Ruger No. 1 in .218 Bee... It is shooting fairly well and I believe I have isolated the cause of some fliers.

There is a lot of variation in the rim thickness of this sorry brass I've been whining about. Out of 100 cases about 70 chamber with no resistance from the breech block, 25 will chamber easily but I can definitely feel the breech contacting the rim, the last five are very tight or won't chamber at all.

I've tried measuring them but can't get a good reading with what I have and have jury rigged. My best solution at this point is to just sort them by how they feel when I close the action.

It would be nice to be able to trim the rims to a uniform thickness. Failing that I would like something to accurately measure so that I could do a better job of sorting.

Any suggestions?

P.S. I full length sized this brass, only to expand the necks. The brass was sized as new way smaller than my die. I plan to neck size only for the next loading. I'm hoping this may ameliorate some of the problem.

At the point where you will most likely have to just do your best to measure with a caliper. After that you have to use a flat surface and some sort of abrasive. I would not get too concerned until after the first firing, then if you have concerns take the abrasive to the range with you and fit them as you shoot. I would however group the tight fitting ones against the other first as you may like the formers results. Just one of the quirks you may find, and not thinking of it ahead of time. Cases that headspace on the rim are always a concern until you neck size only.

Should be enough rim sticking out from the case body to gt a decent reading from a caliper...but sorting by feel will do the trick for right now. IF t he sorted ammo shoots better groups, then you've probably isolated the problem.

Am of the belief that tight cases tend to pre-stress the action a bit (basically get the tiny amount of "slack" out) and if shot mixed with loose ammo, would expect larger groups. No real telling which would shoot best in your rifle, the "tight" group or the "loose" groove, but seperating them would certainly help both.

Unfortunatly, less popular brass is often less well made...they keep the foming dies in service longer.

(NOTE, I was composing while NFG was posting, so some of this duplicates his information. His suggestion of an 8.9 mm drill comes closer to chamber reamer size than my suggestion of the leter S drill, being just 0.0002" over, while the S drill is 0.0022" under. A 9 mm drill is 0.0041" over, a letter T drill is 0.0072" over, and 23/32" is 0.0092" over.)

Looking at a picture of that cartridge, I can see why the caliper isn't working. The chamfer of the back edge of the rim is as big as the rim sticks out.

You need a surface plate and height gauge. Absent that gear, head to Lowe's or Home Depot or even a hobby shop and pick up a strip of 1/8"x1" brass. I would get it an inch wide. Cut off a 2" piece. Drill a pilot hole in the middle. Use a drill press if you have one, but if you don't, use a hand-operated drill centered through an oversize steel spacer held against the work. This lets you see that you are keeping the drill fairly perpendicular to the work. Run a 3/16" drill in, then 5/16", then 21/64", then 11/32". See if a case will drop down into the hole? If not, use a tapered reamer or a letter S drill to clean the hole up to size. Sized cases should fit in.

A 23/64" drill is a about 1/100" over chamber reamer size, and the S drill is about 2/1000" under (but bigger than SAMMI max for the case). However, a lot of fractional drills are actually a few thousandths undersize, so a 23/64" drill may or may not cut out too much. You can try, but be aware you'll have to start over if it is too loose. After making the hole, gently chamfer it so it lays flat against glass on the side you want to insert your cases into.

If you look at a standard 6" caliper, it is what is called a 4-way measuring caliper. The three obvious pairs of meauring surfaces are on the inside and outside jaws and the blind hole depth stem and the flat of the tail end of the beam. The often forgotten fourth pair are formed by the flat head ends of the jaws. As you open the jaws, these form a precisely measured step. This setp is wider than the beam end paired with the depth stem, so it is easier to get them into flat contact with a surface. You want to zero the caliper with the jaws closed, then open them bigger than the rim. Set the end of the beam's jaw on the brass plate in flat contact and up against the case rim. Close the moving jaw down on the face of the case head. Voila! Rim thickness measured!

(Note that if you don't drill the hole perfectly square, a little oversized may be good because it may let the case tilt just enough so the rim is flat on the brass surface anyway.)

I suggested brass here because it is easier to drill than aluminum and won't scuff your cases or hurt your calipers. You can also flatten it by spray gluing some wet/dry paper to a plate glass scrap and pushing it (always in one direction) across over and over until it is flat. A little honing oil really helps. If you have good tools and skills, an ideal gauge would be drilled, then hardened and ground and polished tool steel.

A more elaborate setup using a drill press starts by putting the same plate horizontal in the jaws of your drill press vice such that a case drops in freely. Chuck a linear dial indicator into the drill press. Set a spare piece of flat brass on the case head to cover the head stamp irregularities. Then adjust the table height so that when you feed the drill press quill all the way down, the dial indicator lands on the flat brass cover depressed somewhere into its measuring range. Zero the indicator (if digital) or set its dial marker at the needle. Repeat this for every case and it will give you the difference in rim thicknesses for sorting purposes.

Nice answers, NFG and Nick. Put on your thinking caps and come up with a plan I can implement with a plumb bob, chain saw and large hammer!

I worked in a high-end tool room for many years before I became a bean counter. The funny thing is, I never had these problems when I worked in the shop.

Somewhere around here in a box I have some unhardened tool steel that has been ground flat. I suppose I can still drill a hole.

If you were to try and have a trim die custom made who would be a good person to start with? Wilson?

. . . If you were to try and have a trim die custom made who would be a good person to start with? Wilson?

Wilson already makes two trim cutters to cover all case mouth sizes. They already have a holder for the 218. What is it you are trying to do special?

The rim, Nick. A hardened die with the internal case dimension cut and a counterbore for the rim. Drop the case in, file the head flush.

Here's a thought: Just use the Wilson trimmer backwards. It would be slow cutting, but with a spot of cutting oil added, it may work just fine. Set up one of your properly fitting cases in the holder and back the casemouth up to the depth stop. Adjust the stop until the casehead bottoms out on the cutter.

By the way, if you want to drill a hardened and ground plate, you're going to have to do it with a glass drill or other caribide tooling. Not for the faint of heart. I've drilled hardened Garand recievers before to modify them for a half MOA windage detent. I can tell you, when you start chipping a carbide drill, you get that old sinking feeling. You really want a very stable, rigid and vibration-free platform for that, like a Bridgeport mill.

I can see how the Wilson trimmer would work.

I just sorted another 100 cases and got 72 looseys and 28 tighteys but no more that won't chamber. I best accuracy test those tight ones before I go cutting on them.

I finally had a chance to try my sorted and reworked brass. The results are promising.
That wild shot on the far right target was not the rifles fault. Otherwise I believe it would have been under 3/4" also. Given the size of some of the four shot clusters I think these loads might occasionally yield a 1/2" group.
http://i88.photobucket.com/albums/k191/KGKILBY/Bee003rs.jpg

I loaded ten more of the Speers and gave it another try. I almost got my 1/2" group. Still, five consecutive five shot groups under an inch, with an average of the five at .728 beats the goal I had starting out. Neither rifle nor cartridge are generally noted as being inordinately accurate.
http://i88.photobucket.com/albums/k191/KGKILBY/Bee004.jpg