Free 6.5 Grendel Reload Data

[rickOshay]

Why does the spreadsheet tab for 24" barrel say "use 22in predictions"? Wouldn't a 24" barrel have different nodes than a 22in?

[barrelcactus]

Why does the spreadsheet tab for 24" barrel say "use 22in predictions"? Wouldn't a 24" barrel have different nodes than a 22in?

Theoretically 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.

[barrelcactus]

All I have loaded for the Grendel are the Sierra 120 Pro Hunter and the Hornady 120 SST

Mind sharing all the details?

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

[LRRPF52]

It 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.

Biggest thing you're overlooking is reliability and accuracy, not just accuracy.

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.

[bwaites]

Thats what Arne Brennan (codeveloper)reported on another board he said the orginal Grendel was what we call the Grendel II print.

There were never any Grendel's produced for the public with that print, thus it was never a Grendel. It was one of the MANY configurations which were tried and discarded during development.

[bwaites]

Theoretically 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.

Please identify the WE in this quote. Since you are posting data, it is important to know the background of all those participating.

[Bill Alexander]

I see MSRHunt behind this. This data was presented on the old SnipersHide site quite a while ago.

[rickOshay]

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.

There 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.

[rickOshay]

You 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.

You really have no idea what you're talking about.

[barrelcactus]

Wow this nice discussion of the data went south quick. Im not going to get down in that mud.

[barrelcactus]

I see MSRHunt behind this. This data was presented on the old SnipersHide site quite a while ago.

Mr Alexander yes the data has been shared and contributed on there as well as other boards. Just like it has been shared here. Is that a problem? Is not centered on a single board its the army of the willing. You and anyone here are welcome to contribute the more data the better. Its data its not personnel. The shooters are just shooters with grendels without agenda they just like to shoot. The conclusions from the data is where the 10 pound brains can argue about.

[rabiddawg]

Wow this nice discussion of the data went south quick. Im not going to get down in that mud.

Dude, you already did. You just thought we wouldn't figure it out.

[barrelcactus]

There 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.

Many reasons yes buts patterns can tell a story as well.

[NugginFutz]

Wow this nice discussion of the data went south quick. Im not going to get down in that mud.

Well, what did you expect? Out of the gate, you blew in spouting off about how nobody knows anything about the Grendel except for the unnamed "we" you keep referring to yourself as part of. You trotted out the same, tired rhetoric that the folks on a couple of other boards have been passing around for the last few years and you expected a warm reception? Seriously, BC, you didn't see this coming?

[barrelcactus]

Dude, you already did. You just thought we wouldn't figure it out.

Not sure if i insulted anyone here if i did my apology.