Forster Datum Dial and shoulder bump question

[cmoore806]

Trying to get my measuring tools figured out (new to this). Can I use the Forster Datum Dial set be used to measure shoulder bump or is that something only done with yet another tool?

 

[lash]

Well, I was not familiar with that tool and had to look it up. The answer to your question is Yes. Do you already own this kit? If so, you are good to go. Just make sure that you read and follow the instructions carefully. Then read them again and proceed.

For those that are not familiar with this tool either, here’s a link to the instructions how it works:

Datum Dial – Forster Products

www.forsterproducts.com

 

[cmoore806]

Well, I was not familiar with that tool and had to look it up. The answer to your question is Yes. Do you already own this kit? If so, you are good to go. Just make sure that you read and follow the instructions carefully. Then read them again and proceed.

For those that are not familiar with this tool either, here’s a link to the instructions how it works:

Datum Dial – Forster Products

www.forsterproducts.com

Thanks. Yes I already own it, I thought it was the same as a comparator for measuring headspace and cartridge length to ogive but with a lot of reloading tools they don't use the same terms (datum, shoulder, headspace) and they can be very difficult for a newcomer to make sure Im doing the right thing.

 

[Muley Buck]

Yes, that is exactly what it is for. Just make sure you use the right wheel and size for the cartridge you are measuring. If you have the kit the yellow/gold wheel(s) is for measuring loaded rounds Base to Ogive (BTO) or just bullets (BTO). The black one is for measuring from the datum line (shoulder) to the base (case head), this is the one that will measure "shoulder bump".

 

[cmoore806]

so really wherever the datum line is on the shoulder of the case isnt important. Whats important is using the correct consistent tool to measure and compare measurements using the same hole/dial.

 

[Muley Buck]

so really wherever the datum line is on the shoulder of the case isnt important. Whats important is using the correct consistent tool to measure and compare measurements using the same hole/dial.

Yes, as it relates to YOUR chamber.

 

[Muley Buck]

Also make sure you consistently put the dial kit on the calipers with the dial having full and complete contact on the opposing side. Check by holding it up to a light source and see if any light passes through. If so fix it so it doesn't.

 

[cmoore806]

Yes, as it relates to YOUR chamber.

My gut told me this. Because its not like you're measuring a specific location of the case and comparing it to a SAAMI specification or dimension or whatever. Makes more sense now. Thanks!

 

[wpgk58]

It will measure BTO CBTO Shoulder Bump easily. I have been using it for several months and find it very consistent. The only issue I have had is when changing dial to different caliber the center screw will loosen and need to be tightened up.