Delayed Roller Locking Action Question

[TN-popo]

Piston this, DI that...why hasn't this action become more popular?

Some very successful firearms (MP5, G3, etc.) employ it.  Surely patents aren't an issue after all these years.

 

I was issued an MP5-SD in my youth, but I am, by no means, very knowledgeable on this subject and wanted to get some thoughts.

Thanks

[R1100R]

My issues with the H&K design was they use a fluted chamber which would destroy brass for reloading.
This was the experience on the G3 and CETME I owned. The CZ 52 pistol I have also uses the roller system , but I have only shot surplus. My understanding is the cost of machining makes it to expensive. I read somewhere that a CZ 52 made today would be more than $1000 to produce.

[173rdABN]

My guess, they are super finicky. and on top of that they do wear down faster than the average bear. headspace does shrink and with the gun on full auto it shrinks much faster. rollers need to be changed to combat the headspace change, or just getting it right in the first place. not all barrels are pressed in equally, so right off the batt you're adjusting the headspace to make it right for that particular gun. also locking pieces wear, and can be a pain in the arse. the MP5K alone I think has 3 different angles for different loads being used, suppressed, non suppressed. Also, in the MP5 extractor springs need replacing often. I go through them pretty quick. They are cheap, but just another maintenance issue.

 

I love me a good roller lock gun. Ive had 3 MP5's, still own one and its my favorite gun i own. I'm all for them. But, for the average person thats a lot of work. 

 

Much easier to throw an M4/AR15 together and just have it run right out of the gate with no worries about that stuff over time. 

[173rdABN]

My issues with the H&K design was they use a fluted chamber which would destroy brass for reloading.
This was the experience on the G3 and CETME I owned. The CZ 52 pistol I have also uses the roller system , but I have only shot surplus. My understanding is the cost of machining makes it to expensive. I read somewhere that a CZ 52 made today would be more than $1000 to produce.

 

It was just the bigger guns that created the flute marks. smaller pistol caliber guns just left burn marks that came off when you tumble the brass. So, rifle sucked for reloaders, pistol was good to go.

[dcloudy777]

It's just not nearly as good as gas operation.

Apart from allowing for a submacinegun that weighed less than a cinder block, the operating system was a complete developmental dead end.

Edited January 2, 2015 by dcloudy777

[TN-popo]

Thanks all!

[nightrunner]

I always thought the main reason was excessive cost of manufacture.

I sure have learned a lot about them in this thread!