Good morning my fellow uncle Sams misguided children. This issue has me scratching my head for real. So, to give you an overview I've been reloading for years and never experienced this. So, I'm reloading 338 Lapua, and these brass cases are on their 4th rotation of being reloaded. I didn't do anything different than all the other times I've reloaded these rounds. I clean the brass in dry media, i then remove the old primers, I anneal using the amp annealer, i then full-length size, trim, debur, seat new primers, powder drop, then seat the round. So i noticed when i full length sized, some took less effort than others, and another strange thing is then I'm using a micrometer die from Redding or another name brand which has seated the bullets perfectly previously, but when I seat the rounds some feel like it takes a normal amount of pressure to seat, and some are real easy going in, and when i measure the OAL, I get on some 2.980 which is my OAL i use, and some seat at 2.972. For the neck tension should I full length size with my bushing full length sizing die with a little smaller sized bushing die, and then run the correct mandrel die that I want to set my neck tension to get a more accurate neck tension because I'm sizing from the inside out? Also, what could possible cause my bullets to seat at different depths on a seating die that's been super accurate? Its lapua brass and Sierra HPBT 300 grains. Feels like everything is pointing to the neck tension, and neck tension has an effect on seating, but what would cause such a shift in seating depths on a micrometer die. I checked to see if anything was loose, and everything is locked down. Your thoughts?
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Different neck tension and seating depth from round to round
- Thread starter USMCRUZ
- Start date
Stop annealing every loading cycle. Do it ever third firing. Your necks and shoulders have gotten too soft.
Damn!! On the Annealing Made Perfect machine site the manufacturers specifically say to anneal after every firing before sizing, and ive always bought annealed Lapua brass, but this is the first time in 15 years ive ever annealed after every firing. Now that you said that, it makes sense. Thanks brother!
You didn’t mention if you sort your bullets for an acceptable COAL? If you are measuring at the ogive you shouldn’t see any variance in BTO but with matchkings you will most often find each bullet to have various length. As for the neck tension/seating pressure issue - try annealing - sizing - and on case prep use a nylon brush to clean the inside of the neck. If you are using a bushing due to set neck tension and bump the shoulder don’t stick anything else into the neck of the case except the nylon brush on a prep center or whatever you use. You should feel a very consistent pressure on every bullet seated at this point especially if you don’t over do it with tumbling/cleaning your brass. Hope that helps.
After seating the bullet, im using a starrett caliper and a Hornady O-give Bullet Comparator. For the last 400 rounds everything has been on the money measurement, and bullet seating wise. I tumble in dry media for about 2 hours. Ill use a nylon brush on them after i dissasemble the bad rounds. Maybe a stupid question, but and ive never done it before, but do people use trace amounts of lube on the inside of the necks before seating the rounds. Like i said ive never done it before, but then again before getting the Lapua, the biggest rounds ive reloaded was .308. To answer your question, ive never sorted my rounds before. Thanks for help!
Yessir, there is case neck lube to help with seating. It’s a fine powder but I find that dialing back the cleaning process and using some burnt carbon inside the case neck works too and that’s mainly what the brush is for. Just give it a try for yourself and see if that helps, anneal-prep-load, limit exposure of extra processes and especially if using a bolt action.
Basically just brushes it away leaving residual. I use a nylon brush on my Lyman prep center so it rotates in the case. Just a quick stab after chamfer and debur will do.
overcleaning the necks (eg wet tumbing) has its own problems (ie needing neck lube), and its basically easier to brush the necks.
IIRC people have tested this neck brushing thing and it appears to work. who knows why, maybe the residue is uneven? from the blast/burn, leaving hi or low spots (of gunk). the mandrel might just panckake the junk vs even it out etc. who knows...
When I first started reloading I didn’t brush the neck. Eventually the cases were making a terrible screeching noise on the way out of the die. The expander ball was getting stuck inside the neck. It was then I realized that black residue in the neck is not a lubricant.
Yeah ive never used that before, but ive seen it in the store. its a graphite powder right?
IMHO, it has to do with consistency. . . making the interference more consistent.
That black residue has carbon in it and carbon, as I feel you're well aware, is pretty hard tough stuff. Too much of it can be a problem, as it seems you found. A little goes a long way and works the same as Imperial's Dry Neck Lube.
It reminds me back in the 1970's when various synthetic motor oils came onto the market. Having worked with synthetic oils in the aircraft industry, I was interested in finding which works best in automobile engines. One of the synthetic oils promoted then as having graphite incorporated into it providing better lubrication. From my experience in the aircraft industry, something about that just didn't sit right with me. Sure enough, a year or so later, I read that graphite was a big problem in the engines where there was high pressure on surfaces . . . like the camshaft lobes were getting a high amount of wear over as short period. Surfaces with low pressure, the graphite worked fine as a lubricant additive, just not with high pressure.
there are many forms of carbon and I don't believe that the residue in the necks from burning powder (which has to have more shit in it than just carbon) is at all equivalent to pure powdered graphite.
And if your regime includes getting necks pretty clean...as mine does...and then adding graphite back in as a lube seems like the best of both worlds.
Dykstra just put out a vid showing data related to the benefit of annealing first...then cleaning...as the annealing also seems to add some sort of residue. Personally, I'm a fan of Keith Glasscock who is totally objective data driven. His first take is that he agrees 100% with Dykstra but he has also just put out his own vid on reloading process order and its effect just yesterday. I haven't had a chance to look it over yet.
But their basic point (I think) is anneal absolutely first, then tumble (or whatever you do to clean), lube and size, trim if needed, tumble to clean lube, prime, lube inside of necks (I'm soon to shoot some loads I made using neolube which is colloidal graphite in an alcohol solution...first glance, it leaves a very smooth and even coating of graphite), then seat.
And if your regime includes getting necks pretty clean...as mine does...and then adding graphite back in as a lube seems like the best of both worlds.
Dykstra just put out a vid showing data related to the benefit of annealing first...then cleaning...as the annealing also seems to add some sort of residue. Personally, I'm a fan of Keith Glasscock who is totally objective data driven. His first take is that he agrees 100% with Dykstra but he has also just put out his own vid on reloading process order and its effect just yesterday. I haven't had a chance to look it over yet.
But their basic point (I think) is anneal absolutely first, then tumble (or whatever you do to clean), lube and size, trim if needed, tumble to clean lube, prime, lube inside of necks (I'm soon to shoot some loads I made using neolube which is colloidal graphite in an alcohol solution...first glance, it leaves a very smooth and even coating of graphite), then seat.
This is interesting, as alot of conventional wisdom could be summarized as 'clean first'. Makes you wonder how we all get in the habits we do.
