Last winter I bought a Lyman flash hole uniforming tool from Midway:
http://www.midwayusa.com/eproductpage.exe/showproduct?s...id=729748&t=11082005
I'm prepping some new cases and have them all trimmed to the same length, but I've never used this tool before. The instructions say to insert the cutter until it protrudes through the flash hole. I've tried several cases and on all of them the flash hole isn't large enough for the cutter tip to pass through. I was under the impression that uniforming just removes the burrs on the inside of the case left over from punching the holes. Is this tool supposed to cut the hole larger as well? The only way that cutter tip is going through the flash hole is if it enlarges it. I just want to make sure I'm doing it right before I ruin a batch of new cases.

The first obvious thing to check is to make sure you have a "large" uniformer for large primers and a "small" uniformer for small primers, and hope they didn't get mixed up at the factory. I use the same tool and sometimes a case will have a relatively tight opening at the beginning but I have never felt like it was doing anything more than just smoothing things out. If it feels like you are reboring a new primer flash hole then something is probably wrong.

Try it on a few loads and see what happens. Maybe it's a good thing. roger

I have found mine to be tight. You have to wiggle it a bit to get it in. I am not sure what make it is. You are right, the purpose is to remove the spurs on the inside of the case. You don't mention the caliber. I did find with some cases that the flash hole was too small (it grabbed the decappping pin on the die and pulled it out). For these I used a small drill bit. It was a particular manufacturer either Rem or Win. Mine only comes in one size.
Peter.

I have the sinclair uniformer, and from what I know, it only comes in 1 size. If it doesn't protrude, then run the drill until it cuts it's way through. You may very have run into the burrs on the inside, which is what the tool is made to remove.

quote:

The first obvious thing to check is to make sure you have a "large" uniformer for large primers and a "small" uniformer for small primers, and hope they didn't get mixed up at the factory.

I know primer pockets come in large and small sizes, but aren't the flash holes all the same size? I can't find a size designation for any of the flash hole uniformers I've looked at other than they work with .22 to .45 caliber.

I'm working with .243 Win brass right now. I've tried inserting the cutter through the head end of the case just to see if it would pass through with the same result. I've also tried it on some .223 Rem brass and it won't pass through those either. The only way I can see the point of that cutter going through the flash hole is if it bores it out larger, and I'm afraid that will ruin the cases.

Flash holes come in at least two sizes, but they don't vary in accord with the size of the primer pocket so much, as by who manufactures them.

Generally speaking, Prvi Partisan, Lapua, Sako, and some of the other European brass manufacturers tend to use flash holes of .068" diameter +/- .002", while almost all U.S. manufacturers use flash holes of .080" +/- .002" diameter.

I know that 20 years ago some BR equipment suppliers, such as Sinclair, used to supply flash hole uniformers in both sizes, as I have them both downstairs in the shop right now. Whether they still do or not, I have no idea. Seems to me that because of the taper in their design, the smaller one would work just fine in both size flash holes anyway, but being a gadget freak, I have the two different sizes of flash-hole uniformers from three or four manufacturers anyway.

PPC cases. RWS .222 Rem cases and several others have small flash holes. If you want a uniformer for small flash holes, get a PPC model from Sinclair or K&M.
- mike

The Flash Hole uniforming tool is one size. The Pilot Stop prevents cutting too deep. You can just see the tip of the cutter in the flash hole. Each caliber has a Pilot Stop.

So is the cutter supposed to protrude through the flash hole, or does only the tip of it enter the hole? I even tried it on a few pistol cases, same result. The directions included with the cutter are somewhat confusing. I measured the diameter of the cutter and its about .084"

Hello rowdy,

Just the tip "barely" showing. You have to look into the primer pocket in good light to see it.

All you want to acheive is de-burring around the inside of the flash hole. You don't want to re-cut this area and weaken the case.

Ok, thanks Thats all I needed to know.

You're more than welcome rowdy

Any more questions don't be bashful. We got the best and the brightest posting on AR. Someone here has the answer

As mho already noted, flashholes come in two basic sizes. 1.6 and 2.0 mm. RCBS also offers both diameter tools.

