FL sizing die shaving base of case and inconsistent headspace

[DirtDigger]

New to reloading, and I'm not sure I'm finding good info on my issue so I thought I'd ask here. Sorry for the book I'm about to write, but I'd like some input from some of the experienced reloaders in the room.

Here's the situation:
I've been doing load development on my second rifle (Horizon Carbon Vandal 22 creed 18") and started with 200 pieces of virgin Alpha LRP brass. Before I loaded it the first time, I ran it through my Short Action Customs modular sizing die (set die to not bump shoulder, just size neck) with a mandrel installed to fix some dinged up necks, and trimmed everything to length. Everything went fine, load development went great, found a great load with good SD's (4-5) and shoots in the .3's with the 85.5 bergers. I've killed a couple coyotes and life is great. The load is 42 grains of H4350, alpha lrp brass, gm210m primer, sending 85.5 bergers at around 3170 fps out of an 18" barrel. I've had no signs of pressure during load development except 2 primers leaking gas and one loose primer when I did seating depth testing and got close to the lands and speed/pressure jumped up. I do think the load might be pretty hot according to a free internal ballistics calculator I put my info into, but again no pressure signs anywhere. Also to note, the next good node with less speed (pressure) is around 3,000 fps and that wasn't super exciting.

Now the problem:
I deprimed the first 100 pieces of the alpha brass I used for load development, sent them through the tumbler with stainless media, dried them, annealed them, tumbled and dried again, lubed them with Dillion spray lube and went to sizing. The sizing die is shaving brass off of the bottom 1/3 of the case on around 60% to 70% of the cases, some quite a bit, and it obviously takes more force than it should to run the die down. Note here: So after the first few sized hard I started rubbing the cases with One Shot case sizing wax along with the spray wax that was on them. Also, after the first run through the sizing die some are longer after they come out than before they went in by a couple thou. I'm using Area 419 headspace gauges, Mitutoyo calipers, and I'm competent with them, so I know it's the brass and not the tool in case that gets brought up. So basically brass goes in at 1.538" and some that run through with "normal ish, but on the high side of normal" pressure come out at 1.536-1.5375 which isn't ideal with that big of a spread, but it's something I can live with since I'm new. Some others come out the same as they went in (hard sizing, but minimal brass shaving), and if I run them through again they come out at 1.535-1.536. And then some come out 1 to 2 thou longer at 1.5390 - 1.5400 (very hard to size and shaved brass). If I run the very hard sizing brass though the sizing die again it'll go to 1.538, but it doesn't matter how many times I run it through after 2 times, it stays at 1.538. Now if I take that same exact piece of brass out, and use my fingers to rub the sizing wax around a bit, then run it through it comes out at 1.536 almost every time, and it sizes really nice pressure wise.

So that's where I'm at currently. I did get all 100 pieces of brass sized to somewhere between 1.535 and 1.5375 which gives me .5 to 3 though shoulder bump. Some only got sized one, some two times, and some three or four to get it to that size. I'm guessing neck tension will be all over the place because of how many times it went through, but I am running a mandrel so at least dimensionally it'll be close, and I'll anneal it before I size it next time so hopefully that's just a one time issue. Now I've read on SAC's website that their dies are meant to size more of the case base than "normal" dies. I've also think I've read that if my load is too hot the brass with conform to the chamber and not spring back as much as they normally should. I also didn't clean my die after I sized the 200 pieces of virgin brass, but I don't see that affecting much as it's the same brass and the same lube, but I could be wrong there.

So if you're still with me, what is my issue with this process? Do I simply need to back off on my load? Is my chamber over sized and that's the issue? Is this somewhat normal with SAC modular sizing dies? If it is my chamber, how do I measure it to figure that out? I have 50 rounds of loaded ammo at the above specs that I want to use for coyote hunting this year as I have my elevations out to 600 pretty on point.

Please let me know your thoughts, and I appreciate any feedback you may give.

 

[William Vogel]

You’re over pressure. The tell tale signs are the brass sizing harshness AND the primer situations. The body shaving is an obvious pressure indicator. Brass length growth is a normal condition for full length sizing.

 

[CJ6]

Measure NEW vs FIRED brass at the .200 line.
That should tell you what you need to know.

