Why does the spreadsheet tab for 24" barrel say "use 22in predictions"? Wouldn't a 24" barrel have different nodes than a 22in?
Free 6.5 Grendel Reload Data
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Originally posted by rickOshay View PostWhy does the spreadsheet tab for 24" barrel say "use 22in predictions"? Wouldn't a 24" barrel have different nodes than a 22in?
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Originally posted by IceAxe View PostAll I have loaded for the Grendel are the Sierra 120 Pro Hunter and the Hornady 120 SST
Bullet
Powder increment
Group Size (Center to Center)
Loaded COAL/OAL
Brass
Primer
ES or SD
Velocity
Chamber (SAAMI, 264 LBC, Grendel II, 6.5 CSS)
Barrel Manufacture
Barrel Length
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Originally posted by barrelcactus View PostIt is as good or better as is the 264lbc or the 6 5 CSS. The SAAMI is one option and is not magic.The data shows Grendel II shoots a wide range if bullets submoa. The claims Grendel II is not as good as the SAAMI are not supported by actual real world data compiled from normal real world shooters over several years. If the original Grendel testers were using ARcomp or 8208xbr when testing the 123gr scenars its doubtful the compound throat would have ever been considered as they would have gotten good results. As it is now the SAAMI is a great option as long as your not one of the unlucky ones with stuck bullets like have been reported on here over and over.
Since the 6.5 Grendel was designed from the start to eventually work with steel cased ammo, the larger than normal neck was specified.
The compound throat aligns the projectile in the gas-gun friendly neck.
Sounds like you're getting a lot of bad information from dudes that don't understand engineering, and are coming here with a bone to pick for more drama using a hidden ISP.
And it looks like a retread of Xcountryrider.NRA Basic, Pistol, Rifle, Shotgun, RSO
CCW, CQM, DM, Long Range Rifle Instructor
6.5 Grendel Reloading Handbooks & chamber brushes can be found here:
www.AR15buildbox.com
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Originally posted by barrelcactus View PostThats what Arne Brennan (codeveloper)reported on another board he said the orginal Grendel was what we call the Grendel II print.
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Originally posted by barrelcactus View PostTheoretically yes and thats how we started out but then over and over we were seeing the actual real world data matching the 22in barrel predictions from a 24in barrel. We contacted the OBT guy and he said thats normal as with OBT its common but i don't understand why it just does. To be honest i don't know why maybe you could figure that one out.
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Originally posted by barrelcactus View PostAs it is now the SAAMI is a great option as long as your not one of the unlucky ones with stuck bullets like have been reported on here over and over.
The last round that got stuck in my chamber was due to me being in the desert for a few hours with my bolt locked back and dust cover open.
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Originally posted by barrelcactus View PostYou can tweak Quick Load for specific rifling profiles so this spreadsheet is created with that rifling tuned in for saterns 5R button. Why it works for a Grendel II so well? Maybe because its a conventional chamber design pressure builds at more predictable levels. A short throat may throw it off. Why it does not work so good at the lower or upper ranges but is right on for the 120 to 125 range i don't know. OBT requires good data from quickload to work. OBT theory is sound QL sometimes is not. Its not effected by contour as its timing the bullet exit. Its timing the exit of the bullet to avoid the pressure wave at the muzzle which travels at a known speed its an acoustic wave and not effected by contour. Contour determines who accurate the node is not where or powder increment which deterimes where the node is. It also is not effected by a break. How OBT works should be directed to Chris Long the engineer who discovered it (chris@the-long-family.com). DO you have a working copy of Quick Load? If so tweak it for your rifling you'll need to measure it. Then use this program with quickload http://castboolits.gunloads.com/show...kLOAD-OBT-Tool. It will give you the optimal bullet exit time in milli seconds that represents an accuracy node. You then find the load in quickload that gives one of the predicted barrel times. Thats the predicted accuracy node. Like i said i have no idea why quickload sucks for the 100gr and below and nails it for the 120 to 125gr range of bullets. Its still close for the 130gr bullets usually within .5gr. If your barrel has been lapped it will run slower and that will throw off quickload. It does not predict the higher end barrel like Lilja and JP for that reason there speeds are slower than the liberty barrels. I should say it will get within .5gr though for those barrels just not right on the .1gr that it does for liberty barrels. Quickload and OBT will give you multiple accuracy nodes as well and they will shift with barrel length.
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Originally posted by Bill Alexander View PostI see MSRHunt behind this. This data was presented on the old SnipersHide site quite a while ago.
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Originally posted by barrelcactus View PostWow this nice discussion of the data went south quick. Im not going to get down in that mud.Knowing everthing isnt as important as knowing where to find it.
Mark Twain
http://www.65grendel.com/forum/showt...2-Yd-Whitetail
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Originally posted by rickOshay View PostThere are lots of reasons for rounds getting stuck that have nothing to do with the shape of the chamber. but lots of folks are quick to point to that as a design flaw of the compound throat.
The last round that got stuck in my chamber was due to me being in the desert for a few hours with my bolt locked back and dust cover open.
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Wow this nice discussion of the data went south quick. Im not going to get down in that mud.If it's true that we are here to help others, then what exactly are the others here for?
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