Flash Hole Deburring Question

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Former0302

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Minuteman
Oct 15, 2008
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Baltimore County
#1
I'm new to reloading. I'm working on case prepping my first batch of once fired brass.

I have a Sinclair tool that indexes on the case head. I have a couple of questions though.

1) It seems to open up the flash hole quite a bit. Is this an issue for .223 cases (e.g. does it take too much brass off the case head for a small primer / .223 case head)? This tool is universal, correct?

2) If I chamfer both sides of the flash hole (following Doc's tutorial on this board), will this weaken the case head to a dangerous level. I'm just a bit nervous about removing too much brass (especially for small primer cases). Once it's gone, you can't bring it back.

3) Am I just being too cautious about this whole flash hole prep step?

Replies are very much appreciated.

Cheers.
 
#2
Re: Flash Hole Deburring Question

i really would not get too wrapped around the axle on the flash-hole thingie.....just make certain there is a nice clear hole for the fire column to flash though.....

although there is much to learn from the Bench-rest crowd....one must have a life........and what ever you do.....DO NOT start weighing your primers......it is a sickness from which there is no escape.
 
#4
Re: Flash Hole Deburring Question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: former0302</div><div class="ubbcode-body">
1) It seems to open up the flash hole quite a bit. Is this an issue for .223 cases (e.g. does it take too much brass off the case head for a small primer / .223 case head)? This tool is universal, correct? </div></div>

You might want to check on this one before doing all your cases but I think the small rifle flash holes might be smaller then large rifle. I'm not where I can check a case but maybe someone is that can.
 
#5
Re: Flash Hole Deburring Question

1. The tool is universal for standard .080 flash holes so you should be fine.
2. I have never heard of working both sides of flash hole, just the inside. I have and do use a primer pocket depth uniformer though.
3. If you have the time, then by all means do the deburring. It definently isn't detrimental to accuracy and only has to be done once.
 
#6
Re: Flash Hole Deburring Question

17 and 20 calibers use a smaller flash hole as does 6.5x47 Lapua but 223 uses standard .080. I just ran a Lyman deburer in a Winchester and an RP case and they are both .080 hole.
 
#7
Re: Flash Hole Deburring Question

There have been some articles written about flash hole size in Precision Shooting and the general consensus is that .080" is fine for "standard" cases. I consider a .223 to be "standard". Some of the experiments opened the FH up so that it barely held the primer. It wasn't detrimental to anything but consistency.

Of the three steps you can do to a primer pocket removing the burr on the inside is most beneficial. Uniforming the pocket next and chamfering the outside of the flash hole last.

Be careful of a FH deburrer that indexes off the case mouth. It will vary the depth of your cut based on the OAL of the case. That's why I like the one that indexes on the web of the case.

Cheers,

Doc
 
#9
Re: Flash Hole Deburring Question

I try to keep it simple. I am not a BR guy, I just shoot for fun. From 100 to just under 700 yards, mostly with 308s. The rifle is also for hunting.

I have never messed much with the flash hole. After resizing and tumbling, I use one of the little RCBS tools that have the small brush made of thick wires. Cant remember what it is called, but it does a nice job of cleaning the black out. I only do it after every few firings.
 
#10
Re: Flash Hole Deburring Question

I use the Sinclair tools and find them very good. The flash holes on my 223 based cases are all the same. All my standard cartridges (mostly 308 size and 300 WM head size all use the same flash hole uniformer. I am unfamiliar with any smaller hole size except in the PPC family that uses a smaller flash hole and requires a different depriming pin and deburring tool.

Greg L.
 
#11
Re: Flash Hole Deburring Question

I grappled with this question recently. Since I was happy with the performance of Black Hills match ammo, I looked at their cases. It does not appear that the flash hole has been deburred. Some spent cases have a noticeable burr. On the other hand, I decided to debur my cases because it is not much work. I just use the tool to knock off the worst of the burr without removing much material.
 
#12
Re: Flash Hole Deburring Question

Former,

The deburring is a safe, easy procedure done through the case mouth; a little pilot (to fit into the flash hole) just forward of the cutter, which works with a subtle twist of the fingers as the burr is usually pretty minimal.

When I do a bunch of new or once fired cases, I'll chuck my tool into my cordless drill and run em off pretty quick.

As stated above, it only needs to be done once per case.

For the primer pockets, I just brush them out, also with the tool chucked in a drill. I'm all about productivity dammit!
grin.gif
 
#13
Re: Flash Hole Deburring Question

You would deburr the primer hole if hole was punched as in Win, Rem, LC. Lapua cases have the primer hole drilled and have no burr. Only deburr the inside of the case. You can use a uniformer on the primer pocket to make the hole flat bottomed. This would help in an AR to insure the primer is seated flush or below the case head.

Randy
 
#14
Re: Flash Hole Deburring Question

I've been using Doc's method for over a year now. If you have the tools he recommended you will have no problems. I've loaded some Win case's quite hot (46g Varget 175 SMK) Haven't had problems with flash hole degradation / burn through. Can't thank DOC enough for the post. Good info if followed to the letter.

PS.Don't load them this hot, this was only working up to most accurate load for MY rifle.

bshaw
 
#16
Re: Flash Hole Deburring Question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: doc76251</div><div class="ubbcode-body">There have been some articles written about flash hole size in Precision Shooting and the general consensus is that .080" is fine for "standard" cases. I consider a .223 to be "standard". Some of the experiments opened the FH up so that it barely held the primer. It wasn't detrimental to anything but consistency.

Of the three steps you can do to a primer pocket removing the burr on the inside is most beneficial. Uniforming the pocket next and chamfering the outside of the flash hole last.

Be careful of a FH deburrer that indexes off the case mouth. It will vary the depth of your cut based on the OAL of the case. That's why I like the one that indexes on the web of the case.

Cheers,

Doc </div></div>

That's precisely why I got Sinclair Gen II. Like all their stuff (well not ALL) it's nicely made and does the job.
 
#17
Re: Flash Hole Deburring Question

I once used the deburring tool which indexes on the case mouth and did not notice that the index cone had slipped. I ended up with flash holes which were considerably larger than normal.

Recognizing the potential for trouble, I loaded up three rounds with them and the normal recipe. Firing seems to have generated more pressure signs on the primers, but the rounds shot to the same POI

Accepting discretion before valor, I retired the cases and abandoned further research.

But three rounds do not a valid study make, and I am still wondering if anyone has looked into this phenomenon more deeply.

Well?

Greg
 
#18
Re: Flash Hole Deburring Question

My thinking is that the sealing function of the case base would be unaffected as the flash hole is remote from the primer/base seal. Strength in this region is more an instance of the chamber/bolt characteristics, rather than case dimensions.

I'm thinking the principal performance differences would be in the dispersion characteristsics of the primer flame front, and the effects of chamber pressures on the primer itself.

The POI similarities would suggest the former remains nominal, and the perceived pressure indicator increase on the primer would suggest some differences re: the latter.

But three rounds are not enough samples from which to draw a valid conclusion.

Greg
 
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