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Old September 13, 2018, 07:15 PM   #26
stagpanther
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Hornady dies size .004 under minimum chamber size...same as small base like RCBS small base. All Full length size dies(RCBS, Redding, Forster) size .002 under minimum chamber size.
I think the hornady set is the best all-around die set I've used so far--in addition to sizing to small-base dimensions I find it does a better job of keeping the cartridge from distorting when finishing with seating and crimping. My finished cartridges consistently freely "plunk" in and out of the chamber--I had problems with even the RCBS small base dies to consistently do that with fired brass.

As for the bergers--I'm guessing they could push beyond 90 if they went to an AR hybrid type design as they've done with other calibers.
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Old September 13, 2018, 08:04 PM   #27
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They could but I know what Berger is working on and what Federal will load next year, I just can't say anything yet.

They all know now that the heavy long nosed VLDs are not going to produce the best performance. Lighter faster bullets with a slightly lower BC will out perform the 90gr + because of the extra case capacity from shorter bullets and velocity possible from the lighter bullets.
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Old September 13, 2018, 10:23 PM   #28
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because of the extra case capacity from shorter bullets and velocity possible from the lighter bullets.
Hmmm....and still get past the mystical 1300 yds supersonic and not get wind drifted all over the place?

I keep forgetting--this is for presumably SAAMI-compliant max COL 2.26 factory ammo I assume.
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Old September 14, 2018, 11:16 AM   #29
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What kind of velocities are you getting from 88s, 90s and 95s? Run those through a ballistic program and then run a 80gr ELD at 3000fps then compare. At first I didn't think there would be that much difference in velocity and the higher BC bullets would overcome but actual field tests are showing something different.
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Old September 14, 2018, 01:41 PM   #30
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What kind of velocities are you getting from 88s, 90s and 95s? Run those through a ballistic program and then run a 80gr ELD at 3000fps then compare. At first I didn't think there would be that much difference in velocity and the higher BC bullets would overcome but actual field tests are showing something different.
The long freebore cartridge which I was able to get the 95 MK to just a hair under 2700 fps--and that put it in the ballpark of the magic "just like a creedmoor" projected performance goalpost. But that also was using a very long COL and modified mag (not to mention chamber cut idiosyncrasy).

I'm only just now starting to test cartridges that I would call "SAAMI-compliant" in your new shorter freebore barrel using conventional magazines and COL's--so I don't have any meaningful data yet.

Do you know if these projected performance numbers by the manufacturers are going to be attainable in "conventional" in-spec cartridges? The engineers at Hornady are powder formulation wizards so I wouldn't be surprised if they manage it.
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Old September 17, 2018, 09:51 PM   #31
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No, factories wouldn't dare push a 80 to 3000. This is comparing warm handload to warm handload with all available bullets.
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Old September 18, 2018, 04:56 AM   #32
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I see. This sure has been a very interesting ride.

Quote:
At first I didn't think there would be that much difference in velocity and the higher BC bullets would overcome but actual field tests are showing something different.
I have to admit I haven't done any actual long-range testing--my approach from the beginning was looking at the inherent issues and concluding that to get up there would necessarily involve pushing 90 gr or better bullets hot--but that came up against a "performance wall" where the build/stability of the bullets made them very hard to arrive at consistently-performing cartridge configurations.
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Old September 26, 2018, 05:11 AM   #33
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The plot thickens. I just received notification of this post over on the 6.8forum by Bison Armory (which manufactures and distributes the valk):

Quote Originally Posted by constructor View Post
T
his is how to check the chamber... The accurate way is seat a 1" long .224 inspection pin in a case out until it touches the lands. From the base of the case to the front of that .224" diameter pin should be 1.676+- a few thou for tolerance.


response by Bison Armory:

"This is not true. If I've done my math right the real answer for a perfect 0.224 diameter pin, and assuming a cartridge case that has zero head clearance, is 1.6882 to 1.6982 (or 12 to 22 thou greater than 1.676) for a chamber cut to perfect maximum material condition and then those two numbers are for absolute minimum and maximum headspace, so the real answer will be in-between. Actually the real answer will be somewhat longer still because nobody cuts a chamber to minimum SAAMI tolerance. The number will probably be smaller though by a couple thou if you are using new brass instead of fire-formed brass.

