Grendel Advice...

[cjgemm]

If bustin paper or steel the lighter and faster high BC 6mm bullets will out perform the 6.5 bullets. That is why there has been a big surge in 6mm rifles in tactical shoots over the last 5 years. 6mmCM, 6x47, 6mm Creedmoor, 243.

Fixed it for you...

Although George Gardner has won matches with his 6.5 saum.

 

[corym468]

I put an Ace on a JP lower that I had, and I didn't like it at all. It felt like I was laying my face on a cheap piece of foam, which I was. I tried a friends Vltor, and now all of my ARs have them except my long range rig which has a PRS. I know the way stocks feel is a personal thing, but after using the Vltor, I don't understand why anyone would even consider the Ace.

Good point on the foam. I like the looks of it though. I have a vltor on another ar15 and love it...it's just heavy and I'm looking for a lighter build.

That's one thing I like about my ace stock is laying my cheek on the quality foam. I don't know what you consider cheap or quality foam, but I was impressed with the foam when I got the stock. I should say I was expecting it to be cheap foam, I wasn't expecting lamb skin.

 

[BC83]

If shooting paper the lighter and faster 6mm bullets will out perform the 6.5 bullets. That is why there has been a big surge in 6mm rifles in tactical shoots over the last 5 years. 6mmCM, 6x47, 6mm Creedmoor, 243.

Like I said..I dont get the point, it's just my opinion.. I started on the Grendel path for a few reasons. I wanted a round that has more ass behind it then my .223 77gr SMK's, and I wanted something with a long barrel life.

 

[BC83]

That's one thing I like about my ace stock is laying my cheek on the quality foam. I don't know what you consider cheap or quality foam, but I was impressed with the foam when I got the stock. I should say I was expecting it to be cheap foam, I wasn't expecting lamb skin.

I seen you talk about that soft foam on your face before, kinda makes me wonder what you do in your down time...lol

 

[corym468]

I seen you talk about that soft foam on your face before, kinda makes me wonder what you do in your down time...lol

Where might I ask? When talking about stocks the cheek weld is kind of important.

 

[BC83]

Where might I ask? When talking about stocks the cheek weld is kind of important.

it's was on here..

Agreed.. it's always best to properly fit your rifle.

it was also a Rhetorical Statement..

 

[LRRPF52]

Having built three and tested extensively, I can say this:

Whatever you get, get a barrel with a rifle length gas path. I had to back off my load one grain to accommodate a mid-length gas path in an 18" barrel. I'm getting nearly the same velocity though in my mid length gas/18" barrel as I did with my 24" barrel with rifle gas path. The drop in velocity is about 80 fps and is expected.

A couple notes here:
Once the bullet goes past the gas port, the gasses pushing on it do very little. So, the most important thing is gas path length. The 2" from rifle to mid-length are basically the same as having a shorter barrel in a bolt gun.

The Grendel/6mmAR/6PPC all have about 20 percent more capacity than does the .223/5.56 NATO, Which the AR-15 platform was designed around. This needs to be dealt with so as not to produce too much pressure back on the BCG. Too short of a gas path this will produce too much pressure at the BCG, causing it to open too soon. This causes case head swipe. Because of too high/too soon pressure coming back through the gas path. Why I suggest the long length platform. Also having a controllable gas port, or smaller gas port, helps. Another thing that cause case head swipe is too slow of a powder charge. AA2520 is notorious for this in widely changing temps. The best powder to run IMO is IMR 8208XBR.

As far as the 6mm's go, R. Whitley is the one who developed the 6mm AR, and the 6mm AR Turbo (40 deg shoulder). They fit just as well as the 6.5 G in the AR-15 size platform. It is a question of speed vs. bullet efficiency as to what you like. You like speed, go with the 6mm, You prefer a little more efficiency go with the 6.5. Added: When you get apples to apples with these, the 6.5 wins. Without maximizing the 6.5 (i.e. best B.C) the 6mm will usually win.

Which brings me to the .308 vs. 6.5G. The .308 flat out has more power and will wipe a 6/6.5's ass inside 600 yds. Outside 600 the .30 cal bullet is way less efficient than either the 6/6.5, so they will win past about that mark. The best shooter is the one who will really do it though. I will say, we had three shooters on my last 24" Grendel. We dialed the rifle up to hit @ 1k yds. Each of us put three hits on a 4 moa gong, center mass, within five seconds. For recoil control, the 6.5 (comped) is way easier to handle than the .308 (comped).

It's more about bullet efficiency than power. The 6.5 G will kill anything a .308 will....and then it will reach farther out with enough ability to kill.

Added:

Love the rifle Danco411!

I have had excellent results with a 16" MLGS barrel. Bill A. said there is a big difference in velocity between 18" MLGS and 20" RLGS when looking at large samples of guns, but he did gas shut off tests and hasn't seen noticeable change in velocity, so it's a bit of a head scratcher.

