I have had my 9mm upper build for a few years already, and though I never had a real issue with it, it shot a whole lot like a 5.56. I had increased buffer weight which helped some but it was not all that much different.
I had read about the roller delayed uppers on the market, and have been curious for a while, the problem is they are just stupid expensive, and not knowing if that was worth it despite the rave reviews from people, I never bought one and have never really pursued it much.
Then one day in my daily email spam came something about the Maxim defense RDB system, a buffer with roller delay mechanism built in. Got curious and looked into it more, and having found one on sale for $155 shipped, I bit.
After only 90 rds through it today I have to say it made a heck of a difference in recoil impulse, and seems quieter on the suppressor too. I have a feeling the carrier on the old system despite the heavier buffer was still slamming hard into the rear of the buffer tube. Its also slightly lighter over all too.
The only down side so far is charging the upper is much more difficult as you have to over come the rollers now to charge it, though I swapped to a ambi extended latch handle and it helped that quite a bit.
And you do have to have a bolt carrier with a removable weight. Most of the 9mm carrier groups do, its just a roll pin with a weight in the back of the carrier you drive out and push the weight out, to make room for the guide rod of the spring system, but installation is no more difficult than a standard buffer once that's done.
Seems like a good buy for what it does so far. I have not shot a ground up designed roller delay system, like an MP5 or the CMMG banshee so can't say how it compares.
$160 shipped at Optics Planet for anyone interested.
https://www.opticsplanet.com/opticsplanet-exclusive-maxim-defense-industries-rdb-roller-delayed-blowback-syst.html
