I made another range trip today 10:30-2:30, took 3 rifles and the chrony this time. I was a bit disappointed in the velocity of of Berger 130gr VLD, certainly can't complain about the accuracy tho! If you remember from my last report, I shot some two shot groups to expedite the load work and not heat the barrel too much since I only had one rifle to shoot and get bored waiting for it to cool, so I had some single loads that I hadn't shot, so I ran them thru the chrony, here's the 100yd group I got with one shot each at 39gr, 39.5gr and 40gr!
The best accuracy I got at the last range session was with 41.5gr, a 3-shot group that measured right at ½", judging from the velocity of the 42gr load I shot today which averaged 2502fps, the 41½gr load must have run about 2460fps or so which is considerably less than I expected.
I shot the remainder of my loads even tho the primers were getting a little flat, but they weren't extracting hard, accuracy diminished with the heavier loads tho. I also shot a few more of the 120gr TTSX in the 260, but they shot all over the place, you'll see one of the holes in the 270 Ackley target, velocities varied by as much a 100fps!!
It's been a while since I worked on the 270 Ackley, that's the 24" fluted bull barrel 270win that I bought a couple years ago from Mac, when I finally got around to getting ready to shoot it, I learned the barrel wasn't fitted properly and had a gap at the top of the chamber, so I worked it down until it fit good, but in doing so, I ended up with negative headspace. With the only option being to modify a die so I could push the shoulder back further or rechamber it, I chose to rent a 270 Improved reamer and rechambered it myself. The rechamber job went fine and I ended up with a true 270 Ackley that will shoot factory 270 Ammo. But the first range trip was a disappointment, huge pattern at 130yds, barely on the paper. Slugging the bore revealed a .2795" groove diameter!
I researched bullets and learned I can have a .280" sizing die made to resize jacketed bullets, but chose to try .284" bullets in it first. Actually, .284" bullets measure .2835" if you want to get technical, at least those I've measured, 120gr Nosler BT and 130gr Speer BTSP, having a short shank both measure at that spec and were my chosen test bullets.
Knowing that many shoot .311" bullets in their .308" bores, I figured it wouldn't be much different than shooting .2835" bullets in the .2795" bore, and I learned today it isn't a problem.
They shoot fine, the problem was the neck in the 270Win chamber is a bit small to chamber a 7mm bullet, so I had to neck turn the brass to allow it, not much, just .001" believe it or not, the 270 chamber was very generous in the neck. Unless I ream the throat, I also have to load to a shorter COL. A neat thing I learned was Nosler 280 Ackley brass can be resized to work fine in the 270 Ackley chamber, so no fire forming is necessary!!
Here's the results, not perfect, but acceptable:
The 35 Whelen Improved likes the 200gr TSX, as I've experienced before with the TSX, the faster it's pushed the better they shoot and it was no different with the Whelen.
Tim
