Another Runout Question

[jpistolero02]

I have tried to do some research, but I am having a hard time coming up with a fix. While loading some .270 loads this evening, I was getting around .007-.010 worth of runout. I am using a Lee Classic press and standard RCBS dies. This was once fired Winchester brass that were full length sized without the expander ball. I then run the cases over a Sinclair expander die to try and keep a uniform neck. Measuring the runout at the neck before seating a bullet, I am getting about .001 worth of runout. What in the heck am I doing wrong? I have tried polishing the case mouths and necks, but that doesn't seem to help. I have also tried to rotate the cases while seating but that doesn't seem to do anything either. Also, I am measuring the bullet runout between the ogive and case mouth.

 

[thefitter]

What are your neck measurements for:

Fired case

Full length sized case

Expander die case

Loaded round

 

[fdshuster]

If it is an older set of RCBS dies you are using, the previous suggestion about checking the seater stem/ bullet contact is a good one. Some of the older seater die stems had very shallow holes to fit the bullet points, and when seating newer designed bullets with the pointier tips, the bullet tip made contact with the bottom of the hole. No contact between the seater stem and the bullets ogive. To sum it up: the bullet tip may be bottoming out in the stem. Flat base or boatail bullets? Are they seating smoothly without a lot of undue pressure/ force required on the ram? Look closely ( with magnification) at the mouth of the case, checking for copper jacket shavings.

 

[bozo699]

I have tried to do some research, but I am having a hard time coming up with a fix. While loading some .270 loads this evening, I was getting around .007-.010 worth of runout. I am using a Lee Classic press and standard RCBS dies. This was once fired Winchester brass that were full length sized without the expander ball. I then run the cases over a Sinclair expander die to try and keep a uniform neck. Measuring the runout at the neck before seating a bullet, I am getting about .001 worth of runout. What in the heck am I doing wrong? I have tried polishing the case mouths and necks, but that doesn't seem to help. I have also tried to rotate the cases while seating but that doesn't seem to do anything either. Also, I am measuring the bullet runout between the ogive and case mouth.

The issue you are having here is self inflicted, you are sizing the brass way more then needed with the factory die, just the way they work, now with the neck way undersized because you didn't pull the expander ball back through the neck while the case was some what supported by the die, now you take that largely undersized neck and run a expander mandrel through it while the case is totally unsupported, I am surprised your not crushing the cases, it takes so much pressure to get that mandrel started it starts to collapse at the shoulder neck junction,....ie,...runout!
Wayne.

 

[lurcher]

I have sized cases the way you describe but I have only used this sizing approach after annealing the cases to work the necks a little to regain some springback. The runout after doing this was minimal. In this case the mandrel enters the neck without much force as the brass is freshly annealed and fairly soft.

How many times has your brass been fired? I am wondering that if the brass has been fired multiple times and the necks are work-hardened then it may take considerable force to get the mandrel into brass (that is unsupported as Wayne says) and that this is pushing the necks out of line?

You could try annealing a couple of cases and then trying again to see if runout is reduced. If it comes down to a new quality, reasonably priced seater die my vote goes for a forster benchrest seater, you can get them direct from forster.

 

[bozo699]

I have tried to do some research, but I am having a hard time coming up with a fix. While loading some .270 loads this evening, I was getting around .007-.010 worth of runout. I am using a Lee Classic press and standard RCBS dies. This was once fired Winchester brass that were full length sized without the expander ball. I then run the cases over a Sinclair expander die to try and keep a uniform neck. Measuring the runout at the neck before seating a bullet, I am getting about .001 worth of runout. What in the heck am I doing wrong? I have tried polishing the case mouths and necks, but that doesn't seem to help. I have also tried to rotate the cases while seating but that doesn't seem to do anything either. Also, I am measuring the bullet runout between the ogive and case mouth.

The issue you are having here is self inflicted, you are sizing the brass way more then needed with the factory die, just the way they work, now with the neck way undersized because you didn't pull the expander ball back through the neck while the case was some what supported by the die, now you take that largely undersized neck and run a expander mandrel through it while the case is totally unsupported, I am surprised your not crushing the cases, it takes so much pressure to get that mandrel started it starts to collapse at the shoulder neck junction,....ie,...runout!
Wayne.

jpistolero02,
I had worked hard at hunting all day when I replied to your post, fell asleep in my chair immediately after posting, should have before the posting as I must have had a case of Dyslexia as I totally transposed what I read from one thing to another, sorry about that :-[ In most cases what I wrote could be the culprit but in your case after reading your op while "awake" I believe fdshuster is probably correct, to test that take a bullet and rotate it by hand in your seater stem you may have to smoke the bullet with a candle but you should show a ring somewhere on the ogive if not Frank is probably correct, to further test remove some off the end of a bullet your using and keep repeating until you see the ring, you may have to change dies or open up the bottom of your stem.
Wayne.

P.S
I have not used RCBS dies for years but own a lot of them from when I started loading so I have forgot how they were built, my stem for a 22-250, I know it isn't a .270 but it was one I had here in the house, anyway I removed the stem and noticed it was cut with a square bottom however with 50 grain v-max bullets it lacked quite a bit from bottoming out although it was just above the plastic tip on the bullet where the contact was, not where I would like to see it. If you are seating long vld style bullets I could see how it could easily bottom out as Frank described, best of luck to you.