Don't force a tool that is too large into an otherwise perceft flashhole. Only if they are not uniform in diameter or too tight to let the decapping rod prodrude freely, I would consider opening them up.

If the tool, doesn't fit, but the holes as such are ok, just use a long 4mm (or similar) drill bit for metal. Mount it in a screw-in handle and CAREFULLY debur. Do NOT put on a taper. You want the flashhole to have a near 90 degrees edge on the inside of the case. Experiments have shown (sorry, don't have a source)that a taper on the inside edge will lead to an inconsistent dispersion of the ignition spark.

Also a word on the pilot stop. This is BS. For it be of any use two prerequisites would have to be fulfilled: 1. All cases are trimmed to the exact same length (ever measured your cases after trimming AND deburring?). and 2. All cases have the exact same web dimensions in relation to the rest of the case. If one of the two conditions is out you either get a taper or insufficient deburring.

The only thing that you can rely on when deburring flashholes is your fingertip feel.

This tool just deburrs the inside of the flash hole. All (AFAIK) US brass has punched flash holes and they usually have a small burr inside the case and around th ehole. This tool just knocks that off and is used only once for the life of the brass.

SO now do you want the theory or reality? Well, no time fo rtheory so here is the reality-if you havea true benchrest rifle and consitantly agg below .150, then this might take off .002 for you. For anyone else, it is pissing in the ocean. The theory of what the burr inside th ehole does is sorta out there, but if you are a top level BR shooter then every little bit counts.

But the good news is that it does not hurt anything to deburr the hole. If you like playing with your brass, then I would suggest you get the tool. I have one and have used it on some of my brass. Yes, I like to play with brass at time too!!!

Do it if it makes you feel good (a VERY good reason for doing it) but don't expect to actually see anything change on the range and surely not in the field. If you like minimum fuss with loading, forget it. At times I like to load ammo because it makes me think about future hunts coming up. At times like this I like to do extra prep work on the brass. It sorta increases the time I get to think about th ehunt and be actively involved in preparing for it

McFox:

There is nothing "B.S." about the use of a Pilot Stop. It safeguards against cutting too deep which is a plus for someone just getting started.

What is B.S. is your idea of mounting a drill bit in a handle and CAREFULLY debur.

Buliwyf,

as I already explained, the pilot stop will NOT keep you from digging in too deep on the one or other case. I won't explain it again.

Mounting a drill bit in a handle and deburring is not a just an idea but good practice.

Maybe you should sacrifice some brass by sawing them open after having done it both ways on a couple of cases. Then we talk again.

McFox:

I don't need you to explain anything to me. Mounting a drill bit in a handle is a bad practice. It is a worse practice for someone inexperienced. And, it isn't acceptable when preparing voume.

You need to choose your words more carefully about what is or is not B.S.

Buliwyf,

I didn't mean to offend you personally. My apologies for that. I was just trying to stress my opinion, which I meanwhile know you don't agree with. But that in itself shouldn't pose a problem, I hope.

Therfore, no hard feelings and keep on shooting.

No problems here.

Since the Lyman tool is beveled just past the tip, I never had a problem putting a SLIGHT bevel on the flash hole. I have, as Marc said, only seen small gains from it, and usually only do it in the very instances he mentions, when I just want to think about the upcoming hunt, etc.

Prvi Partisan 7x54 French cases from 10 years ago also have small flash holes, as do some .30-06 cases from both China and Korea. There are others too, in addition to the small cartridge cases like the .222 and the BRs.

On the other hand, most of the Remington-made 6 BR and 7BR cases I have on hand right now, have large flash-holes. NOT large primer POCKETS, but large (.080") flash HOLES.

Like mentioned before, it is more an aspect of who made the cases, rather than what size the cartridge is...

And, though I debur all my case flash holes just because more uniformity can't hurt, I have never seen where it did any good, either, even using my BR guns which are capable of groups in the 0.0s and 0.1s. But, if you feel good about your ammo, that alone sometimes helps you shoot better groups on a particular day.