I recently bit the boolit (so to speak) and purchased a .357 Benjamin Bulldog, in the hopes of having a legit 100 yard coyote and coon / 50 yard small hog airgun. I'm not a fan of the looks, but it's sorta so ugly, it grows on you. Obligatory pics...
Half of my post deals with the quiet part...which this gun is not as delivered. In fact, it's surprisingly loud, sounding somewhat like an unsuppressed hypervelocity 22LR. Way too loud for the type of backyard shooting I'm used to with the .22/.25 Marauder. So I reached out to Matt at Pitbull Airguns to try out his brand new 3D-printed "long" moderator, shown in the pictures at the bottom. Cutting to the chase, it made a HUGE difference in perceived sound. The wife was very impressed, as she was kinda shocked the first time I shot the Bulldog in stock form. It's not Marauder quiet, but it's very manageable now. Matt was awesome to work with, and I mean awesome. Parts fit perfectly. Highly recommended.
So now to the second part, accuracy, which is an on-going effort I'm hoping others have tackled and can chime in. Being the control freak, self-reliant type, I wanted to find a boolit mold(s) so I can roll my own, and I wanted a cup / hollowpoint for hunting. NOE to the rescue except...I wanted the Bob's Boattail RG4 for 357, but there weren't any in sight. So I decided to try a more traditional design in the 150 SWC shape.
I somewhat reflexively went with 0.358 sizing and 2 coats of gold Hi-Tek coating (Gen 1) with a light tumble lube in 45-45-10 to ease the sizing effort, since I don't have the slippery Extreme Catalyst 2. I opted for pure Pb plus 2% pewter by weight, which turned out to be a poor choice for expansion.
On the first outing, things started acceptably (1-2" group at 50 yards), but after about 10 rounds, groups started to open up and after another 10 rounds, I couldn't hit the side of a barn at 100 yards. Groups were 2-3 ft at best. After returning home, I borescoped the barrel and saw pretty significant build-up of what appeared to be 45-45-10. I was able to clean it out without major effort, but lesson learned.
On the second outing (using FP-10 as a lubricant on 2x Hi-Tek coated rounds instead of 45-45-10), the groups were again about 1-2" at 50 yards...not what I was hoping for at all. While at it, I did some expansion testing using 2.5 gallon water jugs. Both the flatnose and cup-pointed boolits went through 2-3 2.5 gallon water jugs long ways and kept going into the dirt backstop. I was unable to recover any slugs, and the holes were caliber diameter, indicating zero expansion and a non-starter for my purpose.
Which leads me to today. Going back to the drawing board, I decided to cast a pure Pb boolit, with a light lubing of FP-10. I finally put the PID controller into action that I bought about 6 months ago, and I have to say...you owe it to yourself to get one. Once it was trained, it kept the pot temperature within +/- 3 degrees of target, which made casting much more predictable with my cheapie Lee 20 lb bottom pour.
I purchased 3 Lee push-through sizer dies, and modified them to put out boolits at 0.3588, 0.3575, and 0.3565, respectively, as measured with my Mitutoyo caliper (+/- 0.0001). I'll be testing them soon to see how the pure Pb does at the various diameters. Pic for fun...
I slugged my Bulldog and somewhat surprisingly got dimensions of 0.3568 / 0.3510. I for some reason expected more like 0.3575 or even 0.3580, but I guess that's why 1 test is worth a thousand theories. I slugged several rounds, including the 0.3565 round, and it fully "filled" the rifling, giving the same 0.3568 diameter as the others, while looking the best with minimal "smear". Testing will tell which shoots best, however.
I'll conclude by asking if anyone out there has already tackled this rifle and have positive results? There are some folks having great luck with AeroMagnum HP sized to 0.3585, and I may try some of those if I'm unsuccessful. Otherwise, I intend to post my results here and hopefully give back a little to this excellent forum. More to come...