Adjusting the hammer spring to get velocities in the 870-880 fps range created a fairly large spike near the end of the string with a wider es than I was willing to accept and I was still filling to 3500 psi and only increasing the shot count to around 45. Now, if I so desire, I could fill to 3000 psi and still get 40 shots with an es of 10-15 psi. I couldn't be more pleased with the regulator adjustment. Major increase in shot count using less air, what's not to like.
I think you should start a new post with this, For some time I’ve been wanting to do the same, I might have few questions for you but I dont want to do them here to avoid high jacking this post. I also believe the regulator comes too set high on the Taipan.
Answering the OP, at 30 yards this rifle should put pellets on the same hole. If the POI is all over the place at this distance then something is not consistent. Decreasing the tension on the hammer spring might have cause that you are now shooting below the knee but even with this change I expect the change in speed when you felt out of the regulator, where you will see an increase on the speed, as h2okenny describes. But while on the regulator you should have a flatter curve.
What Im trying to say is that I don’t expect the adjustment on the HST cause this innacuracy at short distance, past 50 yard, maybe. We need to search what is giving you the incostincency, you will be amaze to find out how many factors could cause this. I’ll rule out first something with the gun, so It is mandatory that you meassure the speed to confirm your speed is consistent, if your adjustment in the HST puts you too far from the knee you could have some variance, another way, there is one optimal position for the HST given a regulator presusre, that position is on the knee of the curve, ohh boy I think explaining the details can make my answer too long, I can writ more about it later.
If your rifle is consistent with speed, then a shift on POI can be caused by:
- Dirty barrel, clean it to test
- damaged pellets or inconsistent weight. Use good quality ones to test
- Wind
- scope
- You
hope this helps ping point your accuracy problem
