Originally Posted by Al_Nyhus
Originally Posted by Swifty52
Make your own as it’s simple.

https://bulletin.accurateshooter.com/2015/04/make-your-own-modified-case-for-hornady-o-a-l-gauge/

5/16x36 tap 10.00. L or 19/64 drill bit and in 5 minutes time you gots a modified case.

Copy/paste is nice but reality is usually different.

A "5 minute" job sounds nice but that's not the reality of making these. Besides the back end drilling and tapping, the neck I.D. needs to be either honed or reamed so the bullet is a slip fit in the neck. If you're doing it in a lathe, you can't just clamp the chuck jaws on the case....you need a way to hold the case in the chuck as the drilling and tapping takes quite a bit more pressure than people think. Unless they've actually done them, of course.

For anyone contemplating doing these at home in a drill press or whatever, use an 'M' bit rather than the 'L'. The 'M' is .005 larger and while the resulting threads will be a bit more shallow, it won't be functionally significant and the tapping effort will be quite a bit less.

For the home hobbiest, you can 'hone' the neck I.D. with a piece of 320 grit rolled tight and inserted in the neck while the case is spinning. Keep checking it often and stop when a new bullet is just a nice slip fit. If the bullet fits sloppy in the case neck, the reading you get will be inaccurate as the bullet will tip in the neck and not contact the rifling evenly.

Before I had a lathe, that's how I did mine....and I'm not very smart. But any hobbiest with basic skills and bit of thought can accomplish this at home. smile

Seems you go about it the hard way. And all I copied and paste was a link to which I never said was the easiest way to do it. No you don’t have to ream the neck ID.
If for multiple same caliber I take a fired case from the smallest chamber, run it through a body die if it chambers hard in the rifle it was fired in, if it goes into all easily all I do is go to step 2 since it naturally has a slip fit from being fired.
Then all one has to do is drill and tap which by the way Amazon sells the whole kit. I used a 19/64 bit which yes the threads are a little shallower but since you aren’t putting it under a strain it doesn’t matter.
So yes since I do have common sense and mechanical ability it only takes 5 minutes unless you want to make it harder doing it the way that article and you state.


Swifty