OAL gage (homemade)

[Bob S.]

OK guys here are a couple of pics of the homemade OAL gage I made from 1/8" brass rod a plastic sleeve on the end to keep it almost centered in the bore and two sight pin clamps from one of my bowsights. I hope the pics are ok. My wife takes them cause I'm not allowed to handle her camera.

Obviously this measures from bolt face for one measurement and bullet tip for the other. After the OAL is determined to the bullet tip the same bullet is used to make a cartridge that length to the tip then a ogive tool is used to get the ogive length for that loaded cartridge. Now I can measure the rest to the ogive for a more consistant length.

 

[Buffalobob]

A picture is worth several thousand words. It took me all three pictures to understand why someone with a set of calipers would build such a contraption. What you have built is a MAXIMUM OAL gauge. Then you work backwards to get to the lands Tens times as much effort but much more accurate than magic marker on the cleaning rod approach.

Its obvious that your wife took the pictures because are they sharp, clear and well focused. /ubbthreads/images/graemlins/grin.gif

P.S. You lose, your contraption is not dumb enough. Better luck next time.

 

[sewwhat89]

This may be a dumb question, but why not use a loaded round to measure the OAL/ogive length? I have always just adjusted my seating die to the OAL I want based on my gun. When I get to where the bolt almost closes, a little swaging on the seat depth, and there is the OAL/ogive length maximum for that particular rifle. I guess that works for me since I only have more than one gun/die in only one caliber, 300 SAUM. As coincidence would have it, brass shot in my Model 7 will not chamber in my Sendero, but both guns shoot the same exact OAL best. Am I lucky or is my method the poor man's equivalent?

 

[Centre Punch]

Nice tool Cowboy, and infinately more variable with your adjustable stops, beats having more then one rod to do the job. Did not think of that when i made mine /ubbthreads/images/graemlins/frown.gif

Ian.

"I meant to shoot the pike but the duck got in the way"

 

[Bob S.]

BB - Oh you want dumb contraptions do ya. I'll have to look and see if I can find one that actually caused damage!
Yes its for determining oal to the lands and then working backwards. Much the same way the stoney point oal gage works but when you get away from the standard calibers you need to have a cartridge modified by them and it starts to get expensive. This thing cost me all of about 3 bucks. Thanks alot now my wife won't ever let me use her camera. /ubbthreads/images/graemlins/mad.gif

SW89 - not a dumb question at all, thats how I have done it till now. I was looking at knowing how far to the lands so I can be a little more precise than a swag. I'm not calibrated enough to know by feel if its the bullet on the lands or the shoulder not bumped enough or whatever. Obviously this has its limits as well since I am measuring to the tip of the bullet and then converting to the ogive after the round is loaded. Using the same bullet to measure to the tip and make the first loaded round takes some of the inconsistancies out but still I feel its more accurate than bolt closing force.

CP - I can't take credit for the idea someone posted a reply to my question on determining oal and had this very tool(similar) he bought many years ago. I can't remember who it was but could go back and look. I tried the marker on the bullet method but wasn't able to accurately tell if I had land marks or not.