Twist rate and bullet length

[Mnt monkey]

Practice sneezing and laughing a lot with them broken ribs

 

[Ka'imiloa]

IF.......... one could get 2250fps with a 120gr VOLUME charge and a 40cal high BC bullet at 300grs.

Red is where the bullet goes subsonic.

View attachment 37669

 

[eekjellander]

I realize the 18 twist is the choice for the long distance big lead shooters ,but it's also the best option for the hunter,, all of my 18 twist barrels shoot the light bullets that those that are looking at the 20 twists want to be able to shoot, in particular the lighter 40 cal bullets in the light blue sabot,,, as for bullet size to bore anything from a 250 to a 400 plus with a jacket and the 18 of course will do lead even bigger. Having so many bullets downrange the last years the only way I would build a 20 and then forgive my sarcasm would be if I wanted to limit myself if I want all the bullet choices I can have in my rifle and better performance even in the lighter bullets it's hands down the 18,,, my position is from shooting 3 to 4 days a week, as I mentioned in another thread I have for the most part ignored the barrel twist bullet length charts and just sit down and shot myself ,, I think many see the 18 as too much twist, and you can get too much spin on lead bullets, and sabots,even with a jacketed bullet,, however to me the 18 is at that Perfect Limit it gives me bullet choices, that the 20 does not and with the bullets that I wanted to shoot in the 20 in my experience the 18 does just as good if not slightly better again I'm talking statistically with multiple rifles not just one pet rifle in 20 for one pet rifle in 18.

And just to be different my Rice barrel is a 17 twist and so is the Sharps 74 thanks to Lee Shaver/Ed

 

[Ka'imiloa]

Sure appreciate that printout, Encore. I'm remembering best I can to a whole lot of study on 1000 yd. shooting, starting maybe 30 years ago or more when I lived in Hawaii where there was no BP. Moved to the Mainland here 20 years ago and finally got to shoot BP at 8, 9,1000. Your chart sure suggest to me that that bullet and velocity should be spot on with its potential accuracy at 1000, going thru the sound barrier just beyond that - and thus that odd time of bullet unstability and wobble.
Tho I've written some of the following elsewhere on this Forum, for whatever its worth here, the rifle I had was the Pedersoli Mortimer-Whitworth, with its' 1:21 (actually 1:20.7) twist rate, made of international match shooting at 100 meters. Fine barrel slightly choked near the muzzle by Pedersoli. Best possible bullet size was .4495. Everybody in LR said it would never shoot to 1000, forgetting ( or even refusing to believe) that bullet rps at the muzzle and beyond is what largely matters for bullet stability, not nominal twist rate of the barrel.
I knew pretty well (approximating) what my MV was using 547 gr. swaged 1:20 alloy PPed bullet, and simply calculated what was needed to equal the usual MV (and thus the muzzle rps of the bullet) of the well known LR guys using 1:18 twist .45 barrels. For my rifle, that turned out to be 107 gr. by wt. of Swiss 1.5F. I only had a really good spotter once, at a BPC match, and with that load (tho I think it was grease groove bullet and thus slightly longer bullet for that match) we were literally walking the bullets in on the bull at 900 yds. Astounding accuracy, and thus I think a bit past 900 was probably where the bullet went subsonic. Accuracy seemed a bit less at 1000, but the spotters, asked to watch closely, reported that my bullets were still making perfectly round holes there. I was quite inexperienced compared to most LR shooters, and the match was cut short since all the BPCR shooters finished shooting and thus I did not get to shoot all my shots at 1000, but I still placed in the middle of the pack as though the only ML shooter.
I told the U.S. Pedersoli Rep somewhere along the line in all this that if they would make the .45 Mortimer with a 1:18 twist barrel they would sell a lot of them worldwide. Nine months later the Gibbs came out. So maybe my words were just coincidence in timing with something Pedersoli was already working on. Perhaps not!
Anyway, if you and your rifle can put up with the recoil, pushing your bullet faster can possibly accomplish remarkable things, and barrel twist rate is always just part of the very complex ballistic equation, not some fixed and critical milestone in it.
Of note: very recently I read a good piece on BC and how it is definitely a fluid number, varying via different factors such as wind, range, velocity, etc.
Aloha, Ka'imiloa

