Does everyone think the new A5 vented block is better than the previous adjustable one
I'm sure it's been discussed here, but I'd love to know the backstory about why HK changed it.
Honestly, i think it comes down to maintenance and parts wear.
Controlling the gas at the source with dynamic systems has proved problematic. Carbon sticks to parts that need to move freely on demand, locking them in place unless PMCS is performed and that involves small parts, springs, etc. The pressure and heat is much higher leading to gas cutting of the parts and small parts erode quickly, regardless of what they're made from.
Controlling exit gas on the back end though, is much easier, has much less fouling involved, has larger, easier to clean parts, little to no gas cutting due to the drop in pressure and heat, and overall makes for a more robust system.
Is one more effective at doing the job? Not really. Both accomplish the same task just at different places in the action cycle. But the external gas release control is much more durable and easier to maintain in the long run and thereby lends itself to being a better system for HK to use.
I have helped several HKPro members achieve this kind of gas control with cut down 416 and MR556 barrels, but have done so with static results (modifying gas systems for use with non AGR blocks) and have had quite a bit of success in dialing guns in to run both suppressed and unsuppressed without need for an AGR.
I am also a firm believer in KISS and if you can make the gun run properly with all variables and without an AGR, do it. I hate adding more moving parts as that's more crap involved that could break.
As someone with a HK factory vented gun (and b&t signature dampers), there is zero issue with the hk vented block and the b&t rotex-v. It just works out of the box like a charm.
What must not be discounted are the massive detail improvements HK has done on this gun family, you can not compare the current ambi-chrome-lined-short-barrel-civilian guns with the 10 year old quadrail drumsticks.
I thought the a5 vented block was only for a 11.5 inch barrel and specific low back pressure can, not necessarily better just mission/requirement specific.