 

[Ccrider]

Sounds like the die does not fit your chamber and needs to be opened up at the .200 line.

 

[Fire Dog]

You’re over pressure.

^^^^^^^^^^^^^^^^This!!

The tell tale signs are the brass sizing harshness AND the primer situations. The body shaving is an obvious pressure indicator. Brass length growth is a normal condition for full length sizing.

If you have gas leaks and primers that fall out, you are well past the point of safety…
As for the shaving brass off the case, perhaps it is the Alpha brass as I see that they often require an “ALPHA” chamber = a bit larger at the 200 line, and that is perhaps what you have and your SAC dies are for the somewhat smaller chambered brass…
As suggested, dies may not be compatible with your chamber, contact SAC as they are helpful and send in 5 pieces of brass fired in YOUR chamber along with the die and I would think that they will be able to hone out the die to suit the requirements of your chamber.
Also, get yourself a tin of Imperial Die Wax or Ballistic Case Wax {my new favourite} and see if that does not help as well..
Spray lube just does not do the job… Especially when the going gets tough…

 

[SKWERLZ]

Leaky primers + sizing problems,,,,,sounds like you’re a bit overly spicy.
If you developed your load with virgin brass it’s common to get more pressure on the second firing as brass is closer to matching chamber.

Also a lot of quality cases have less volume inside than factory cases and you need to accommodate that with load data.

 

[big5ifty]

The sizing die has an unpolished edge on the inside of the mouth.

If you can return it to the manufacturer, do so, otherwise you can remedy the situation yourself with 1000 grit water paper, a dowel stick and a cordless drill.

This is a die problem. It should not shave brass, no matter how much the fired case has stretched.

 

[SKWERLZ]

The sizing die has an unpolished edge on the inside of the mouth.

If you can return it to the manufacturer, do so, otherwise you can remedy the situation yourself with 1000 grit water paper, a dowel stick and a cordless drill.

This is a die problem. It should not shave brass, no matter how much the fired case has stretched.

I’ve had that happen recently on a Hornandy die.

I’d be surprised if a SAC die went out in that condition.

 

[Fast14riot]

First off, go buy yourself a lotto ticket. 42gr of H4350 under an 85 is several grains over most book max loads! Should be down around 37gr for even 80gr bullets! Also, that powder may be on the fast side for that heavy of a bullet, look at slower powders like RL26, H1000, N555 and use LRM primers to be sure to get good ignition.

 

[searcher]

To emphasize some of the above posts - and to add to:
1) Leaking and loose primers are a sign of over-pressure - back your load
2) Getting longer case measurement after sizing is normal. When you "squeeze" the brass smaller, the brass flows towards the neck. This is OK., though if cases are growing a lot in length on each firing (and your load is not hot), you likely need to tighten up your headspace.
3) Getting shaved brass on the bases of the cases would tell me a) you may be overpressure, b), you may have a very rough die, c) The spray lube you are using isn't applied in enough quantity or being allowed to evaporate before running into the die. I love Dillon spray lube, but it is not the best for challenging situations. Try the Imperial wax lube AFTER cleaning your cases. Based on what you said about the die, it sounds like that die is built more as a small-base die. They do require a bit more effort to size - but not that much. If backing off the load and using Imperial wax don't help - I'd replace the die with a different brand to alleviate the chance of getting another like it. I've never stuck a case in a die using "traditional" case lubes, but I have with the spray lubes.
4) New dies typically come with anti-rust protection. Did you thoroughly clean the die before the first use? I spray clean and swab my sizing dies after each reloading session or every few hundred rounds, whichever comes first.

Are there a lot of individual scratch marks on the bases after sizing, or more like larger uniform gouges?

 

[Steve Donlon]

First off, go buy yourself a lotto ticket. 42gr of H4350 under an 85 is several grains over most book max loads! Should be down around 37gr for even 80gr bullets! Also, that powder may be on the fast side for that heavy of a bullet, look at slower powders like RL26, H1000, N555 and use LRM primers to be sure to get good ignition.

Good call. H 4350 powder is not even listed for a 62gr. bullet in my loading books. Powders like H4831 or H1000 like you said.

