Primer Pocket Cleaning - Quick & CHEAP

[GeoffLinder]

Thats what I use for my tumbling media

I have tested large rifle (.270) cartridges with specifically cleaned to bare metal against cases just tumbled with a small amount of carbon left in outside areas of primer pocket in comparison with a chronograph. The results I got gave me same velocity range over ten rounds for each test with a standard deviation spec of less than 1 percent different.

If velocity range limit does not change (SD), then there is no difference on the target face. This test was done with one batch cases very well prepped, trimmed, flash hole reamed, neck shaved and then primer pocket uniformed (primer pocket uniforming was done before my chrono test and after an initial firing to fire form the new cases to chamber so I could neck-size only before final chrono test).

I have spent a lot of time playing with each variable at a time over the chrono and I tend to only pay attention to things that effect velocity spread. If all else in done right in your reloading method, the velocity range is the final item on your agenda for result on target face. It is almost entirely responsible for vertical shot displacement. Control round concentricity and barrel resonance node (directly related to velocity) and you have controlled random dispersion on target face. Tighten velocity range and you have controlled vertical dispersion. These are all that matter on the target face.

BTW, I meant to ask the poster about photo test done, so I will do so here. Was that test run with two different cases, or with the same case processed same after first test firing photo. If not with same case, then the test is invalid as all cases are slightly different in key things even after flash hole uniforming and primer pocket uniforming has been done. If all these steps have not been done and you run this test using different cases, the flash hole can be wildly different from case to case.

When working with items in reloading process related to powder, pressure and burn rate, you are working entirely with vertical spread (assuming you have controlled round concentricity and found a good barrel velocity node so it's resonance mode is not scattering the rounds on you). Vertical spread is controlled by velocity so the only testing that matters at this point is testing done over a chronograph.

Thanks for listening

BTW, BTW, If you would like to read some really good stuff on what this is all about go HERE

[Kappy]

I've been using my drill for case prep almost exclusively. I use the Lee setup for trimming, including their lock stud. After I've popped the primer, I...
1. Trim.
2. Bevel.
3. Clean with a piece of steel wool (finest grade).
4. Pop out the lock stud and put in the end from the RCBS pocket cleaner and run it through the butts of all those cases.

I can usually do 150 cases if I'm careful before the battery runs out. I might order another battery for the drill soon.

[curisu]

@GeoffLinder - thanks for the link - makes for some very enlightening reading. I think you and scrat and some of the other folks in this thread could take this conversation to the next level. Looking forward to it!

But, man, I feel like a kindergartener trying to build his first non-snaptite model kit (did i just date myself, or are models still popular with kids?) when i consider all the variables at play when trying to build up a load.

For those of us very new to the game, what are some of the critical, "must get it right" bullet points to hit? I know Geoff chimed in on my SAAMI and case length thread, so case prep is right up there in the top 3. What else can I (we) pay close attention to when starting out?

[sunborder]

I use something a little better than a lock of hair from chuck norris, something a little harder and more rare to find. I use the tears of chuck norris in my ss. Some say they are the only tears that he has ever shed, and I believe it because it turns my brass into gold.

As much as I can't stand Mr. Norris, that is some pure poetry there...

(the guy who trained me knocked Mr. Norris through a plate glass window with a spinning back kick, back in the days when Mr. Norris was still training with Mr. Lee in San Diego...some bad blood there, from what I understand).

[sunborder]

For those of us very new to the game, what are some of the critical, "must get it right" bullet points to hit? I know Geoff chimed in on my SAAMI and case length thread, so case prep is right up there in the top 3. What else can I (we) pay close attention to when starting out?

Please. I am operating almost solely on the Lee manual and stuff I've picked up here, on THR, and on castboolits. My best groups/loads so far are about 1.25" @ 100 meters from a 16" AR using bulk FMJ bullets. I'd like to find some things I can do, even using cheap bullets to get it down under 1".

I just got myself the Redding competition seating die, and am working up a load with some 55gr Z-max. I find most of my outliers in my groups are actually horizontal, rather than vertical. I'm guessing that primer pocket cleaning probably wouldn't do very much in this regard, based on what I'm reading here. Still, with so many variables in play, every variable that I can eliminate or mitigate should theoretically get me closer to better groups, right? (of course, it's probably not my ammo that is the problem--It's my crappy shooting skills and "the wind", right?)

[GeoffLinder]

First, start with one batch of case brand, then do some case segregation (weigh and set aside ones outside a 1.5-2 grain range). Then trim cases uniformly (you can additionally ream flash hole, uniform primer pocket and neck shave at this point if you are going for the whole shebang, remember to weight segregate AFTER case prep if you add these extra steps) and then seat bullets properly at consistent depth with no crimp (to start). Then run a series of tests with .2 to .4 increases of powder charge. Fire each test charge batch (five rounds) over a chrono AND on the target face carefully. When group tightens as velocity goes up, note that velocity. Continue and watch how group sizes change with rising velocity until max charge point reached. Look at targets and pick a velocity point where group on target is tightest. Then always using that same velocity (you will have to juggle charge to get back to it anytime you change something), experiment with other variables to see if they tighten group more. This is what load development is all about. Not just making everything nice and clean and similar in prep. You can only experiment with things like different bullets, seating depth and powder choice after you have found a barrel velocity node for your barrel. You must repeat each test at this velocity node or you will not know what is doing what on the target face.

Edited to add: All this assumes your group shooting technique is fairly decent. YMMV

For even more on this I highly recommend the following book.

http://www.zediker.com/books/handloading/hlmain.html