sungazer wrote:I am thinking of making one of these does anyone have a few good pictures and tips for making on. Apollo anything you could pass on would be very appreciated. I have a small lathe and drill and taping or threading is no problem at least on the second try
The Tap you need is a 5/16-36 Tpi HSS available from a lot of places. Mine came from HSS a long time ago.
http://www.hss.net.au/product_info.php? ... cts_id=643 If you can wait they are about 1/3 the price on eBay from China. The correct drill is a 9/32" HSS but you can use one slightly bigger like 7.20mm. I have used one up to 7.5mm when I was trying to cut the thread in a cheap drill press but it wasn't near as tight a final fit.
In the small lathe I used a 3 Jaw Chuck and gripped the case head at the strongest point at the case head level with the chuck jaws so as to not put any pressure on the actual case body. Just tight enough not to slip when drilling. That was the only time the lathe was powered up. Swap the drill out of the headstock for the Tap and cut the thread by hand, slow feed and clear the cut numerous times until it is threaded all the way. Then swap the Tap out for a large drill or countersink and clear the Burr created on the case head so it is flat. Lube the Tap.
Before any of this for the Cases I wanted to use, typically two cases just in case. I FLS the cases then fired them in the Chamber twice to make sure they were fully fire formed. Check the case neck with a bullet to make sure a bullet slides down the neck into the case without any resistance at all. If not and some I have had were too tight for the bullet to fall into I would then neck turn some material off the outside of the neck and fire again. You could also ream the inside of the neck if you have the equipment needed. I then used a Primer Punch to remove the spent primer before drilling.
Other than the first FLS I do not touch the case again with a standard Sizing Die. You do not want to change the case in any way after fire forming.
I use a Sinclair Comparator Nut &/or Sinclair Comparator Inserts and Mitutoyo Calipres for taking measurements several times or more, especially if I'm seating bullets on the lands or a couple of thou off the lands.
I have a Modified Case or two for every Rifle/Chamber I own as well as a couple of friends chambers.
Hope I covered most things, it's been some time since I needed to make a Modified Case.