Canadian Airgun Forum

Hi!
I thought I’d share with you how I managed to adjust the non-adjustable sights on my Umarex HPP. The HPP is not a particularly accurate bb gun but like many others it can achieve just over 2 inche groupings at around 20ft. But I absolutely love my HPP for its overall qualities rarely found in a single gun…Realistic look (Sig 229 ish) and weight, heavy blowback, hard hitter (over 400fps), around 60-70 good shots per co2 cartridge.
I mostly practice IPSC shooting with it and only need “A” zone accuracy but its fixed sights resulted in POI slightly low and to the right of POA.
A lower POI is an easy fix requiring filing the front post until the desired elevation is achieved.
But adjusting for windage on the rear sight would required some head scratching… I started by determining how much windage adjustments I needed by adding multiple layers of masking tape on the left side of the rear notch until the POA coincide with the POI. With a Vernier caliper I first measured the remaining rear notch gap. Then the layers of tape were removed, and I measured the full width of the rear notch. The full width minus the remaining gap measured with the layers of tape in place gave me the material thickness I needed.
I manage to find an aluminum ruler that had the exact thickness I was looking for. I cut a slightly oversize piece of the ruler with the same profile as the rear sight and epoxied it in place.
I let it dry overnight and filed all protruding sides flush to the original profile. A couple of coats of paint and the added shim is barely visible.
One added benefit I only noticed after it was finished is that the rear notch is now just slightly larger than the front post. Compared to the original where there were large gaps of lights each side of the front post when aiming. I found that the smaller gaps are easier to center the front post in the rear notch.
Hope this could be of some help to others…

_________________
«It's not enough that we do our best, sometimes we have to do what's required»
- Winston Churchill

Daisy 953
Umarex HPP
Walther PPK/S
Smith & Wesson M&P 40
Colt Python .357 (polymer)
Walther CP99
Smith & Wesson TRR8
KWC 226-S5

Clever idea, and you certainly did a fine job of it. RC

That’s a great fix. So simple. Some of the best ideas are the simplest. I can’t wait to do this to my x-five. I’ve been compensating when we shooting steel. This will speed up my hits. Thanks