That's what I did not want to do; stress something so expensive. I am new to the nfa scene and the post was intended to see what people with your level of expertise would say.
Thanks for commenting.
Yes, I get that the subguns have a high market value. Most owners would agree that they don't want to do anything to negatively effect the value of their subgun. From my perspective, the actual value is from the fact the firearm was entered into the NFA as a machinegun before May 19, 1986, therefore is a transferable machinegun. So to me, that paperwork is the reason why the subgun is worth thousands of dollars. So as long as the serial number and the rest of registration information is still on the receiver, receiver repair should not be an issue.
There have been many members over the years that have posted that they have shot thousands of rounds and have not had an issue with a speed cube type of cyclic rate increase device. While others ended up pounding the back of the receiver and caused the back plate of the receiver cracked. The man who I know that has been repairing these guns for over 20 years, Sam Schneider of Practical Solutions. If you are concerned, that is who I would ask. It is my understanding that a speed cube is not the best choice for longevity. But if that is what you want to do, roll the dice. If the back plate cracks, send it to Sam and get it fixed.
For me, my focus is slowing down the cyclic rate, not speeding it up. Like the US government, I feel that the factory cyclic rate is too fast already. Using 3 to 5 rounds at a minimum of rounds per target/trigger pull is a lot of ammo to use per target. Lage Manufacturing uppers and CF(W) bolts for the M11 family make these subguns easier and safer to use, in my opinion. Congratulations on the transfer of your subgun.
Scott