SAR 18 neck thickness or RCBS die malfunction

[Nemo186]

I started reloading a bunch of Primed-presized brass from Zincpoint. I took 50 and checked them in a Lyman cartridge gauge, all 50 selected fit and slid right out. I am using Hornady 150gr FMJ projectiles. When I go to seat the bullet, occasionally I'll come up against a case that won't seat. Forcing it will buckle the case. All the seated case necks measure less than .340" on the outside, the un-seated ones measure all around .360" The die I am using is not a taper crimp seating die. What I think is happening is that the neck portion of the die is too small and really doesn't like thick brass. The scraped parts of the neck measure right at .340" Should I be content pulling the bullets and discarding the case, or do I get a different die?

 

[fkimble@charter.net]

Almost looks like you are using a sizer to seat the bullets. Either the seater die has a too tight neck I.D. or the brass has very excessively thick necks or the bullets are too large a diameter. Take a problem brass and stop as soon as you feel it being too tight. Do some measuring. Is this the first time using this seater die? First time using this particular batch of bullets

All the seated case necks measure less than .340" on the outside, the un-seated ones measure all around .360"

This doesn't sound right. The neck should get a couple thousandths bigger after seating the bullet. If true then the die is sizing the neck down. Try running a couple cases in the seater die with out a bullet. Does the neck come out smaller than when it went in? Maybe you have the seater body screwed in too deep. Back the seater die out a couple turns and then run a empty case in. It should not touch the die. Slowly turn the die down til it touches the case. Then back the sizer out a full turn. Then try seating a bullet in that same problem case. Let us know what happens. If that doesn't fix you problem, then tell us more details.

Frank

 

[243winxb]

What cartridge? 308 win? Maximum loaded round neck diameter is .3435" None larger. Case neck wall thickness can be different between brands. https://saami.org/

 

[fkimble@charter.net]

OK,, one question solved, he's having a problem with a 308. Found another post from him in the introduction area. it says: Hello, I am glad to be here after lurking a few years. I currently reload .300 Blk, .223 and started reloading .308Win. I have actually joined because I havent been able to find answers for my current issue with 308.

Frank

 

[Nemo186]

Thank you for all the replies, sorry about the misinfo. The Cartridge is in fact a 308Win. The die I am using is a RCBS seating die, without the crimper. This is my first batch with this Brass, this die AND these bullets. Currently the die sits about .125" above my Forster CoAx shell holder That .360" is a mistake, it should read loaded necks are less than .340". The unloaded necks are around .332"-.325". Even on necks that seated properly the seating die rubs a little on my necks, necks that measure .339" after seating the bullets.

 

[Nemo186]

So when I measure all the neck thicknesses, and find brass that's too thick, do I just trim the necks? And then which would be a decent neck trimmer to acquire with as much cross caliber compatibility as possible?

 

[fkimble@charter.net]

OK, 3 new parts don't make nice reload when combined. Not familiar with the CoAx press but can't see where that could cause this issue.
Just had a popup saying a new message has been posted. Let me reload this page and look see

 

[fkimble@charter.net]

Please give us a lot more info. Need chamber info, factory or custom, brass brand, bullet diameter(one that causes the problem plus the measure of a couple others. Did you chamfer the inside of the case mouths? Check out ALL the stuff in my first post and get back to us. Your caliper is not the best thing to measure neck thickness but it should easily show a difference in neck thickness.
As to trimming the necks, never a bad idea. But you would need to "turn" the necks if the brass is too thick to seat bullets in. Turning necks by hand isn't fun, but its would be a onetime job.

"Currently the die sits about .125" above my Forster CoAx shell holder" means nothing to me, I don't have a CoAx. Go back to my first post and check everything listed. You will most likely find your problem. Keep us posted.

 

[243winxb]

loaded necks are less than .340".

As it should be. This is ok, for a 308 Winchester cartridge.

The unloaded necks are around .332"-.325".

Is this the outside neck diameter after sizing, with the expander in the full length sizing die? Does sized brass chamber in the gun? Read the instructions again.

The competition extended shell
holder is only used with the competition seater die. A standard RCBS
shell holder should be used with the competition sizer die.

 

[243winxb]

So when I measure all the neck thicknesses, and find brass that's too thick, do I just trim the necks?

Your case neck wall thickness is ok. Outside neck turning is used to thin case neck walls. Maximum loaded round neck diameter is .3435"

Trimming is case length. Case head to case mouth. The maximum case length for a 308 Winchester is 2.015" (51.18mm) and the case trim length is 2.005" After fl sizing.

