Do you have a TM PSG1 that needs that extra "oomph" for it's accuracy? Are you building the MSG-90 of your dreams, but you yearn for consistent groupings at 300 feet? If so, maybe you've heard of the mythical Chamber Block... well here it is. The PDI Chamber Block for the PSG-1 connects the inner barrel, outer barrel and receiver, making them one solid unit, and eliminating flexion between the three parts. The weight of the inner and outer barrel, coupled with the material of the receiver, makes this a common weak-point in the TM PSG design, but the PDI Chamber Block changes all that. Unused and in original packaging, this was bought years ago for a project that just never happened. My loss is your gain. Prices do not include shipping. Located in Central Texas.