My first 6.5mm Grendel Project - after 3 .223 Rem AR-15s

[Kohoki]

Hi there,

I registered here because all the german gun forums lack of sufficient information about this young and potent caliber. After some experiences with custom .223 AR15s, (DMR556 & SBR556 (yes, they are allowed in Germany) I am planning my first 6.5mm Grendel Rifle and hope to receive some advice or hints from all you professionals out here. Maybe I start with the setup I planned by now, here comes a list of the parts I like to use:

Upper Receiver: VLTOR MUR 1A
Lower Receiver: DAR - DAR Lower Advanced
Handguard: GenIII Delta Carbon Fiber Forearm Rifle Length Black
Top Rail: Gen III Delta Forearm SPR Straight Top Rail rifle length (does anyone know the height this rail adds to the flat top receiver?)
Barrel: 20" Lothar Walther 1 in 9 twist (what twist would you recommend? My intention is to use heavier bullets)
Barrel Extension: Les Bear Custom
Bolt: Alexander Arms
Bolt Carrier: DPMS M16 (due to its mass)
Gas block: Noveske Switchblock 5.56 Rifle length (I know, there is one available for 6.8SPC, but only in Midlength, do you think the Switchblock will work?)
Stock: MAGPUL UBR was my first choice, but maybe a standard A2 is suits that concept a little bit more, what do you think?
Trigger: Geissele High Speed Match
Charging Handle: Rainier Arms Raptor™
Mag Release: Norgon Ambi Mag Catch
Magazines: AR-Stoner 10 rd
Grip: TangoDown Battlegrip
Muzzlebrake: GUNWORKS VAULT762 - not released yet
Scope: Schmidt & Bender PMII / LP
Scopemount: ERATAC BlockMount

This is my first approach, what do you think? Did I forget something? Does anyone know who sells the corresponding reamer like this one from PTG?

Thank you very much in advance for all your suggestions!!

@Mod
I am not quite sure if this posting is at the right place here, feel free to move it to a more appropriate place

[LRRPF52]

Welcome. Looks like a good start so far. I've also wondered about the appropriate Noveske Switchblock to use with the Grendel, if any. A lot of the Grendel gas port diameters/gas system lengths seem to be comparable with how a 5.56 gun is set up. What suppressors are you considering?

You will NOT need the PRI top rail, as it will add excessive optic height with the ERA-TAC. Get the appropriate 1-piece mount that will give you the eye-relief you need, and get a Magpul PRS stock, or the Magpul ACS. If the gun will be riding the bench more and accuracy at distance is your main goal, go with the PRS. You might need the extended ERA-TAC mount with the 3-12 PMII.

Looks like a great start to a top-end build. Maybe consider a higher-end barrel to match your component selection. Does LW have select match barrels in Germany?

The 3-12x50 S&B is the largest I would go for a 20" Grendel. ERA-TAC mounts look good. I would definitely go with the 20 MOA model, even though you will have plenty of elevation travel with the S&B, as you'll be closer to optical true at distance. Remember to get the 34mm rings of course.

[txgunner00]

Sounds like you have a top of the line shooter planned out. Is factory ammo available in Germany or will you be loading it all?

[Kohoki]

@LRRPF52
I came to the same conclusion concerning the Noveske Switchblock. I will try this one out, if it does not work, it will be changed with a PRI Adjustable. I already ordered a british TRIDENT MODERATOR, I saw them at the IWA 2012 in Nürnberg and their modular and caliber adjustable concept combined with thei value for money blew me away! Every moderator can be adapted by bushings to suit a certain caliber.

I have to admit, I chose the PRI TOP Rail just for design reasons (thought it looks cool) - On the PRI website you can see a Delta Rifle Rail equipped with it (MOD 0 SPR)and it seems very high - this is the reason I asked for the height of the rail. If it does not suits me, the rail will stay off the rifle.

I thought about the PRS, too. The reason I selected the UBR or A2 Std. is that I already have one of these on the 18" AR-15. I tried to avoid two similar setups. I do agree, accuracy at distance is the main goal of this built up. Are there other stocks on the market with adjustable cheek pieces?

The Lothar Walther Barrels do have an excellent reputation in Germany, but so does HEYM Barrels. The HEYM barrels are made from stainless steel - cold hammer forged! I think it is possible to get a selected barrel from both of them, I will try to have a chat with them tomorrow I´ll keep you informed. What twist should I choose if I want to use bullets heavier than 100 grs.?

LRRPF52, you are absolutely right with the scope, every other S&B PMII scope is in my opinion too large for the AR-16 platform. The 20 MOA is a must have

@txgunner00
I think factory ammo is very limited, a Redding S die set is ordered - I hope it ships to Germany.

[Bwild97]

"Kohoki"

I thought about the PRS, too. The reason I selected the UBR or A2 Std. is that I already have one of these on the 18" AR-15. I tried to avoid two similar setups. I do agree, accuracy at distance is the main goal of this built up. Are there other stocks on the market with adjustable cheek pieces?

Here are two very nice alternatives to the PRS!

This one is the Mako SSR25, it uses a rifle length buffer, tube, spring. A little on the light side but very durable.


This is the Mako recoil reducing stock, uses the carbine length buffer, tube, spring.