I think 8208XBR is a great powder for 100gr pills, but it isn't ideal for 123gr weights when looking at pressure and speed. Reasons are that you are pushing the pressures and there is a clear wall at 28.5gr under a 123gr, but it has some of the lowest pressures and fastest speeds with 100gr, making it very efficient in that bullet weight range. That said, it is one of the known accuracy powders for 123gr, along with AR-Comp.

For 123gr, I personally have had better than expected results with CFE223, even to the point where I am exceeding speed of a lot of longer barrel loads with the older powders (BL-C2 and AA2520), but staying well away from pressures. CFE23 is an extremely forgiving powder, that doesn't seem to have much of a rigid ceiling like the others, as you hit maximum load density and very fast speeds with it in that happy window.

I'm easily under max charge weights with CFE, but still hitting 2500fps under a 123gr, which is excellent for a little 16" gun with a .510 G1/.260 G7 BC bullet.

For a lightweight hunting set-up, choose balance and natural pointing characteristics of the rifle. That usually is a 16" - 18" gun for most people, with a lightweight handguard and stock of their choice.

PSA blem receivers will be fine if you make sure your upper receiver face is square, if you are chasing accuracy. The Lilja drop-in barrels are great, and 9130 AQ bolts can be had from several sources. AA, PF, Maxim, Underground Tactical, and JP all have excellent bolts for the Grendel.

It's the most versatile cartridge in the AR15 when looking at hunting across a number of species weights, then being able to turn around and match or exceed practical performance next to .308's in a rifle match, while keeping rifle weight and recoil much lower.

 

[Downzero]

I dont see the point in the 6mm when you can run the 108 lapua scenars past 2800fps just fine.

I dunno, let's compare:

6.5mm
108 Lapua Scenar, G1 BC, .465
107 SMK .420

and if you could push them (which you can't):
123 SMK, .510
140 SMK, .526
142 SMK, .580

6mm
107 SMK, .520
115 DTAC, .585


Let's see, .465 vs. .520/.585. Which would you pick, all else equal? The answer is self-explanatory. If a Grendel could push the 6.5 bullets to .260 rem/6.5 CM velocities, it'd be a different story, but it can't.

 

[BC83]

I dunno, let's compare:

6.5mm
108 Lapua Scenar, G1 BC, .465
107 SMK .420

and if you could push them (which you can't):
123 SMK, .510
140 SMK, .526
142 SMK, .580

6mm
107 SMK, .520
115 DTAC, .585


Let's see, .465 vs. .520/.585. Which would you pick, all else equal? The answer is self-explanatory. If a Grendel could push the 6.5 bullets to .260 rem/6.5 CM velocities, it'd be a different story, but it can't.

Yes it has better ballistics. I just said that I don't see the point, and the reason i choose the Grendel is for the low maintenance. But i guess you missed that from my previous post in this tread because you were to busy stating the obvious about the differences in ballistics.

And WTF???

and if you could push them (which you can't):
123 SMK, .510

90% of all Grendal shooters use the 123 Amax and we push them just fine

 

[jasonfaz]

Cant push high BCs out of a 6.5G? You can indeed. Can you hit AR10 cartridge velocities? Nope. But that's not necesarily the point. Comes down to readily available ammunition, a large variety of bullets that provide value to people feigning high BC projos for a little paper punchin' and some of that heavy shit for hunting. The below are speeds acheived with high BC projos in factory loads. You can do better with hand loads...

129gr Nosler ABLR @ 2550fps out of a 24" pipe:
G1 BC .561

Berger 130 gr VLD Hunting @ 2450fps out of a 24" pipe:
G1 BC .552

123 gr Lapua Scenar @ 2445fps out of a 24" pipe:
G1 BC .527

 

[BC83]

I have a 14.5" and still supersonic with 123amax at 1K

I guess White Mamba can't push the 123 either...

 

[BC83]

Cant push high BCs out of a 6.5G? You can indeed. Can you hit AR10 cartridge velocities? Nope. But that's not necesarily the point. Comes down to readily available ammunition, a large variety of bullets that provide value to people feigning high BC projos for a little paper punchin' and some of that heavy shit for hunting. The below are speeds acheived with high BC projos in factory loads. You can do better with hand loads...

129gr Nosler ABLR @ 2550fps out of a 24" pipe:
G1 BC .561

Berger 130 gr VLD Hunting @ 2450fps out of a 24" pipe:
G1 BC .552

123 gr Lapua Scenar @ 2445fps out of a 24" pipe:
G1 BC .527

Hey Jason have you shot Black Hills 123 Grendel ammo yet??

 

[jasonfaz]

Hey Jason have you shot Black Hills 123 Grendel ammo yet??

