480 Ruger Rifle... SUBSONIC
Posted: 22 Feb 2015 15:43
So Ive been toying with the idea of getting a suppressed rifle since they've been made legal for hunting in Ohio. In reading up on the subject I stumbled on claims that a 45-70 loaded subsonic isnt much louder than a 22LR, but still carries thump similar to a heavy loaded 45LC revolver. With further reading I found that fast burning pistol powders, big bore rifle barrels, and heavier bullets create lower muzzle pressures. Low muzzle pressure, combined with lack of a supersonic crack can lower the noise level quite a bit.
One of the outputs of QuickLoad is muzzle pressure. So i set out to find what i could use as a standard for muzzle pressure. I looked around and found that a rifle in 22WMR puts off about 2500psi or 172 bar. My .223 load when put into QuickLoad generates about 560 bar. A 375gr 480Ruger bullet, propelled by 7.5 Grains of Unique in a 20" Rifle barrel should be around 40 bar. FORTY! It should leave the barrel at about 1000 FPS & 832 ft/lbs of energy... and at 100 yards still be over 900fps & 700 ft/lbs... Sign me up!
Lastly, i wanted to make sure that small of a Unique charge in a 480 ruger would be OK. Long story short, I found plenty of reports of people loading Unique in the bigger 45-70 case, less load density, and varying bullet weights.
So today I tried it. And I was impressed. I set up my chronograph about 10 yards outside of my walkout basement. I told my wife what I was up to, and asked her to let me know what she heard. She was one floor up and about 30ft behind me in the kitchen, frying meat for a pot of chili, (just to give you an idea of the noise in the house). I closed the door behind me, and fired my first shot. To me it sounded about like a 22 revolver. I shot them all, (8 shots)and recorded my velocities, then fired a 22 magnum, and went back in to ask her what she thought. "I only heard two shots, and they didnt sound like gun shots, it sounded like you dropped something."
I fired the highest charge weight first, 2 shots each and this is what they averaged over the chrono: (8.5gr - 1021fps) (8.0gr - 975fps) (7.5gr - 920fps) (7.0gr - 902fps)
I think I found myself a whole new level of fun! Hopefully soon I can load some up and test for accuracy.
One of the outputs of QuickLoad is muzzle pressure. So i set out to find what i could use as a standard for muzzle pressure. I looked around and found that a rifle in 22WMR puts off about 2500psi or 172 bar. My .223 load when put into QuickLoad generates about 560 bar. A 375gr 480Ruger bullet, propelled by 7.5 Grains of Unique in a 20" Rifle barrel should be around 40 bar. FORTY! It should leave the barrel at about 1000 FPS & 832 ft/lbs of energy... and at 100 yards still be over 900fps & 700 ft/lbs... Sign me up!
Lastly, i wanted to make sure that small of a Unique charge in a 480 ruger would be OK. Long story short, I found plenty of reports of people loading Unique in the bigger 45-70 case, less load density, and varying bullet weights.
So today I tried it. And I was impressed. I set up my chronograph about 10 yards outside of my walkout basement. I told my wife what I was up to, and asked her to let me know what she heard. She was one floor up and about 30ft behind me in the kitchen, frying meat for a pot of chili, (just to give you an idea of the noise in the house). I closed the door behind me, and fired my first shot. To me it sounded about like a 22 revolver. I shot them all, (8 shots)and recorded my velocities, then fired a 22 magnum, and went back in to ask her what she thought. "I only heard two shots, and they didnt sound like gun shots, it sounded like you dropped something."
I fired the highest charge weight first, 2 shots each and this is what they averaged over the chrono: (8.5gr - 1021fps) (8.0gr - 975fps) (7.5gr - 920fps) (7.0gr - 902fps)
I think I found myself a whole new level of fun! Hopefully soon I can load some up and test for accuracy.