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Milling an ammo holding block

Ledd Slinger

Silver $$ Contributor
I was thinking about making an ammo block to hold my cartridges near the loading port during a string of fire with a single shot rifle.

My question is, would it be ok to drill holes in an aluminum block slightly smaller than my case neck diameter, then chuck up my JGS chamber reamer in my mill and bore them out to make perfect fitting holes for the rounds? Thinking of only making 5 holes. Maybe 10. I wouldn't think milling aluminum will dull my reamer much at all, but that is the concern I have. Thanks for any input on this.
 
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I would think to tight of slip fit, probobly grab on you pulling one and slip out of you fingers.
I think you need more slip maybe .005-.010 now if you were only about .2-.4 deep it may not be an issue.
 
If you can't interpolate on your mill maybe you can pilot drill say .3125 and plunge a .5 endmill in there and have plenty clearance or a .5625 endmill if a short mag.
 
My plan would be to chuck up the reamer in my milling tool head and the aluminum block will be clamped in a precision vise on the mill table. No problem interpolating the reamer. There wont be any way for it to slip, nor will there be any fingers involved. My milling machine will be doing all the work.

I could easily plunge mills into the block, even do a controlled depth and ream and angle on the bottom with a smaller hole all the way through for the neck and bullet, but the point is for the holes to hold my cases as perfectly as my barrel chamber does. Main question is if this is a bad idea because I plan on using the reamer on another rifle barrel in the near future. Thanks
 
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Oh Your block will hold the case with the bullet down:rolleyes:
Ok I see makes sense now.
Try it and see, I still think it will be to tight.
Maybe after anodizing it will slip nice.
I don't think it would be a problem for the reamer as long as you aren't (interpolating) putting side pressure on reamer. You will probobly need a pilot hole .005 or more then neck of cartridge so only shoulder suports cartridge.
How deep from shoulder would you go?
 
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My use of the word interpolate was from a machinist use I'm not sure how you understand it.
I use it to describe milling a hole in a part larger the the size of the endmill.
Say a .501 slipfit hole with a .375 endmill.
 
Oh sorry, I'm new at machining. Bought a mill this spring and have been teaching myself while making all sorts of different things. Do a lot of rifle stock work with it. Don't know all the machinist lingo yet ;) I was thinking the literal meaning of interpolate which is to 'insert something into something else that it was not designed for. ie; inserting my reamer (designed for a lathe) into my mill spindle.

But yes, the plan is to have them bullet down so that they are facing the same direction as they will be loaded in the action. I will test the depths as I go to see how deep I want it. I have 3/4" thick blocks and bar stock that should work well enough. Might pick up some 1" square bar stock too. I can hone and polish the inside of the holes if they are too tight. I size the brass with a custom FL Whidden die that's perfectly matched to my chamber reamer. The sized brass fits my chamber perfectly with no tight spots. Anodizing is a good idea tho, hadn't thought of that...


I know the reamer is not an end mill so I will definitely avoid any sort of side loading on it.
 
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Sounds good
Maybe a great idea to do it that way, in my mind all I could see at first was bullet up the way I have seen others and couldn't see what you were doing.
 
Maybe after anodizing it will slip nice.

Depending on which type anodizing you choose, remember half the thickness builds on the surface, half in the top surface. So it can slightly reduce clearance. For Class III type 2, expect 1 to 2 mils, but this is worst case.
 
Depending on which type anodizing you choose, remember half the thickness builds on the surface, half in the top surface. So it can slightly reduce clearance. For Class III type 2, expect 1 to 2 mils, but this is worst case.
The anodizer can plug the holes.
 
For a ammo block, bullet down, just use the next size up drill bit of your neck diameter almost completely through your material. then repeat for the body diameter, just deep enough to hold yet leaving enough exposed to grab. There’s no need to risk your reamer.

And your going to need much thicker material than 3/4”.
 
For a ammo block, bullet down, just use the next size up drill bit of your neck diameter almost completely through your material. then repeat for the body diameter, just deep enough to hold yet leaving enough exposed to grab. There’s no need to risk your reamer.

And your going to need much thicker material than 3/4”.

Thanks. I'm a little worried about risking my reamer. Not because of cost, but because of the wait time and tho JGS is probably the best at making reamers to print specs, there's no guarantee a replacement reamer will be 'exactly' the same.

3/4" block will be fine. Plan to drill the 5 holes into it from the side. The blocks are 4" wide, plenty of material to hold a case, but I can cut the width down if need be.
 
For a ammo block, bullet down, just use the next size up drill bit of your neck diameter almost completely through your material. then repeat for the body diameter, just deep enough to hold yet leaving enough exposed to grab. There’s no need to risk your reamer.

And your going to need much thicker material than 3/4”.
I agree with this. The cartridge will never know the difference. Matt
 
Ahh, drilling from side, that sounds good. 3/4” should be plenty then. Post a picture when you’re done, I’d like to see it and I’m sure others would too.
 
This may be somewhat off topic but it does concern reamers. A reamed hole will only turn out as well as the hole the reamer is going in to. If you want a precisely reamed hole, drilling a hole followed by reaming won't work. Sometimes you may get lucky, most of the time, not. To achieve a precisely reamed hole you need to drill, bore, and then ream. Using a roughing reamer after drilling doesn't make things any better. A reamer will always follow the center line or axis of what was placed there before reaming. Hope this makes sense.
 

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