I pulled out my Stevens Tip Up New Model Range Rifle (No. 10), deciding that I need to shoot it. The chamber cast shows a slightly long 32/40 Win. chamber with a .313" groove. I am guessing that this might have been a rechambered 32/20, as the twist is 1:20". My question is what is the longest/heaviest bullet that this twist will stabilize at a lower velocity mode. Unfortunately, my range is only 100 yards long, so that is the limit of my shooting. Intent is breech seated offhand practice.

There are 3 common Lyman molds that will work for your twist rate but, may cast slightly small.

3118 or 311008

311359

311410

If they cast a little small, you can ream the base band or GC area, to .315 - .316 and it will cast .314 on the base band and shoot well.

I did this for my 8.15 x 46R rifle, using a 311413, that cast .314. My groove was .315 and I reamed the GC area, to cast .316. I've shot many 3/4" groups with that rifle/bullet combination @ 100 yd.

The only other easy option, is 32 pistol bullets, in WC and SWC. I've never seen that type bullet produce accuracy at 100 yards and beyond.

Frank

Dave,
Bullet length shown is .694". I was going to modify an Accurate 150gr design, but now think I may just be happy with the 125gr. Mods being tapered bands to suit breechseating as were the 31-125's.

So a 150gr at .805" long might be a decent option? I was thinking of having the gas check removed off this design and then tapering lands for breechseating.

Caliber      0.313      Inches            
Bullet Weight      150      Grains            
Bullet Length      0.805      Inches            
Barrel Twist      20      Inches/turn            
muzzle velocity      1400      fps            
Temperature      50      degrees Fahrenheit (59 is standard)            
Pressure      29.92      inches of mercury (29.92 is standard)            
                       
Sg =      1.43                  

Caliber      0.313      Inches            
Bullet Weight      150      Grains            
Bullet Length      0.805      Inches            
Barrel Twist      20      Inches/turn            
muzzle velocity      1200      fps            
Temperature      50      degrees Fahrenheit (59 is standard)            
Pressure      29.92      inches of mercury (29.92 is standard)            
                       
Sg =      1.36                  

Caliber      0.313      Inches            
Bullet Weight      150      Grains            
Bullet Length      0.805      Inches            
Barrel Twist      20      Inches/turn            
muzzle velocity      1400      fps            
Temperature      32      degrees Fahrenheit (59 is standard)            
Pressure      29.92      inches of mercury (29.92 is standard)            
                       
Sg =      1.38      

The 150 grain bullet would be at the edge at normal conditions; but would fall below 1.4 if you reduced velocity, if the temperature dropped, or if you had a high pressure system - and more so if you had a combination of these conditions.

A 140 grain flat nose would probably be the heaviest bullet you could use wisely.

For anyone looking for light bullet 32-40 loads, below are the results of todays chrono work. Stevens Tip-Up New Model Range Rifle. 32/40 with .313" groove. 28" bbl. 1:20" twist. Accurate Molds bullets 31-125C & 31-125M. Cast at 122gr. in 17:1. Pan lubed with a modified Pope Lube. I used Gredag in addition to the graphite. Breechseated. Same case. Rem 9 1/2 primers in all loads listed. Unless noted, velocities are the avg. of 5 shots.

31-125C   14.0/Re7       1432fps
31-125M   14.0/Re7       1410
31-125C    15.0/Re7       1467

31-125M   11.5/4227   1352fps
31-125M   12/4227      1428
31-125M   12.5/4227   1493
31-125M   13.0/4227    1519
31-125C    12.5/4227   1465

31-125C     9.5/2400     1402fps
31-125M     9.5/2400     1407
31-125C     10.0/2400    1466

31-125C     9.0/AA9        1398fps (10)shot SD 13
31-125C     9.5/AA9        1474fps (10)shot SD 18
31-125M     9.5/AA9        1458