Arc problems AGAIN!!!

[rsbhunter]

New brass 1st firing....book load, 29.4,29.7 lever, Berger 105 BT Target, .020 off . Tried to post pictures, but won't let me. Anyway, have shot Hornady Black and new load 6.5 cases necked down.On the new cases necked down had 4 cases crack, from body shoulder junction down the body between 1/4" to almost 3/4" long. None of the Hornady  cases had cracks, or were scratched. The new cases other than the 4 I have discovered so far look ok. I did have some that after sizing, had the "belt".  I discarded the belted ones...but I am really skeptical about reloading any of the new/ resized cases....I was expecting the Hornady brass to be the throw away brass, but even though the primers were flat, the brass held up better than the new cases. Would really appreciate an education on the idiosyncrasies of loads, brass, tricks to make the ARC run smoothly. I do have 100  6.5 Grendle Lapua brass I could size, but till I know it's not going to be one and done, I won't risk it. Thanks for any help....rsbhunter

[Dino11]

Did you anneal the brass before you sized it?

First firing should have been a light load.

Sounds like you have some type of issue with your sizing and loading technique.

Measure a fired case and provide the size to the datum line, then measure a sized case and tell us what it is to the datum line. You need a comparator to do this.

Pics would be a real plus. This site needs a sticky to help folks use some of it's features.

[LaMan]

Did I miss what make of new brass your trying to downsize?  I have done 75 new Starline Grendel brass down to 6ARC without any trouble whatsoever.  Lee full length sizer die with shoulder set back appropriate amount, trim and shoot.  Some of these brass are on their 6th firing with some pretty stout loads.  In fact I'm tired of waiting on ARC brass so I will be doing another 50 cases soon.  This is for an AR btw.

I with Dino in thinking that you have a sizing issue, shoulder pushed back to far?

[rsbhunter]

Ok, StarLine brass new...annealed after firing. I have .003 shoulder setback, using g Hornady .350 insert, trimmed to 1.485. These were new cases....were not a annealed before forming....original base to Datum was 1.184- 1.185, resizes to 1.182-1.183. Have been forming wildcat cases since the 70's (7mm IHMSA), and have a decent grasp on the procedure. I also shoot multiple 6mm Norma Dasher in competition, so I do pay attention to the proper details. This isn't meant to say I'm perfect, just that I do have experience loading for different calibers/cartridges. My main grips is that the factory loads that had mild pressure signs (flat primers, slight ejector marks,) which a couple of the cracked cases (StarLine)didn't show pressure signs. The datum measurement was measured off of multiple factory cases fired in rifle, without problems, before the BTD was set up on new cases. There was no fitment problems in chamber. Feed ramps were polished before ever being fired with bullet tip felt polishing tip and Dremel polishing compound until mirror shine and no sharp edges at all. Please let me know what other info will help with solving this dilemma.. rsbhunter

---

Just reread the posts, I'm not experiencing inciepient head separation, these cracks run length wise on the case, not above the extractor groove. And besides, on a new case , if I did that much shoulder set back, it probably wouldn't have fired for excessive head spacing.....rsbhunter

[StoneHendge]

I'd wager that a hot load is at least part of the problem. Hornady Black likely uses Lever near max charge, so if you put a max charge that flattens primers in a different unfireformed case without any load work up which may (or may not) have lower capacity, something is going to give somewhere. I've had more than one barrel that can't handle max published charges and that would probably go boom if I dropped a max charge of ball powder in them on a hot day.

Two thoughts: are you using an expander ball and if not, are you checking for the dreaded "donut" (ring that can form in the inside of the neck). The donut can lead to pressure spikes. It might also be worthwhile to compare the bearing surfaces of the Hornady 105 HPBT with your Berger's. If the Berger has more, you could be getting an early pressure spike, especially with the short jump. But regardless, I'd back off on the charge. The Hornady Black is telling you that.

[rsbhunter]

I understand the Hornady Black is hot. Have a friend that has same barrel set up. Hornady Match ammo trashes the case on almost every shot. One and done. The loads were worked up , and multiple cases fired using same load that didn't crack, or show high pressure, but even the cracked cases didn't show excessive pressure. That is where my confusion comes in....High pressure is high pressure..... Unless some component or situation is changed, you'll get the same results. I'm going to reload the once fired Hornady to the same load, and test the results......I should see at least high pressure signs, even though I didn't see pressure signs on the cracked cases. The load data is taken from the printed Hornady data, under max. I'm starting to wonder if I need to rethink the ARC undertaking....? Thanks for the help, this has me wondering.... rsbhunter

---

P.S. I did get the picture of the cases to load as my AVATAR !!!!

[Lemonaid]

This is the second report I have read of reformed starline brass neck to shoulder cracking. The other report was that the cracks happened after 3 to 5 reloads. One of the possibilities discussed was a bad batch of starline brass. More details of your firearm (barrel make, barrel length, bolt or gas) will help. I use this free pic. resizer to make them work on these forums. Give it a try, use the resize fit to screen 1024 rez option then save. It will make a version with re in the title. https://picresize.com/

[Dino11]

This is the second report I have read of reformed starline brass neck to shoulder cracking.  The other report was that the cracks happened after 3 to 5 reloads.  One of the possibilities discussed was a bad batch of starline brass. More details of your firearm (barrel make, barrel length, bolt or gas) will help.  I use this free pic. resizer to make them work on these forums.  Give it a try, use the resize fit to screen 1024 rez option then save.  It will make a version with re in the title. https://picresize.com/

This is very interesting, I have resized only a 100 pieces of Starline brass with out issue. But I do anneal it before resizing it and anneal it each time it is resized. I have 500 more pieces of unfired brass to do, but will defiantly keep a close eye on it. I also fire form it with a minimum load and a lighter 100 gr. bullet before full on loading it for my heavies.