[IndyGrendel63]

Welcome to the party!
Just my two cents but if you want to shoot heavier projectiles then you might want to opt for a faster twist (similar to what is used in the .223 with 69 gr and up). My Grendel has a 1:8 twist Lilja barrel (Precision Firearms upper). I thought the faster twist might give me a bit of an edge with the heavier projos.

[Kohoki]

@IndyGrendel63

I think I will order the 20" barrel (whether its from Lothar Walther or Heym) with a 1:9 Twist as shown here.

Maybe the barrel reveives a fluting between muzzle and gasblock, well see.

I just found out, that the PRI Rail adds 0.45" to the height of the receiver.

[bwaites]

Kohoki,

According to Bill Alexander, the 1:9 works great in 20-24" barrels, so that is a good choice. I'd love to have a hammer forged Heym in that length!

[Kohoki]

@bwaites
I think I will go for a HEYM, due to the fact that my two other ARs are equipped with LW barrels.

I talked to my gunsmith today, and we came to a some interesting facts about this caliber.

First of all it has not a european C.I.P. entry. This is similar to the U.S. SAAMI Standard listing and makes the 6.5 Grendel a wildcat in Europe.

Second: Although it has been added to the SAAMI standard in Feb. 12, it is still not listed in the SAAMI Cartridge and Chamber Database.

Or did I miss something? Is the 6.5mm Grendel still a wildcat in the U.S.?


Third: The conflict between these components could be solved

1. S&B 3-12x50 PMII (P / LP / MTC): 57mm (2.244") Objective Lens Diameter
   
2. Gen III Delta Forearm SPR Straight Top Rail rifle length: Adds 11,43mm (0.450") to the height of the upper receiver
   
3. ERA TAC BlockMount w/o slope: Height (rail to bottom of middle tube): 22mm
   

This leads to a distance between the scopes objective lens and the Handguard of about 1.5mm (0.059") and a middle tube height of about 33,42mm (1.31"). Unfortunately I have to waive the 20 MOA Slope. This can be covered if I order the scope with the double turn feature which adds about 160 bucks to the scope.

Das ist irgendwie doof, oder?

[bwaites]

The Grendel has been accepted and is now known as a SAAMI cartridge. However, their publication of actual drawings lags behind significantly.

No CIP entry as yet, but we keep hoping that Lapua, who makes the brass, will push it through.

I run a 56mm objective on my 28" Grendel, but it does reside on a 20MOA rail above the main rail, which puts it about 12mm extra above the main rail at the scope center.

[LRRPF52]

There is also this buttstock, CAA Sniper Stock:

[Kohoki]

I heard from a special A.R.M.S. Mount which should fit perfekt for this setup. Does anybody know which one is meant?

[Kohoki]

@bwaites
Do you know when we can expect the chamber drawing? I mean, what´s the SAAMI listing, when they do not share the measurements??

[bwaites]

@bwaites
Do you know when we can expect the chamber drawing? I mean, what´s the SAAMI listing, when they do not share the measurements??

SAAMI is an interesting group. They are a "members only" organization, and you have to be invited to join. I'm sure that if you are a SAAMI member, all this stuff is easy to get. If you aren't, you are stuck waiting until they get around to publishing.

You are aware that I posted the chamber drawing, though, right?

http://www.65grendel.com/forum/showthrea...#post37678

[Kohoki]

@Bwaites
Yes, thank you. I found the drawing a few days ago and already forwarded it to my gunsmith to get a reamer prepared. I just wondered why we do not find a drawing of the chamber measurements although the SAAMI Membership. Maybe it would be more efficient (if they really want to spread the word about that caliber) to have it C.I.P. listed. You do not have a drawing of the AR bolt, haven't you?

The lower receiver came last weekend, I think I will have the Grendel skull lasered on both sides

[Kohoki]

The guys from HEYM asked me about the diameter of the gasport today. What would you recommend? It will be a 20" barrel.

[ricsmall]

I would try calling Alexander Arms monday and talk to Bill A. There has been some discussion on here about it, if you can find those threads. That is, if noone here can help you out.

[txgunner00]

My gas port is .0980" on a 20" Satern barrel. I know that because I reamed it to that diameter when tuning my rifle for sub-sonic loads. It is a little on the large size and the rifle is very slightly over gassed with full power loads but not to the point where it causes me much concern. I do plan on installing an adjustable gas block but I just haven't gotten around to it. I would recommend a slightly smaller gas port for unsuppressed full power loads and even smaller for full power suppressed. If you intend to shoot suppressed sub-sonic loads a port slightly smaller than .0980" should still work due to the added pressure.

[Kohoki]

@txgunner

Thank you very much for your reply! I will tell my gunsmith to start with a diameter of about 2.45mm (slightly smaller than the mentioned .098" (2.4892mm)).
I will mount a Noveske Switchblock on that rifle, so the function can be controlled with that device.

Another way would be to measure the max. diameter of the 20" Switchblock port who enables unsurpressed shooting - the gas port on the rifle should be almost the same size, maybe slightly (.02 mm) smaller. Does anybody know the port sizes on the 20" Switchblock models?

[Kohoki]

I would like to laser that Grendel skull into my new lower receiver, would someone be so kind and provide a .dxf, .ai or .eps file? Your help is highly appreciated!!Thanks in advance!