Flash Holes and Primer Pockets

[quicksylver]

Just curious as to how often and what do you use to clean your primer pockets and flash holes.

Lately I have taken to "Clearing" my flash holes with my Lee hand case trimmer.

I have found the tip of it to be larger than the decaping pin on my neck sizing die, so a quick
push trough seems to make them more or less uniform, no necessarily the correct diameter
but consistent.

I do this every third firing or so, at the same time I clean the primer pockets.

Like to hear about your practices on this topic.

Thanks ...Dan

 

[Rick]

Primer pockets are all uniformed with the Sinclair tool to max SAAMI spec, all primer pockets on all brass. Flash holes are uniformed from the inside of the case because they are punched rather than drilled when making the case leaving a bur on most cases. New brass is always checked for the flash hole being centered but the size of the flash hole is left as is.

 

[RicinYakima]

Well, new brass to be used for matches gets the Whitetail Uniformer that flattens the bottom of the pocket. Plinking stuff gets nothing, but ex-military with crimps goes through the Wilson cutter. After the first time, just a twist with the Lee two ended scraper. Flash holes only get looked at if they pull the decapping pin.

 

[Rick]

After firing each primer pocket gets "cleaned" with the same Sinclair tool. Pressure inside the case is uniform in every direction and that includes against the web of the case. Every time the case is fired the primer pockets slightly shallower not to mention the build up residue and cleaning the already uniformed pockets keeps the depth uniform through multiple firing. Varying the primer pocket depth has an effect on firing pin strike and thus consistency of the ammo and inconsistent ammo will effect groups

 

[quicksylver]

Varying the primer pocket depth has an effect on firing pin strike and thus consistency of the ammo and inconsistent ammo will effect groups.

Ric...this was my concern, cleaning the primer pocket inevitably (IMO) would remove some brass, either from the bottom or the sides, either way ,not good.

But the build up of residue is also problematic.

So seems like "easy does it" would be the way to go.

 

[JWFilips]

Gee! Now you got me thinking….I clean my primer pockets each firing with the little RCBS wire brushes chucked up in a mini B&D cordless screwdriver….Now I hope I'm not overdoing it! Never touch the flash holes, However.

 

[KHornet]

I inside deburr all primer pockets. Sometimes clean primer pockets (yes I know, should do it all the time). Did a test a number of years back with 06 cases, 50 ea with primer pockets cleaned, 50 without pockets cleaned. Could see no difference (at the time).

 

[RBHarter]

I haven't reached a point .....or a rifle grade where it makes a significant difference. Most of my brass is decapped before I tumble and most of the time most of the carbon is out of pockets.
I have spent a lot of time cutting pockets in crimped brass , I have a pocket swager now so I hope the cutting is in the past .

 

[Josh]

I like to say "it doesn't matter till it matters" I like to start my loads for a new rifle with as little variables controlled as possible. I will use mixed brass, unweighed bullets, and OAL's that vary by the die. Once I get the coarse adjustment taken care of to get a good group I then start to do the fine tuning, same HS brass, same OAL, same trim length, check primer pockets.

Some rifles will never shoot better by doing the small stuff, and there is no need to waste time with case prep that doesnt matter.

 

[Rick]

It's like any of the bench rest steps taken to improve accuracy, in a firearm capable of seeing the difference several of these steps added together can and does improve consistency and thus accuracy. In the average off the shelf hunting rifle not so much, in a firearm capable of good groups improvements can be made but none of these steps such as neck turning or primer pocket uniforming will turn a sows ear into a silk purse.

I started primer pocket uniforming for long range handgun competition but continued with it for all of my brass. I had a couple of thousand pieces of once fired WW 45 ACP brass from the LAPD & thought it's just plinking brass, no need. To my surprise this brass averaged 1 in every ten with shallow pockets and high primers and slam fires. Since then all my brass gets the pockets done with the Sinclair tool. Most important is brass for my M1A, specs for this brass calls for seated primers to be .005" below flush because of the free floating firing pin.

In addition to cutting the pockets to max SAAMI depth I have rigged up a system of putting the same amount of pressure for the same length of time on every primer. All primers are seated completely bottomed out against a cut flat primer pocket with a slight crush.

Cutting all primer pockets on all brass can be a PITA but it is a one time operation for each lot of brass just as is inside flash hole uniforming/deburring. I use a power tool with the Sinclair tool and I can do the pockets on a 100 count box of brass in about 20-25 minutes. Once the pockets are all cut uniform using the same Sinclair tool to clean the pockets after firing a 100 round box is about 10 minutes.

These steps no doubt are not for everybody but for me and my time invested it's far more than worth the effort.

.

 

[Josh]

It's like any of the bench rest steps taken to improve accuracy, in a firearm capable of seeing the difference several of these steps added together can and does improve consistency and thus accuracy. In the average off the shelf hunting rifle not so much, in a firearm capable of good groups improvements can be made but none of these steps such as neck turning or primer pocket uniforming will turn a sows ear into a silk purse.

