My OAL tool (HDY/Stoney pt) is probably obsolete now

[Hohn]

I feel a bit dumb for not thinking of this before.

1) Remove bolt
2) Chamber the OAL tool’s modified case with bullet. It is not attached to the tool here.
3) Slowly point muzzle downward to let bullet seat to lands
4) keeping rifle angled down, place the depth rod end of a 8” or 12” caliper against the base of the modified case by inserting it into the action from the rear. Close jaws and zero.
5) open the jaws until the depth rod touches bullet base. Record this.

6) measure BTO of the same bullet and add that to the recorded value from step 5.

Bam. You now have a precise CBTO value for gentle (gravity) bullet-on-lands. No need to strip bolt or remove barrel. No error due to consistent pressure applied to bullet. No measuring error because the Hornady tool rocks on the gauge.

Try it and tell me what you think. Most 6” calipers will be too short to span a short action, so you’ll need a larger caliper.

 

[Hohn]

When my longer caliper comes, I’ll post a video of how well this works.

 

[brokeasajoke]

Did you mean case base in step 5? Would a once fired case be more of an accurate measurement?

 

[Hohn]

Did you mean case base in step 5? Would a once fired case be more of an accurate measurement?

Once-fired doesn’t matter. You don’t even need a threaded case, just drilled big enough to let the depth rod of the caliper get inside the case and contact the base of the bullet.

You’re measuring the distance from the cartridge base to the bullet base while both are seated as far forward as they freely go.

Add that to the bullet BTO and you get a CBTO.

 

[284winner]

Once-fired doesn’t matter. You don’t even need a threaded case, just drilled big enough to let the depth rod of the caliper get inside the case and contact the base of the bullet.

You’re measuring the distance from the cartridge base to the bullet base while both are seated as far forward as they freely go.

Add that to the bullet BTO and you get a CBTO.

Good point. There's a better way to do this if you've ever seen Alex Wheelers vid. Seems to be a more accurate technique as often times using the OAL tool, the bullet gets too far into the lands and most people don't really know how far in that jam it actually is.

 

[Hohn]

Good point. There's a better way to do this if you've ever seen Alex Wheelers vid. Seems to be a more accurate technique as often times using the OAL tool, the bullet gets too far into the lands and most people don't really know how far in that jam it actually is.

Better is debatable. Alex’s method is excellent if you strip the bolt and use a custom action that supports such precise feel.

But what if you don’t want to strip the bolt? What if you use a Savage action with awful bolt lift?

This approach should give you the speed of the Hornady tool, but with much better precision and repeatability.

 

[284winner]

Better is debatable. Alex’s method is excellent if you strip the bolt and use a custom action that supports such precise feel.

But what if you don’t want to strip the bolt? What if you use a Savage action with awful bolt lift?

This approach should give you the speed of the Hornady tool, but with much better precision and repeatability.

Yes I see your point. I have Savage and Remington custom and non customs and his method works on them as well. While taking the spring out of the bolt body makes this method work, I understand many do not or cannot do it. I use my Stoney Point tool most of the time but for those that can't find one, Alex's method will work also

 

[284winner]

I feel a bit dumb for not thinking of this before.

1) Remove bolt
2) Chamber the OAL tool’s modified case with bullet. It is not attached to the tool here.
3) Slowly point muzzle downward to let bullet seat to lands
4) keeping rifle angled down, place the depth rod end of a 8” or 12” caliper against the base of the modified case by inserting it into the action from the rear. Close jaws and zero.
5) open the jaws until the depth rod touches bullet base. Record this.

6) measure BTO of the same bullet and add that to the recorded value from step 5.

Bam. You now have a precise CBTO value for gentle (gravity) bullet-on-lands. No need to strip bolt or remove barrel. No error due to consistent pressure applied to bullet. No measuring error because the Hornady tool rocks on the gauge.

Try it and tell me what you think. Most 6” calipers will be too short to span a short action, so you’ll need a larger caliper.

BTW Amazon sells them still