Hal--If you look real close at the second photo in my post above, you should be able to see "17 Rem" and "194 NK" stamped on the left side of the barrel. It is a .1945" neck and that is what you would call a tight-neck chamber. Most SAAMI chambers probably measure somewhere around .200" to .202". One reason I went with this neck diameter was because of the crappy neck wall thickness on Remington brass. I had several thousand .17 Remington casing on hand and the ones that I measured neck thickness on with my Mitutoyo tubing mic were about .01235" all the way down to as thin as .00980". To get uniform neck thicknesses on all my casings I turned them down to .00985". The neck diameter on my loaded rounds measures about .1917" to .192".
The rifle shoots pretty decent. I am still working to find the magic load with some 27.8 gr. Hammett BTHP bullets. I did some experimenting with Danzac, but will be trying hexogonal Boron Nitride when the wind goes down and it warms up enough to get out and do some shooting at the range.
Right now, with the 27.8 gr. Hammetts I am trying to decide between H4895 and N-540. For the 25 gr. Hornady HP bullets I use 23.2 gr. of H4895--not real fast, but very accurate. With the 25 gr. Hornady V-Max I have tried Varget, H4895, N-135, and N-540. The 25 gr. V-Max seem to want to tumble once in awhile out of this rifle??? I shot a bunch of the 25 gr. HP Nagel bullets using 21.8 gr. of N-135 with good success. I tried the 30 gr. Kindler Golds and no matter what powder or load I used, I got shotgun-like patterns
The little 27.8 gr. Hammett does a number on prairie dogs. When I was using the bare bullets I had a load of 24.8 gr. of N-540 and was getting 3,998 fps at the muzzle. With Danzac coating on the bullets and a load of 25.3 gr. of N-540, I am getting 4,017 fps at the muzzle. Here's what the little 27.8 gr. bullets do to prairie dogs from around 125 yards.
Here's a double I got at 170 yards in distance.