A simple flash hole deburring tool that does not chamfer the hole?

[chkunz]

Has anyone actually proven improvement, if so how, & where, after " primer de burr flash hole"
Group size, documented chronograph readings. We all have our little quirks, or anal thinking about everything we do or try. My question is how or in what way does it improve. Where is the documentation?

My point exactly! See my post above.

Making important decisions with insufficient data and rigorous data analysis bothers me a lot more than deburring flash holes.

 

[RegionRat]

I haven't "had to do it" in a very long time. However, a generation ago we were trying to make a silk purse out of a sow's ear and it was easy to find brass with very bad flash holes in both commercial and surplus brass.
Would it go bang? Yes. Would it work for serious 600 to 1000 yard work, no. So we did what we had to back then.

 

[Homerange]

I haven't "had to do it" in a very long time. However, a generation ago we were trying to make a silk purse out of a sow's ear and it was easy to find brass with very bad flash holes in both commercial and surplus brass.
Would it go bang? Yes. Would it work for serious 600 to 1000 yard work, no. So we did what we had to back then.

And today.
Other than precise charge measurement and weighing primers, camphering and uniforming flash holes has the greatest effect on ES when a Pet load is found.
Target don't need to tell us this when we have a chrony......

 

[cptjack]

the one I use has a stop collar ,can adjust for no camper

 

[fkimble@charter.net]

With a hand turning tool, you can easily tell if there is a burr and easily tell when the burr has been removed. It would be very hard to damage a flash hole unless using a powered drill. Even then the average person would realize it was time to let the trigger go.

Just use a hand collet with needed drill bit size.

And the burr is frequently not in the hole but pushed back inside the case so a slight chamfer is really needed to actually remove the burr.

Frank

 

[wildcat3d]

K&M advertises that their tool chamfers as well as deburrs. I suppose that many reloaded just use a tool like that lightly, so that they don't end up cutting into the brass to chamfer or enlarge the flash hole, but I guess I might ruin some brass accidentally chamfered the hole when I don't want to.

The Wood River pin vise from Woodcraft.com, plus a drill bit of an appropriate size, looks like an interesting potential diy solution.

I used the K&M tool on my 220r match brass for many many moons and have yet to Ruin any brass...

 

[AlNyhus]

For those that have never uniformed flash holes, even Lapua flash holes can be significantly mishaped.

For those asking for data as to whether it matters, why not run your own A-B-A test and find out?

 

[Retired shooter]

Where is proven data that shows it improves anything.
Does anyone concerned with flash hole debur use a bushing inside case mouth that matches OD of debur tool to insure concentricity and angleuarity of flash hole after debur.

Seems to be one big rabbit hole.

 

[DShortt]

You may be right but not so much more than a lot of topics that are taken seriously on this forum.

When I first started reloading in the 1960s I was told that flash hole deburring was important and I have heard it many times since but have never seen any data supporting the practice. I have examined many cases and have been appalled at how bad the flash hole burrs look.

It is easy to fix and the cases look better so I do it. I have a technical education and understand aerodynamics so I feel better about doing it and do not think it can do harm.

Making important decisions with insufficient data and rigorous data analysis bothers me a lot more than deburring flash holes.

Best wishes.

I didn't explain my thinking very well. I can easily understand knocking out the burrs. What I question is why worry about a small champher on the back side of the hole?

 

[Rat Rifle]

I didn't explain my thinking very well. I can easily understand knocking out the burrs. What I question is why worry about a small champher on the back side of the hole?

Why Worry indeed ? To Me, You just answered Your Own Question.

 

[AlNyhus]

Where is proven data that shows it improves anything.
Does anyone concerned with flash hole debur use a bushing inside case mouth that matches OD of debur tool to insure concentricity and angleuarity of flash hole after debur.

What does your testing show?

 

[Blowout]

This is what the head of the K&M looks like. The chamfer looks minimal and there is a stop to set the depth. The shaft of the tool has a collar to also set depth if desired. This would be the tool to do what the OP is asking.


For precision reloading you want to take out all the variables between case when prepping. I've come across enough cases where there were large burrs on the inside left from the flash hole being punched out that deburring is part of my case prep process for precision loads.

 

[DShortt]

Why Worry indeed ? To Me, You just answered Your Own Question.

If you read the first post, that's what started this thread. It has since changed to a discussion about deburring at all.

 

[Straightshooter1]

Where is proven data that shows it improves anything.
Does anyone concerned with flash hole debur use a bushing inside case mouth that matches OD of debur tool to insure concentricity and angleuarity of flash hole after debur.

Seems to be one big rabbit hole.

Like this one where there's a bushing inside case mouth that allows the deburring part to rotate inside the bushing?

 

[Jon Leary]

This site could easily be renamed as Overthinkers Annonymous.

No kidding. Beyond annal.

 

[Jon Leary]

Now some one has tested chamfering the primer side of the Flash hole and that showed improvement in consistency.

 

[AlNyhus]

Now some one has tested chamfering the primer side of the Flash hole and that showed improvement in consistency.

Yes, it's been tested.