Bullet seating issue

[Hidalgo]

It sounds to me like your dies sized the necks down tighter, and now you have more neck tension than before. That increased neck tension may be shaving copper off of your bullets.

This interests me. If what you are saying is the case .... what is the fix? A larger expander ball? Or would going to a bushing die be the better option?

 

[DiRTY DOG]

I often use(d) unfired cases in which to develop a load, but have never compared groups between fired/unfired brass. Over the years, I have noted that MV with a given load is usually a bit lower w/new cases than with once fired cases, and a MV variation would also add to the variation.

This week I tested that very thing in my 6.5x47L with virgin Lapua brass vs 1x fired and resized. Exact same load, 5 shot groups, velocity on a Garmin. 130gr Berger Hybrid, 36.5gr Varget. Savage 12, 22" Criterion prefit, Leupold VX-5 3-15x42, Harris bipod & rear bunny bag.

Virgin Lapua brass got just a sizing mandrel run down the neck, then chamfer/debur and loaded.
Ave: 2758.2 fps
ES: 10.2 fps
SD: 4.4 fps

1x fired Lapua brass got annealed, sized w/Forster custom honed FL die (2 thou shoulder bump) no expander, then the sizing mandrel down the neck, and chamfer/debur, and loaded.
Ave: 2760.7 fps
ES: 12.3 fps
SD: 4.6 fps

Small sample size, but no significant difference in velocity. Accuracy was slightly better in the fireformed brass:

In 6mmDTI, Starline 1x fired brass was only about 5 fps faster than virgin brass over several 5-shot groups of each.

 

[mbaysinger89]

How much are you bumping from fired? How much longer or shorter are you from the virgin brass?

I have seen one rifle I had that was headspaced fairly long. The load changed from virgin to once fired brass. It grew 7 thou from virgin brass after sizing, 9 thou before. I had to change my charge a couple tenths of a grain to get back to the same pressure. I'm making an assumption that the brass expanding takes some of the energy from the powder charge making the fireform load have less pressure than the fireformed load.

If youre oversizing it could also be the opposite. If you set your die to die soecifications it may greatly oversize. Also just had this problem with a 6 creed. The die set up to touch the shellholder sized about .005 more than I wanted. Have 223 dies/rifle that I had to buy the Redding Comp shell holders, because the combination sized .010 too deep. That could definately change the chamber pressure.

 

[Stu Farish]

I keep coming back to runout at the neck. That's what my problem was. After resizing the brass the necks were basically canted at an angle, not true to to the case. This caused the bullets to be the same & accuracy simply wasn't possible.

I use this tool:

RCBS Case Master Concentricity Gauging Tool

The RCBS Case Master Concentricity Gaging Tool is a tool designed to help reloaders create the most accurate ammunition possible. This tool easily...

www.midwayusa.com

 

[Stu Farish]

If it's a runout problem it can either be the sizing die (I also had a Dillon 22-250 neck sizing die do this) or the seating die. You need to measure runout on the case necks after resizing but before doing anything else. If it's acceptable, the seat a bullet & measure it on the bullet just in front of the case mouth.

The 2 times this has been a problem for me both turned out to be the sizing die.

 

[hm1996]

I keep coming back to runout at the neck. That's what my problem was. After resizing the brass the necks were basically canted at an angle, not true to to the case. This caused the bullets to be the same & accuracy simply wasn't possible.

I use this tool:

RCBS Case Master Concentricity Gauging Tool

The RCBS Case Master Concentricity Gaging Tool is a tool designed to help reloaders create the most accurate ammunition possible. This tool easily...

www.midwayusa.com

View attachment 3902

That'll work! I like to tinker while saving a few bucks, so built this one. Even added a sight base so I could check repeatability on my TR sights.

 

[JTPinTX]

This interests me. If what you are saying is the case .... what is the fix? A larger expander ball? Or would going to a bushing die be the better option?

