The QB78 HDD is Now Available!

The QB78 HDD is now available. AND IT WORKS REALLY WELL!

Our tests show that it provides between 40 and 50% greater total energy than a QB78 family air rifle in factory condition. And that means a whole lot more shots per fill of CO2. And no reduction in muzzle velocity takes place either.

Steve_in_NC's design is highly sophisticated and produces remarkable results. Yet it looks so small and light...

I'm certain that we've given this product far more testing than any other QB78 family aftermarket accessory ever to reach the market - thousands of shots and dozens of installations. All that work has enabled us to really understand why and how the QB78 HDD works, together with its limitations - which are very few.

Here's what we find:

- The HDD will work with all QB78 family models.

- It works with the entire range of factory hammer weights. However, it performs somewhat better with lighter weight hammers (59 Grams and below).

- It works with all factory hammer springs of 62mm length and less. That's about 90% of the known population of factory springs. Shorter springs give better results. A few factory guns have hammer springs of about 66mm length and these will show a lesser improvement.

- The HDD works with 90% of the hammer pins in factory guns. For those hammer pins that are too fat, a little gentle filing will provide the required clearance. And we'll have CNC-manufactured pins to the correct dimensions available with the kit shortly.

- As the HDD requires friction against the hammer pin slots to work, it will not work in guns where the surfaces of these slots have been smoothed, such as can be done in tuning.

- It works with the XP Tune Kit. The XP/HDD combination gives tremendous performance from any QB78 air rifle without the need for an expensive tune. And you can do it yourself!

- The HDD significantly reduces temperature fluctuations in the main tube compared to a stock gun. These temperature changes are less marked due to the better use of gas and they result in less shot-to-shot differences in muzzle velocity. More consistent shooting is the result.

- Installation requires a different technique from that I normally describe. So we've written careful and explicit instructions for how the HDD should be installed.

Phew!

Thanks for your patience. I know that many of you have been waiting for this hammer debounce device. I'm glad to confirm that it's now ready for prime time. You can see it on our website.