Has anyone sorted their brass by rim thickness to alleviate the dreaded rim thickness dependant priming tool dilemma? There is one good hand priming tool (Sinclair) to steer around this issue but no good bench primer (excluding Lee APP/ACP). I really like my Primal Rights CPS so I have to sort by rim thickness to achieve +/-0.0005" or better.
Sorting Centerfire By Rim Thickness
- Thread starter Bench Addict
- Start date
I tend to inspect a new batch of brass when it will be used for anything picky. That tells me what to expect if I do or don't sort.
I find I don't need to try very hard for anything 600 yards or under.
I agree that primer seating depth is important, but I have also tested enough to know that there is a decent window where you get some tolerance to the issue before you have problems.
When you combine all the other parameters that affect ignition, it isn't difficult to stay in the window and as often as not I don't have to sort. When it matters, if the pocket depths are part of the issue I will cut them based on the rim sort so that I can just run the tool and get the right result. You only have to do that once.
I do have the Sinclair tool, (and just about every other tool made in the last 50 years too). My poor wife will have a hell of a time when I'm gone.
All I will add, is there is a cottage shop fellow who makes a stand/holder for the Sinclair tool at essentially bench mounts the tool.
I think Bryan Z recently showed it in a YT video as part of his brass priming series. If I can find it without a lot of fuss I will link it here.
The fellow that makes the stand is Todd Criswell who is a BR competitor and fellow Hoosier.
Here is a snapshot of the tool stand.
I find I don't need to try very hard for anything 600 yards or under.
I agree that primer seating depth is important, but I have also tested enough to know that there is a decent window where you get some tolerance to the issue before you have problems.
When you combine all the other parameters that affect ignition, it isn't difficult to stay in the window and as often as not I don't have to sort. When it matters, if the pocket depths are part of the issue I will cut them based on the rim sort so that I can just run the tool and get the right result. You only have to do that once.
I do have the Sinclair tool, (and just about every other tool made in the last 50 years too). My poor wife will have a hell of a time when I'm gone.
All I will add, is there is a cottage shop fellow who makes a stand/holder for the Sinclair tool at essentially bench mounts the tool.
I think Bryan Z recently showed it in a YT video as part of his brass priming series. If I can find it without a lot of fuss I will link it here.
The fellow that makes the stand is Todd Criswell who is a BR competitor and fellow Hoosier.
Here is a snapshot of the tool stand.
Funny you mention this video. I am the designer and manufacturer of that RPG tool laying on his bench (next to the Sinclair/Criswell setup) which he uses for sorting rim thickness, measuring pocket depths, measuring seated primers, etc. Bryan has tested this primer seating topic as well and tends to agree that the optimal window for seating depth generally allows a 0.002-0.003" tolerance for variation (or +/-0.0015" of mean).
If you watch enough of his videos, you'll hear my name come up every so often (Bench Addict / Justin Nehring). Small world, lol. He'll be doing a video on the RPG tool in just a few more days.
If you watch enough of his videos, you'll hear my name come up every so often (Bench Addict / Justin Nehring). Small world, lol. He'll be doing a video on the RPG tool in just a few more days.
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I use a CPS as well. I just use a primer pocket uniforming tool set to .130-.131" for LRP's and uniform all my brass pockets. Gives very consistent seat depths with the CPS.
RPG ToolI use the 21st Century micrometer primer pocket uniformer so I can dial in exactly the depth I want for the intended primer height I'll be using.
Maybe it is just me. I use a primer pocket uniformer so I know the depth of the pockets are uniform. Then depending on my feelings for the day I may seat primers with my Hornady hand primer seating tool or simply use my Co-ax press or one of my RCBS presses to seat the primers. If my feel is good I feel when the primer hits the bottom of the pocket and call it good. I may visually see that the primer is below the rim or run my finger across it to verify.
If you are using a tool to set the primer to a specific depth and don't have uniform depth primer pockets, how do you know if the anvil is against the bottom or has been crushed into the cup?
I only measure rim thickness on rimfire ammo. My 2 cents.
If you are using a tool to set the primer to a specific depth and don't have uniform depth primer pockets, how do you know if the anvil is against the bottom or has been crushed into the cup?
I only measure rim thickness on rimfire ammo. My 2 cents.
