So I continue to work on new slug loads for the "MIGHTY" 410. I have published two new reloading pages on my website with new test results:http://mcb-homis.com/slug_410/slugloads/contents.htm
The first new page (data set 4) is for the heaviest slug I have loaded to date. turbo1889 sent me some of his 163gr (~3/8oz) slugs. My first test utilized two different powders. Herco did not perform very well but H110 performed very well and I believe that energies above the "mythical" 1000ft-lbs will be achievable with this slug and H110. Unfortunately accuracy with both loads was pretty bad. The slug appears to be right on the edge of going unstable, but I have hope that it can be stabilized and accuracy improve.
Speaking of improving accuracy the second new page (date set 5) is what I hope will bring the accuracy of the 163 gr slugs around. Utilizing the 90gr and 127gr slugs I received from Buck Ball and Slug (in the UK) I did some testing with an attached polymer base on the slugs. These attached bases were machined from Ultra High Molecular Weight (UHMW) Polyethylene (similar material to many shotgun wads and sabots). These bases are similar to the attached gas seal of a Brenneke hybrid slugs. The base lengthens the slug by 3/8 inch moving the center of pressure further aft of the center of mass increasing the stability of the slug. A noticeable increase in accuracy resulted, especially with the 127gr slugs. My previous test with the 127gr slug I shot a 4-shot 4.8 inch group at 25 yards. With the attached base I achieved a 2.6 inch 5-shot group at 25 yards. The results are promising and I have already machine and loaded similar base for the 163 grain slugs.
Finally, on this past testing trip to the range I tested a potential new low cost peak chamber pressure sensor. I ran across this sensor in my day job as an R&D engineer. From my initial limited test it did appear to predict the peak chamber pressure of my reloads fairly accurately. I tested all the above loads and two factory loads. I have further testing to confirm the results and establish a more realistic error range but if this work as hoped it could be a very cost effective way to measure peak pressure without requiring a strain gauge glued to the barrel and associate expensive data acquisition gear.
If your interesting is this sensor please seem my thread in the reloading section on that:viewtopic.php?f=13&t=189851
Rambling as usual