I don't want to spend a ton of money is the something ingenius out there or something that I can rig up. I have an indicator and a v block maybe that would work.

I took a 3" x 6" x 1/2" piece of flat steel, mounted a post for my dial indicator at one corner. Centered, 2" from that end of the base (will call that the short end), drilled a hole and pressed a 3/8" round stud (protrudes 1") to act as a stop for head of case. Moving .6" toward long end of the base plate, I drilled two 1/8" holes .650" apart, center to center. These holes are equally spaced on either side of the stud. Next, move 1" toward long end of base and drill two more holes same spacing as above. Move .60" further toward long end of base and drill two more 1/8" holes through base .650" apart.

Now, using 1/2" drill bit, drill each of the 6 (1/8") holes out to a depth of .30" to point of drill. Place 1/2" ball bearings in the two holes closest to stud to form V block for head end of case. For 308 Win. length cases, two balls are placed in the next set of holes and for 30-06 or longer cases move the balls to last set of holes.

Don't skip the 1/8" holes as they are necessary to push the balls out of their hole when moving for different length cases.

Have used this set-up for other special purposes, such as checking repeatability on target peep sights. Mounted a Redfield sight base on side of the plate and you can check both elevation and windage screws for repeatability.

Regards,
hm

I tried for 10 years to get a 1" group.
I tried to use a V block and dial indicator, but it did not work.
Then I bought a Sinclair concentricity gauge [$75].
I immediatly figured out that the expander ball system had to go.
But that same month I also tried a couple dozen other new things.
So I went to the range three times and have a .84" aggregate now on the first 14 groups with 72 gr bullets.

Like Clark, I sprung for the Sinclair gauge and really like it. Before that I used a homemade rig and it worked okay, but it was not in the same league as the Sinclair. Straight ammo does make a difference.

Sinclair makes Good equipment and concentricity is important to accuracy.

Having said that,however, if Sealdoggy wants to save a few bucks, the base described above works well.

All that is required is to support the case just forward of the expansion ring and just behind the shoulder while providing a stop for case head to assure that each case is positioned the same.

I have no problems getting sub moa groups from any of my rifles/loads using this device(Well, all except the 300 Win Mag Mod. 70 sporter, but it is now down to 1.1 moa 5 shot groups and we're still working on that one. ). My pet load w/30-06 shot 2.61" 14 shot group from prone position w/iron sights @ 600 yds.

Regards,
hm

I use the RCBS casemaster, wayyyy cheaper than the NECO, and shows me under .001" variations, so I would say it was well worth spending money on.