6.5 Grendel build, looking for enlightenment

BlackSheepJ · Nov 10, 2013

I have been wanting to put together a 6.5 Grendel AR-15 for some time, and am hoping somebody out there can help answer some questions I have before I finally bite the bullet on it. I'd also like to try and keep whatever parts I do buy fairly local, just to help out the PNW area's manufacturers. The longest distance I get to target shoot with my rifles is 300 yards, but am hoping to start pushing that out, hopefully to a thousand yards with this particular build. I am not looking for a bench rest rifle, but more of a DMR set-up that I could take deer-sized game with, something that can be carried around in the hills quite a bit and not weigh a ton.

Are there any true 6.5 grendel barrel manufacturers in the area? I'm familiar with with Blackhole Weaponry, but my understanding is that the chamber that they use isn't a true 'Grendel' chamber in their barrels. I've scoured the internet as much as I care to, and haven't found a satisfying answer to why or what difference it makes. Any first hand experience would be greatly appreciated.

My other option that I'm looking at is Shilen Rifles' 6.5 offerings, probably the 18 inch midlength barrel. Shilen's website says that it is a "tactical" contour, but I frankly have no idea what that would be in comparison to standard AR contours. Hoping somebody can break that down for a dumbie, would this be comparable to a pencil, government, or other contour? They also have a 20 inch rifle barrel, which I'm reasonably sure would compare to a HBAR contour. Am I really going to lose much accuracy/velocity going with the, what I assume, lighter contour/shorter barrel? From what I have read Shilen make fantastic barrels, probably better than my shooting ability could live up to, but would greatly like some input.

I've already settled on a Seekins Precision SP223 lower with a Geissele SSA-E trigger, but is there any reason this lower wouldn't work with the 6.5 Grendel's magazines? Supposedly the Grendel's magazines will fit in any mil-spec'ed lower, but would rather have confirmation on that. I have also been trying to decide between an Aero Precision COP or a Seekins Precision upper, possibly with a Geissele Super Modular Rail if I can't find something else locally. Any pros or cons with either upper receiver, and is there another rail or receiver that would be from the Northwest?

Lastly, for those reloaders out there, is there a particular grain weight the Grendel likes? Any powders that work better than others? Is there a certain brand of small rifle primer that works well? The Grendel is still a newish cartridge, and I'm limited to what I've managed to snag online, since my Speer manual doesn't have load data for it.

I'd be immensely grateful for any help you guys can provide and thanks in advance.

jluck · Nov 10, 2013

Stick with Seekins upper/lower combo to avoid a abortion/mixed parts mess for fit and finish. The mags will be fine, There the same mag body as standard 5.56.

There has been many Grendels built with seekins lowers and or uppers you will be fine. The oddball chambers (slightly different) will fire factory ammo and was just done to rip off the Grendel glory and avoid law suit (or paying for useage) from Bill Alexander of Alexander Arms (The originator of the Grendel). Google lightweight 6.5 Grendel as this had been done successfully a bunch of times. FWIW you will be basing your build on the heaviest of lower/upper receiver combos available.

Check out Proof Research for barrels and there is even one for sale on Armslist.

Hope this helps.

Oh.... And bullet weight will be heavily influenced by rate of twist chosen.

BlackSheepJ · Nov 11, 2013

Thanks for the response jluck, and I know the Seekins receivers are heavy, but I'm left-handed and really wanted an ambi lower. I'll check into Proof Research a little more, but they look interesting.

K2V53 · Dec 23, 2013

BlackSheepJ said:
Thanks for the response jluck, and I know the Seekins receivers are heavy, but I'm left-handed and really wanted an ambi lower. I'll check into Proof Research a little more, but they look interesting.

I have a 6.5 Grendel with a Sabre Defense upper that shoots better than I do. It will do .3 moa out to 600 yards. I haven't taken it further than that.
Blackhole seems to make a good quality product but has very mixed reviews in the customer service area.
When I was looking for a 6.5 Creedmoor barrel for my AR-10 build, GA Precision pointed me to Specialized Dynamics. (<broken link removed>). They make a 6.5 Grendel.
Go to the 65 Grendel forum (Welcome to the 6.5 Grendel Forum : : The World's Tier One AR Cartridge). Those guys are a fountain of knowledge and several are from the NW.

Spec.-K · Dec 26, 2013

The 6.5 Grendel and 264 LBC are identical cartridges.
They were codeveloped and when Les Baer was told he'd have to pay for the "Grendel" moniker, he just said screw that, and named it 264 LBC (Les Baer Custom)

bigbrianaustin · Jan 21, 2014

Just traded into a 20" Grendel myself. Has a Blackhole barrel, a DPMS competition upper on a PSA lower. Going to take it out this weekend to check it out. Trying to figure out the reloading data myself as AA's ammo is through the roof. The thing I've heard the most about when researching the round is that the barrel length is far more important than in a 5.56. There is 14.5" barrels for them I've seen, but most say minimum of 18" and 20" is ideal for the round due to muzzle velocity. I am actually supposed to be getting a custom manual for reloading data on the Grendel with the accessories from the guy I traded. If he remembered to include it, I will try to scan and send you the data if you want. Check out 65grendel.com if you haven't. More info there than I could ever get through.

CV-66 · Mar 29, 2014

Try Curts gun shop in Portland, OR - he sells barrels made by a local manufacturer John Benjamin chambered for this cartridge. There's a difference between the Grendel throat angles and those made for the other cartridges. Some older brass has an extractor groove with angles cut differently from modern mfg, consequently ejection issues may come about if your extractor isn't cut specific to those angles. The key is the extractor needs a rounded and beveled edge for the older brass and two angled cut for the modern day stuff. Curts also has bolt assemblies for same. Built mine using a seekins billet upper and lower and it performs as well as it looks. I put a 24" on mine to shoot across the course and long range. Has a .875" gas journal and .75" muzzle step for mounting front globe sight. Love the built in ambi bolt catch of the lower. Loads for this go beyond 140gr but they're hard on the bolt lugs especially if you don't regulate with an adjustable gas block. I load for accuracy and let the velocity fall where it may. 123 Scenar's by Lapua with their brass gives me best long range performance. Hornady 123 amax are outstanding. Grendel mags are problematic. Regardless the mfg, it appears to be 50/50 whether they work or not so be advised to buy them from a vendor willing to accept returns for exchange or refund so you don't get caught holding the bag. The cartridge is sort of like a 7.62x39 but with a lot less taper. Some AR15 mags for that cartridge will work with the grendel, others won't. Alexander Arms has some very good load data and velocity/drop charts for various barrel lengths. Check their website and you'll see some good info. Too bad they never have anything on their website in stock for sale. Varget is really good for this cartridge, but H335 is the only one that doesn't require a compressed load column when nearing the maximum safe load. hope this helps -tim