I have done different things in the past. You could probably get a larger expander ball, I have never tried to do that. I have turned/polished down expander balls before when they were too big or too rough to get more neck tension or smooth things out. To get less neck tension probably the easiest is go to a bushing die and control it that way. Or you could use a dedicated expanding mandrel in a separate step, you can get them in any size you need. But that would be a PITA. I had a die one time that was sizing down just nearly the right amount without the expander ball in it, but the ball was causing some runout issues. So I just took the ball out, left the decapping stem in, and then slightly neck turned my brass to fit. A little unconventional, but it worked.

Copper shaving issues in the past, I have seen several things and dealt with it in various ways. I have seen the necks work harden really fast because the die was sizing it down way too far, the ball was then having to work the brass hard opening the neck back up, so then the necks got really hard after a few firings. Then it would shave copper while seating (seating hard) and consistent neck tension went to crap. I have seen a good load go south several times in that situation. In that case annealing fixed the hard brass issue, but different dies is the long term cure to stop over working the brass.

If I am going to use a die with an expander ball, I will always choose a Forester if I can. The way they are set up the expander ball is barely below the neck, the neck portion of the die is still supporting the top of the case neck as the ball starts to expand the bottom, and generally runout is controlled very well (I know we are talking shaving and not runout, but thought I would just throw that in there). I have never had any strange expander ball issues in Forester dies. I have in nearly every other brand of dies out there.

I had an issue in a 6.5 Grendel shaving bad too. It did not really show the problem with most bullets, but the Speer 120 Gold Dot was horrible about it. Great bullet as far as being a real hammer on pigs, awesome terminal performance. And accuracy was pretty good too. But those bullets are not made with a conventional jacket swaged around a lead core. They are made by plating a thick layer of copper on a lead core and then swaging to size. Cheap way of making a bonded core bullet, and they perform well. But it seems to me that copper is different, really "grabby" so to speak. And the bullets were a touch oversize. I dipped the bullet bases in mica, that helped quite a bit. Polished the inside of the necks with steel wool, that helped too. In the end I did not use many of them because 1) it was too much of a pain, 2) They actually held together too well, and on running shots on pigs at night I could hear them ricocheting across the countryside on misses. Not good at all for liability. (I actually use varmint bullets on pigs most of the time. They kill pigs just fine, but don't bounce near so bad on misses. Much safer on big groups of pigs running all directions).

EDIT to add: Thick case necks (especially if fairly hard brass) can contribute to copper shaving issues at times. Especially in an expander ball die the neck gets sized down further, and with thicker brass it is harder for the expander ball to open it back up enough due to more material and springback. Sometimes in that case neck turning a a bit and thinning them down can help since at that point your die is not having to fight it as hard. I'm not talking about turning a bunch off. Normally just enough to kind of clean the neck up, maybe half a thou, or .001, something like that.

 

[Hidalgo]

Great response and much appreciated !

I haven't ran into bullet shaving before, but as with all reloading I'm certain it is going to pop up sooner or later. I'm using Redding bushing dies on my 6.5CM but not on the 223 or 7-08. So far ... so good. Thanks again for taking the time to write all that out.

 

[hm1996]

The 2 times this has been a problem for me both turned out to be the sizing die.

99% of the runout I have experienced traces back to the sizing step. I firmly believe it occurs as the expander ball is being extracted from the case. Most shell holders do not support the case snugly, allowing slight movement of the case, which is necessary for the case to center as it enters sizing die. This, however comes back to bite us when extracting the expander as it allows the case to tilt slightly, many times this tends to pull the necks off center.