I started primer pocket uniforming for long range handgun competition but continued with it for all of my brass. I had a couple of thousand pieces of once fired WW 45 ACP brass from the LAPD & thought it's just plinking brass, no need. To my surprise this brass averaged 1 in every ten with shallow pockets and high primers and slam fires. Since then all my brass gets the pockets done with the Sinclair tool. Most important is brass for my M1A, specs for this brass calls for seated primers to be .005" below flush because of the free floating firing pin.

In addition to cutting the pockets to max SAAMI depth I have rigged up a system of putting the same amount of pressure for the same length of time on every primer. All primers are seated completely bottomed out against a cut flat primer pocket with a slight crush.

Cutting all primer pockets on all brass can be a PITA but it is a one time operation for each lot of brass just as is inside flash hole uniforming. I use a power tool with the Sinclair tool and I can do the pockets on a 100 count box of brass in about 20-25 minutes. Once the pockets are all cut uniform using the same Sinclair tool to clean the pockets after firing a 100 round box is about 10 minutes.

These steps no doubt are not for everybody but for me and my time invested it's far more than worth the effort.

.

I wasn't implying your case prep didn't matter, I have a Ruger Precision Rifle in 308 that the small stuff makes the difference. It can be frustrating how picky a precision rifle can be to shoot groups you know it is capable of.

I was just implying that it isn't necessary for all rifles. My milsurps are a good example, while they shoot very well, none of the advanced techniques make them go from 2" to 1" at 100 yds. When I do all the case prep, check runout, and uniform bullet tips (smk's) for the RPR my groups shrink from roughly 3/4" to around 3/8" on a good day.

 

[Ian]

Most all of my primer pockets get cut with the appropriate Redding uniforming tool. This makes primer seating MUCH more consistent and uniform, and eliminates proud primer syndrome when loading on a progressive press with mixed-headstamp brass. Only occasionally do I debur flasholes, I don't do the kind of shooting where that has really ever proven worthwhile.

 

[Rick]

Josh, my post wasn't directed at you. I was simply explaining what I do and why and how I see it.

As for the inside flash hole deburring many years ago I saw a series of high speed photographs in still frame of primer detonation. They used brass with all of the case body removed (nothing left but the case head) and an action with no barrel and photographed the primer flash of several different primer types. Some of the brass had the flash hole deburred, some didn't. The brass with the flash holes uniformed had a beautiful round cone of flame. Some without deburring was a lopsided finger of flame to one side only. It was an incredible article and extremely well documented, it left a permanent impression on me and all of my flash holes get deburred. I can't remember where that article was, possibly Hand Loader or maybe the Rifleman back in the day when the Rifleman actually had worthwhile articles.

 

[Tony]

My procedures are very much in line with Rick's. Where Rick uses a drill I use a Sinclair adapter to hold the Sinclair uniformer in a Forster DBT base and perform the operation manually. Rick's method may be a bit faster than mine.

 

[Rick]

No drill . . . Rick made this, does everything to brass that you don't need a press for. No, all that brass isn't from primer pockets. Here it was turning 414 Super Mag brass into 41 Mag. I made an adapter to hold the Sinclair tools for the primer pockets and several other tool mounts.

 

[smokeywolf]

I always clean primer pockets; use a single ended long reach, four flute endmill, held and spun by hand. Like RicinYakima I use a Wilson tool to cut the crimps out of old military brass. Only clean flash holes when they start appearing like they need it. That's typically every 3rd or 4th reloading. If I feel the need to deburr a flash hole I usually use a long center drill; again, spun by hand.

 

[Tony]

Rick, thanks for the photo!

 

[RicinYakima]

When just cleaning primer pockets, especially with the sharp Lee tool, the tool just lightly touches the pocket. I just want to get the black lumps out so the legs of the primer are seated flat on the bottom. Modern brass that has the flash hole lanced instead of drilled, often is not flat on the bottom. The lance seems to push the bottom of the pocket inward.

 

[Rick]

If I feel the need to deburr a flash hole I usually use a long center drill; again, spun by hand.

That's what I use also. It can't be seen in the picture but on the left side of the machine is the output shaft of a DC gear motor that runs at 60 RPM. I have the center drill in a tool holder that mounts on this motor and that's what does the inside flash hole deburring. On the other end of the machine are two output shafts that hold chamfer/debur tools at 800 RPM.

 

[Brad]

I use a Sinclair tool for primer pockets. I use a LR tool even on LP cases. Yeah, the primer is seated deeper but it has never given me problems. I also know the primers seated such will never be an issue in a lever action.
That said, not all cases get reamed or even cleaned up. I sure don't clean the pockets on mass produced handgun ammo for 9 mm, 38 special, or 45 ACP.
Rifle cases get the flash hole deburr job done with an RCBS tool and a cordless drill.

Cordless drills are an awesome way to speed the process and save wear and tear on the wrists. I even use a Sinclair tool to hold my case mouth deburr and camp her tool. Makes that a quick and easy job.

Case prep done is in proportion to the desired results. Ammo to be shot at close ranges on large targets gets little work. Ammo to be shot on more demanding targets or at longer ranges gets more prep work.