Weird question regarding FL sizing

A

_ACGuy_

Private
Minuteman
Sep 30, 2024
7
1
Arizona
#1
Not sure if this is just me and my guns but here is what I see after firing and resizing with a Redding Elite type S bushing die set.

I have 300 WM, .308win, 6.5cm and they all seem to fire a few times with neck sizing only then after the first 2 or 3 firings I would assume they would be my chamber size. So my 300 WM like 2.010 on my SAC comparator with a Mitutoyo caliper. I spray lube and I set my sizing die(on a Forrester CO-AX) until I get a 2.010 measurement(They are 2.014ish) when I start. I run 10 cases and I get 2.009, 2.006, 2.011, 2.012...

I cant for the life of me figure out why I get such a weird range of sizes with a fixed die in a decent press. I assume the cases arent all the same size when I start.

Below is my numbers from 50 rounds of PPU brass(I know its crap, It was factory ammo I bought for the brass when 300wm was hard to find). Its weird that the numbers get worse from min to max after sizing I would expect .0005 to .001 range after my process.

Any constructive thoughts would be appriciated. I know I need to invest in Lapua brass, I can't find any when I look locally.

Average
2.2140
SD
0.0006
Min
2.2125
Max
2.2145
ES
0.0020
 
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#7
large jaws, homemade 99% alcohol w/Lanolin 11:1 ratio. Spray it in a metal pan. roll it a little wait 5 - 10 minutes. resize first case was set to resize to 2.210" with a SAC 300WM comparator.

These are the numbers I got a 47 case I just resized. 3 second dwell time also.

Average
2.2079
SD
0.0015
Min
2.2040
Max
2.2105
ES
0.0065

I would think if there was variance in the case length from shoulder datum to the base after three firings it would be negligible.(I anneal after ever de-prime, wet tumble, drying cycle). Its so weird to get so much variance. I made sure I used the forester lock ring and the die was tight. Its super frustrating. MY velocity ES was between 7 and 14 per every 5 shot group last weekend. That doesn't seem too bad.

I am using an auto-trickler v4 currently so I know the powder charge was fairly consistent.
 
#8
I think it is the lube. Either it isn't being applied evenly or you aren't giving the alcohol enough time to evaporate. Possibly both. A good practice is to spray the brass in a gallon ziplock bag, shake the brass until evenly coated, and then dump the brass into a open box for 30 to 60 minutes. You may also want to clean out your dies and coat them inside with lanolin.

Make sure your brass is sitting against the shell plate without the jaws holding it up. The automatic jaws are known to cause case length and COAL variation.
 
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#9
Personal observations, benefit in decreasing order for sizing (not so much for maximizing case longevity or neck splits):

1. Dwell Time (compress brass, count to ten) and / or Number of Compression Strokes (until the final stroke “feels the same as the one from prior brass”)

Hit your brass...

AAA1.gif


...and hit it again...

AAA2.gif


...hit it hard!

2. Consistent (and Generous) Amount of Lubricant

AAA3.gif


AAA4.gif


After #1, multiple strokes still exhibit resistance, so you reapply lube…

…only to feel how “loose” the brass actually is in your die.

Dwell Time and Number of Compression Strokes trumps Lubricant, but appropriate Lubricant makes the process so much easier.
Click to expand...

3. Consistent Annealing, quantitatively calibrated (i.e. an AMP Induction Annealer)

AAA5.gif


Brass Springback...

IMG_4648.jpeg

...is fickle and highly variable. While using boutique brass and the above acrobatics minimizes such - the only true way to figure out what’s going on is by measuring each case. Can't rest one's laurels after making the assumption that one has "perfected a method," unless one chooses to excessively headspace brass to account for measurements on the upper end of the Range (or Extreme Spread, as shooters somehow choose to refer to it). Personal opinion - nothing beats this tool in the combination of consistency, ease of handling, accuracy / precision, and speed.

There are some other things you might encounter later, like Delayed Springback and the like… But that’s for another day.

EDIT: No idea why the picher came out so yuuuge.
 
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#10
the example you gave shows a .006 variation is shoulder bump. This is very high. The coax press is known for erratic shoulder bump especially if you are not getting a firm contact between the shell holder jaws and the die ( cam over). With the coax you cannot use the Redding comp shellholders so you normally don’t get camover unless you get lucky and your bump goal coincides with camover. I would try another press and get a firm die-to-shellholder contact with camover.
 
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#11
I had the same problem I traced back to not letting the achohol evaporate. I don't use my lanolin alcohol mix unless I have 30 minutes or more to let the alcohol evaporate. I use one shot when I am in a hurry.
 
