I have the No5 action with a 54 caliber Green Mountain barrel.  I'm going to send it off to be lined and chambered for 50-90.  I have no desire to shoot this monster in competition,  I plan on hunting/plinking with it.  I have 2 molds; a 450gr and 500gr. and see no need for heavier competition boolits. 
That being said,  what twist should I want in the liner? I'm having the barrel cut to 28", Beach front and rear sights. 
Thoughts please?

Caliber      0.512      Inches            
Bullet Weight      450      Grains            
Bullet Length      0.8066      Inches            
Barrel Twist      28      Inches/turn            
muzzle velocity      1200      fps            
Temperature      50      degrees Fahrenheit (59 is standard)            
Pressure      29.92      inches of mercury (29.92 is standard)            
                       
Sg =      4.54            

Caliber      0.512      Inches            
Bullet Weight      450      Grains            
Bullet Length      0.8066      Inches            
Barrel Twist      30      Inches/turn            
muzzle velocity      1200      fps            
Temperature      50      degrees Fahrenheit (59 is standard)            
Pressure      29.92      inches of mercury (29.92 is standard)            
                       
Sg =      3.96                  

Caliber      0.512      Inches            
Bullet Weight      450      Grains            
Bullet Length      0.8066      Inches            
Barrel Twist      40      Inches/turn            
muzzle velocity      1200      fps            
Temperature      50      degrees Fahrenheit (59 is standard)            
Pressure      29.92      inches of mercury (29.92 is standard)            
                       
Sg =      2.23                  
                       
Sg shouldn't be less than 1.4.  If Sg is greater than about 2.0, you may gain some accuracy by going to a slower twist barrel.                        

     

T.J.'s liner show a 50 cal. , 500 bore ,510 groove with 1 in 20 twist.
I have 1 in 28" twist on my 50-100. 
Jim Carpenter (208-582-2091 ) can do just about any twist you want on a new barrel.
Bullet length has a lot to do with what twist rate to use.

John Taylor wrote on Jul 12^th, 2026 at 11:08am:


Thanks,  what Bullet Weight and style do you use in your 50? What Bullet does it like and not like? 

I'm a fast twist guy.  I'll preface my remarks with that.  

I don't believe you can overstabilize any bullet (within reason) that you shoot more than 100 or 200 yards with.  

My first obsolete blackpowder cartridge was an original New York State Contract rifle.  I think the twist was 36 on that one.  It would only stabilize the 450 grain government bullet.  Anything else went totally wild.  I chalked that up as a lesson, and built a 45-90.  Put an 18 twist barrel on it, when lots of people were advocating slower so "you won't strip the bullet by too fast a twist".  As BPCR showed the real performance of the bullets and twists, 18 became the norm and I never see anyone advocating for slower, some shoot 16 twist, or even 14.  

I rebarreled that NY rolling block to 50 Alaskan, and used an 18 or 20 twist barrel.  I also built a .50-110 and used a 20 twist barrel.  Both shoot excellent with either light or heavy bullets, my long range bullet is a 720 grain, and I've shot it accurately to 1000 yards.  

I see absolutely no detriment to using a fast twist, even if you shoot lighter bullets.  However, if you use a slow twist, you will never have the option of shooting heavy bullets.  If you hunt with the rifle, a fast twist is excellent for terminal ballistics, keeping the bullet penetrating and going straight once it's inside the animal.  That's the reason .458 dangerous game rifles use 14 twist barrels, to keep DG solids stable after impact, to penetrate deep into the vitals on big animals.

I'd use anywhere from 18 to 26 twist for your application, preferably about 20 twist.

Bullet weight for the 50-100 is 450. This is an 1886 so the length has to be right for it to feed. It's actually built on a model 71 frame with a 30" octagon barrel. I have not shot it enough to see what it likes.
[/quote]

Thanks,  what Bullet Weight and style do you use in your 50? What Bullet does it like and not like? 
[/quote]

All this has me thinking about recutting my 74 Sharps kit gun 50-70 chamber to  50-90 but then I'm pushing 68 years old and my shoulder is still in pretty good shape. I have the brass on hand but I don't know. Last time I shot it I felt it a couple days. Need to get it out and shoot it some more to make up my mind.


JMH

The torque can be substantial with fast twist big bores.