This Mossberg Heat Shield is not compatible with 590 7-Shot models w/ +1 extension, 590 Shockwave, 590A1, 590M, breacher barrels, or ghost ring sight barrels.
While the New Haven 600 and Mossberg 500 can interchange most parts like barrels and stocks, I cannot confirm if this heat shield would also be compatible with the New Haven 600. Although it is likely to be compatible, I would recommend contacting Mossberg directly for confirmation.
According to the manufacturer the Mossberg Heat Shield will only work with standard model 500s and 590s. I recommend contacting Mossberg regarding the compatibility of the Mossberg Heat Shield with the Mossberg 590 Chainsaw.
This Mossberg Heat Shield will not fit your Stevens 320 Security 12 Gauge. I would recommend the ATI Outdoor Standard Heatshield, which will fit your Stevens shotgun, and can be found by using the link below:
https://www.opticsplanet.com/advanced-technology-standard-heatshield.html
Yes, this will fit.
No, this is not compatible with the Shockwave.
No, this will not fit the 590 Shockwave.
Yes, mounting hardware is included.
It will fit the variants with an 18" barrel.
No, this will not be compatible.