Go- no go gauge question

[bobcat93]

Can some one tell me if a set of 221 fireball go, no go headspace gauges will work for 20 vartarg, and 17 fireball..I would assume there all the same but unsure..
I was going to have a barrel made in .20 vartarg for my model 12 Savage .17 fireball and would like to switch barrels back and forth with the use of only one set of gauges if possible to cut costs
Thank

 

[XBBR Shooter]

Not the same.

 

[Jammer Six]

They'll work as well as a set of .30-06 gauges.

 

[XBBR Shooter]

They'll work as well as a set of .30-06 gauges.

I don't think the 30-06 gauges will work very well.

 

[NorCalMikie]

You got brass? Use a full length resized piece for a gauge. That way you can set the headspace as snug as you want and keep the brass movement to a minimum when sizing.

 

[bobcat93]

Thanks smart ass..I don't think a 30-06 gauge will work..
With the .17 fireball, and the .20 vartarg being based on the .221 fireball case I would think the head space would remain the same.. considering the only difference is the neck size..
I thought the head space would be measured from the shoulder to the bolt head..I will have to check if the shoulder angel is the same on all 3 cartridges , and if that measurement is consistent..

 

[L.Sherm]

The 20VT shoulder length is shorter than the Fireball

 

[L.Sherm]

Let me rephrase this from the base to the start of the shoulder it's shorter.

 

[232]

221 is 23degree angle, vartarg and 17fb are 30degree. Datum line for 221 is measured at .330 diameter, and .300 diameter for the vt and 17fb.

Close but no cigar. A .311 or .312 bullet is close to a .308, but I won't go there.

Will not work.

 

[Jammer Six]

Thanks smart ass..I don't think a 30-06 gauge will work.

Well, you thought other random gauges would work.

Glad I could help.

 

[bobcat93]

232, thank you for your post that was the info I was looking for..
Was this question a brain fart?.. apparently log jammer thought so..
I guess even if the cases were the same other then case mouth dia. The shoulder angel would have to change.. that would then make sense to me why the head space length would change..

 

[johnfred1965]

232, thank you for your post that was the info I was looking for..
Was this question a brain fart?.. apparently log jammer thought so..
I guess even if the cases were the same other then case mouth dia. The shoulder angel would have to change.. that would then make sense to me why the head space length would change..

Glad you got a real answer for your question. Not a brain fart, nor is it a random selection as some less educated would think. Many families of cartridges can use the same headspace gauge, and wildcatters sometimes design cartridges to take advantage of this also. Good luck with your 20VT, mine is on financial hold right now!

 

[232]

bobcat93,

I have had my share of brain farts and have had a few farts that turned into a runny brown mess.

This is the neuternet, and you will get a lot of info that may be right or wrong, or be presented in ways that are not easy to comprehend the true gist of the information posted.

If you pm me, I can send you links to the saami specs for 221fb and 17fb, and also copies of ptg and grizzly prints for chamber specs of the 20vt, or you can search and find yourself.

As far as trying to measuring headspace at the shoulder, I really do not see how that can be done with any degree of certainty, at least with the equipment/skill set I have.

You could make your own mind up using a 17fb go for a 20vt. .0004 difference datum.

 

[Shaggy357]

If making a switch barrel gun, set both barrels to a center-line index off of contact with bolt. That way you screw in the barrel to index point, tighten the nut, and go shoot.

Steve