 

[JFrank]

it is my chamber, how do I measure it to figure that out?

Compare fired to resized like this will give you insight as to the chamber to die compatibility .

 

[dhagerty40]

the primer leakage is a sign of overpressure. along with that I ran a quick test through quickload and it definitely shows you are over: Also, Alpha brass I have found to be thicker compared to lapua brass.

 

[Fast14riot]

Good call. H 4350 powder is not even listed for a 62gr. bullet in my loading books. Powders like H4831 or H1000 like you said.

The other problem with H4350 and the slightly faster powders under heavy for caliber bullets, it will pressure up very quickly. OP is very lucky he didn't have a catastrophic case separation locking up the bolt. I would double check bolt lugs for galling.

This is why checking published reloading manuals and cross referencing between at least two sources is very important.

 

[mic2377]

Too hot. You are getting every pressure sign possible. To see this with Alpha brass, which is quite tough, means you are WAY over. I shoot a 22 CM with Alpha brass and have never seen any of these issues.

Die may not have much chamfer. But this is just compounding the problem of sizing overexpanded cases.

There is a some nice threads with data for the 22 CM both here and in SH. If you want that velocity with those bullets, H4350 isn't going to get you there safely. N560 or RL26 is your friend.

 

[ELR LVR]

Sounds like the die does not fit your chamber and needs to be opened up at the .200 line.

Sounds like overpressure, case head expansion
other than that, the sizing die may be rough?
There is sometimes a small chamfer at the start of the die, this could have a sharp corner which could be smoothed out and polished
But if this edge is shaving brass, sounds like reducing the load will help.
Load workup - means starting low, and working up
---
BTW, when you measure at the .200 line of the case head
you must measure with a .0001" Micrometer, not a caliper
if the head measures .0005" or more over you are over pressuring the case.
Try some RL 22 if you wanna run 42 grains and the 85.5's, (Awesome bullet!)
But start at like 39.0 grns, or maybe even 38.0
Load workup - can be done 1 bullet at a time, as opposed to 5 shots at a time to find where pressure signs are quickly.
IE: 38.0 ; 38.5 ; 39.0 ; 39.5 ; 40.0 ; etc
that way you dont have a bunch of ammo loaded above that you cant use once you get to your pressure load and you found it within maybe 10 or 20 shots.
This is the first thing to do with trying a new powder. Find where the pressure signs show first.
And very often, you will find a load that works extremely well at the lower end.
When I see 3 shots suddenly go into the same hole during the ladder, with this type of 1 shot ladder to find the pressure load...
...it usually means thats where it likes it, and is almost always, before seeing pressure signs.
---
so you will find your magic load, before reaching overpressure
---
If it has not shoot well once you start reading pressure signs, that tells you you have the wrong powder
Switch powders.
Once you see pressure signs, such as primer flattening at the edge, and ejector marks on the rim
back the load off AT LEAST 1 Full grain, maybe 2
If I find an accurate load 3 grains before reaching pressure, so much the better, less powder used in the long run and more barrel life.
Try not to get stuck on the "Velocity Train", if you want that much more velocity use a bigger case.
---
Backing off 1 grain from pressure, isn't a hard fast rule but a general recommendation
at least it gets you back into a safer zone for tuning your load, for now.
Consider the outside weather temps in doing this
if it is summer and 90F I may only back off 1 grain
If it is 50F, I will back off 2 grains or so, in anticipation for when it gets hot later
this is also dependent upon the primer you are using such as if it is a hotter primer or not etc.

 

[coldboreshot]

Agree with all here...over pressure, chamber dimensions at the .200 line vs brass selection. Not much more to add to all the responses other than, disassemble the bolt and make sure you have no blow back residuals in the bolt or on firing pin that make cause future igniton problems. Also for shits 'n' giggles, inspect the firing pin tip.

 

[Rick300]

I would add one other issue in addition to the above. Are you chamfering the necks after tumbling? If not, you can get a build up of shaved brass from the necks the will cause streaks, hard sizing and other issues. Look in your die and see if there is brass on the wall. If so it's probably coming from the neck, if not then your 200 line is likely too big.
Follow the excellent advice given above to take you out of the danger zone.