#14
Marine52 said:
the example you gave shows a .006 variation is shoulder bump. This is very high. The coax press is known for erratic shoulder bump especially if you are not getting a firm contact between the shell holder jaws and the die ( cam over). With the coax you cannot use the Redding comp shellholders so you normally don’t get camover unless you get lucky and your bump goal coincides with camover. I would try another press and get a firm die-to-shellholder contact with camover.
Click to expand...
You can convert the coax to take shell holders.

@_ACGuy_ As mentioned above, sort out the lubing situation. Ive never used that lube so I cant comment directly, but lube conditions do change inside the die through use. A clean freshly lubed die will size differently from a well seasoned crusty die.

Annealing may be playing a roll too.

Im a big fan of redding comp shell holders, and I converted my coax years ago to use them. Takes press deflection out of the equation entirely, and the coax, like every other press, has deflection.
 
#16
I think your annealing process isn't softening the the neck & shoulder. The brass is too hard and still elastic - you cannot get consistent permanent deformation hence inconsistent shoulder length.

I use a flame annealer. If I look into the brass when it leaves the flame, the entire inside neck glows - from the top of the neck to the bottom of the neck. The glow disappears after about a second. The templaq technique did not work for me, when templaq said it should be softened, it wasn't.

My process reduces shoulder length by 2.5 to 3 thou. When I size 308 brass (Lake City LR or Lapua), I get about 1.624 plus or minus 0.0005 with a maybe 3 or 4 out of a batch of 50 that are 1.623 or 1.625. I mandrel the necks. I have no gauge for neck tension but it seems consistent to me when using Wilson seaters.

About lubrication: I use either Lyman Quick Slick and OneShot and a hard-finish cotton bag that tire chains came in. I toss the brass into the bag, spray 3 or 4 seconds, close the bag, tumble the brass, pour it into a tray and start sizing. The bag has lubed probably 5,000 cases so it is well impregnated with lube, the new spray is just insurance. I rarely wait more than a minute or two before sizing, the cases are a little slick because the alcohol is not completely gone. This works for me. For those who have experienced lube issues, I believe you but I don't experience such issues. BTW, I never get lube dents and haven't stuck a case is years.
 
#19
Supersubes said:
Without knowing the brass ID prior to the expander ball, that's a bad data point.
Click to expand...

Yeah... considering that people have reloaded cases many more than just 2x for a lot of years long before annealing was even remotely common - and in the overall scheme of things, most reloaders still do - I would attribute zero credit to that particular anecdote.
 
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#20
A very simple experiment would be to take a few fired cases and use some Synthetic Motor Oil as a lubricant. Put a thin layer of the oil your finger and apply it onto the case. Don't use too much or you will get shoulder dents. Run the cases through and check shoulder length. That might tell you if it is a lube issue.

I use the home made 99% alcohol / Lanolin for big jobs. If I'm doing 10-20 cases, I'll use synthetic motor oil. It works well as a sizing lube. Never have stuck a case with it.
 
#21
FLIGHT762 said:
A very simple experiment would be to take a few fired cases and use some Synthetic Motor Oil as a lubricant. Put a thin layer of the oil your finger and apply it onto the case. Don't use too much or you will get shoulder dents. Run the cases through and check shoulder length. That might tell you if it is a lube issue.

I use the home made 99% alcohol / Lanolin for big jobs. If I'm doing 10-20 cases, I'll use synthetic motor oil. It works well as a sizing lube. Never have stuck a case with it.
Click to expand...
ya could maybe try

Imperial Redding Sizing Die Wax or an equivalent .I find I have to touch each case and it just so easy to use​

 
#22
+ 1 for Imperial it is very good. When I was making bullets, I used a lube made from anhydrous lanolin and vaseline. The homemade stuff was very good for jackets but I didn't try it on brass. Using Imperial, in order to lube a case, you tap or slightly drag your finger over the lube in the tin then wipe or smear it onto the case - you just need a film, it is VERY slippery. One tin-touch will probably do two to four cases. I switched to spray because I don't like lubing my fingers; that is the ONLY thing I don't like about Imperial. I currently possess three tins, I will never run out.
 
#23
misser said:
ya could maybe try

Imperial Redding Sizing Die Wax or an equivalent .I find I have to touch each case and it just so easy to use​

Click to expand...
I also use Imperial wax.

I posted the Synthetic oil use for the O/P for just a test so he wouldn't have to run around and try to find a tin of Imperial or some other lube marketed for reloading. He might have some synthetic motor oil on hand at home, wouldn't cost him anything.
 
#24
Yup, I have quarts of synthetic oil and transmission fluid on my shelf. Synthetic motor oil and transmission fluid are the same as premium gun oil. I happen to like Imperial better than oils because it is less messy. The spray products are even less messy. When you adapt your process to the product, they all (mostly) work so it is (mostly) just preference.
 
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