After getting the rifle all together (which you can read about here), all that was left to do was develop a load that would work for hunting…at least that’s what I thought. Unfortunately it didn’t work out like that.
It seemed like no matter what I tried I couldn’t get the groups to shrink. I found early success with velocity: using Accurate 2520 I had a Speer 180 grain flat point bullet going almost 3000fps, but the group wasn’t very impressive. Admittedly, I have high standards. Some of the 100 yard groups were edging below two inches, which for deer at under 200 yards is probably adequate. But since I come from a target shooting background where a one inch group is considered a good start, I wasn’t about to settle for adequate. Another reason I pursue small groups in a hunting rifle is that there are already enough things going on in a hunting situation to prevent a perfect shot (like awkward shooting positions, numb fingers, bad light, not to mention “buck fever”) that I’m not going to add questionable accuracy to the pile if I can possible avoid it.
I initially identified two areas that might have been affecting accuracy: rifle bedding, and barrel fouling. Although the stock looked good, the pillar bedding for the rear action screw had some odd cut-outs that left only three small stubs of metal in contact with the action, and they appeared to be getting slightly crushed when the screws were tightened down. I remedied this with my first ever attempt at action bedding. The finished job certainly wasn’t professional, but apart from one medium sized void, I think it came out quite well. The slideshow below shows some images of the process, including shots of the bedding before I tidied it up, and the rear tang area of the stock which I relieved a little bit to reduce contact with the action:
The barrel fouling I addressed with more aggressive cleaning at shorter intervals.
The first bullets I experimented with were 200gr Hornady round nose, and Speer 180gr flat points. I soon added 225gr Sierra Game Kings to that selection which began to show more promise. The first powders I experimented with were Accurate 2520, and 2230C, but after doing some research I added IMR 4064 to that list. After doing more load tests with the 225gr Sierra Game king with IMR 4064, I was finally getting groups I could live with, but the development showed up another wrinkle. Despite starting out with 55.5 grains of powder and working up to 58 grains, the velocity only increased by about 60 fps. The best groups occurred at both ends of the development ladder, so I decided to just go with the lower charge since the extra powder didn’t appear to bring anything extra to the table. The velocity of the final load was just over 2500 fps.
Early on in the rifle build I was concerned about a potential headspace issue that revealed itself through protruding primers. After rechecking the headspace, I narrowed the problem down to the case dimensions, and determined to limit how much the case shoulders got pushed back the next time I resized. But the undersized brass also resulted in consistently flattened primers throughout the load development irrespective of powder charge, probably caused by the case stretching to fit the chamber and reseating the primer as it went. This denied me an important pressure indicator, and left me reluctant to try chasing any more velocity. So I went hunting with what I had, and never fired a shot. So it goes.
After hunting season, and after cleaning the rifle thoroughly, I took it back to the range to use up the few rounds I had left. I first fired a single shot to check the point of impact from a clean barrel, and then I fired three shots from a kneeling position, braced against a shooting bench. The results were very satisfying:
In hindsight I think the barrel fouling might have slowed down the barrel break in, and it wasn’t until I put plenty of rounds through the barrel, and thoroughly cleaned it a bunch of times as well, before everything came together to my satisfaction.
And that’s where things stand for now, but not where I intend to leave them for long. I have in my cupboard a box of Barnes 200gr TTSX, a solid copper hunting bullet that is popular with other .35 whelen shooters. And a pound of IMR 8208 XBR, which is a relatively new powder that is claimed to be very temperature stable (useful in Minnesota). These two components were used with great success in an article I read recently, so I plan to try it for myself.