Uploaded December 2017 | Updated September 2026, 12 hours ago
Let's look at an affordable 300 blk Upper for an AR-15. Today we have an affordable 300 blackout conversion kit from NSR Firearms. The Concept is simple, Re-use your current bolt carrier group, charging handle, and magazines from your AR-15 5.56 vs. .223 and put them in the 300 blk upper receiver.👇 Gear Sheet: toolboxspecs.com/pages/access?setup=specs-34
[NOTICE: Per YouTube’s Firearms Policy, this independent technical evaluation (EDSA) provides professional documentation and does not sell firearms or regulated goods directly.]
[IMPORTANT UPDATE: As of 2026, this channel has transitioned to an 'Independent Technical Evaluation' (EDSA) format to comply with updated safety standards. Legacy verbal mentions of 'Parts Lists,' 'Discounts,' or 'Off-Platform Tutorials' in this video are no longer active and have been removed for compliance.]
With that said, if you join my private engineering community at the link below, you unlock access to Behind the Scenes Content and technical data that far outweigh anything we've ever offered in the past.
toolboxspecs.com
LEGAL & SAFETY DISCLAIMER:
Tactical Toolbox is an independent media outlet. This video is for educational, documentary, and scientific purposes (EDSA). We do not sell or give away firearms, ammunition, or regulated accessories directly. All local and federal regulations apply. *This video was filmed in a highly controlled laboratory and secure range environment. It is strictly for educational, scientific, and documentary purposes. We do not manufacture, sell, or process transactions for firearms or regulated components, nor does this video provide instruction on how to manufacture them. To remain in 100% full compliance with YouTube's 2026 Safety Guidelines, this channel does not provide direct links to regulated items in the public description.*
Let's look at an affordable 300 blk Upper for an AR-15. Today we have an affordable 300 blackout conversion kit from NSR Firearms. The Concept is simple, Re-use your current bolt carrier group, charging handle, and magazines from your AR-15 5.56 vs. .223 and put them in the 300 blk upper receiver.👇 Gear Sheet: toolboxspecs.com/pages/access?setup=specs-34
[NOTICE: Per YouTube’s Firearms Policy, this independent technical evaluation (EDSA) provides professional documentation and does not sell firearms or regulated goods directly.]
[IMPORTANT UPDATE: As of 2026, this channel has transitioned to an 'Independent Technical Evaluation' (EDSA) format to comply with updated safety standards. Legacy verbal mentions of 'Parts Lists,' 'Discounts,' or 'Off-Platform Tutorials' in this video are no longer active and have been removed for compliance.]
With that said, if you join my private engineering community at the link below, you unlock access to Behind the Scenes Content and technical data that far outweigh anything we've ever offered in the past.
toolboxspecs.com
LEGAL & SAFETY DISCLAIMER:
Tactical Toolbox is an independent media outlet. This video is for educational, documentary, and scientific purposes (EDSA). We do not sell or give away firearms, ammunition, or regulated accessories directly. All local and federal regulations apply. *This video was filmed in a highly controlled laboratory and secure range environment. It is strictly for educational, scientific, and documentary purposes. We do not manufacture, sell, or process transactions for firearms or regulated components, nor does this video provide instruction on how to manufacture them. To remain in 100% full compliance with YouTube's 2026 Safety Guidelines, this channel does not provide direct links to regulated items in the public description.*
