01-12-2023, 11:10 PM
Group size without cold bore.pdf (Size: 112.89 KB / Downloads: 13)
Before and After Drop Tube Use.pdf (Size: 241.27 KB / Downloads: 10)
2.2985 and 2.26 inch Seating Depth.pdf (Size: 1.77 MB / Downloads: 9)
2.1795 and 2.11 inch Seating Depth.pdf (Size: 203.7 KB / Downloads: 5)
Hello again. I made a trip to the range last week to further test out the Reloader 15.5 and try to dial it in some more for my rig. As I stated in the previous posts the load at 28.6 grains was showing very good sign as far as the velocity I wanted to obtain as well as having very good ES and SD's. The only thing lacking was the accuracy. I was short on time so this was the only powder charge I focused on. My goal for the trip was to see if I could tighten up the groups by playing with seating depth. Since I'm shooting a gas gun with steel magazines my seating wasn't based off of jam rather I loaded the bullets to maximum magazine length and used the Berger method of seating progressively deeper. The four seating depths were mag length which is 2.298", 2.26", 2.1795, and finally a very shallow 2.11". The 2.11" was odd looking as it seemed the ogive was below the case mouth.
I should give thanks to StoneHendge and Old Bob. The recommendation of a drop tube offered amazing results! I fashioned one out of a cheap BIC pen by pulling the guts out and forming one end with heat to the size of the case mouth. The other end used the tapered part of the pen to fit inside the funnel. There was more machining that went into it in order for the powder to flow smoothly through it but that basically sums it up. Length of drop is approximately 5-5.5 inches. There was a large noticeable difference in how much powder the case was able to accept. I have attached a photo of the result. The two cases closest to my Intellidropper were loaded using the drop tube and the two cases below them were loaded without the drop tube. It's hard to see in the picture but the ones loaded with the tube were just a hair below the shoulder of the case where as the other ones were at least halfway up the neck. I'd say that's a huge gain in capacity especially when you figure how little real estate ARC case has. It also appeared to help alleviate some of the pressure signs that I reported before.
The attached picture of the targets speak for themselves. The mag length load was my best one and came in at a .75 MOA and that's a seven shot group! It also happened to be the first group I shot so it even takes into account the cold bore shot, which by the way it was only 37 degrees that day! I think if I would have shot this group second it would have shrank down to around .6 MOA. The other groups shown were all six shot groups. I labeled the seating depth on the top of the targets in blue ink.
Velocity for all four groups was boringly stable so I only based my ES and SD's off of my seven round group.
AVG Velocity = 2577
ES = 30
SD = 4.7
Temperature stable powder, check. Low ES and SD's, check. Good accuracy, check. Yep this is the powder I'm settling on and it's time to stack it deep. I may try to tweak it a little more to see if I can get it around .5 MOA before cranking out some surplus rounds but if anyone was wondering about using this in the little ARC I would recommend it. LOAD SAFELY HOWEVER BECAUSE THERE IS NO PUBLISHED LOAD DATA FOR THIS IN 6mm ARC! THIS LOAD COULD BE OVER PRESSURE! Thank you all for your help and for reading!