212eldx in .308 hybrid cases?
- Thread starter Eo12
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As I've mentioned in another thread, I've sorted through 5 boxes of these hybrids. From the 5 boxes I received, 287 of them have the "24" headstamp, 158 have the "277 Fury", 87 have the "23" and 22 just have the "Sig" for a total of 554 cases altogether.
The 24's were the heaviest and the 10 of them that I fire formed had case volume of 56.3 grs H2O. Most of the 23's were in the same weight range as the 24's, but a few were substantially less. The "277 Fury"s were consistently way lighter than the 24's and those few Sig's were about the same as the Fury's. Once I fireform the Fury's I've loaded up, I suspect the case capacity will be more like ~57.5 grs of H2O due to that weight difference.
The ten 24's that I only fire formed produces really good results both on paper and in terms of SD's and ES's, which surprised me as I had loaded them with the same primers I had removed in order to anneal and size them up to a .308. But then, it's only 10 rounds fired.
The 24's were the heaviest and the 10 of them that I fire formed had case volume of 56.3 grs H2O. Most of the 23's were in the same weight range as the 24's, but a few were substantially less. The "277 Fury"s were consistently way lighter than the 24's and those few Sig's were about the same as the Fury's. Once I fireform the Fury's I've loaded up, I suspect the case capacity will be more like ~57.5 grs of H2O due to that weight difference.
The ten 24's that I only fire formed produces really good results both on paper and in terms of SD's and ES's, which surprised me as I had loaded them with the same primers I had removed in order to anneal and size them up to a .308. But then, it's only 10 rounds fired.
Have only gotten the 6.5CM to work well so far. My current load so far is 44.5gr H4350 with the 140 ELDM goind about 2900 with a 24" Proof. Going to load up some RL16 for tomorrow. Historically, it should be another 100fps according to my old barrel. Been saving RL16 since it's sometimes impossible to get and now it's crazy expensive when you do find it. That's easily with in if not faster then 6.5PRC speeds. Also tried one of my friends load with the 130gr bergers and 2000MR. Was running them around 3100FPS but it was too hot. Haven't too much at distance yet only about 20 rounds at 600 with the 6.5. Still trying to nail this 308 load. Not sure why it doesn't want to shoot well. Brass cases still under MOA with ammo I loaded over a year ago.
I've noticed all my cases are either around 150grains with no primer or 161gr. The 161g cases take almost a grain less powder to achieve the same velocity. The lighter cases seem more consistent but I need to look at all my data to see if that holds up
Primers have not shown to be a problem at high pressures of 75k to 80k.
These are still rounded and all are high pressure loads, from 2 factory rifles with standard firing pins and springs.
Never pierced a primer, but if you hit 90,000 psi the teat will grow but the primer hardly flattened...the primer teat is a pressure indicator, ya don't want a slight increase over these.
Stainless steel case heads don't expand and leak gas around the primer, like brass.
The old Sig cases didn't have a year stamped on them.
They are a bit lighter, and some very consistent if weighed out, 58 pcs out of 100 were within just 1 grain total weight.
I have a few with the 22 yr and a new bunch with a 23 yr...the 23 yr are all Sig. I have none stamped Fury.
The 23 yr are a bit heavier also have powder stuck in the cases and needs to be blown out with compressed air.
LC was supposed to have begun production of hybrid cases, and may be why more variations of the case being offered.
LC always stamps year on case heads, as far as I know.
So it appears more are getting involved in the contracts of making them.
Meaning we'll have to be careful and aware with the volume of these cases...
With respect to 308 accuracy with all 3 cases the early Sig hybrid, Lapua LR, Lapua Palma SR, I did a small test .
A 10 shot group with each style of case on the same day with the same load, using 230 gr SMK 9 twist 22" barrel that the barrel liked.
The hybrid case had the lowest S/ D, and the best 10 shot group out of the three, followed by the Lapua LR cases...Plama cases were the worst.
Plama cases also lose 40 to 50 fps with the same powder charge.
So you have to up the powder charge to get the same velocity as the Lapua LR cases.
Which would mean the powder ignition is lacking and the higher S/Ds with this powder and less accuracy tend to prove that out.
So for all round consistency in all temperatures, and powder combos today I prefer LR primers in 308.
I have shot good groups with Palma cases yrs past, still have a few hundred new ones.
But from my experience I generally do not use or promote them, today.
But there are places where group shooters find during the spring & summer with a certain powder these Palma cases give the smallest groups. Use em where needed.
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Likewise, my cases with the 24 and 23 stamped weighed at 161 grs and the ones with Fury stamped on them and those only showing Sig all weighed around 150 grs. I'm pretty sure you're right that there at least a full grain difference between them.
My hybrid cases that have some powder still suck in them after I tap what's loose out, I just leave in and when I anneal the case the remaining powder just burns out. Which is ok since my next step is to wet tumble with SS pins for 25 minutes before sizing.
Here's what they look like when finished before fire forming:I've really liked using the Lapua Palma cases here in AZ in the warmer weather and don't really find much difference in velocity from the LRP's. . . maybe ~10 fps difference??? This is with 41.1 grs AR-Comp pushing 169 SMK's with a COAL of 2.974. Most of that shooting is between 70°F and 90°F. And I do get better SD's and ES's out of my Palma cases than the Lapua LRP cases. So, I think velocity difference in the .308 one might see SRP and SLR cases will depend on the powder and the ambient temperature they're being fired in.
The problem with the Palma Brass is in my load notes....200.2 20X with Varget at 36° dropped 50 fps in velocity over Lapua LR brass same load.Likewise, my cases with the 24 and 23 stamped weighed at 161 grs and the ones with Fury stamped on them and those only showing Sig all weighed around 150 grs. I'm pretty sure you're right that there at least a full grain difference between them.
My hybrid cases that have some powder still suck in them after I tap what's loose out, I just leave in and when I anneal the case the remaining powder just burns out. Which is ok since my next step is to wet tumble with SS pins for 25 minutes before sizing.
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I've really liked using the Lapua Palma cases here in AZ in the warmer weather and don't really find much difference in velocity from the LRP's. . . maybe ~10 fps difference??? This is with 41.1 grs AR-Comp pushing 169 SMK's with a COAL of 2.974. Most of that shooting is between 70°F and 90°F. And I do get better SD's and ES's out of my Palma cases than the Lapua LRP cases. So, I think velocity difference in the .308 one might see SRP and SLR cases will depend on the powder and the ambient temperature they're being fired in.
Did the same with 230 gr SMK and Atip with around 50 grs of slow powder at around 50 degrees.
But look in the summer the Palma brass, BR 4, shot small groups, as seen here in load notes.
That's exactly what I'm saying, things change with Palma brass with respect to temperature and also powder, along with heavy bullets with 50 grs of slow powder.
It was about 55° when I was shooting yesterday.
It hardly ever gets 90° plus and I'm thankful for that.
So if you sight in at 80° or 90° and go hunting at 30° or 40° with Palma brass you could have a large velocity drop, even with Varget. More so than temperature sensitive powders when using SR primers in 308 cases...I found the velocity drop quite a surprise the first time and noted it in my load notes.
Just another thing to be aware of.
Use em where they work and change to regular LR brass for those special times...in colder climates that's most of the time.
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