Ruger No.1 shop built chambering tool

  • Last Post 30 July 2019
MarkinEllensburg posted this 01 September 2018

In this discussion Scearcy asked for more detail on my shop made seating tool. Credit goes to my father as this was part of the inheritance. He mainly used it to push fixed ammo with oversize or long bullets into the chamber for his match shooting.

For my use as a breech seating tool first I took two decapped cases that have been fired in my rifle. In case one, on left in picture, I belled the mouth with an expander so that it would just go into the chamber. I cut two brass rods so that the bullet would drop in the case for starting into the breech. My thought was to push it in in short steps. I found this not necessary, although with harder bullets it might be. FWIW I'm using WW cast bullets. Case number 2, on right has a brass rod that is threaded on one end and the case is as well. this should make for uniform depth. My target is .080" past the case mouth. If this works I'll experiment with the final depth to see if I can dial in accuracy.

breech seating cases and rods

Next picture is the tool and cases together.

chamber seating tool


Close up of the top:

And bottom:

Finally how the tool fits in the action:

chambering tool in use

Note the action is one waiting for building with just a barrel stub screwed in. You might notice the safety is not standard. One of the first things I father changed on every No.1 he owned was to modify the safety so that it rides in a milled slot on the tang. With a button more streamlined than the factory bump.

As I mentioned in the other thread, it appears that a 1903-a3 bolt is nearly the same diameter as the round body. The rear locking lug also looks to be the right size for one side. If you had a surplus one that might be a good place to start. However if you have access to a lathe and mill it likely would be less trouble to start with steel and mill each part. This one has several visible seams  where my dad silver soldered it together. the golden part is what I had to replace and sourced a cut out from a circ sawblade that was otherwise junk. There it is. Let me know if you wish for more pics.

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frnkeore posted this 01 September 2018


Well done, it looks very functional and should do the job well.

For the initial setting of the piston, the way that a lot of ASSRA & ISSA shooters, set the depth is:

1. Install the bullet in the BSer, base forward, put it in the chamber and push the bullet against where ever it stops in the throat.

2. Measure that distance. In your case, it will be the amount that the piston rod protrusion to the case.

3. Remove the BSer and reset that distance. The amount that the base of the bullet, protrudes from the case mouth, is the setting that you want your piston to protrude, when you BS.

If you've ever heard of Russ Webber, that is his recommend start setting. I've used that setting info, for the last 10 years for all the rifles that I've built and even though I make my BSers adjustable, I've never had to adjust them, from that initial setting.

What it does, is set the bullet base at a point that it will seal and have the least base deformation, when the powder gasses hit it.


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Ken Campbell Iowa posted this 03 September 2018

here is a simple push tool for my ruger3 ...   kinda a 45-70 case on a stick, with a stub on the end to seat ball/bullet ahead of case .... ... middle is smaller dia. to clear factory safety ..  with the fat 45-70, drop the bullet down the chamber, slide in pusher, tap a few gentle taps with plastic hammer.... pusher stops on ""  case rim  "" built into pusher .   non-adjustable; this one seats deeper to get balls to hit rifling.

aluminum material doesn't scratch rifle.

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GP Idaho posted this 04 September 2018

Ken: That looks a lot like the Stoney Point (Hornady)  O.A.L. Gauge.    Just as a trial I might try B.S by tapping a cast bullet into my old beater M.N.  The style of shooting I'm involved in doesn't require the Nth in accuracy but I like to tinker with loading techniques. Gp

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mashburn posted this 30 July 2019


I like this simple idea.


David a. Cogburn

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