Concentricity Question/Help

[MikeMcCasland]

Where are you measuring the case and bullet runout? I measured 3 rounds in various places to see what the differences were using a Sinclair concentricity gauge and a 1/2 thou dial indicator (estimating some of the readings) and checking each several times. The necks were turned on 100% of the surface. On #7, I used a seater insert and modified the gauge to read from the tip of the bullet like a Hornady gauge.
View attachment 1109063

On that diagram, I am measuring case neck runout between #4 and #5, and I'd be measuring bullet runout at #6.

 

[Evan]

Have you tried seating a bullet half way, lowering it out, rotating the case ~180, then seating the bullet the rest of the way?

 

[Nature Boy]

I’m finding that figuring out things to stop doing is almost as rewarding as adding things to do at the reloading bench.

Like I’ve seen others say on this subject. Identify what’s causing the runout and fix it at its root cause.

Out of all the resources constraints in this hobby, time is the one I have the least of

 

[MikeMcCasland]

Have you tried seating a bullet half way, lowering it out, rotating the case ~180, then seating the bullet the rest of the way?

Just did, about .002 of bullet run-out. Definitely something wrong with the Forster comp seater; probably going to call them today.

 

[jim_k]

For cheap, you could do the test I did: Size with a Redding body/shoulder die, size necks with Lee Collet/mandrel die, then run an expander mandrel down the neck. Seat short with the Forster seater, then finish the seating with a Lee Dead-Length bullet seating die. The test was a success, and my CBTO is now spot-on (+/- 0.002"), and my TIR is fine, never over 0.002". No neck turning; but done this way, I mix the turned and unturned cases, and they all shoot to the same POI. Web area of my chamber has fairly tight tolerance for my sized cases (0.005-0.006"), and the neck has the standard SAAMI copious clearance. If my group size was not to my liking, I'd get a custom sizing die to give 0.003" clearance at the case web.

 

[Evan]

Just did, about .002 of bullet run-out. Definitely something wrong with the Forster comp seater; probably going to call them today.

I do it every time with all my seating dies and it seems to make a difference. Easy/quick to do and gives good results

 

[dstoenner]

Have you tried seating a bullet half way, lowering it out, rotating the case ~180, then seating the bullet the rest of the way?

This is what I had always heard and did. Then I learned this talking to an older guy at a F-Class match of what he did. He said he seats the bullet half way, then rotates 90 degrees and seats the bullet the rest of the way, then he rotates another 90 and lets the handle bounce twice.

I know this seems crazy but I tried it. On a batch of 308 where I was getting like 40% 1's and sort of an equal amount of 2's, when I tried it my 1's went up by 20 more %. The 2's group went down some but the 3's dropped also.

Try it.

David

 

[msinc]

Maybe I have just been lucky, or perhaps some of my dies are exceptional, but I had trouble with necks getting out of whack during sizing and I called Forster. The cat said to remove the expander and size a case and measure the neck. I did and it was dead zero perfect. He said, and I have found this to be true so far, "the size die should always bring the case back to zero or very minimal run out at the neck. He further said, "if it don't always correct neck run out then there is something wrong and it needs to be sent back and fixed". I ran all of the out of whack cases back thru and it corrected them {with no expander in the die}. I ended up having to change the expander stem because it was bent.
I have always heard it said that .003" or less was fine for bullet run out. I was also always told to check bullet run out just ahead of the case mouth not up towards the tip where it is exaggerated. I have spent a lot of time and a lot of money to try and get cases with zero neck run out {been successful} and .003" or less bullet run out {also been successful}. I am not shooting benchrest per se, but I found that it made very little to no measurable difference at 100 yards off a good benchrest whether I had rounds separated for zero run out, less than .003" or as much as .008".
In Tony Boyer's book he talks about bullet run out gauges and tells a story of winning some big benchrest shoot somewhere. While there he runs across a vendor selling his version of a bullet run out gauge. Mr. Boyer asked if the guy would mind if he checked a few of his rounds. The man agrees and they all test at .008" or so. The vendor, not realizing he is the guy that just won, tells him he better trash that batch because it is no good. Mr. Boyer said in his book, "I decided right then I didn't need that thing"......
I'm not saying don't make your bullets as straight as you can, I still strive to get it and all I do is shoot for fun and hunt. The two things I have done to positively get results making bullets with low run out is make sure the die is getting the neck right and use a L.E. Wilson straight line seater die. Everything else I tried accomplished zero, as far as getting bullets concentric. Wish I could say, "yeah, getting those bullets below .003" knocked my groups from 3/4" down to 3/8"........but I cant.

 

[MikeMcCasland]

Well, I finished loading up 100 rounds of .308 for Saturday. Rotating the cases during the seating process got me about ~.004-.005. Even if the bullets are crooked, I'll at least get back to concentric brass once fired (assuming SPR did as good a job with the chambering as I think).

I then tore the die back apart again; it's driving me crazy that I can't find what part of the die would be inducing runout. You'd think it'd be either the 'chamber sleeve', or the seating stem but I can't find any problems with either. Stem looks concentric, with no damage. The chamber sleeve thing also appears good, but short of cerrosafe'ing it, I don't know how you'd measure.

I didn't get time to call today, but will tomorrow.

