How important is primer pocket/flash hole prep?

[338 dude]

Bill I happen to have that exact same Harbor Freight work bench...my press is on the right side...I also have a set of the heavy duty shelves to hold bullets, boxes of loaded ammo, powder and "stuff"

It's a great bench for the money I have no problems with it whatsoever there are a lot of other areas I would like to improve on but my bench would be dead last

 

[Scott E Ames]

Like those above I do both because a very smart benchrest shooter taught me to reload and said I should do the inside flash holes and ream the primer pockets. No evidence it helps but it will make you smile to clean the fired brass with the pocket reamer as it shines like the top of the Chrysler building with only a 1/2 twist of the tool. Probably an OCD thing mostly.

 

[Capt RB]

I don't dispute your results but do you think your improvement could be attributed to case volume consistency after fireforming? That said I DO deburr and uniform, at least until I started using Peterson brass. The pockets on these are too tight for my tool.

I use peterson in the 6.5 creed Lapua and LC118lr in the 308 for matches or when I need to make a point in a class. These are all uniformed to produce the same result. I neck turn to make sure each piece is round not for a tight neck but round as close as possible to .015 thickness.
To me if I have uniform primer depth no matter the brass used I shoot better. I concentrate more and make the shots count. I wish I could say that with virgin brass but I'd be lying. I will look for seating depth and pressure while shooting virgin brass and then prep and finalize my load or look for a different bullet powder or primer if it's a common load with a good reputation.
In domestic brass of the past if you didn't uniform the brass to the nth degree at a shoot you were an also-ran. As far as tuning the firing pin protrusion spring weight and loaded spring height. Imho there is not one single thing after bedding that will contribute to better vertical control and wider loading nodes than this. My 308 with several different powders and bullets will shoot well at. slow newbee low recoil, medium competition and top pressure hunting speeds. The savage in 6.5 went from 1-1/2" at 300 to a hole. That took me 6 different springs to accomplish. Also I am now running .048 vs .042 with the heavier spring it came with. Vertical is less than a bullet width at 650 vs 3/4" at 300 in the stock configuration.
Does it work? In my mind YES. However, I can shoot FGMM and Hornady match in 308 and Hornady match in 140 and 147 in the creed almost as well because I know it shoots.
Shooting is a mental game if you think you can or think you can't your right

 

[RevJim]

I also take into consideration the "accuracy" of the rifle in question, i.e. between and factory model and a rebarreled, Blueprinted, speedlock, etc and good trigger. Or a bonafide BR quality setup. Lipstick on a pig thing...

 

[CNC Apps Guy]

A few of you guys have REALLY nice bench setups.

 

[DRock]

I can't vouch for accuracy but I've always done it. I just finished uniforming and deburring 100 Hornady 6.5PRC brass and I had a pile of brass shavings I could almost make another piece of brass from. Some brass had a large amount of brass removed and others very little. In my mind knowing they're all the same gives me confidence I've done everything on my end to ensure consistency between rounds. Then I just have to do my part at the range.

 

[Duckhunter394802]

Is factory ammo, especially factory match ammo, reamed and uniformed? I think not.

 

[Savage 12BVSS]

I use the Lyman tool to remove the burr in all my brass. SD average on my last 10 shot load development was in the 3's. It does make a big difference in my opinion. I even do my Lapua and ADG brass.

I use same tool and agree, I spent some time looking at inside brass flash holes one day. The norma brass is deburred but somewhat roughly by my standards, about 6 or so in a hundred have metal hanging in the hole radius. That's the brass you see when you deburr, you can feel it when the tool hits it initially. The lapua have no radius on inside just drilled straight thru, I like the radius so I still do them. It takes very little time so why not? Its the combination of many small things that make a difference that can be seen in most cases. Just because someone else doesn't do it or believe in it doesn't make any difference to me. Its all about uniformity and consistancy in reloading and I don't leave something I can do right to chance.

At the end of the day you must also own an accurate rifle and be capable of shooting accurately enough to see a difference........................... if there is one.

This one here explains it for me, you have to have a gun that will show you improvement in very small increments. If you are shooting small groups and do nothing good deal, I'm always pressing towards improvement and small ragged holes. One target shooter will post a video that you need to full length resize and another will say chamber formed neck size. One will say ignore prep work while a fellow shooter will obsess over it. One cleans necks squeaky clean while another leaves carbon in for consistent neck tension.

At the end of the day do what it takes to get out of your rifle what its capable of. Some guns are simply capable of more, and show it to you with small improvements.