I have not my man. I use my 6.5 almost exclusively to punch holes in grey wolves at distance in the mountains of the beautiful state of Idaho, hence, I like the VLD Hunting and the 120 gr TSX. I put some of the Scenars through it early on though and those bad boys hit right where you want them to. Cant imagine the SMKs being much different.

 

[BC83]

I have not my man. I use my 6.5 almost exclusively to punch holes in grey wolves at distance in the mountains of the beautiful state of Idaho, hence, I like the VLD Hunting and the 120 gr TSX. I put some of the Scenars through it early on though and those bad boys hit right where you want them to. Cant imagine the SMKs being much different.

Im getting 2620-2630FPS from a 24" tube, with the BlkHills 123 Amax if you want to try some pay for shipping and ill send you some.

 

[Downzero]

I am not claiming it's a slam dunk. But common sense should tell you that the same amount of powder capacity pushing a 107 grain bullet vs. a 140, the 107 is going to come out on top due to speed. If it's the 123 vs. the 115 DTAC it's not even the same league.

The 6mm might even be a better choice in an AR-10 sized action, but in an AR-15, while not a huge difference, you have to admit that the 6mm comes out on top. In a bigger action, the 6.5 is a strong choice and maybe the best choice. But in a '15-length action, the 6mm is the winner.

 

[White Mamba]

The factory hornady and 28.5g of 8208 shoot great. I have had multiple one hole 3 shot groups with my 2-10x nightforce. With a 200yrd zero it took me about 46 moa to reach 1k at SAC Valley this Sunday. I would like to try a few different powders but I want something temperature stable for hunting .
I have a few other lengths for the Grendal and the 14.5 pinned to 16 " is the most practical when im hiking with a 2 point sling for miles and through tall grass and brush.

 

[jamcoconut1097]

I have had excellent results with a 16" MLGS barrel. Bill A. said there is a big difference in velocity between 18" MLGS and 20" RLGS when looking at large samples of guns, but he did gas shut off tests and hasn't seen noticeable change in velocity, so it's a bit of a head scratcher.

I think 8208XBR is a great powder for 100gr pills, but it isn't ideal for 123gr weights when looking at pressure and speed. Reasons are that you are pushing the pressures and there is a clear wall at 28.5gr under a 123gr, but it has some of the lowest pressures and fastest speeds with 100gr, making it very efficient in that bullet weight range. That said, it is one of the known accuracy powders for 123gr, along with AR-Comp.

For 123gr, I personally have had better than expected results with CFE223, even to the point where I am exceeding speed of a lot of longer barrel loads with the older powders (BL-C2 and AA2520), but staying well away from pressures. CFE23 is an extremely forgiving powder, that doesn't seem to have much of a rigid ceiling like the others, as you hit maximum load density and very fast speeds with it in that happy window.

I'm easily under max charge weights with CFE, but still hitting 2500fps under a 123gr, which is excellent for a little 16" gun with a .510 G1/.260 G7 BC bullet.

For a lightweight hunting set-up, choose balance and natural pointing characteristics of the rifle. That usually is a 16" - 18" gun for most people, with a lightweight handguard and stock of their choice.

PSA blem receivers will be fine if you make sure your upper receiver face is square, if you are chasing accuracy. The Lilja drop-in barrels are great, and 9130 AQ bolts can be had from several sources. AA, PF, Maxim, Underground Tactical, and JP all have excellent bolts for the Grendel.

It's the most versatile cartridge in the AR15 when looking at hunting across a number of species weights, then being able to turn around and match or exceed practical performance next to .308's in a rifle match, while keeping rifle weight and recoil much lower.

Wow! Thanks for this! Leaning towards an 18" fluted Lilja RLGS.

 

[Will_Power]

A lot of helpful information in this thread, guys. Thanks.

I'm starting to really get the Grendel itch, but have a couple outstanding concerns:


1. Ammo: Any word on the Wolf Gold coming back? That seemed to be the only factory loaded budget option out there, and I'm not certain how much I trust the steel case for anything more than plinking (and it's sold out until the next shipment, which is due in November, anyway). For my purposes, more cheaper ammo means more time behind the gun learning to stretch things out, which is a win for my circumstances.

2. Magazines: Seems like the ASC (I think that's the name) 25 rounders are solid. Haven't run into any complaints about them, but everything else looks suspect. Still, that 25 rounder looks awful tall to shoot from prone with.

3. Bolts: Once upon a time, I heard lots of gripes about fragile 6.5 G / 7.62x39-based faced bolts. Has that been fixed, years later? LRRPF52 answered that "9130 AQ bolts can be had from several sources. AA, PF, Maxim, Underground Tactical, and JP all have excellent bolts for the Grendel." So those will be some places to look, which is really good to know.

4. What chambering? What barrel manufacturer? We all know there are numerous slight variations of the 6.5 G chamber out there, from before AA released it and it got SAAMI status. Which should I use? What manufacturer is putting out quality work? If I wanted something similar in profile to my 20" SAM-R barrel from WOA, where would I look? Lilja is doing 6.5 G these days right? Would I be able to get something close to that from them?

