large bore rifles, 16 through 10 as fast as 2 or 3feet. These fast twists would not allow heavy charges needed to kill dangerous game without the ball and patch stipping. Accuracy suffered and of course, the trajectories with the light loads make hitting problamatice and the wounding of game, the norm.

The slow, shallow rifling of Forsyth's design allowed easy loading, heavy charges and the accuracy actually improved the more powder was used. A man's capability to handle recoil was the only block to the amount of powder used  -  large bores - remember that.

Today, in our .50's, .54's, .58's and .62's, with their 60" to 80" twists, we can use the heaviest powder charges they can use that allow flat shooting loads and top velocities with great accuracy. They too, give better accuracy with the higher speeds we give the ball.  Forsyth rifling may or may not help in these guns - but.

 That style of rifling will allow looser fitting loads to be used - that's a plus for those with small wrist diameters, but it won't allow more powder than can already be used. Today's normal twists are almost slow enough to be Forsyth-style and allow about all the powder than can be utilized.

The difference is some gun makers today still think deeper is better, when that's the wrong direction to go from a hunting rifle standpoint. Yeah - rounded deep rifling easily until they foul out for most people, then they have to wipe  - to the point they think everyone must do the same.  A tight combination like Taylor uses in his .016" rounded rifling Rice barrels, doesn't foul, doesn't build up fouling and it is as easy or easier to load the 50th than the first. THAT's a nugget - pure gold, but it's a tighter combination than some people can load, it seems.  With deep grooves, more of the ball's mass must be moved by the lands if accuracy is a requisit.

Hopefully, the same caliber with Fosyth-style rifling will allow the same or similar accuracy, same clean shooting chacteristics but with loading that can be accomplished by someone who has difficulty with current barrels.

For them, or someone who has to use ITX-type balls, this form of rifling might be a hobby saver.
 
Logged
Kermit
Hero Member
*****
Posts: 2127


« Reply #4 on: September 25, 2011, 03:01:03 PM »

Forsyth recommended one turn in 100 to 144 inches, and maintained that heavy balls didn't need faster twists to stabilize. Renner says his experience is that Forsyth rifling looses when the ball is smaller than .58. And it's fun to read Renner's inclusion of the Taylor Knock-out Values comparing a .600 ball with a muzzle velocity of 1700fps with modern cartridges. The thing to remember about the chart he shows is that the .600 ball's energy at range is compared to energy at muzzle for the cartridges! For example, the .600's energy at 150yds is equal to the 180grain .340 Weatherby at the muzzle.
Logged

"Anything worth doing is worth doing slowly." Mae West
Daryl
Guest
« Reply #5 on: September 25, 2011, 03:24:37 PM »

Unless it is mandated by lead-less balls. Then, this style of rifling might be a savior for those such afflicted.  Energy, smenergy - #'s mean nothing and formulae can be contrived to present whatever result is desired - which has nothing to do with the rifling.

Ken Prather had a barrel made up in Forsyth's style, but I haven't heard how it shoots with the ITX balls.
Logged
Kermit
Hero Member
*****
Posts: 2127


« Reply #6 on: September 25, 2011, 03:40:42 PM »

...just as easily as numbers can be denied if you don't like them. It's like religion or politics. Just sayin'. I don't have a dog in this fight, I just think it's fun to watch from a neutral corner.
Logged

"Anything worth doing is worth doing slowly." Mae West
Ken Prather
Hero Member
*****
Posts: 895



WWW
« Reply #7 on: September 25, 2011, 11:43:06 PM »

Yep-- I had a forsyth inspired 50 cal 38" 1:80" .008" deep rifled barrel made for me by Jason at Rice. It is in an Isaac Haines Chambers gun. Daryl helped me choose this barrel.

I have hunted squirrels with it with both lead (.490 and with .487 ITX non-toxic roundball. .018 cloth patch for lead, and a denim or chamois patch with the ITX (using a range of 80-95 FFF). So far I am three for three on tree rats. I have to say that I am confident hunting with this gun.

I have done only preliminary target work with it, and I am admittedly not a great shot with a rifle... I have had moderate success with paper and gongs and small iron targets out to 100 yards. My usual flinch makes it shoot a little high and to the right--but it shoots that way consistently--which says alot.

Not any kind of solid proof, or perfect test---so far, the only conclusion I can say is--- it certainly has not hurt the accuracy of a flintlock gun to have this type of rifling.

Ken Prather

Logged

Galations 2:20
Daryl
Guest
« Reply #8 on: September 26, 2011, 10:01:47 AM »

TKs Ken. How's loading with a decent patch?
Logged
Ken Prather
Hero Member
*****
Posts: 895



WWW
« Reply #9 on: September 26, 2011, 11:24:47 AM »

I have had no trouble loading it. I DO use a shortstarter, as the muzzle has a standard crown--not coned.

I think I could go with a .495 lead ball and the .018 patch. The .487 ITX ball loads fine too, but I use a thicker patch--denim or chamois.

I have not shot her since May--my son went off to college this year and I my hobby fund and hobby time is in serious depletion. With Fall-- I always get the bug to get out and burn powder so I will probably be out there soon.

