Gunsmithing Custom Reamer

[CanSniper]

Starting to put together my next project. Looking for some advice/direction. That way I don't screw it up from the very beginning.

The build is going to be a AR15. 6mm Grendel, high end heavy barrel like a Bartlien. Probably going to run 95 SMK. I want to make up some dummy rounds that fit the mag and then have a reamer ground to fit and touch the lands from the mag.

I have never been this route before.

#1. Do I need to get a roughing reamer and a finish reamer?

#2. Do I get the reamer cut exactly how I want it, or short throated and then have a Smith custom finish the throat? (Don't really know if that is even possible)

#3 Any thing else I might need to know?

Thanks in advance!

 

[fdkay]

No, you don't need a roughing reamer, unless you plan on chambering a lot of barrels.
If you want to have it short throated and use a throater, you don't need to provide dummy rounds to the reamer manufacturer, just to your gunsmith. Just work with your smith on it.
Your bullets won't touch the lands for long, while the 6mm grendel is not extremely overbore, you'll likely be running at high enough pressures to wear that throat.

 

[Supersubes]

Just a finisher. Lots of Smiths use throat reamers. That’s a not a bad way to go. Have you figured out what sizing die you want to use? The 6mm Grendel has been done quite a bit, and there are many variations. Have you considered contacting Robert Whitley and having him do your upper?

 

[mcfred]

#2. Do I get the reamer cut exactly how I want it, or short throated and then have a Smith custom finish the throat? (Don't really know if that is even possible)

If you have a pile of components you intend to use with the cartridge and you intend to spec/purchase a reamer, you can load a few dummies and measure the loaded cartridge neck OD. Take that average diameter and add .003-.005" and you will save some wear and tear on your brass from sizing. This is sometimes called a "no-turn neck." However, if you don't have any ammo/components, then you might err on the side of loose to save yourself the possibility of having to neck-turn hundreds of cases.

Of course if you have a reamer specced with large diameter features, you can send the reamer back for additional grinding later to shorten throats, shrink neck diameters etc. You can remove material, but can't put it back.

 

[CanSniper]

Thanks for info guys!

Have you considered contacting Robert Whitley and having him do your upper?

I had looked at his web site a little, but it doesn't seem to work very well. Is he a good Smith? I might give him a call. I am sure he could supply dies. My plan was to use my existing 6ppc die for the initial neck down, just not tighten it down all the way. Then I figured I could use Redding 6.5 Grendel dies with the appropriate 6mm bushing and seating stem...thoughts???

 

[Supersubes]

Thanks for info guys!



I had looked at his web site a little, but it doesn't seem to work very well. Is he a good Smith? I might give him a call. I am sure he could supply dies. My plan was to use my existing 6ppc die for the initial neck down, just not tighten it down all the way. Then I figured I could use Redding 6.5 Grendel dies with the appropriate 6mm bushing and seating stem...thoughts???

The website sucks for sure. I’d call them if you have questions.


I designed my own reamer for bolt gun use, and bought his 6mm AR die. The couldn’t find an standard Grendel bushing die at the time. Whitley’s is a Redding type S, which means it’s middle of the road quality, and wildly overpriced($200 delivered I think). It does work though. He said his chamber was special, but I took a casting of my 6mm AR die before I finalized my reamer, and it appears to be a standard Grendel necked down.

My gripes with overpriced redding stuff aside, an upper from him would be easy button. I don’t think he’s doing the gunsmithing, but he’s an accomplished shooter, so the work must be good.

 

[jzerfoss]

If you call JGS they can walk you through all of this and get you the custom reamer you need. Their quality is awesome.