The OAL for typical chamber dimensions, i.e. ones that are cut 0.0005 greater in diameter than MMC, the length increases for minimum headspace from 1.6882 to 1.6977 and max headspace from 1.6982 to 1.7077. In either situation we're looking at about 22 to 32 thou greater than 1.676, a fair bit more than "a few for tolerance." The actual tolerance for a SAAMI chamber is 0.002" for the diameters, so the .224 diameter pin could result in a substantially longer OAL to the lands in a chamber that is still technically correct and within SAAMI specification.

This chamber thing is really getting on my nerves. I have to answer way to many "Are your .224 Valkyrie chambers in spec?" questions every day, and also "My chamber is out of spec because my bullets are seating blah blah blah" based on false information. It needs to stop here."


I admit this is way above my pay grade and I don't want to be an instrument of spreading false information--my comments have been specifically related to the the distance(s) forward of the case mouth and the length of freebore to the point where the bore constriction forces the bullet to engage the lands/grooves. I don't know if that issue is implicitly addressed by either the SAAMI spec diagram or the comment above.
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Old September 26, 2018, 03:54 PM   #34
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He'll figure it out eventually just like he changed his 6.8 chamber to one with a shorter freebore like mine after 9 years.
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Old September 26, 2018, 04:07 PM   #35
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He'll figure it out eventually just like he changed his 6.8 chamber to one with a shorter freebore like mine after 9 years.
The scary part is not knowing how many of the LFB barrels are out there being pushed in the tidal wave of publicity.

I was talking to a custom cartridge manufacturer today and he told me he often gets calls about the mediocre performance of existing valk factory offerings from the bigger outfits.
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Old September 26, 2018, 04:38 PM   #36
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Right, unless the reloader just happens to find the sweet spot in jump length it's tough to get decent accuracy at mag length when the jump is 50+
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Old September 26, 2018, 05:03 PM   #37
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My word--I just took a glance over there on 6.8--guys really went at it! Why not just challenge him to a shootout to produce the best groups he can with the "developmental" chamber cut and conventional mag length cartridges. I think that 90 vld load I found could be refined a bit
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Old September 27, 2018, 02:29 AM   #38
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Sweet! How do you like that muzzle brake? I have a 224 Valkyrie barrel for a future project and looked at the muzzle brake.
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Old September 27, 2018, 04:18 AM   #39
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Sweet! How do you like that muzzle brake? I have a 224 Valkyrie barrel for a future project and looked at the muzzle brake.
Brake works fine--not that the valk is a huge thumper or muzzle-flipper to begin with. Reduce movement in the various components of the gun--and configure the barrel so that you get a reasonably short jump to lands--and you should be able to attain .5 MOA or less with the right load--though I'm not sure if that has been attained with a factory load of the ones that are out there. I've only tried the 90 fed fusion when the valk "tidal wave" first broke and wasn't very impressed with it.
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Old September 27, 2018, 08:50 AM   #40
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Wow, missed that conversation since not active on the Forums lately. The problems and causes of the problem with the cartridge goes over my head and knowledge. But one thing I'm certain of, there's been a problem with this cartridge since the day it was introduced where some have good accuracy but most don't. For someone to say there isn't a problem with this cartridge, just doesn't make sense. Maybe he doesn't get it.
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Old September 29, 2018, 10:38 PM   #41
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Wow, missed that conversation since not active on the Forums lately. The problems and causes of the problem with the cartridge goes over my head and knowledge. But one thing I'm certain of, there's been a problem with this cartridge since the day it was introduced where some have good accuracy but most don't. For someone to say there isn't a problem with this cartridge, just doesn't make sense. Maybe he doesn't get it.
IMO, what all the rigamarole boils down to is that the issues are mostly related to pushing the cartridge onto the market in a rush before the kinks were ironed out. Like that's never happened before, right? I bought plenty of 6.8 spc and 6.5 Grendel dogs in the early days of those cartridges as well. I understood the explanation of the long free bore conceptually--but it was only after I did a cast of the chamber and measured the dimensions that I really verified for myself the problem--I was having problems with getting consistent lands engagement measurements simply by shoving the bullet into the chamber and "feeling" where the ogive was engaging.
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