 

[wapiti25]

I don't like the way the "older dies" were designed with concentricity in mind. Go to the Sinclair catalog as they have great pictures as how dies are made. The Wilson type, Redding Competition seating, and Forester are some of the best. I don't like a seating die that has the seating stem held in place with a thread, It is hard to run a tap and have the threaded hole stay concentric to the "chamber" of the die. During the tapping (cutting ) the tap will wander off the center line a few thousandths of an inch. The threaded seating stem has the same problem unless the stem is single point threaded in relation to the cavity for the bullet. This makes costs go up. I think you may be over sizing the neck, you only need about .002 smaller than the bullet. Get some Imperial Dry Neck sizing Lube and it will reduce the drag on expansion. You may have you sizing die honed out to a larger dia so you don't need much expansion or try the Lee collet neck die which is cheap. A quality bushing die will work but they cost more. I have never had a case where annealing has hurt, in fact it has made things better in all cases for me. Good Luck

 

[necchi]

Here's a simple fix for the RCBS dies jpistolero, once you know the bullet fit's in the seater plug.
The seater plug sits on a threaded stem that goes through the die and is held in place with a lock nut,,right?

The problem lies in the play between the stem thread, die threads and that darn lock nut. Everything can be in the right position, then when you tighten that lock nut the stem "cants" in the die against the very threads that hold it. This "cant" or tipped stem will push the bullet in sideways and concentricity is really messed up. Further proof can be seen when you loosen that lock nut and you'll see that the stem will wobble a bit in the die.

The Fix;
A trip to the hardware store with the seating stem in hand is due. Go to the plumbing section and find the faucet washers. Find a small rubber "O" ring that'll fit on the stem.
When you get back home put the stem in the die, put the O-ring down between the die and the seating stem lock nut.
Now, when you adjust for depth and find the spot you want, just turn the lock nut down on the O-ring firmly but not over tight, just enough to hold the stem in place.
The O-ring allows the seating plug to "float" in a straight position and not be pushed to one side or another by the lock nut and threads.
Viola`, an olde school fix for a stubborn seater.

When I first started loading, I had this same trouble with RCBS seater dies. I remember talking to a couple experienced silver hair Gents at a gun show about this "O-ring" thing and they responded like,,
"Yeah, you just figured that out? We thought it was common knowledge for decades"

 

[bozo699]

Here's a simple fix for the RCBS dies jpistolero, once you know the bullet fit's in the seater plug.
The seater plug sits on a threaded stem that goes through the die and is held in place with a lock nut,,right?

The problem lies in the play between the stem thread, die threads and that darn lock nut. Everything can be in the right position, then when you tighten that lock nut the stem "cants" in the die against the very threads that hold it. This "cant" or tipped stem will push the bullet in sideways and concentricity is really messed up. Further proof can be seen when you loosen that lock nut and you'll see that the stem will wobble a bit in the die.

The Fix;
A trip to the hardware store with the seating stem in hand is due. Go to the plumbing section and find the faucet washers. Find a small rubber "O" ring that'll fit on the stem.
When you get back home put the stem in the die, put the O-ring down between the die and the seating stem lock nut.
Now, when you adjust for depth and find the spot you want, just turn the lock nut down on the O-ring firmly but not over tight, just enough to hold the stem in place.
The O-ring allows the seating plug to "float" in a straight position and not be pushed to one side or another by the lock nut and threads.
Viola`, an olde school fix for a stubborn seater.

When I first started loading, I had this same trouble with RCBS seater dies. I remember talking to a couple experienced silver hair Gents at a gun show about this "O-ring" thing and they responded like,,
"Yeah, you just figured that out? We thought it was common knowledge for decades"

Or you could just buy a Forster they come with the O-ring from the factory
just kidding that's a good idea necchi
Wayne.

 

[jpistolero02]

Thanks for all the great information. I am going to check the seater plug and try the o-ring trick. I don't seem to be changing the neck runout with any of my process so it seems to come during the seating process. I don't have any copper coming off the bullets and the tension feels the same between each case.

 

[ordnancemarine]

At Ace hardware, it's a number 7 o-ring. I've been doing that trick for sometime now with excellent results.

 

[hotrodlouie]

Reading all the problems with bullet run-out and had the same problems. I found the center guide screw in the die is I think is the biggest problem, checking the threads are tapered and loose in the die by .012" to .016". I made a new guide screw to fit the die with a tight fit and bored the end out to fit the OD of the bullet instead of the ogive to seat the bullet length. New to reloading rifle cartridge not a expert by any means, machinists by trade interesting to read all the problems with bullets, concentric means more then you cam imagine when solving problems.

 

[bozo699]

Reading all the problems with bullet run-out and had the same problems. I found the center guide screw in the die is I think is the biggest problem, checking the threads are tapered and loose in the die by .012" to .016". I made a new guide screw to fit the die with a tight fit and bored the end out to fit the OD of the bullet instead of the ogive to seat the bullet length. New to reloading rifle cartridge not a expert by any means, machinists by trade interesting to read all the problems with bullets, concentric means more then you cam imagine when solving problems.

hotrodlouie,
Welcome to the forum and the reloading/shooting world. What do you mean by to fit the OD and not the ogive?
Wayne

 

[hotrodlouie]

Wayne, what I did was bore the center screw guide out to the bullet diameter plus .001' about 1/16 inch deep so the misalignment is less of a problem. I use redding dies they have a 1/2" sae screw so you have more diameter for machining, some dies use a screw about the same size of the bullet od so you can't machine any thing. Try a grade 8 sae bolt in your die and see how tight it is compared to your original center screw and you can see why everybody has problems with run-out. Hope this helps.

 

[spclark]

Or you could just buy a Forster they come with the O-ring from the factory
just kidding that's a good idea necchi

Yep, me too, for some years now. Point of fact I use two o-rings: one under the die locking nut against the press bushing, the smaller under the seating stem locknut against the die body. With case sizing dies, only the larger at the bottom. Neck bushings float a bit with the stop plug backed off an eighth turn once I establish where the bushing needs to be.

Sometimes tight is what you want, other times a little give is better. Each has its proper place; you need to determine what works for you.