Modified case for Hornady head space tool

[PaddyD]

Well that was super easy. Went to MidwayUSA and they're selling these modified cases for anywhere from 5.49 to 12.00 + shipping depending on caliber. I made a wooden Collet out of a section of scrap 2x4. Drilled a hole through it for the case to fit in and then took my saw and partially split the block so it would squeeze down on the case. Clamped it in the drill press and used a 9/32 bit to drill out the primer pocket. Transferred it to the bench vise to cut the threads then back to the drill press where I flipped the case right side up and chucked another larger bit upside down and used it to swage open the case mouth so the bullet will slip in and out freely. For 6.99 I am now able to make these cases in about 10-15 minutes in my garage and they are custom sized for my rifle chambers. Screws on the tool and works just like the store bought item only better because I made it.. I just can't believe I never thought of doing it before I went out and bought the two I already had for the .223 and .308

[Zero333]

Nice.

I think I'll get myself the 5/16x36 tpi just so I have in "IN CASE" I ever need it.

Thanks for the idea of splitting the wood to hold the brass !

[Fat Albert]

People, you are over thinking the situation. The headspace gage that you should be using is what comes out of you rifle when you shoot it. Take those go-no go things and stick them up Hilarys rear end. A fired case tells you what the distance from the shoulder to face of your bolt is. If you have the Stoneypoint/Hor comparator system take out the fired primer and measure the distance from the datum point on the shoulder to the base of case. I use this measurement to set my sizeing die. Take you mod. case and then measure it the same way your did the fired case. Lets say that the mod. case is 0.005" less than your fired case. When you measure a bullet for seating depth with the mod. case you will need to add that 0.005" to the measurement to know were the rifleing is when you seat your bullets.

[Nor Cal Mikie]

People, you are over thinking the situation. The headspace gage that you should be using is what comes out of you rifle when you shoot it.

The "modified case" is NOT for setting headspace. It's for finding the distance to the lands. That measurement tells you how far the bullet has to jump to or jam into the lands.
I got rid of all my go/no gauges long ago. 99.99% of my rounds are Wildcats so SAAMI specs don't count. No factory ammo available and if it was, it wouldn't chamber anyway. The headspace on my rigs is set on the "snug side" so the brass doesn't have much of a chance to grow. Ever see any 6.8 BR or "20" TCM "factory loaded" ammo for sale?? Even factory loaded ammo won't fit. Tried it with some factory 6 BR. No Go!! I get 25 to 30 firings and reloads out of my BR brass. No trimming needed. All headspaces are set with new or once fired brass. Never any issues.

[PaddyD]

I don't think anyone here has been saying that these cases are to be used for anything but measuring COAL.. Especially not to be used for setting head space when installing a barrel. I think some brought up head space Go gauges to use to compare the store bought modified cases against to be sure the modified cases were within SAMMI specs. My whole point to this thread was wanting to make my own modified case. Since not all chambers are cut the same and largely are dependent on the tool used and the tool operating said tool, I wanted a modified case, custom tailored to my individual chambers and not a SAMMI spec one size fits all Stoneypoint/Hornady mod. case.

[Texas10]

I am in the same court with you Paddy. I made my own cases from FF brass but I FL size them and the seat a bullet a bit long. Slide it into the chamber with a firm push and retract. If it tends to stick, the bullet is in the lands, so I seat it a bit deeper and repeat until there is no tendency to stick. That is my distance to lands.

It's way easier and there's no guess work involved. This method will get consistent results to .001 and basically replicates the wooden dowel method of shuttling the bullet back and forth to "feel" for the lands, only you're shuttling the whole cartridge back and forth.

I keep and label my modified case with date, gun, bullet and OAL measurement, and use it periodically to measure throat erosion. Very easy to use and accurate piece of tooling.

[Phranque]

While I appreciate a good DIY, at $5.99 from Cabela's, I'd rather have one properly made.