20 Vartarg SAAMMI specs needed; can't find

[Smitty550]

I am trying to reload some new brass cases and need to know measurement from base to the datum line as per SAAMI, plus max length, etc., so that I can set up my die and check it with the rifle's chamber. I am using a new Forster CoAx for the first time and don't want to bump the shoulders down too far, so I need to know the "ideal" amount to bump, using the SAAMI spec as a starting point.

I have looked everywhere on the internet, and the 9th edition of the Hornady Handbook has nothing. A drawing, such as Hornady provides for other calibers would be a great help.Todd Kindler is gone until May, so no help there, and the diagram in his "Terrific Twenties" is not helpful.

Any help would be appreciated.

 

[1raggedhole]

It's a wildcat, so there is no standard. Contact Todd Kindler at the woodchuck den. He is the originator and is very helpful. (330) 897-0614.

 

[1raggedhole]

You should contact gun/barrel maker for the reamer dimensions.

 

[JohnHenry]

Obviously I have no idea what your chamber spec is, but attached is a 20VT reamer print for the PTG reamer sold by Grizzly.com.

http://cdn0.grizzly.com/specsheets/t23225_as.pdf

PS: If forming your 20VT from 221FB brass you will have to bump the FB shoulder back because the FB shoulder is longer than the VT shoulder do to the difference in shoulder angles(23*FB vs 30*VT). One can compare the above 20VT print with the SAAMI minimum 221FB chamber print on the SAAMI website to see that approx difference.

 

[SS427]

You may be over-thinking this. Most 20VT reamers are designed around Todd's specs so unless it was chambered with a special reamer, I would set the die flush with the shell holder and size. If the case doesn't fit your chamber, set the die a little lower and try it again. With my Cooper 20VT, Redding FL die and an RCBS press, I had to set it up so the press slightly cams over to size the brass enough for it to fit the chamber.

Take a measurement after you fire-form the brass, and then set the die up so that it bumps the shoulder back about .002. If your chamber is anything like mine that amount of bump will happen at about the same place you had the die set up when you formed them.

 

[BoydAllen]

I read about guys bumping once fired cases a lot. In most cases, if you set your die to duplicate the head to shoulder length of once fired brass, and the die reduces the diameter of the case body a bit, the cases will chamber easily. This is because it usually takes more than one firing (neck sized) for a case to reach its maximum head to shoulder dimension. I think that the OP is making this way too hard, unless he does not trust his gunsmith, in which case he needs to order a go gauge.

 

[Shaggy357]

Take a brass in hand, attempt to chamber empty brass in your gun. If it fits, debur, prime, and load. If it does not fit, attempt to size brass with sizing die about 1 full turn up from shell holder. Does brass fit? If no, adjust die down 1/8 turn and try again. Repeat until action just closes on your new brass in your chamber. Good for first loading.....

 

[BoydAllen]

A full turn of a die is an adjustment of approximately .071". An eighth of a turn is approximately .009".