 

[LRRPF52]

A lot of helpful information in this thread, guys. Thanks.

I'm starting to really get the Grendel itch, but have a couple outstanding concerns:


1. Ammo: Any word on the Wolf Gold coming back? That seemed to be the only factory loaded budget option out there, and I'm not certain how much I trust the steel case for anything more than plinking (and it's sold out until the next shipment, which is due in November, anyway). For my purposes, more cheaper ammo means more time behind the gun learning to stretch things out, which is a win for my circumstances.

2. Magazines: Seems like the ASC (I think that's the name) 25 rounders are solid. Haven't run into any complaints about them, but everything else looks suspect. Still, that 25 rounder looks awful tall to shoot from prone with.

3. Bolts: Once upon a time, I heard lots of gripes about fragile 6.5 G / 7.62x39-based faced bolts. Has that been fixed, years later? LRRPF52 answered that "9130 AQ bolts can be had from several sources. AA, PF, Maxim, Underground Tactical, and JP all have excellent bolts for the Grendel." So those will be some places to look, which is really good to know.

4. What chambering? What barrel manufacturer? We all know there are numerous slight variations of the 6.5 G chamber out there, from before AA released it and it got SAAMI status. Which should I use? What manufacturer is putting out quality work? If I wanted something similar in profile to my 20" SAM-R barrel from WOA, where would I look? Lilja is doing 6.5 G these days right? Would I be able to get something close to that from them?

1. Ammo: If you compare pricing of the Wolf Gold line to Hornady, for a 200rd case, we're talking about the difference of ~$150 vs. ~$183, or $33. For the accuracy, consistency, and brass value of the Hornady over the Wolf, the extra $33 can be recovered and then some in sale of the brass, or reloaded, whereas the Wolf brass only lasts maybe 3 firings in most of our experience. With mild loads, you could get it to last maybe 1-2 loads more, but you see my point.

Check here on availability, as prices are very appealing, even compared to .223 and .308 FGMM. 6.5mm grendel ammo rifle

That isn't even all the sources, just what Ammoseek hits with its engine. Precision Firearms, AA, and Les Baer also have a wide selection of loads. PF has 21 alone, all Lapua brass cased.

2. Magazines: I personally have not had malfs with any of my old CProducts, CProducts Defense, or ASC mags. There are also new Elander high quality mags that AA just introduced this year, after years of testing and tweaking with Elander. The straight 15rd mags can usually be loaded with 10rds and they function fine, but AA rejected them from CProducts since they spec'd a curved mag body back then, only to receive pallets of straight mag bodies. I use 10rd ASC mags as well for good ground clearance. I have not seen mag problems in a long time, whereas we used to have a specific dedicated thread for magazine problems with the old 6.5 Grendel Forum.

3. Bolts: AA has always made a great bolt that lasts. It was other shops that sourced their own bolts without using the same metallurgy as AA. Some worked fine, and others not so much. The sources I listed have gone above and beyond 8620 and use 9130 AQ steel bolts, the AA "hard use" 9130 bolt having some different features and a more smooth, grey finish, the others having a black nitiride finish and correct dimensions. AA Grendel bolts are .010" longer, with a .135" face depth, and the other new shops have adjusted to this Grendel standard.

4. Chamber and barrel manufacturer: I like the SAAMI chamber, and have been criticized to no end for it, but the SAAMI chamber is a proven accurate and reliable chamber for a gas gun. It is the most forgiving when looking at different types of brass, like when sizing 7.62x39, and running dirty, or shooting the steel case.

The .264 LBC-AR is a great chamber as well. Most shooters will not notice much difference between the two. The Grendel chamber has a compound throat to handle a wide variety of projectile shapes, and does so very well. What I have noticed with my AA barrel/SAAMI chamber is that no matter what bullet I load, from 100gr NBT to 129gr SST, it shoots predictably, averaging around 1 MOA, with best groups hitting .75 MOA, and worst 1.2 MOA when shooting for groups.

Fastest barrels will come from Brownell's, Lilja, Midway. The Lilja's will have a true Grendel chamber. I don't know what chamber they are using in the Brownell's or Midway barrels, but after an initial hiccup, they seem to be pretty solid from what other people have reported. I don't have one in hand, so I can't measure it and evaluate dimensions or performance, but the prices are the lowest right now.

You don't need a 20" barrel, unless you are chasing speed with a 123gr. I am able to hit 2550fps safely with 123gr from a 16" using CFE. I actually hit 2698fps with the final load in a pressure ladder that I was ok with just for that test, but would never produce that load again, as I saw a ~40fps increase in velocity, and slight cratering-signs that many people would call good, but I know is probably over the SAAMI MAP. My velocity increase per charge weight was very textbook at 12-25fps per rung on the ladder until I started to get into 2600fps and beyond. The 2600fps, and 2648fps loads were already way more than I ever thought I would get, and I would not mass produce them either, even though I saw no signs at 2600fps.