Something is not the norm here.

[rsbhunter]

I would love to be able to use the primers and bullets to fire form the cases...I have 3 rifles I shoot in competition , and they all use cci 450...so for now, load development and fireforming are going to be delayed....like I said, I have formed 100 Lapua and 100 Star line 6.5 grendel brass for my 243 LBC AR, and all cases have 3-5 loads on them....and the load for that is 2.0 gr heavier, without pressure or any lost cases....brass was bought and formed about 1-1/2 years ago, so maybe something changed since then? rsbhunter

[KenC]

New brass 1st firing....book load, 29.4,29.7 lever, Berger 105 BT Target, .020 off . Tried to post pictures, but won't let me. Anyway, have shot Hornady Black and new load 6.5 cases necked down.On the new cases necked down had 4 cases crack, from body shoulder junction down the body between 1/4" to almost 3/4" long. None of the Hornady  cases had cracks, or were scratched. The new cases other than the 4 I have discovered so far look ok. I did have some that after sizing, had the "belt".  I discarded the belted ones...but I am really skeptical about reloading any of the new/ resized cases....I was expecting the Hornady brass to be the throw away brass, but even though the primers were flat, the brass held up better than the new cases. Would really appreciate an education on the idiosyncrasies of loads, brass, tricks to make the ARC run smoothly. I do have 100  6.5 Grendle Lapua brass I could size, but till I know it's not going to be one and done, I won't risk it. Thanks for any help....rsbhunter

I have found 29.4, 29.7 to be way to much for a 105. In my 24", 28.9 of LVR got me 2813 at .010" off the lands for velocity testing(slightly hot). These were Hornady Black rounds which I pulled and replaced the powder. I found the factory Black, on one box I pulled, had a range of 30.4 to 31.4gr of powder. First cold bore shot got me over 2913. Way to hot. Let Hornady know and told them what I got. They told me on a 24" test they were getting 2705-2750. They said they would reload them for me, but I declined since I bought them for the brass anyway. I seem to have found a velocity node around 28.1 and 28.9(I think this is too hot). With a Barnes 105 Match burner, around 28.6 is a node(2775) and 107 SMK is 27.9(2650+-) and 28.4(2750, but getting OP signs with re-sized Grendel brass and going to test this with Hornady brass later). This is what I measured in my barrel. I go a little light on first fire after re-sizing, annealing the brass after the initial re-size. I found some 100gr cheap pulls for this function. Be careful on your test. More to come, but for now, I have work which has to be done.

[Bologna]

Loading Hornady 105's at 28.5 lever in factory brass with no issues, have many loadings per case. Monster 20" barrel

[Thelaststraw]

Loading Hornady 105's at 28.5 lever in factory brass with no issues, have many loadings per case.  Monster 20" barrel

  I'm running the same in starline grendel brass resized  from a 20" Monster barrel. There may be something else at play with the OPs pressure issues since it's so out of the ordinary with what is a pretty common load nowdays. I'm still learning myself trying to get better consistency. Could poor concentricity cause pressure spikes? Not necessarily just bullet concentricity in the case but chamber to bore...I mean it's possible there is something up with the barrel.

[johnnyw]

The way to get rid of the belt is to grind 0.020/0.025 off the face of the shell holder. This will allow the case to go deep enough in the die to not leave the belt.

[Dino11]

29.4 gn Lever and a 105 Berger or RFD is my pet load for my gas guns, some of that brass has been loaded 10-12 times, have yet to loose a case. I have not even popped a primer out of the case yet. I keep my bolt gun and gas gun brass segregated from each other as both require different sizing technique. Check you scale with some check weights to make sure it is not telling you any lies.

https://www.amazon.com/gp/product/B078H9...UTF8&psc=1

[BluntForceTrauma]

Don't know what would be causing the cracks running down from the case shoulder.

As far as the "belted" issue goes, our barrels are engineered to offer more chamber wall support in that case web area. That may or may not solve "belting" if it's from some other cause like hot loads or bad timing with early extraction, but we consider it the correct technical solution for most of the "belting" problems.

[Cwlongshot]

Was this resolved?

Again late to the party...

Cracking cases are almost always work hardened. But I read annealing was done. Are you properly annealing? (Not to insult) But like anything in life improperly done correct things can still be wrong. Just like "brand new" dosent mean right or correct all the time.

Also ARC cases are shorter. Are these trimmed correctly as this can cause issue too.

I have formed cases for a dozen calibers and ONLY time I battled cracking was when I had annealing issues or bad old unknown history brass.

As for "belting" this is generally because that case was either:
1) severely over pressured.
2) Shot in a "fat chamber. Or BOTH.

I just went thru about two hundred 7.62x39 cases. (Brass) Fired from a Mini Mauser bolt and SKS rifle some 30 years ago. I know because they cane from a old friend and thats the rifles he had. I got about 125/130 good formed pieces to 6arc. (Some twenty casualities, were my fault battling multiple issues at start.) Once sorted the process went very smooth. Now I just need fire form them. They will serve as my break in ammo.

CW