Good news is my Whidden dies will be here on Sat, so hopefully those yield better results.

As far as Tony Boyer's results, I'm guessing run-out didn't matter for him because he was jamming everything .015.

 

[T-shooter]

If the case is not straight and springs back after resizing, no bullet seater will make much of a difference. Something I have tried with some success is to do a full length resize, turn the case 180°, and do it again while stopping at the bottom of the stroke for a few seconds. And doing the same when seating a bullet by seating half way, turn 180° and finish. You may try to check the necks (if they are turned) before loading. If the necks aren't turned, checking the outside is probably meaningless. If it is not straight before loading, it won't be later. If you can or have someone anneal some of your cases before you resize next time, you may find the answer. You should use a wide flame in this area which will also heat the shoulder allowing it to align in the press. Don't put the flame on the neck. The black mark on the this case is a 450° Temperature crayon that just started to melt. The heat ring on the case shouldn't be any lower than this. On .308 cases, I use a small wider flame for about 5 seconds at about 1" away while slowly rotating the case in a drill.

I don't know if or how much runout really matters. I look at it as it may not help but can't hurt. Someday I want to test this theory with some near perfect rounds and some of the worst that come out of the same batch. I usually reload 100 at a time and then run them on the runout gauge and group them by the results. Let us know how you do Saturday. Good Luck.

 

[Barlow]

Lots of good advise. Some more, put an o ring under the seating stem nut so the expander can float a bit as it comes thru the neck (lube neck a little), leave seating stem nut a tad bit loose (technical term) and when you feel the expander enter the neck tighten the nut down. Good luck, Barlow

 

[MikeMcCasland]

Update: Got off the phone with Forster customer support; nice folks.

We talked through everything I'd done, and nothing obvious jumped out at them. Sending the die back with some fired cases, and some test bullets next Monday.

Whidden's come in tomorrow, so I should have more to report.

 

[dstoenner]

Mike,

Regardless of which sizing die you settle on, if you are going to use a sizing button, you need to polish it really well. I chuck my sizing stem in my drill press and use slowest speed with 500 or better sandpaper or emory cloth.

For my 308 cases after a lot of experimenting I found that using Redding neck lube (graphite) on the neck and roll them on a case lube pad gave me the necessary lube on the inside of the neck to keep it from pulling out of shape.

Also take one of your fired cases and roll it for concentricity. Then take the decapping stem out and size a case. Now measure concentricity. If it got worse it is you die set up. If it is still the same, then put your decapping stem back in and size that same case again. Did it get worse? if so then you have your answer.

There is an old adage that there is no free lunch. If you want the lowest runout you need to turn necks. then use a bushing die. Whidden are great but I actually got into a case where the bushing was not symmetrical and it gave me runout out in my Whidden die. Whidden makes bushing and they are a little more expensive than Redding but they are WELL worth the money.

As I said earlier, I have gone to Forester FL sizing dies that I send back to Forster and get them honed to exactly what I would use as a bushing. They are amazing, even taking crocked cases and straightening them much like firing in a chamber straightens them.

One more thing, when you set your sizing or seating die up in your press for deep. Before you tighten the locking ring, put a washer between the shellholder and the bottom of the die. Then bring your ram up and make good contact with the washer. This will center your die on the threads. Now tighten the locking ring both to the press and then the set screw in the collar. Every .001 counts in this game.

Also you mentioned that Tony jammed his .015. Remember that he also has a really tight necked chamber which helps align the case with the bore that our loose chambers do not do.

David

 

[Evan]

Also you mentioned that Tony jammed his .015. Remember that he also has a really tight necked chamber which helps align the case with the bore that our loose chambers do not do.

David

Not true. Cases do not center by the neck ever. They have to have clearance. Even tight neck PPCs are running a thou or two. A case always centers on the shoulder when the cartridge fits correctly.

EDIT: Couple drawings to show what I mean:

 

[MikeMcCasland]

Update:

Welp, the Whidden dies fix it.

I went and shot all 100 cases to blow the brass back out. Came back home and measured; most had ~.0005-.001" TIR, so the chamber is good.

I then did the usual deprime, wet tumble, anneal routine.

I've gotta say, I've seen a lot written about Whidden dies on these forums, and about how they're works of art etc.... and all of that appears to be true. I've never had a sizing die that looked/felt like this before.

I set it up to expand up higher in the die 'ala Forster', and went to work. They were coming out of the sizing die showing anywhere from ~.00025 to a max of .003, however most were in the .0015 range. This is also on un-turned brass, so I think I'm seeing the high spots pushed to the outside via the expander, whereas before using an expanderless bushing, I was just seeing pure run-out.

I've got most of my brass dry tumbling lube off now, but grabbed a few cases out of the tumbler to seat some dummy rounds to test. The bullets are visibly straighter coming out of the die, and the 21st century gauge confirmed it. On my test cases I'm seeing an average of .002 on the bullet ogive, which is a far sight better than what it was with the Forster seater.


Again, I'm not on a quest to get consistent .0005 bullet run-out, I just didn't want to shoot rounds in a match that looked like a pregnant dolphins. I'm loading back up and heading out tomorrow to test.

In summary, Whidden makes some nice shit.