You have to answer what you really plan on doing with the rifle before I can give you a specific barrel recommendation. I always wanted an 18" barrel, and now have several of them. I think the best 18" barrel set up is from Precision Firearms with the Arion Type I, Intermediate Gas System Length. Those are high end rifles with PF Billet sets, top end barrels, all high quality parts in every aspect.

JP is another excellent source for barrels and bolts for 6.5 Grendel.

 

[Reck18]

I have been hunting with my Grendel for three years. White tail drop every time at 300+ yards. That is using Hornady A-max 123 gr. I don't know all the fancy numbers about the Grendel but I know that it is a great round for hunting. It doesn't hold up to bad for target shooting either. I didn't go expensive on mine and I can hold decent groups with it. Good luck with your build and unless you are looking to make money off of shooting, just get what you like.

 

[FlyfishNM]

Just a heads up, midway has 123 grain amax bullets in stock. Replenished my stock this morning

 

[BC83]

Just a heads up, midway has 123 grain amax bullets in stock. Replenished my stock this morning

As did I about a month ago, already burned up half up them...

 

[FlyfishNM]

As did I about a month ago, already burned up half up them...

They do get burned up quickly! Besides powders these have been the hardest thing for me to find on a regular basis.

 

[Will_Power]

Thanks for the thoughtful reply, LRRPF.

1. Ammo: If you compare pricing of the Wolf Gold line to Hornady, for a 200rd case, we're talking about the difference of ~$150 vs. ~$183, or $33. For the accuracy, consistency, and brass value of the Hornady over the Wolf, the extra $33 can be recovered and then some in sale of the brass, or reloaded, whereas the Wolf brass only lasts maybe 3 firings in most of our experience. With mild loads, you could get it to last maybe 1-2 loads more, but you see my point.

Check here on availability, as prices are very appealing, even compared to .223 and .308 FGMM. 6.5mm grendel ammo rifle

That isn't even all the sources, just what Ammoseek hits with its engine. Precision Firearms, AA, and Les Baer also have a wide selection of loads. PF has 21 alone, all Lapua brass cased.

Sure, there are a small number of manufacturers pumping out the 6.5 G. I check the various ammo search engines just like you. But that's not what I asked about.

The Wolf Gold MPT was going for around $13-$15 when it was in stock, compared to the Hornady boxes which go for $19+. That adds up when you're wanting to pick up a lot for a class, for a long weekend, or for generally saving up. I'll be getting into handloading soon enough, but that doesn't mean I'm suddenly not interested in affordable, accurate enough factory loadings - of which the Wolf Gold / Pvri load seems to be the only option.

4. Chamber and barrel manufacturer: I like the SAAMI chamber, and have been criticized to no end for it, but the SAAMI chamber is a proven accurate and reliable chamber for a gas gun. It is the most forgiving when looking at different types of brass, like when sizing 7.62x39, and running dirty, or shooting the steel case.

The .264 LBC-AR is a great chamber as well. Most shooters will not notice much difference between the two. The Grendel chamber has a compound throat to handle a wide variety of projectile shapes, and does so very well. What I have noticed with my AA barrel/SAAMI chamber is that no matter what bullet I load, from 100gr NBT to 129gr SST, it shoots predictably, averaging around 1 MOA, with best groups hitting .75 MOA, and worst 1.2 MOA when shooting for groups.

If I understand this correctly, the .264 LBC chamber was built around a specific bullet and load, correct? Match accuracy and all that - in additional to getting around AA's rights before the Grendel was released. But the to-spec 6.5 G chamber is a bit looser and allows for various loads and bullets. Is the argument made that the 6.5 G chamber has less accuracy potential as a result of this? Correct me if and where I'm wrong, as I'm out of my depth here.

I imagine I could get reamers for either if I got a barrel through Lilja, right?

You don't need a 20" barrel, unless you are chasing speed with a 123gr. ... You have to answer what you really plan on doing with the rifle before I can give you a specific barrel recommendation.

I really like the form factor in my 20" WOA SAM-R barreled .223 setup and would really like to copy that as much as I could to a 6.5 G upper if I decide to make the jump. The majority of the time this thing is going to get used target shooting and coyote hunting. Don't want to take it out to 24", but I'd like to get as much speed out of the cartridge as I can with a 20" setup.

 

[BC83]

The OP of this thread was given some good advise, I suggest you go back and read you will find your answers..also Google is your friend.

 

[346ci]

If I understand this correctly, the .264 LBC chamber was built around a specific bullet and load, correct? Match accuracy and all that - in additional to getting around AA's rights before the Grendel was released. But the to-spec 6.5 G chamber is a bit looser and allows for various loads and bullets. Is the argument made that the 6.5 G chamber has less accuracy potential as a result of this? Correct me if and where I'm wrong, as I'm out of my depth here.