 

[freddiej]

A few of you know that I am a former 1K shooter. What most all of you do not know is that I started out as a M-1 Grand Class Palma shooter. I was average with my 1943 Garand. I started hanging out with the "real match" shooters. BR guys, 1K'ers, 50 cal Milers, and Palma guys that took the "sport" seriously. Now a really long story as condensed as I can.
I was average in my class. I wanted to make better ammo to compete with the "big boys", that lead me to start asking aobut case prep and other advanced reloading techniques. The amount of information I had to digest in a short time was rather huge. Some of it was pure BS.
I did get a bunch of really good, useful information from all these guys. Especially the things that make your brass more consistent. My groups off the sand bags went from around 2.5" to just under 0.750" edge to edge at 100 yards. For those that must hear the C to C; that would be 0.342" from a 1943 M-1 Garand. That is a vast improvement in my log books. So, yes, I believe in case prep. No matte the brass' head stamp.
From all of the things I was told to do to that first 100 pieces of brass.. I am not proud of what I did to that first set of brass. I had to completely trash that set and went to another 100 pieces and this is what I did to them. Trimmed to uniform length, Reamed the necks for uniform thickness and concentricity, uniformed the pocket depth, then drilled the flash hole with a jig for consistent center and uniform diameter (0.085"). Then weighed the brass for uniform weight. I found that I had to prep most all of my supply of 30-06 brass in my father's collection. He was happy. He got his brass prepped and he did not have to do it.
I ran an experiment on what made the biggest difference in ES, SD, and such. what steps made the biggest difference. Here are the results directly from my log books.
#1 is neck uniformity (length, concentricity, and thickness)
#2 is uniform weight of case (the less the variation if combustion chamber the more uniform the speed down the barrel)
#3, is uniform neck hardness (annealing)
#4, is uniform ignition (flash hole uniform diameter and centered)
#5, is uniform primer depth
from here it is all reloading uniformity
#6, is uniform powder charge
#7, is uniform projo weight
#8 is uniform projo shape

The improvement from primer pocket depth uniformity, flash hole uniformity and centering is seen better the farther you go out. At 500 yards you see about a ½" to 2" improvement depending on diameter of the slug. At 800 you can start seeing improved/more consistent grouping. At 1,000 yards your groups should be at least 30% smaller. At 1,500 yards I saw all of my rounds not only on paper but nearly all were in the black. 18" black (7 ring to bullseye). I saw less and less errant flyers. I saw less and less SD's (average 8 or 10 shot group was just under 8 FPS) best SD's were seen at being 4 FPS.
I apologize for taking so much space to say what I found out 25 years ago. This was seen in both Palma and 1K, and 1,500 yard competitions. I did not see a need to distinguish since they were pretty much uniform/linear improvement.

 

[MoaFlat]

I always ream and deburr flash holes, only required once on new brass and on occasion on fired client ammo for match precision. Used on both Norma or Lapua and found excellent correlation with single digit low SDs. So easy to do with most brass prep stations - the flash hole deburr rod thread fits nicely... right next to pocket depth uniformer, carbon cleaner, inner and outer chamfer 15 - 20 secs all done.

 

[foul bore]

There are many reloading procedures that may seem minor, but as a whole they can add up to making a larger impact. I use all I know to make the most accurate load I can

 

[Tree Farmer]

I checked some Nosler brass and can clearly see the flashole is chamfered. Quality brass is more expensive because it is very uniform and, after paying more for quality, it probably is unnecessary to prep primer pockets and deburr flasholes. I use a lot of cheap brass and try to emulate the quality stuff, so I routinely deburr and uniform primer pockets. If the big boys pay attention to detail, I figure I should too.

 

[338 dude]

I checked some Nosler brass and can clearly see the flashole is chamfered. Quality brass is more expensive because it is very uniform and, after paying more for quality, it probably is unnecessary to prep primer pockets and deburr flasholes. I use a lot of cheap brass and try to emulate the quality stuff, so I routinely deburr and uniform primer pockets. If the big boys pay attention to detail, I figure I should too.

Nosler has two grades of brass their bulk and the black box the black box comes fully prepped

 

[lgwatson]

In my reloading experiences thus far I've never messed around with deburring flash holes, specially cleaning or uniforming or in any way correcting primer pockets or flash holes...

Am I missing out on a very important practice? How big of a difference does this make for es numbers and accuracy? Please share if you do this, and please I'd love to see some "before and after" data regarding consistency of performance.

thanks.

I have not had to with Lapua and Peterson brass. I did both to some Hornady brass that I used for making 6.5-06AI brass. It shot very well, but I did not do a comparative test.