The upper target sheet I'm counting 10 shot groups, 5 for the lower target sheet.

If mine, I would clean the beejeebers out of that barrel, check the butt stock bolt's tightness as well as the forend snuggness and try some more 44.5 through 45.5 gr. loads.

With efficient ctgs. I find near maximum loadings usually give the best accuracy.

I personally would make a test to find the 'sticky' point, as there is no loading data for this gun. Finding the max. ie: 2 gr. under the start of sticky, gives one a range to load in. This should be done with all powders expected to be used. I'd load upwards one gr. at a time, or 1/2 gr. if you wish, until I feel stickiness of the bolt. Reduce that by 2 full grs. and that is a very safe maximum load.

With Improved or straight walled wildcat cases, it is not that easy. Sometimes there are no signs of pressure(straight cases only) and one must stop and step backwards when one becomes frightened to go further forward. This is one reason why a chronograph is helpful.

If you don't know what you are getting for speed, you really don't know much about your loads. By this, I mean if you aren't getting 2,100fps or more with that bullet, then you have a ways to go before load development is close to completion.

Using ADI powders (Hodgdon Extreme) is a blessing as they are less susceptable to heat caused pressure spikes than other powders. In other words they are easy to work with in a broad range of temps.

One must go carefully - watching all pressure signs - stickiness of the bolt being the primary 'sign' with rear locking lug actions. The tapered case causes stickiness to happen at relatively low, safe pressures.

Further note, insipience head separations with low round count per case is not a sign of pressure. It is a sign of headspeace problems.