I believe most of the LBC chambers were designed for the 123gr Amax. I had a .264 from ARP that was a laser with factory G ammo(123gr Amax), they dropped them for a few years but should have some more this Dec in 18" and 20". If I do decide to get back into one, that will be the barrel.

I used that .264 for a few matches, ran great. Accurate and low recoil with a massive brake. I had a chance to shoot a 6.5 Creedmoor and sold the .264 after that. The way a 140gr CM smacked steel sold me, lol.

My main deer rifle is a suppressed 12.5" 6.8, used a 16" last year and it worked great but a little long with a can. If you are looking to lay down some pigs or deer, check the 6.8 out. I will be getting my old 18" back together for some 600yd matches this coming spring/summer.

 

[Constructor]

The SAAMI Grendel spec states the tolerance is +.002" different from most reamers +- .001"
Using the minimum SAAMI Grendel spec. .0178" in front of the max case length is the end of the cone and start of what we normally call the freebore the diameter is .2644"
The throat of a SAAMI Grendel tapers at .5 degrees. .023" in front of the cone the throat reaches .264 diameter and the lands begin to engrave the bullet. At .2635" in front of the cone the lands reach full height and the land to land diameter is .256" According to the SAAMI Grendel print.
When using a maximum diameter spec Grendel reamer (+.002)things change.
The diameter at the end of the cone is .2664" at .5 degree the bore does not reach .264 diameter until .137" in front of the cone. That is .114" further forward than the minimum spec reamer. That is like having a .137 freebore that is .0024" larger in diameter than the bullet. At .3775" in front of the cone the lands reach full height and .256" diameter.
Using the minimum spec reamer if you have a big blunt round nosed bullet it must be seated deep in the case to keep it from jamming into the lands .023" in front of the cone.
Remember the issues with bullets getting stuck in the lands on the Grendel forum a few months ago?
If using a Lapua 123gr Scenar .040" (.023+.017 cone length)of the full diameter of the bullet may protrude outside the case mouth and be very close to touching the lands.
However if the max chamber spec is used the same Lapua bullet must be seated .114" further out to get as close to the lands.
Considering same brand Factory ammo is all loaded the same length some bullets could be very close to the lands and some could be way off depending whether the reamer was at max spec or minimum spec.
A normal non compound throat chamber has a 1.5 degree throat. instead of having .114" difference due to tolerance they have 1/3 of the difference or .038". It also splits on the reamer spec +.001 or -.001. Lets say the 264LBC, Grendel II and the Grendel V1.0 as Arne calls it has a design spec of .120. Due to reamer tolerance the freebore could be any where between .101 and .139" Kind of close to the max SAAMI Grendel freebore. Still much longer than the minimum spec Grendel. Now if JGS makes the 264LBC reamers the tolerance is half of PTGs or +- .0005" That reduces the freebore to a .019" difference min to max. .1105-.1295 for the LBC .0715-.0905 for my chamber...just about the same as mid spec of the Grendel but with a lot less movement of the lands due to tolerance.
The 264LBC has a neck diameter or .295, the grendel .300. Most loaded ammo is .292"
I guess we could say a minimum spec Grendel chamber is good for High BC bullets like the Lapua, SMK, AMax and SST and not so great for blunt nosed bullets it could cause pressure spikes.
At the same time we can say a maximum spec Grendel chamber is good for blunt nosed bullets but not so great for long high BC bullets unless you load long and single feed them. One question, how do you know if you're getting a minimum spec or a maximum spec? A .023 or a .137" freebore?
I still say The Grendel is like a 5.56 NATO chamber and the 264LBC is like a 223 Wylde for the reasons above.
This shows where some bullets will touch the lands in the 264LBC or Grendel II chamber. The SAAMI Grendel chamber could be .017" more or .097" less depending on the size of the reamer.
100gr. Nosler Partition OAL= 2.271
100gr. TTSX OAL= 2.330
100gr. Nosler BT OAL= 2.308
120gr. Hornady Amax OAL= 2.2575
120gr. Barnes TTSX OAL= 2.333
120gr. Barnes TSX OAL= 2.2945
123gr. Hornady SST and Amax OAL= 2.335
129gr. Hornady SST OAL= 2.380
129gr. Hornady SP Interbond OAL= 2.252
140gr. Nosler BT OAL= 2.316
140gr. Hornady SST OAL= 2.380
140gr. Nosler Partition OAL= 2.302
140gr. VLD OAL= 2.398

Pretty easy to see the 264LBC was not designed for the 123 Amax.


BTW OP, the 6.5s a good choice for the hunting and long range paper killing combo. Geissele trigger and a good scope should be about all that is needed except handloading.