Several things can be done to minimize this problem.
1) Clean inside case necks; I use a bronze bore brush on the inside of necks after running them in a tumbler.
2) I also apply graphite to inside of neck to help minimize friction.
3) I replace the original expander ball on all of the dies used for target ammo. For all other purposes I polish the original ball to high gloss in a drill w/crocus cloth.
4) Set up sizing die/expander stem properly. I think Jeff mentioned this above and I agree this is probably the biggest offender. First, you will notice a bit of runout as you turn the exander stem so I try to find a sweet spot as I tighten down the lock nut so as to find the center of the die as best as possible. As Jeff stated, set up the ball as close to the bottom of the case neck portion as possible, thus the case is still held centered in the die as the ball enters case neck and a bit farther as it is extracted. If the ball is not centered when it enters, the neck, it only becomes worse as it is extracted.
I've never used an expander mandrel, as I'm old school and they were not available back in the day, but sounds like a lot better arrangement than the balls. The ideal setup IMO is eliminating the expander ball completely with a die that sizes cases to proper neck tension and completely eliminating the expanding step. Neck turning & proper sized neck dies, such as BUSHING DIES in combination is probably best solution today.

The seating step can induce a bit of runout, but not so much as sizing. Someone mentioned previously that partially seating the bullet, then turning case a third or so and seating a bit farther...repeat to fully seat decreases chance of runout in standard dies. For target work the benchrest seaters hold the bullet straight(er) as it is seated.

IME, runout has negligable effect @ 100 - 200 yards, especially in factory hunting rifles but comes into play moreso beyond.

 

[DiRTY DOG]

Bet you a cheeseburger it's just that your case mouths need a better chamfer and/or your inside necks are rough maybe from a galled or non-lubed expander. Show us a close up pic of your sized ready to load case mouths.

 

[DiRTY DOG]

Using a standard sizing die with both the expander ball and decapping pin attached to the assembly stem can cause headaches. If the assembly stem somehow gets bent (usually during decapping) then the bent stem will introduce concentricity issues when the expander exits the mouth.

I once used my good 223 Rem FL die (dedicated to a bolt rifle) to size some AR15 brass. An off center flash hole bent the decapping pin, and also slightly tweeked the assembly rod. I didn't realize the latter until my groups went to shit and I eventually narrowed it down to the bent rod. A new rod instantly cured the problem and groups went back to fantastic.

I now use dedicated universal decapping dies for all decapping. I remove the expander balls in most of my dies and use 21st Century mandrels to expand necks. If I was going to use the factory expander ball, I would dedicate that stem assembly to ONLY expand and never decap, to ensure it never gets bent.

 

[DiRTY DOG]

Which brings up another point. Lapua brass has small flash holes. If you used a standard size decapping pin to decap, you may have unknowingly enlarged the flash holes. That could explain the accuracy loss.

 

[YoteslayerWA]

Thanks for all the input guys. I will look into things this weekend when I’m not navigating the work week.

 

[JTPinTX]

I also use dedicated universal decapping dies a lot. For sure on any military stuff that has crimped primers or sealed primers, or cases that decap hard. I have bent decapping stems on loading dies several times causing sizing/runout issues. But even without those type of major issues though I still use them frequently. The reason is a bit different though. Most of my shooting produces very nasty, dirty cases. Suppressed AR's, high rates of fire, chasing pigs at night in sandy country, cases get thrown around in coat pockets and the console of the truck and they may ride around there for weeks. I also usually process in large batches. I don't want to ruin my dies so my first step is always universal decap, then throw them in the wet tumbler with SS pins for an hour or so to get all the nastiness out and off of them. Then I will spray lube with home made case lube (lanolin and alcohol), size, do any other trimming or whatever I need to do, and then I will run them in traditional media to get lube off them before I load.

 

[Bowhunt]

So my original reloads were with virgin Lapua brass. Second go around were once fired brass. I FL resized them and then tumbled them to clean. After tumbling I clean out primer pockets and flash holes then seat new primers. Then I chamfer and debur before giving them a powder charge and seat a bullet.

I never load new brass without first running through my sizing die. Case volume and neck tension will likely be different than what your dies will set it to. I also recommend that you don't try working up a pet load on "never fired" brass. Also, I would chamfer BEFORE seating primers......less chance of shavings remaining in the case.