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Aside from destroying brass, the splits are kind of cool. There are rings in the necks, but they were a remnent of resizing, not from firing. The photo really accents the rings, but they aren't very prominant.

Bases don't line up at the bottom, so the tops look different in the photo. The brass all measures 1.574 now. I bought the super-bolt at the same time as the barrel. ARP does a head-space check with matched sets, so that should be ok, but worth a check. And I was using that same bolt to bump back the original shoulder. To my eyes, the fired brass shoulder dimensions look exactly like the pre-fired loaded rounds that I didn't shoot.

I bumped the shoulder to match the chamber, but I'll go through the excercise with a new piece of brass to verify the shoulder.
 

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Something is way off--that's basically "catastrophic failure" for brand new brass; your distance from bolt breech face to shoulder datum is obviously way too long. Not saying it to be snarky, but that's the way it looks to me. Every now and then a chamber out of compliance gets out there--just had one myself that kaboomed an AR. Not saying that's the case, but something to check (I believe H checks them all?).
 

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I shoot 2 cartridges that require fire forming. one of which moves the shoulder forward 0.100 inch. The other is not so radical. I always anneal the cases after I form them and before I load them and start with a starting load. My fire forming has resulted in better than a 98% success rate. The ones that do fail show cracks very similar to yours, just not as many.
Before I shot anymore of these I would break down any loaded rounds and anneal the brass, make sure they fit the chamber properly, and load a lighter bullet with a lighter powder charge. Load four or five or even just one and see what they/it look like.
Best I can do from just looking at pictures.

Good luck.
 

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Agreed. Catestrphic failure on new brass.

Here's photo of fired brass with unfired loaded rounds. The datum looks very close. If my sizing was an issue, wouldn't the fired brass be obviously longer to the shoulder than the loaded/unfired brass?

I've seen YouTube fire forming of other wildcats that have crazy differences in shoulder locations and those operations don't spilt the brass.

It's a head scratcher for sure.

Definitely no more shots until this gets figured out.




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Discussion Starter #905
I'm short on time at the moment but headspace doesn't mean anything when there is no factory loaded ammo. The person sets the shoulder location, that is the headspace,
 
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I have had similar splits, but have only used Hornady, Nosler, and FC brass. It was mostly a problem with the batch of Hornady Brass I had. I got splits like that in about 8 of the first 25 rounds in my first loads with Hornady. Much better result with both Nosler and FC, but would still get maybe 1 in 25. That was just a reason for me to pull the trigger on an anneal eez I was already looking into, and have never once had that problem since, whether annealing before sizing 6.8 to 30HRT or doing it after sizing. As long as it was before the first fire I havent since had a single split.

I dont believe headspace is a problem, sounds like you set your die similar as I did. Using the 350 bushing on the Hornady comparater I get 1.310" when I size, and 1.314" after I fire. Maybe more than some prefer, but it works for me.

****
On edit, I didnt consider my splits like that catastrophic. Hated losing a piece(s) of brass, but splitting brass around the circumference and leaving half the case in the chamber starts to get closer to catastrophic for me. I just consider that kind of split a nuisance crack.
 

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I bought the same barrel from ARP a while ago and all I've ever used is the Hornady 30 Herret dies. I've used well-used SSA brass until I finally bought some new stuff. I've never had any notable issues other than the primer cups getting loose and a bit of bulging at the case head--but this was with old and fired many times in a 6.8 spc rifle brass resized to the tac 30/hrt. Obviously that doesn't help you any--but like H says nothing really fancy is needed other than being aware you start with the sizer die above the shell holder plate and gradually dial it down until you get the bolt to close on the brass. I didn't mean to imply there is a "spec headspace" --you set it yourself.
 

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Looks like anealing is the course I take. That and a lighter load.

VA6.8FAN. You are right. Better to have a split in the shoulder than a total case head separation or a trip to the ER.