 

[sandwarrior]

Since I can't resist keeping the discussion going on about 6mm vs. 6.5, I found the old thread:
http://www.snipershide.com/shooting...ild-6-5-grendel-wildcat-fans-6mm-fat-rat.html

A new thought on the 6mm vs. 6.5 here. I have talked to a number of competitors who run 6mm's over 6.5's One of the biggest things they say is they reduce loads as much as possible to conserve barrel life. And, still remain competitive with 6.5's. Given the 'all-out' factor and 'barrel cost be damned' it's come more to my attention that with the newest crop of 6mm's are beating the 6.5's.

In the Grendel size case I don't think you are going to run into barrel life problems nearly as bad as full size cases. Yes, you may wear barrels faster, but I'm thinking anything 6mm on the Grendel case is going to last you long enough. 6mm BR guys are having great life expectancy from that little case, and the Grendel case is smaller yet.

Downzero, you may just have the ticket.

 

[LRRPF52]

Les Baer said he has tested barrels into the 20,000's for round count, and still is shooting superbly. Low pressure of the Grendel doesn't torch the throat like higher pressure cartridges, so barrel life exceeds .308 easily.

For UKD competitions with small plates, you definitely will have an advantage with a super fast cartridge, which is where the appeal is for the 6mm variants.

For the majority of people who want a multi-purpose AR15 that has excellent and affordable factory ammo available for it, the Grendel has no peer, and you will have a competitive edge against even .308 bolt guns with longer barrels, especially if the competition involves a lot of movement.

Even I was surprised last year and this year at the number of 6.5 Grendel's showing up in the hands of teams at Sniper Adventure Challenge, where a lightweight rifle that can still reach out is part of the formula for being competitive against other teams, at least a third of which are former or active Marine Force Recon, Scout Snipers, Ranger Regiment, SF, etc.

I had an interesting conversation with one of the teams, both members having brought 6.5 Grendel's, one for the carbine and one for the rifle, and they were one of the few teams that were actually hitting targets at a UKD long range stage, as well as a UKD shorter range stage. One of them was an instructor at one of the Division Level Scout Sniper Courses, and he felt strongly that 6.5 Grendel should seriously be considered as a new SASS cartridge, and let .308 go away entirely for the precision guns. Since they have a very specific and niche segment supply of match 7.62 Special Ball anyway, his argument was that it wouldn't be a big deal to go to Grendel, and they are using the M40A5 less and less in the wake of the Mk.11's.

One of the biggest benefits of 7.62 Special Ball or M118 Long Range is barrel life, which is a huge deal in the training side. Chasing burned out throats with magnums is a significant logistics burden and training distraction, because we run pretty high round counts in formal sniping courses in the US military. For civilians who can't fathom the idea of shooting more than a few days straight, several of the sniper courses are at least 8 weeks in duration, and a lot of that time is spent on the range learning trajectory and wind compensation.

When you look at the fact that the Grendel brings with it a higher BC bullet, half the recoil, longer barrel life, and the same muzzle velocity as M118LR from a carbine barrel that fits inside the M4 or SPR form, with exceptionally high accuracy potential even compared to the M40's, and bolt guns have zero appeal at that point. Then factor in the reality that a Sniper team can actually fight with the carbine or rifle from close quarters out to 1200yds with this platform, and the final nail rests in the M40's coffin. I know I felt very cheated carrying around the M24 after seeing what a little Grendel carbine is capable of.

 

[Danco411]

Early on there were some poorly reamed barrels sold by manufacturers who had no idea what they were doing. A guy on our local forum bought a rifle with a Doublestar barrel that would not shoot. He had no idea what was wrong but I suspected it had a short throat and was jamming all the bullets. He ended up buying a new Shilen from Midway and gave me the Doublestar for swapping out his barrel. Sure enough the throat was so short bullets seated to 2.45 were jammed. I rented a 6.5 throating reamer from 4D rentals and with a few turns opened it up. Now rounds seated to 2.65 drop in and out and it shoots superbly. I used it to make an upper for my shooting partner. FYI the barrels from Midway are made for them by Liberty which is an offshoot of Satern. They shoot very well for the money. I bought mine off of Satern but I think it is the same barrel. Mine shoots sub MOA with a variety of bullets although I mainly shoot the 123 Amax. I would like a Lilja no doubt as I have used both .308 and .260 Lilja barrels. They are awesome but expensive.

I'm now thinking of a building a short barreled Grendel upper for a tree stand gun. My 20" is a tad bit long. We can't have SBR's in Michigan unless we get a stamp so I may just get a 14.5 and pin a comp on it.

 

[Constructor]

A new thought on the 6mm vs. 6.5 here. I have talked to a number of competitors who run 6mm's over 6.5's One of the biggest things they say is they reduce loads as much as possible to conserve barrel life. And, still remain competitive with 6.5's. Given the 'all-out' factor and 'barrel cost be damned' it's come more to my attention that with the newest crop of 6mm's are beating the 6.5's.

