6.8 SPC Forums banner
1 - 16 of 16 Posts

· Registered
Joined
·
51 Posts
Discussion Starter · #1 ·
I've been reloading since 1986 and never had an issue with loads not chambering until I started loading the 6.8SPC. The issue has been tracked down to my Hornady sizing die. I always full length size cartridges and you can't do that with the Hornady die. It's creating a raised ring 0.05" from the base of the case. The base should be about 0.417" in diameter. With the Hornady die and the ring, it's around 0.425 - 0.435" causing the case to not fit all the way in the chamber. These cases are near impossible to extract too. Surprised my charging handle has not broken yet. Need full strength to exact these bad cases.

The solution is to not full length size the case. I don't like this method though as it takes time to figure out the gap/space needed between the die and shell plate. I found a better solution and that was to buy the small base RCBS dies. These work fine sizing all the way down to the sheel plate. Never heard of small base dies until I started researching this issue. Must be a problem with 6.8SPC? The small base dies are a few thousandths smaller in diameter at the shoulder and base. My barrel is an AR Performance spec barrel, so the chamber is a bit tighter I believe.

Cylinder Tin Nickel Auto part Metal
 

· Registered
Joined
·
72 Posts
I use Hornady "custom grade" die and it (my unit) is good to go. I had also bought an RCBS standard (not small base) sizer die to compare it with. My verdict with my two dies: hornady doesn't size the neck down very small at all, leaving less work for expander ball and therefore less working of the brass; the sized body dimensions were nearly identical to those sized with RCBS (again, not their small base die); the case body to neck concentricity was demonstrably better, by 1-3 thousands iirc.
I think your die is likely defective.
(Sidenote: both my new 6.8 spec rcbs die and my old hand-me-down rcbs .223 rem give awful runout/neck concentricity, which has really soured me on them).
For .223 rem I use Redding body die + Lee collet die, and as I said I like Hornady sizer for 6.8.
 

· Registered
Joined
·
696 Posts
I am having a hard time understanding how the die is causing the base of the case to be oversize.

It seems to me that the brass must be expanding from firing, and the die does not size the brass to the base.

What load are you using? Are your primer pockets tight?
 

· Registered
Joined
·
51 Posts
Discussion Starter · #7 ·
I am having a hard time understanding how the die is causing the base of the case to be oversize. It seems to me that the brass must be expanding from firing, and the die does not size the brass to the base. What load are you using? Are your primer pockets tight?
I am using factory S&B ammo and then reloading the brass. I reload the brass several times, but the issue happens even with the once fired factory ammo brass. I am using hot loads but no signs of bulging or flat primers. I worked my way up from light loads and had the same issue with light load fired brass. I assume the case expands fully to the chamber size, unless that last tiny bit of the base is unsupported. The issue is that raised "ring" at the point where the die stops. You can see the little hump in the picture. It's 0.420" before the ring, 0.422" after the ring (the part not touched by the die), and the ring is 0.427". Factory ammo is 0.417 in this whole area. If I set the Hornady die to have about a 0.05" gap from the shell holder, the rounds load and there is no "ring".
 

· Premium Member
Joined
·
11,671 Posts
Measure new brass, then measure the ring area. If the ring area just above the groove is larger after firing, the load is too hot and the case will eventually rupture. The rule of thumb is if the case just above the groove expands more than .0005"(one half of 1 thou) then back off.
That area is not supported by the chamber because AR barrels need a larger chamfer to feed quickly.
 

· Registered
Joined
·
1,109 Posts
What you have there is die mouth radius ....or the lack of it . The radius is too square and is pushing up a ridge instead of flattening it out . I have had 2 dies do that both were modified by Bubba Hamfist and both were made serviceable by breaking the hard edge and a light lap of the mouth .

I get that a little bit with heavy case forming like forming 6.5×50 SR Japanese from 6.5 CM where the .470 head has to squeeze down to .455 as long as it's on the head not the web turning to get the last .005 the last .05 doesn't hurt anything.

That's not , and is, what you have going here . With the correct or smoother radius on the die mouth the problem will go away .

If I paid $10 4th hand at a show I'd just spin my chamfer tool in the mouth and thumb pressure some oiled 600 grit wet/dry .
If I paid $50-70 for a new die or set I'd send it back and get it fixed , unless I needed right now yesterday
 

· Registered
Joined
·
670 Posts
what constructor said. You are probably seeing pressure signs in the load. I bought a bunch of once fired 308 LC brass and my die was doing the same thing. I assumed all or majority of the brass fired from a full auto. I wasn’t going to get rid of the brass so I bought a small base and fixed it.


Sent from my iPhone using Tapatalk
 

· Registered
Joined
·
51 Posts
Discussion Starter · #11 ·
Measure new brass, then measure the ring area. If the ring area just above the groove is larger after firing, the load is too hot and the case will eventually rupture. The rule of thumb is if the case just above the groove expands more than .0005"(one half of 1 thou) then back off.
That area is not supported by the chamber because AR barrels need a larger chamfer to feed quickly.
Thanks, this is what I was thinking. The base is about 0.004" larger than the factory load. This brass has been fired at least 2 times. I'll check it again after firing new factory loads, then after my loads.
 

· Registered
Joined
·
51 Posts
Discussion Starter · #12 ·
What you have there is die mouth radius ....or the lack of it . The radius is too square...
You might be on to something here. Could be a combination of this and what Constructor mentioned. The wall of the resized case does look more "scraped" than other rounds I load. Like it's pushing metal.
 

· Registered
Joined
·
38 Posts
I switched to redding and started shoulder bumping until I could extract the cartridge easily once you get to the point that you like then set your die and you are done. But you can only reload those cartridges for that particular rifle.
 

· Registered
Joined
·
47 Posts
No issues here with my Hornady dies. New to the caliber, just shot my first re-loads on Friday....all flawless. Sized another 198 pieces of once-fired brass with 7 different headstamps, and today sized another 56 Rem LRP cases gifted to me from a forum member. No issues. Hope you get your die issue sorted out.
 
1 - 16 of 16 Posts
Top