Noise. I run a CPS and get plus or minus .001 variation at most. The biggest thing I was able to actually measure was SD. Nothing else changed in my testing. SDs went from around 8-9 to 4-5, everything else was the same. That was a .002 crush on primer and that is where I run everything. I run ADG, Alpha, and Peterson brass.
I think some of these later answers really depend on what the intended use is. If you're loading up to compete against top level fclass or benchrest shooters at a national level match with your $10k+ rifle, would that change some of these answers? I have not stated my personal use case but it is 1,000yd fclass just so we are on the same page. If I just needed to bang steel at distance, I wouldn't go through nearly the trouble.
I'll try and keep this short and simple.
I would rather not re-create the whole diatribe on small arms primers, but I will state that there is more than one primer design type.
If we split the discussion between the type where the anvil feet are flush with the cup, say like a BR-2 or BR-4 version, and contrast it to something like a CCI-450 where the feet are proud of the cup, those are the two sets of issues for a simplified installation discussion.
With a flush cup, you just get the cup to the bottom of the pocket and Bob's your Uncle. Done and over, not complicated.
Trouble comes when the cup is left short of the bottom. This issue is simpler because the "crush" or "consolidation" is built into the design and all you have to do is get it to bottom.
And then there is the second kind where the burden is on the reloader because the feet sit proud and are not meant to be driven flush with the cup.
When the anvil feet sit proud of the cup, the responsibility for "crush" is up to the user. The dimensions are not such that they are intended to be crushed to get the feet flush. The ideal values are on the order of 0.002" - 0.006" for typical ones, so say on average you are targeting 0.004" +/- 0.002" crush or reconsolidation. (Some other brands used to run 0.002" - 0.004")
When I used to specifically test primers on a test stand, you would all agree with the manufacturer's recommendations for seating, and the door opens for trouble when you are outside of their intended range.
When I have tested my own ammo it does show an effect on target, and on the chrono, but we would all probably agree the "good window" shouldn't be too difficult to hit if you are paying attention to your brass inspection.
My own pet peeve is that they do not publish these dimensions or recommendations to the consumer right on the packages. It would end a lot of arguments but once again I am left shaking my head. There really isn't much direct information in the public domain, and that is a shame. YMMV
I would rather not re-create the whole diatribe on small arms primers, but I will state that there is more than one primer design type.
If we split the discussion between the type where the anvil feet are flush with the cup, say like a BR-2 or BR-4 version, and contrast it to something like a CCI-450 where the feet are proud of the cup, those are the two sets of issues for a simplified installation discussion.
With a flush cup, you just get the cup to the bottom of the pocket and Bob's your Uncle. Done and over, not complicated.
Trouble comes when the cup is left short of the bottom. This issue is simpler because the "crush" or "consolidation" is built into the design and all you have to do is get it to bottom.
And then there is the second kind where the burden is on the reloader because the feet sit proud and are not meant to be driven flush with the cup.
When the anvil feet sit proud of the cup, the responsibility for "crush" is up to the user. The dimensions are not such that they are intended to be crushed to get the feet flush. The ideal values are on the order of 0.002" - 0.006" for typical ones, so say on average you are targeting 0.004" +/- 0.002" crush or reconsolidation. (Some other brands used to run 0.002" - 0.004")
When I used to specifically test primers on a test stand, you would all agree with the manufacturer's recommendations for seating, and the door opens for trouble when you are outside of their intended range.
When I have tested my own ammo it does show an effect on target, and on the chrono, but we would all probably agree the "good window" shouldn't be too difficult to hit if you are paying attention to your brass inspection.
My own pet peeve is that they do not publish these dimensions or recommendations to the consumer right on the packages. It would end a lot of arguments but once again I am left shaking my head. There really isn't much direct information in the public domain, and that is a shame. YMMV
I cut my pockets for the primers I use to give me .002" crush and -.004" below flush. 21st Century adjustable is what I use also like benchaddict. I bought the CPS for ease of priming but it's adjustable by .001" seating depth so I figure might as well make everything uniform. Necessary? Nope. Another thing to have complete control over consistency if you want it? Yep, and it has improved my average SD's. I made just as accurate by group size at 100 yards ammo not doing it but then I started shooting a mile plus and wanted to eliminate as much vertical stringing as possible in my loads at ranges where everything helps. The only step it adds is cutting and measuring my pockets on new brass. A one time exercise. I enjoy geeking out with reloading consistency on my ELR loads though.
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