Due to the tighter twist rates of 1/8 or less, I find 6.5 Grendel transonic and subsonic performance at distance to be very predictable as well, unlike 24" .308s with a 12 twist in the same conditions.

Stab factor with 1/8 or 1/7.5 twist Grendels is excellent, even from short barrels out to at least 1200yds for me, and I even shot my old AA 16" out to 1500yds using bottom edge of scope for an aiming point one day.  I could see the impacts easily hitting repeatedly in the same place, just didn't have an MOA cant that would allow dialing-in that far.

Before I ever tried shooting at 1200yds on a dare, I had just written the little cartridge off as nothing to be taken very seriously past 800yds.  I soon saw that I needed a 20 MOA base and realized it was time to drop coin on a top notch barrel for my next build, which was my Lilja 318 Wasp build.  That rifle proved to be everything that I wanted it to be:

Exceptionally-Accurate
Lightweight
Maneuverable
Reliable

I've made shots with it that you would just have to be there to believe, including 1000yd center-punch forehead shots, rapid-fired sub-MOA 6rd groups at 1000yds, consistent cold bore 1st-round hits from 560-600yds, rapid-fired head shot groups at 500yds, just a very fun, confidence-inspring rifle to shoot.

Attached File

Interesting.

"As you can see in the above drawing, it is a .243 caliber (6mm) cartridge with a rebated rim to .223 Remington rim size and an overall length of 2.26? meaning that it is designed with the intention of being loaded in AR-15 size magazines."

Standard .223/5.56 BCG?

Yes 223 bolt/bcg but it will have LESS capacity than a 6X45. Waste of brass  and steel. It will  run at 55,000 MAX per SAAMI. It is SMALLER in the body than the VALKYRIE that is right on 223 size now capacity wise now and with the rebated rim it will drop even more.  Low case capacity low pressure, what's to like?

Greg

The new small frame Nosler rounds seem to leave much on the table.

Good initiative, but less than stellar execution.

What?  It's based on the 6.8, just like the Valkyrie.

They need to bump the shoulder back a bit to allow use of longer bullets.

Shoulders have been bumped back to allow for that.  It's the overall length with enough neck that sets the limits. As long as the case is too long big bullets won't fly.  This new 24 Nosler is the stupidest case design I've seen in decades.

Greg

55k max isn’t a bad idea but I agree this is a silly case.

6mm would be a good offering, but as you stated bore ratio is a big thing.  I'm not sure what bullet makers could do with a .257 bullet with decent BC. I've got a .68 based .257, and finding good bullets can be a challenge. I'm curious if the .257 is just too fat for an AR, which would make the 6mm a faster option, but you would end up with a 20" barrel at least.

Bill Alexander looked at .257 in the PPC case as one of the initial options.

No good bullet selection existed.

Hornady is looking at .257 Creedmoor, wildcats have already been made.

If the bullet makers supported it with modern boat-tailed bullets, it would be the best of worlds between a 6mm and 6.5mm.

It needs at least Grendel case capacity.  With better BC bullets, it would allow a 115gr to do 2700fps without pushing the pressure.

JLK currently makes a 108gr .257 VLD with a .500 G1 BC.

We have too many bullet diameters as it is. Would be nice to cull it down to 4.85MM, 6MM, 6.5MM, 7MM, 7.62MM, etc.

JLK makes a lot of bullets... their 6MM and 6.5MM bullets have much better BCs. The .257 is a joke.

When I compare the Grendel to something like a 6.5c or a .260 I consider that you can shoot the heavier higher BC bullets from the latter. The Grendel is limited in OAL of an AR mag and the same can be said with the AR style 6.5/260s. I would also be comparing factory ammo only as I'm not a reloader.

Doing this with readily available factory ammo the 260 should be able to gain one 300+yards of supersonic range. The wind drift at equal ranges is also quite a bit better with a 260.

So basically I want to ask, is the Grendel that good to all but throw out the 260?

The Grendel is a different "weight class" it will never have the punch of the 260.  Both will take game or ring steel, the advantage of the Grendel is the light AR15 platform.

I guess I already knew the answer to my question. The Grendel has the advantage of a lightweight, compact, semi auto platform. Most if not all 260/6.5c rifles will be at a disadvantage except ft-lbs of energy, wind drift, and maximum SS range.

The 6.5Grendel also has an amazing barrel life and Buds has the 123g ELDs for .78 a shot right now.

I am trying to justify or talk myself out of a "step up" from the Grendel in a bolt action 260/6.5C

"The Grendel is a different "weight class" it will never have the punch of the 260. Both will take game or ring steel, the advantage of the Grendel is the light AR15 platform."

Yes, this.

I have both.   I use them as different tools for different purposes.

With what I've learned and experienced over the last few years, if I could only have one of those, it would be a Grendel, but I would seriously consider going with a bolt gun instead of an AR with at least a 22" barrel due to my usual shooting altitude.

The only way I can get 300yds of additional supersonic reach is if I load or compare the .260/6.5CM with a different bullet.  You can still load 140s in 6.5 Grendel, but it eats a lot of case capacity.

For competition, the 6.5CM and .260 Rem have clear advantages, because .1 - .3 mils of wind drift can still mean the difference between hits and misses on small plates.

A 6.5 Grendel bolt gun shooting the 130gr Nosler RDF with .307 G7 BC closes the gap to the point of having the same wind drift as a 6mm Dasher pushing the 105 Berger Hybrid, but with way more retained energy for impact on the plates.  If I shoot the 130 RDF from a .260 though, I will have slightly less wind drift than the Grendel of course, but there's an argument for reduced muzzle blast and recoil from the Grendel, particularly when you shoot a 3-day match.

Dasher is competitive in PRS.