The "click" when extracting a case?

[adamsgt]

Sort of what I said. What I said was the resize reamer should match the dimensions of the brass. Many try but you can't resize the brass smaller than it was to start with and expect it to work. Except for the neck and shoulder it has already developed a memory from the manufacturing process. Compared to the resize reamer have the finish reamer made +.003" on the case head and +.004" on the shoulder. That has worked for me for 20 years now.

Dave

Dave, couldn't quickly find your post, hence the "I believe Dave said". My point is that a chamber reamer print does not necessarily contain sufficient data at face value to construct a re-size reamer. I got into this line of thought after playing with the Quick Design software and started thinking about what dimensions I would put on a cartridge drawing.

 

[Dave Tooley]

Yea

 

[feffer]

Actually, your experience is quite common for folks using Lapua brass in a tight chamber. Most of my reamers for .308 class cartridges spec. .471 at .200 in front of the bolt face datum. My reaming and polishing technique results in the back of the chamber coming in at about .472. This combination works perfectly as long as I size every time.

If your chamber is as close to the new brass size as your measurements suggest it may be difficult to size the base of the cases enough. If the small base die solves your problem all is good. If it does not, you could benefit from having the chamber polished up just a little larger.

Well, I've learned a lot from this discussion! Here's what happened after using the Redding small base FL "body" die. I had a very hard time adjusting it. I could get a very nice "feel" bolt close on my first case, but it would not work consistently with subsequent cases. Some were OK, others still very tight and still others resized too much! I don't think this was a matter of my adjustment or technique as I've set up many wildcat cases before. I think the brass may just have been too old and work-hardened. In any case, I seated the bullets to my normal depth...just off the lands. At the range, I had 2 burn-throughs in the first 5 shots. These occurred about 1/4" beyond the web. So I pulled the bullets and re-seated them into the Jam. This prevented any more burn throughs, but there was a clear bright line at that point which looks like incipient case head separation. I'm not sure why this happened except that these cases had been fire a LOT before, and maybe the resize just stressed them too much.

In any case, I decided I had to bite the bullet, throw that batch of RWS cases out and prep some new brass. Since I had some new Lapua, I used that. Turns out the Lapua brass was too big (at the base) for my chamber. They would NOT chamber and a scrap mark showed on the brass just a bit up from the extractor groove. Bummer! Finally, I went to some Norma brass that was also on hand and was able to prep it. Haven't shot or resized yet.