K
Logged

Galations 2:20
AmBraCol
Guest
« Reply #10 on: September 26, 2011, 11:54:19 AM »

I keep reading that the Forsythe rifling is not effective on smaller bores.  What I don't understand is WHY.  Why does the concept only work on larger bores?  I've read also that even in the heavier bores one must use heavier charges to see the best accuracy results.  Does this mean that the loads used in the smaller bores with this type of rifling have been too light, folks simply haven't used enough powder to reach the velocity at which they will give the best accuracy?  I like the concept, especially with the idea of being able to use shot in the same barrel and not have it scatter to kingdomcome.
Logged
Ken Prather
Hero Member
*****
Posts: 895



WWW
« Reply #11 on: September 26, 2011, 12:25:13 PM »

"I keep reading that the Forsythe rifling is not effective on smaller bores."

I dunno, but it seems to be working ok in my .50 cal. 1:80" would still not work so well for shot I am thinking.

K
Logged

Galations 2:20
Daryl
Guest
« Reply #12 on: September 27, 2011, 11:19:42 AM »

I've not read about Forsyth-style rifling not working in small bores - could be just as I guessed at above - rifling twists are already 80" as in GM and 66" in others. These twist rates allow heavy charges already.

The only advantage I see with very slow, shallow rifling, is it will allow a hard ball to be more easily used.

The disadvantage might be the requirement to use heavy charges all the time.

Forsyth was concerned with very LARGE and dangeous game (large 10 rings) hunting accuracy - not with cutting X rings inside an already small 10 ring.  To make a very slow twist barrel give great accuracy, you're going to have to feed it a lot of powder. Not very many people like shooting over 60gr. of powder these days - for them, faster twists should be used.
Logged
Ken Prather
Hero Member
*****
Posts: 895



WWW
« Reply #13 on: September 27, 2011, 12:03:01 PM »

I think this Isaac Haines stock is pretty straight and has a pretty good geometry for heavier recoil, as my rifle is a pleasure to shoot at 85-95 gr of FFF. But any heavier and it might get to be bothersome when target shooting for any length of time.

Daryl, what would be the max load for this barrel that I might not wish to go above? I have shot 110 gr of FFF out of it a half a dozen times, but nothing over that, because I kinda felt that the accuracy was starting to open up after 95gr. But I did not notice huge dramatic differences in accuracy once I got up to 80 grains...

Again, my skill level is not high, so some variations I have to attribute to me... I might try to start high and go down to lower charges next time I shoot, to try and eliminate some of the fatigue factor....

Ken
Logged

Galations 2:20
Daryl
Guest
« Reply #14 on: September 27, 2011, 12:44:41 PM »

What you put in it for a mximum is your choice. I can only suggest you stay with Rice's guidlines.
 Personally, I'd be switching to 2F as it produces less stress to the patch (and gun), which might be your downfall in accurcy with heavier loads - it is with many people who do not use the tighter combinations we enjoy here.  3F acts more violently with the ball and patch combination, peaking pressure much faster and at a higher level whereas the slower burning 2F is not so abrupt in it's burning characteristics nor does it peak as high for a given speed.  This slower peaking I think, is why it is easier on the patch. Certainly, the info below shows or suggests that the slower peaking is what saves the patch, rather than peak pressure being the culprit.

This difference in powder granulations was shown to me quite dramatically in my .69 cal. rifle, which with a certain denim patch, would not allow more than 90gr. 3f  producing 1,285fps to be used without burning the patches and hurting accuracy. 100gr. burnt the patches - holes as well as shreds, that day of testing, normal spring weather - maybe 60F.  The same patch would allow over 200gr. 2F for 1,700fps without burning the patches, delivered good accuracy and the patches were re-usable, but slightly brown scorched, but not burnt. Obviously, 1,700fps needed more pressure to produce than 1,285fps, yet the patches weren't burnt. I alluded to a possible reason for this, in the preceeding paragraph.

The only .50 I had that would not improve accuracy with more than 110gr.@f was a TC - .004" rilfing and 28" of bl. In it's 48" twist, 110gr. 2F was "it's" load.  Other .50's I've used, mostly Bauska barrels, liked 120gr. 2F with a patched round ball. Great accuracy, little recoil - certainly not noticable for a young, solidly built guy. Wide butt plates certainly help.

I would have no qualms of using up to 130gr. of 2f in that barrel. You should be able to hit 2,200fps in a .50 using 2f powder, with safe pressures.  With 3F, I don't know, but would try with 2F.

A 66" twist will allow 2,000fps with good accuracy, this much I know from my own testing. The 80" twist should allow (or demand) even higher speeds for maximum accuracy. Therein lies the possible 'problem' with the exceptionally slow twists in small bores, in that they possibly demand more powder than most people are willing to use - or  - they demand higher pressures and speeds than the looser combinations will allow.

The slow twists answered the problem originally, of rifle makers putting in too much twist for round balls, indeed, even the slug shooting paradox rifles didn't need faster than 100" of twist to shoot accurately. The slower twists worked perfectly.  In ratio, a 104" (Forsyth's 1/4 turn principal in 26" of bl) in a 14 bore, is equivelent to about a 75" twist in a .50.

From what I've seen with 2f in regards comparrison with 3F, is that switching to 2f is like using a wad between the ball and patch (in comparrison) but without the accuracy harming tendency of patches in some guns and thus allows even greater ie: higher velocity loads to be used.
Logged
Pages: [1] 2 Go Up Print 
« previous next »
Jump to:  


Login with username, password and session length

Powered by MySQL Powered by PHP Powered by SMF 1.1.19 | SMF © 2013, Simple Machines Valid XHTML 1.0! Valid CSS!