In the Grendel size case I don't think you are going to run into barrel life problems nearly as bad as full size cases. Yes, you may wear barrels faster, but I'm thinking anything 6mm on the Grendel case is going to last you long enough. 6mm BR guys are having great life expectancy from that little case, and the Grendel case is smaller yet.

Downzero, you may just have the ticket.

Agree, most are trying to use the slowest burning powder possible to keep the temps down and spread out the burn. I have about 4000 rounds on a 6BRX shooting 95gr SMKs at 3150 out of a 22" barrel. Using N540 in a 6mmAR I can get 2900fps out of a 20".

 

[corym468]

Early on there were some poorly reamed barrels sold by manufacturers who had no idea what they were doing. A guy on our local forum bought a rifle with a Doublestar barrel that would not shoot. He had no idea what was wrong but I suspected it had a short throat and was jamming all the bullets. He ended up buying a new Shilen from Midway and gave me the Doublestar for swapping out his barrel. Sure enough the throat was so short bullets seated to 2.45 were jammed. I rented a 6.5 throating reamer from 4D rentals and with a few turns opened it up. Now rounds seated to 2.65 drop in and out and it shoots superbly. I used it to make an upper for my shooting partner. FYI the barrels from Midway are made for them by Liberty which is an offshoot of Satern. They shoot very well for the money. I bought mine off of Satern but I think it is the same barrel. Mine shoots sub MOA with a variety of bullets although I mainly shoot the 123 Amax. I would like a Lilja no doubt as I have used both .308 and .260 Lilja barrels. They are awesome but expensive.

I'm now thinking of a building a short barreled Grendel upper for a tree stand gun. My 20" is a tad bit long. We can't have SBR's in Michigan unless we get a stamp so I may just get a 14.5 and pin a comp on it.

Hey man nows the time to build that Grendel SBR with a Lilja barrel at a great price.
Grendel Short Barrel Group Buy Orders
http://www.snipershide.com/shooting...269039-lilja-6-5-grendel-sbr.html#post3302777

 

[jamcoconut1097]

For the majority of people who want a multi-purpose AR15 that has excellent and affordable factory ammo available for it, the Grendel has no peer, and you will have a competitive edge against even .308 bolt guns with longer barrels, especially if the competition involves a lot of movement.


This is why I am building one!

 

[jamcoconut1097]

Thoughts on the JP Grendel 18" barrels?

 

[BC83]

Thoughts on the JP Grendel 18" barrels?

I just recently finished JP Grendel build and for the most part it came out nice, but the accuracy is just not there like it is with a single point cut barrel..I would stick with Lilia of you won't a button cut baarel.

But if your in a hurry to do this Grendel build and you just want to get your feet wet and you want to hold out on the high quality parts till you get some experience then JP will do just fine.

 

[jamcoconut1097]

I just recently finished JP Grendel build and for the most part it came out nice, but the accuracy is just not there like it is with a single point cut barrel..I would stick with Lilia of you won't a button cut baarel.

But if your in a hurry to do this Grendel build and you just want to get your feet wet and you want to hold out on the high quality parts till you get some experience then JP will do just fine.

Not in a hurry by any means. Just formulating a plan and happened upon the JP barrels. Sounds like Lilja still...

 

[LRRPF52]

I just recently finished JP Grendel build and for the most part it came out nice, but the accuracy is just not there like it is with a single point cut barrel..I would stick with Lilia of you won't a button cut baarel.

But if your in a hurry to do this Grendel build and you just want to get your feet wet and you want to hold out on the high quality parts till you get some experience then JP will do just fine.

What upper receiver did you use, and did you make sure you had a square receiver face by any chance? Did you bed the extension? As an experiment, I took that .223 Wylde JP barrel and just threw it in a cheap square forge code upper with a loose tunnel.

It shot about 1.5" at 100yds.

After checking the receiver face squareness with a lapping tool, bedding it into a tight Aero upper, it shoots .25" at 100yds for 5rds in the hands of a child. Go figure.

 

[BC83]

What upper receiver did you use, and did you make sure you had a square receiver face by any chance? Did you bed the extension? As an experiment, I took that .223 Wylde JP barrel and just threw it in a cheap square forge code upper with a loose tunnel.

It shot about 1.5" at 100yds.

After checking the receiver face squareness with a lapping tool, bedding it into a tight Aero upper, it shoots .25" at 100yds for 5rds in the hands of a child. Go figure.

No I didn't do all that..

The upper was a mega and the bcg and handguard were JP

I'm just not a huge fan of JP barrels from what I've seen..I'm working on a dual Cal project now. As soon as I get my LRP-07 comes in its going to Jeff Hayes to install a 22" bartlien 6.5 cm barrel and a PRI delta handguard.