The Loadout Room
Menu
  • Shooting
        • Pistol
        • Pistol Accessories
        • Rifle
        • Rifle Accessories
        • Shotgun
        • Machine Guns
        • Air Guns
        • Ammunition
        • Optics and Sights
        • Weapon Lights
        • Tips & How-To
        • Concealed Carry
        • Holsters
        • Suppressors
        • Precision Rifle Shooting
        • Firearms Training
        • 1A Gun to Ride the River With: The Smith & Wesson 686
        • The Tristar folding shotgun is ready for your wilderness adventuresThe Tristar folding shotgun is ready for your wilderness adventures
        • maxim defense cqb stock (8)The Maxim Defense CQB Stock: Short and Sweet
        • Perfecting your zero | A little help goes a LONG wayPerfecting your zero | A little help goes a LONG way
    • Close
  • Gear Reviews
      • Mission Gear
      • Camping Gear
      • Survival Gear
      • Medical Gear
      • Adventure & Travel
      • Knives & Tools
      • Overland
      • Disaster Preparedness
      • Footwear
      • Womens Gear & Clothing
        • RIP-MVehicle Preparedness: Fast access to essential items | Grey Man Tactical RIP-M
        • Midland radioOverland Essential | Midland Radio MXT275 | GXT1000
        • ppGrab your gear and go | Here’s everything you’d need to build an adventure go bag
        • Scrubba Washbag: Keep your clothes clean in the fieldScrubba Washbag: Keep your clothes clean in the field
    • Close
  • Men’s Lifestyle
      • Fitness
      • EDC
      • Eyewear
      • Watches
      • Electronics & Technology
      • Downtime
      • Mens Clothing & Accessories
      • Manly Skills
      • Style & Grooming
      • Gentleman Drinks
      • Crate Club
        • The Outdoor Edge ParaClaw: A concealed stingerThe Outdoor Edge ParaClaw: A concealed stinger
        • How to determine how long you have before the sun setsHow to determine how long you have before the sun sets
        • fireWilderness survival expert breaks down how to build a fire
        • 5.11 Tactical Expedition Long Sleeve Shirt5.11 Tactical Expedition Long Sleeve Shirt, SWAT Tested and Approved
    • Close
  • News
  • Video Demo
  • Shop

How It Works: H&K’s Roller-Delayed Blowback Operating System

May 2, 2018 by The Arms Guide Guest Writer Leave a Comment

The roller-delayed blowback system can be confusing at times to understand, but I hope this video is educational in understanding how G3/MP5 type actions work. The term “roller-locked” is an incorrect description due to how this system is designed. Unlike the FAL and other popular .308 rifles of yesteryear, the G3/PTR91/C308 do not use a gas system to cycle the heavy .308 cartridge.

It uses the power of its own recoil to cycle the action. It actually does this very well since the .308/7.62×51 NATO is very stout. The roller-delayed blowback system is not rare by any means, nor is it new. The MG42 used a similar system and the design was adapted to a later experimental rifle, which ended up being the influence for the design of the CETME rifle out of Spain.

With a storied history and a good track record for reliability, this rifle also comes with some flaws, just like any other system. The rollers on the roller-delayed blowback system are the center of the systems function and how well it works, hence it being the first word in the description of the operation. Their size and the angle of the locking piece dictate what kind of loads will be able to cycle out of this rifle.

I personally had issues cycling PDX-1 ammo out of my PTR. But this issue is simply caused by the fact that the springs, rollers, and locking piece were built to military spec, meaning it was built to function best with military ammo or hotter .308 rounds.

As with any system, if you take care of it, it will take care of you. Watch for the weak points, check the headspace occasionally, and keep it clean. If you do all this and keep it oiled in the right places, you will be golden.

by David Donchess

David Served in the USMC, deployed twice and got wounded. Retired and moved to Alaska. Has a passion for reviewing and testing guns and gear of all kinds. Enjoys working to dispel myths and show that you can train and practice in a realistic, safe, and practical way.

Image courtesy of Heckler and Koch.

Share This

Filed Under: Firearms Technology Tagged With: .308, blowback, blowback action, blowback operated, c308, delayed blowback, g3, H&K's Roller-Delayed Blowback Operating System, hk91, MP5, operation, ptr 91, PTR91, ptr91 gi, Rifle, roller delayed, roller locked

More From The Loadout Room

Comments

What’s Hot

Top 8 upgrades every Kel-Tec Sub 2000 owner needs: MCARBO parts review
Featured

Top 8 upgrades every Kel-Tec Sub 2000 owner needs: MCARBO parts review

Ammunition

The Reasons Why FBI Went to Back to 9mm

Why .45ACP is an outdated caliber
Ammunition

Why 45 ACP is an outdated caliber

Dogs

Tactipup Extreme Collar and Leash: Tactical dog gear, Perfected

Safariland Model 7304 ALS/SLS holster
Firearms Accessories

Safariland Model 7304 ALS/SLS holster

Email Newsletter

Sign up to receive email updates daily and to hear what's going on with us!

In Case You Missed It

Gear Reviews

A Gun to Ride the River With: The Smith & Wesson 686

October 9, 2019 Leave a Comment

Camping Gear

The MSR Pocket Rocket | Your little camp dragon

October 8, 2019 Leave a Comment

The Outdoor Edge ParaClaw: A concealed stinger
EDC

The Outdoor Edge ParaClaw: A concealed stinger

October 7, 2019 Leave a Comment

Gear Reviews

A plate carrier for the big boys: AR500’s Testudo Gen 2 is a good pick for large frames

October 7, 2019 Leave a Comment

Get it on Google Play

© Copyright 2021 Crate Club Group · All Rights Reserved.

  • Privacy Policy
  • Terms of Use
  • Advertisers