 

[ENCORE50A]

Sure appreciate that printout, Encore. I'm remembering best I can to a whole lot of study on 1000 yd. shooting, starting maybe 30 years ago or more when I lived in Hawaii where there was no BP. Moved to the Mainland here 20 years ago and finally got to shoot BP at 8, 9,1000. Your chart sure suggest to me that that bullet and velocity should be spot on with its potential accuracy at 1000, going thru the sound barrier just beyond that - and thus that odd time of bullet unstability and wobble.
Tho I've written some of the following elsewhere on this Forum, for whatever its worth here, the rifle I had was the Pedersoli Mortimer-Whitworth, with its' 1:21 (actually 1:20.7) twist rate, made of international match shooting at 100 meters. Fine barrel slightly choked near the muzzle by Pedersoli. Best possible bullet size was .4495. Everybody in LR said it would never shoot to 1000, forgetting ( or even refusing to believe) that bullet rps at the muzzle and beyond is what largely matters for bullet stability, not nominal twist rate of the barrel.
I knew pretty well (approximating) what my MV was using 547 gr. swaged 1:20 alloy PPed bullet, and simply calculated what was needed to equal the usual MV (and thus the muzzle rps of the bullet) of the well known LR guys using 1:18 twist .45 barrels. For my rifle, that turned out to be 107 gr. by wt. of Swiss 1.5F. I only had a really good spotter once, at a BPC match, and with that load (tho I think it was grease groove bullet and thus slightly longer bullet for that match) we were literally walking the bullets in on the bull at 900 yds. Astounding accuracy, and thus I think a bit past 900 was probably where the bullet went subsonic. Accuracy seemed a bit less at 1000, but the spotters, asked to watch closely, reported that my bullets were still making perfectly round holes there. I was quite inexperienced compared to most LR shooters, and the match was cut short since all the BPCR shooters finished shooting and thus I did not get to shoot all my shots at 1000, but I still placed in the middle of the pack as though the only ML shooter.
I told the U.S. Pedersoli Rep somewhere along the line in all this that if they would make the .45 Mortimer with a 1:18 twist barrel they would sell a lot of them worldwide. Nine months later the Gibbs came out. So maybe my words were just coincidence in timing with something Pedersoli was already working on. Perhaps not!
Anyway, if you and your rifle can put up with the recoil, pushing your bullet faster can possibly accomplish remarkable things, and barrel twist rate is always just part of the very complex ballistic equation, not some fixed and critical milestone in it.
Of note: very recently I read a good piece on BC and how it is definitely a fluid number, varying via different factors such as wind, range, velocity, etc.
Aloha, Ka'imiloa

We're limited on propellant charges to 120grs volume, so an increase in velocity really isn't going to happen. Now if there was no limit, or limited to the manufacturer of the rifles maximum, that might change things significantly. I could easily get the bullet over 2,400fps. Recoil on the other hand would be pretty rough.

 

[Pathfinder60]

I have had some amazing accuracy with the 275 Fury and some 18 twist barrels I might have to just break down and try some 300 grain

How do you think the .402 Fury 275 in a LBS would do out of a 1:22 twist barrel? Should i try a lighter bullet with that slower twist rate...such as a 225 or a 250? Strictly for hunting and informal target work by the way.

