Silencing foam will work as a barrel spacer, however it does not reduce mechanical vibration and sound as well as a solid spacer.
Since sound is a vibration, once you reduce all the vibration in the inner barrel and outer barrel assembly, you nearly eliminate any noticeable sound involving these two pieces.
Solid spacers will reduce vibration the most and therefore reduce sound the most.
I've chosen to use a wax-spacer mod for my testing rifle as it encompasses the whole length of the inner barrel and fits VERY tightly into the outer barrel.
I've done electrical tape spacers (3-15+ segments), teflon tape spacers, e-tape+teflon tape spacers, one-piece paper spacers, rubber washer spacers, packaging foam spacers, memory foam spacers, sound absorbing foam spacers, after-market spacers, etc.
I feel if you want the best out of barrel spacers, you MUST use a spacer that surrounds the majority of the barrel and is hard in composition. The one-piece paper spacer and wax barrel mod are the two that I have had the most success with.
Since sound is a vibration, once you reduce all the vibration in the inner barrel and outer barrel assembly, you nearly eliminate any noticeable sound involving these two pieces.
Solid spacers will reduce vibration the most and therefore reduce sound the most.
I've chosen to use a wax-spacer mod for my testing rifle as it encompasses the whole length of the inner barrel and fits VERY tightly into the outer barrel.
I've done electrical tape spacers (3-15+ segments), teflon tape spacers, e-tape+teflon tape spacers, one-piece paper spacers, rubber washer spacers, packaging foam spacers, memory foam spacers, sound absorbing foam spacers, after-market spacers, etc.
I feel if you want the best out of barrel spacers, you MUST use a spacer that surrounds the majority of the barrel and is hard in composition. The one-piece paper spacer and wax barrel mod are the two that I have had the most success with.