By David Crane
defrev (at) gmail (dot) com
July 27, 2011
DefenseReview first became aware of the TNW SGP-QCB (System Gas Piston-Quick Change Barrel) 5.56x45mm NATO (5.56mm NATO)/.223 Rem. gas piston/op-rod tactical AR carbine/SBR (Short Barreled Rifle) weapons/upper receiver assemblies in December 2009 in a NorthwestFirearms.com forum thread. We subsequently did some additional research on the system in early June 2010, but got side-tracked with other things. Cut to the present, and SWAT Magazine just published a cover piece by Jerry Cannon on the system in their Sepetember 2011 issue.
Designed and developed by the boys at TNW Firearms, Inc., the TNW SGP-QCB quick-change barrel system utilizes a dual-lever cam system that’s reminiscent of the Lewis-Machine & Tool Monolithic Rail Platform Quick Change Barrel (LMT MRP-QCB) and MGI MARCK-15 HYDRA QCB-C systems. The primary goal of the TNW QCB system would appear to be to create a mission-configurable weapon that enables barrel and caliber swapping to be executed at the end-user level in the field, between missions.
So, how does the TNW SGP-QCB quick-change-barrel system work, exactly? Well, we’ll let Mr. Cannon tell it:
The heart of the take-down system [consists of] two levers, one on each side of the forearm. In the open position, the levers have no contact with the barrel. When closed, the levers cam down on the barrel extension, exerting enough force to securely hold the barrel in the upper receiver. The levers themselves are held securely in place against the forearm by a spring latch over the top of each lever.
Changing the barrel is as easy as releasing the catch and letting the lever lay open. Remove the barrel by grasping it and pulling it straight out of the receiver and forearm, guiding it into the receiver—this includes the piston rod if so equipped. When the barrel is fully seated, the levers on each side are closed and the ends trapped under the catches. The barrel exchange is complete.
Sounds (or in this case, reads) easy enough. Cannon describes the barrels themselves as “essentially milspec”. The barrels, available in 10.5″, 14″, and 16″ lengths, are made by E.R. Shaw. The weapon/upper receiver can be had in either direct-gas-impingement (DGI) or gas piston/op-rod (operating rod) configurations, but the barrel, receiver, and bolt carrier group (BCG) “must be the same system throughout”.
For sights, Cannon went with the Burris FastFire II Red Dot Reflex Sight/combat optic mounted on an American Defense MFG (ADM) quick-release mount and a Midwest Industries (MI) Flip-Up Emergency Rear Sight and Flip-Up Front Sight BUIS (Back-Up Iron Sight) system. Defense Review has never used the Burris FastFire II, but we have used ADM mounts and MI BUIS. The ADM mounts and MI BUIS systems are both very good, and we highly recommend them. ADM mounts utilize the patented and well-designed QD AutoLock Lever System.
As the base SBR platform for his testing, Cannon used a POF P416 PDW (also written POF P-416 PDW) 7.5″ (or 7.25″?) personal defense weapon-type piston-driven tactical AR SBR with ambi mag release and bolt carrier release, and Robar NP3 Plus nickel/teflon internal firearm coating. Oh, and he used a Plano Molding tactical gun case for transport.
Cannon appears to have done a VERY short, VERY low-round-count “grab-and-go” T&E (test and evaluation) of the TNW SGP-QCB upper receiver with barrel swaps, and hit a temporary snag while swapping the barrels out when his bolt closed spontaneously, but you’ll have to read his article for the details.
DR looks forward to conducting our own T&E of the TNW SGP-QCB piston-driven tactical AR carbine/SBR system at some point in the not-too-distant future. Hopefully we can get an upper for eval, soon.
Photo(s) Credit: TNW Firearms, Inc.
Company Contact Info:
Midwest Industries, Inc
W292 S4498 Hillside Rd.
Waukesha, WI 53189
Email Contact Form: http://www.midwestindustriesinc.com/index.cfm?fuseaction=page.display&page_id=8
Lewis Machine & Tool Company
1305 11th Street West
Milan, IL 61264
Sales Phone: 309-732-9527
Sales Fax: 309-787-2636
Email Contact Form: http://www.lewismachine.net/contact.php
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