 

[Nemo186]

The brass fits in my standard 308 chamber just fine, the bolt closes as it should when I let it slap closed, ejection is fine also, with no need to "mortar" the AR10 and no broken rims. I did check about 35 bullets, they all measured .306 on my Hornady calipers. As all the cartridges I've loaded so far fit the cartridge gauge before and after seating, I'm leaning heavily on the die being a smidge tight. I'm using some preprocessed SAR 18 brass from ZincPoint (annealed, resized, primed, primers sealed) so I didn't see the need to remove the decapping pin to run them through the FL sizer. I'm just feeding a semi auto with this ammo, so not too worried about getting a match perfect fit. To test the theory that the die was a smidge tight, I got a Lee seater, I've done 2x as many rounds as I have with the trouble RCBS seater with zero buckled shoulders and zero scraped necks. And thank you for all the help, as well as the helpful reminder to quadruple check my info next time, I really meant neck turning.

 

[fkimble@charter.net]

Nemo186, glad to hear you got it figured out. It's always a little tougher when you have multiple unknowns involved. Call RCBS and sent them the seater die so they can fix it for you. Never did hear what brand the brass was. I suspect LC.

Frank

 

[Nemo186]

The headstamp on the 308 brass is SAR 18. I've never had to reload 308 before, just 300Blk, and 223 Rem, I never started with a baseline.

 

[divingin]

Here's a thought: Ignore most of the stuff you're thinking about it (too many variables), and concentrate on what's causing your initial problem.

Measure the neck diameter before trying to seat a bullet (in your case, brass as received.) Measure a neck diameter after seating (non-crushed case.) If the difference between the two is more than, say, 3 or 4 thousandths difference, the necks on the brass (as received) are too small (which would cause your crushing problem. It appears that way in your pics where there is a smaller diameter above the shoulder up to the point that the bullet base sits in the neck.) If that is the case, you'd need to open them up a bit (sizing die with expander ball but decapping pin removed will work. Run the cases deep enough to get the ball through the neck but not deep enough to resize the neck, then extract the ball the other way.)

Your bullets should measure .308" within about a half thousandth (because, well, it's a .308 bullet.) Adding 2 times the brass thickness (let's say a nominal .015") should bring you to just under .340" for a loaded round. If you assume the same .004" interference fit, your unseated neck exterior diameter should be in the .336" range (give or take, depending on actual interference, and actual neck wall thickness.)

Once you get that part verified, make sure your die is set up correctly.

For seating die setup, pull the seating stem way up into the die. Pull the die body up in the press. Place a piece of brass in the press, run it up, and screw the die down until it encounters resistance (which should be the crimp ring hitting the case mouth.) Unscrew the die about a half a turn to get the ring off the brass, and lock that in place. Lower the brass, place a bullet on the mouth and run it back up. You shouldn't feel any resistance doing so. Screw the seating plug down until you hit a stop (plug contacting bullet.) Lower the ram slightly and give the plug a turn or two of down. Raise the ram again, which will partially seat the bullet. Lower the ram and inspect how things are progressing. Repeat lowering the plug until you get to the length you want.

Note that brass will "fit" in a rifle or a case gauge even if it is way undersized in the neck or shoulder or body. Fit (or rather, lack thereof) will tell you if it's oversize, but not undersize.

 

[KMart]

loaded necks are less than .340".

The unloaded necks are around .332"-.325".

In my opinion and reading between the lines, you are loading brass that you ARE NOT sizing in YOUR sizing die first. You are trusting that this company properly sized the brass. Never do that even with new factory brass.
You are expanding the necks between .007" and .014" using the bullet as the expander.
Run ALL of your brass through YOUR sizing die using the expander ball to get all neck diameters the same.
The Max difference between the unloaded neck and the loaded neck should be no more than .003-.004"

Start over and try again.

 

[NZ_Fclass]

SAR-18 is Turkish made 7.62x51 brass. Can I suggest that you dump it and get some US made cases?
Remington or Federal would be fine for now. When you get the skills and want more accuracy-Lapua or Norma. Best of luck,

 

[Nemo186]

The only reason I bought them is because they were primed already, I don't pick them back up, because I already have a 5 gallon bucket full of Federal and LC 308 brass. I've been guarding my brick of CCI 250's for my 375 Raptor ammo.

 

[Nemo186]

And on another note, how consistent are CCI's #41 primers? Ive been using some Wolf 223 primers in my subsonic loads, getting SD's at 12fps. I tried the #41's and my SD's from my tests were 60fps. Powder was thrown on the same day, same session, same batch of annealed brass, same powder on my A&D FX120 with my Autotrickler. So I tested it with 223, just the starting loads, same SD's. My question is, do the CCI's just suck? Or is there something I am missing?