 

[Mnt monkey]

I think you have it right the one in 22 is not going to shoot the 275 I don't believe, I would stick with the 225s, but I would test the 240 OT and the 250 ,and by the way I've had pretty good accuracy out of the Pitman 225 40 cal in a light blue I haven't had any success with his 250 grain however in the light blue I know it does great sized to bore

 

[Mnt monkey]

I do believe in testing a gun out completely for what it can do if I had a 22 twist that showed accuracy with a 240 or a 250 I might go ahead and try the 275 I have had barrels that functioned a little bit out of what the norm was supposed to be I personally like to find every little potential in my gun barrel almost every gun I have I might start with the Baseline of what the twist should shoot once I establish an accurate load on that Baseline I'll work the edges a little bit I'll try as light as I can and I'll try as heavy a bullet as I can I'll try a light charges I'll try heavy charges.

 

[Mnt monkey]

It's crazy as it sounds I can get bored real quick with a gun that just shoots one bullet in a hole, I love variety and I love searching for another accurate load working up a load, most of my muzzleloaders with good barrels will shoot multiple bullets in multiple loads very very accurately I think a lot of guys have guns like that they never really discover their true potential understand if that's just a season extension tool for many hunters

 

[Pathfinder60]

I do believe in testing a gun out completely for what it can do if I had a 22 twist that showed accuracy with a 240 or a 250 I might go ahead and try the 275 I have had barrels that functioned a little bit out of what the norm was supposed to be I personally like to find every little potential in my gun barrel almost every gun I have I might start with the Baseline of what the twist should shoot once I establish an accurate load on that Baseline I'll work the edges a little bit I'll try as light as I can and I'll try as heavy a bullet as I can I'll try a light charges I'll try heavy charges.

I guess I need to get ahold of Dennis and get some of those 225 and 250 slugs coming my way. I loved the way the 275 in a HLBS felt going down the bore of my Paramount. After fighting it with bullet to bore I have hope a sabot/bullet combo like we're talking about here will shoot out of this thing. If this doesn't work I'll have to rebarrel it and I really dont want to spend that kind of money on this thing.

 

[Mnt monkey]

I think his 240 and it's 250 black tip are going to shoot,, the only twist I have been able to shoot that 275 out of so far accurately have been 18 16 and 14 it sure worth a try though in the 22 again out of all of them I think it's 225 is going to be your best bullet Captain Todd on the side here is taking a couple of animals recently and some Hogs he's having really good success with that bullet

 

[Pathfinder60]

I think his 240 and it's 250 black tip are going to shoot,, the only twist I have been able to shoot that 275 out of so far accurately have been 18 16 and 14 it sure worth a try though in the 22 again out of all of them I think it's 225 is going to be your best bullet Captain Todd on the side here is taking a couple of animals recently and some Hogs he's having really good success with that bullet

I saw that hog he got with that 225. I'm not going to be shooting much beyond 250 if that much so I really dont need the weight of the bigger bullets. I'll try the 275s just for shits and giggles but I agree with you on all your predictions. I guess a bonus with the 225 is a bit less recoil too.

 

[Doccbst1]

I think his 240 and it's 250 black tip are going to shoot,, the only twist I have been able to shoot that 275 out of so far accurately have been 18 16 and 14 it sure worth a try though in the 22 again out of all of them I think it's 225 is going to be your best bullet Captain Todd on the side here is taking a couple of animals recently and some Hogs he's having really good success with that bullet

I looked at these cutting edge 240’s for the Paramount w/sabot but JBM said 1/24 unstable. Anxious to try in .45 1:18 Traditions.
This was researching hunting load low recoil low charge (100g) 84wt BH maintain Energy to 250 yds. Principal basically the same.

 

[Mnt monkey]

I like The Cutting Edge bullets ,they're limited a little bit to me if you shoot them smokeless they will blow plastic and if you shoot them with black horn or a sub you can only push the load so far otherwise you're going to end up with Sabot issues again. Upshot quite a few deer with that bullet the 240 Cutting Edge it is performed very well on game for my I like all of The Cutting Edge bullets. I've only had good accuracy out of that 240 and a light blue out of 20 twist barrels,, however if I had a Paramount and I was trying to find a good hunting bullet in a load for it I would try and see again it's a great hunting bullet