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Discussion Starter #909
I have not used any S&B in the Herrett so I don't know how hard the brass is. I know the Federal is soft, I had 4000 pieces of the once fired stuff from LWRC so I decided to use that for the Herrett. When you are sizing /forming you can feel the difference in the lever. I don't know but I am thinking the same as the other guys about the brass may be too hard or possibly the charges a little high for the first firing. 6.8 cases are .402 at the shoulder, the Herrett is .410 so they are being fireformed somewhat.
 

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In the photo of the fired/loaded unfired, a split is visible in the shoulder area of the loaded unfired.

I think annealing prior to forming is the first course of action to take. If you still get splits, then you likely have a batch of brass that wont take having the shoulder set back.
 

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Nice catch you can definitely see the split in the loaded round. I guess S&B being the best brass for 6.8 doesn’t translate to the best 30Herret brass. I have used older SSA for all of mine and have never had a split neck other than 3-4 during the sizing process.
 

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I inspected all my loaded unfired rounds under a magnifying glass, twice. Didn't spot a split in any case. Some of the lines in the photo might be surface scratches due to feed-testing in a fresh magazine with sharp edges. There might be micro-splits/cracks, but I can't spot them under a magnifier.

In any case, I think annealing before resizing will be a best-practice for me and this brass. Maybe the ring around the neck will disappear too, as its the former crease corresponding to the top of the 6.8 shoulder where it met the 6.8 neck.

I'm going to pull all the remaining loads apart and anneal some of those, then reload and fire to see if those results are all good, or if the damage is already done. I'll also load up some with new brass, annealing before sizing and see how that goes. That will take several weeks; super busy with work and summer stuff for the near future.

I'll lighten the load, was at 26.5 grains of SW BO. With that powder do I need to worry about lower %-fill affecting pressure in the opposite direction, i.e. causing higher pressure? I believe that's a "feature" of H110 or maybe Lil'Gun. The only thing I'm aware of with SW BO is if pressure is lower, there could be a yellow residue buildup.

I was surprised to get signs of high pressure on the primer from that load. Was it the load, or maybe the CCI 400 primer being soft?

Thanks guys, I'll post an update when I get the next round of testing done.
 

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I use SWBO, CFE BLK, 1680 and on occasion 8028xbr for my loads. The biggest difference between my loads and your's (and I go well past your powder charge weights) is your bullets--I generally find the sweet spot in performance around 125 gr bullets. I have no idea how--but maybe that's where you might look for your issue. Use the same brass on a smaller bullet and see if it does the same thing. A big bullet "stoppering" in the throat or lands could conceivable run up your start pressures.
 

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Just got my 16” tac30. Next step cut it down to 12.5. I think. Just a little spoiled with the 12.5 6.8.


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Got my 16” 30 herrett cut down to 13.5




assembled




Did some pressure sign testing with 110gr Lehigh defense. Started from 30 to 31.5 of sw blackout. Not sign of pressure. Loaded some more at 31gr to check function and adjust gas block. I probably need to open the gas port but need to verify it first.


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Got my 16” 30 herrett cut down to 13.5




assembled




Did some pressure sign testing with 110gr Lehigh defense. Started from 30 to 31.5 of sw blackout. Not sign of pressure. Loaded some more at 31gr to check function and adjust gas block. I probably need to open the gas port but need to verify it first.


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Beautiful rifle
 

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That looks SWEET! A lot handier looking than my 18", but I love mine and the knock down ability is awesome.
 

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That looks SWEET! A lot handier looking than my 18", but I love mine and the knock down ability is awesome.
I love my 12.5 6.8 spc. I hunt from a building and moving around inside, the 12.5 with suppressor is great. Hoping this will replace the 6.8. I tried a 16” with suppressor, just to long. A lot of testing first before it takes over as my favorite coyote rifle.


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Love that dip job on that rifle. Hmmmm.... now you have me thinking.
 
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