Noise suppressor for firearms

Abstract

A firearm includes a noise suppressor comprising ports in the barrel opening into an annulus provided between a barrel and a sleeve extending from adjacent the muzzle to adjacent the receiver. In the annulus are a series of baffles. The most upstream port opens upstream of the most upstream baffle and downstream ports open between adjacent baffles. In some embodiments, the upstream ports are considerably larger than the downstream ports. Propulsion gases escape from the barrel into the annulus before the projectile clears the muzzle. Sabot rounds or shotgun rounds can be safely fired in the weapon because the sabot carrier or shot cup don't begin to expand until it is past the muzzle end so it cannot damage the noise suppressor.

1 . A firearm comprising
 a receiver;   a barrel extending from the receiver and having
 a muzzle end and a bore providing a predetermined cross-sectional area from adjacent the receiver to the muzzle end, and 
 a ported section extending between 10-50% of barrel length from the muzzle end toward the receiver, the ported section having a series of ports opening between the bore and an exterior of the barrel providing a cumulative area at least four times the area of the bore; 
   at least one baffle on the exterior of the muzzle, the baffle being between adjacent ports; and   an imperforate rigid sleeve surrounding the barrel and extending from adjacent the muzzle end to adjacent the receiver.   
     
     
         2 . The firearm of  claim 1  wherein the barrel provides rifling extending substantially to the muzzle end. 
     
     
         3 . The firearm of  claim 2  wherein there are multiple rows of ports parallel to the rifling. 
     
     
         4 . The firearm of  claim 1  wherein the ports comprise at least one upstream port and a series of downstream ports and the upstream port is substantially larger than the downstream ports. 
     
     
         5 . The firearm of  claim 4  wherein the area of the upstream port is at least twice the area of a downstream port. 
     
     
         6 . The firearm of  claim 4  wherein the area of the upstream port is about four times the area of a downstream port. 
     
     
         7 . The firearm of  claim 1  wherein the ported section is of an outer diameter smaller than a diameter of the exterior of the barrel. 
     
     
         8 . The firearm of  claim 1  wherein the baffles are of one piece with the barrel. 
     
     
         9 . The firearm of  claim 8  wherein the baffles are of the same piece of material as the barrel. 
     
     
         10 . The firearm of  claim 1  wherein the ported section extends about one quarter barrel length from the muzzle end toward the receiver and the cumulative area of the ports is at least fifteen times the area of the bore. 
     
     
         11 . The firearm of  claim 1  wherein there are a multiplicity of ports and a baffle between each pair of adjacent ports. 
     
     
         12 . The firearm of  claim 1  wherein there are a multiplicity of baffles and the ports between the baffles extend at least half way between adjacent baffles. 
     
     
         13 . The firearm of  claim 1  wherein there are multiple rows of ports and multiple baffles, each row of ports comprising
 an elongate upstream port opening into a first section of an annulus between the sleeve and the barrel, the annulus extending from a most upstream baffle to the receiver, and 
 the downstream ports opening between adjacent baffles, 
 at least some of the upstream ports being at least twice the area of the downstream ports. 
 
     
     
         14 . The firearm of  claim 13  wherein the downstream ports are elongate extending at least half way between adjacent baffles.