The orginal Grendel now called the Grendel II was first designed in 2003 by Arne Brennan and Bill Alexander and announced at Shot Show in January 2004 by Alexander Arms. It is the OG of the Grendel variants. As in the Original Grendel. The Grendel II which is the real Grendel and original chamber shoots a wide variety of bullets with greater velocity than the newer SAAMI Grendel. The reason it gets better velocity is easy to understand it has a longer throat which allows bullets to be loaded longer in the case allowing more room in the case. The SAAMI Grendel with the compound throat forces bullets to deep in the case taking up room needed for powder. After the 6.5 Grendel was on the market Alexander Arms changed the throat to a compound throat that they borrowed from Lother Walter and did not design it as commonly reported.
AA changed to the compound throat because it seemed to shoot the 123gr lapua and 108 Lapua Scenars with more accuracy than the original throat when they assumed a mag length of 2.26in. Current mag length is 2.29 to 2.305in depending on the mag. It was an engineering trade off that sacrificed performance on the majority of hunting bullets which have a shorter nose than the scenars. The shorter nosed hunting bullets were then forced to deep in the case with the new compound throat which makes the the case give up 100 to 200fps depending on the bullet. The assumed main function of the rifle was target range time so getting accuracy from the Scenars was determined to be more important that velocity of hunting ammo. A incomplete list of bullets that have sacrificed potential velocity are the following.
Nosler 100gr Ballistic Tip Spitzer
Hornady 120gr Amax
Sierra Pro-Hunter 120gr Spitzer
Nosler 120gr Ballistic Tip Spitzer
Speer Hot-Cor 120gr Spitzer
Remington Core-Lokt 120gr Pointed soft point
Swift A frame bonded 120gr Semi Spitzer
Barnes 120gr TTSX
Nosler Partition 125gr Spizer
Hornady Interlock 129gr Spire Point
Nosler Accubond 130gr Spitzer
Sierra GameKing 130gr Hollow Point
140gr Nosler Partition Spitzer
140gr Nosler Ballistic Tip Spizer
The original Grendel now called the Grendel II is available again this year by several vendors. I took a AR Stoner Grendel II to the range last week and worked up a load with 120gr Noslers. I found an accuracy node at 31.6gr of LEVER with a COAL of 2.9in with a velocity of 2780fps with an ES of 24. That's about 200fps faster than the current SAAMI chamber that needs the Nosler buried down to somewhere around 2.23 to 2.24 depending on the barrel. I'll be exploring that load again this Saturday to see how tight i can get the groups. Its already sub MOA but would like to get some 1/2in groups.
My 24in Grendel II barrel sends out 123gr factory SST out at 2624fps and was already sub MOA during my barrel break in last weekend.
so cal, I have to ask what was the purpose of your post. I think many of us already know if you load the grendel up to in excess of 60k psi you can get ALOT more speed out of it. Bolt failures have been reported when you try to do this. I am as much a hotrodder as the next guy but know that is a risk your taking.
the grendel II was created because liberty/saturn barrels used the wrong reamer and cut their barrels throats too short, instead of saying YES we screwed up, their solution was lets offer a new chamber with a longer throat that will make sure and cleanup the chambers of all the messed up barrels. worse yet liberty barrels said lets also charge the people shipping to and from to fix our mistake. The problem was the throats they had were too short to chamber even factory ammo. They blamed everyone but themselves but never could explain why their barrels could not chamber factory ammo other than to say its a saami spec chamber.
lastly I look at your chrono data from 31.3-31.6 I am seeing a pressure spike I would be concerned about that much increase in speed with that little extra powder charge.
further, I own a grendel and frankly I am sick of the whole fiasco, I can't get the right bullets for it, and yes to do its thing you need the right bullets for it. I haven't looked in the last couple months but I don't think I can even get factory ammo for it. with the advent of the gen 2 dpms soon my grendel will be for sale because with the weight savings on the new dpms I don't see the point of the grendel.
