Critique my parts list!

[pontoon]

Sure, if you intend to single load by hand. You're constrained by the mag length and this negates any "advantage" the saturn chamber offers. Also to much jump to lands can be detrimental to accuracy.

I read up on it more. It looks like longer mag lengths are up to 2.3 and the COAL allowed by the Grendel I barrel is 2.23, so you gain up to .07 with a certain mag choice. The massive FPS gains I read about were someone who must have been hand loading into the chamber. I suppose the .07 real world advantage of the Grendel II would offer a minimal FPS gain and probably more importantly potentially better accuracy for a hand loader who has .07 more to play with. I'm not a hand loader (yet) so my knowledge is very limited.

[cory]

I read up on it more. It looks like longer mag lengths are up to 2.3 and the COAL allowed by the Grendel I barrel is 2.23, so you gain up to .07 with a certain mag choice. The massive FPS gains I read about were someone who must have been hand loading into the chamber. I suppose the .07 real world advantage of the Grendel II would offer a minimal FPS gain and probably more importantly potentially better accuracy for a hand loader who has .07 more to play with. I'm not a hand loader (yet) so my knowledge is very limited.

If your chamber only allows you to load to 2.23" COL, you've got a short chamber, or an older liberty barrel that lead to the Saturn Chamber cya exercise.

A (SAAMI) Grendel chamber should allow you to load to 2.26" at a minimum. Most will allow you to load to somewhere between 2.27" to 2.29".

These measurements are with the common 123gr bullets in mind.

[LRRPF52]

I read up on it more. It looks like longer mag lengths are up to 2.3 and the COAL allowed by the Grendel I barrel is 2.23, so you gain up to .07 with a certain mag choice. The massive FPS gains I read about were someone who must have been hand loading into the chamber. I suppose the .07 real world advantage of the Grendel II would offer a minimal FPS gain and probably more importantly potentially better accuracy for a hand loader who has .07 more to play with. I'm not a hand loader (yet) so my knowledge is very limited.

There are a lot of factory ammo 6.5 Grendel loads that are 2.245" to 2.260" COL. If someone is saying that the SAAMI chamber is limited to 2.230", they are misleading you or are not very knowledgeable about the actual dimensions of the Grendel chamber.

You don't get any real world gains by loading out longer. You get much better behaved pressures by sticking to the specified COL's and I have tested this myself with several different projectiles. If you run a projectile close to the lands, you will spike the peak pressure and produce more velocity, at the expense of departing from the working pressure of the cartridge.

There was a guy here on the forum a few years ago who was doing exactly that, just picking out loads without any basic reloading procedures (working up), then getting insane velocities with a short chambered barrel, claiming the 5R rifling was giving him an extra 400fps. He refused to listen to seasoned hand loaders, some of whom have been doing this since the 1970's, and claimed there was some type of campaign out to get the barrel maker.

The main issue is the AR15 magazine well length limitations. For a production gun, you have to work within realistic dimensions, accounting for variation in magazine lengths across tens of thousands of magazines, not single samples. To manufacture a magazine that tightens up those specs raises the magazine price 4-fold, with no performance gains.

What that means in the real world is that there are people with the existing SAAMI chamber and dimensions slaying every beast they point the Grendel at, as well as shooting small targets at 1518yds with mild hand loads that are 100-150fps slower than the equivalent factory load.

Then you will hear these guys who want to "make it better" start talking about moving the throat of the chamber forward a few thousandths, getting $42 mags, and "really pushing" the cartridge. I think some people just like to tweak, and that's fine, but if the established SAAMI chamber is doing what it does, and is able to shoot a wide variety of projectiles accurately, while extending the effective range of the AR15 beyond what anyone would believe unless they see it, why bother?