Would like some help with First Build "6.5 Grendel 12.5" Ultralight

[chadwickz71]

First build here so ignorant to some of this stuff so bare with me. rifle is for thermal hog hunting, already us some heavy 308s and want to try a ultralight 6.5 grendel. If all works well i'll basically give this to my 69yr old dad and build a second for myself as we would like to transition out of the heavy 308s.

6.5 grendel 12.5" 100% suppressed. Keep light/compact as possible

I'd like to stay as "top of the line" as possible, but some of these choices like the billet matched set are purely because they are in stock local for me in Dallas where i can also file my tax stamp for it being a SBR.

Noveske gen 4 matched set "in stock at Riflegear in dallas" but would entertain other options that are in stock i can get
JP lower parts kit
JP Full mass bolt carrier
What 6.5 grendel Bolt should i get ????????????
charge handle Noveske or radian both in stock at riflegear
Triggertech Trigger
JP JPSCS2-15H2 buffer system
Smoke composites buttstock (looking at short pull vs Rifle length) need some opinions here...
Smoke handguard "Need some help with what length im thinking 10" ????
smoke pistol grip "not sure if that saves much weight, maybe more for matching furniture than actual weight help"
Forward assist / dust cover "do i need this, looks like the Noveske comes with it ???
precision firearms barrel 12.5 bartlein/kreiger "can i get a way with a pencil profile here on the 12.5" figure i would talk to these people for advice
SLR adjustable block and gas tube, titanium Block
Should i go a ASR brake or direct mount to save weight?
I have omega 30s, and 36m suppressors with ASR brakes on my heavy guns and i like them but not a necessity.

Does this look pretty solid?
Need some opinions on this.... Can i save weight anywhere else that would mean a lot?
Durability of the Smoke furniture? ya'll have good luck with it,,,

Hoping LRRPF52 will circle by and check my parts, as i've been reading lots of his work with a 12.5" grendel, and lots why i wanted to go this route.

 

[hlee]

Here, I’ll give you a bit of an assist…

@LRRPF52

And, efiling a SBR tax stamp is super easy- you shouldn’t need ffl assistance with that. Getting the engraving done may be a different story, but the paperwork is cake.

 

[chadwickz71]

thanks, just looking for y’all to check over my parts. And make sure I’m ordering thr right stuff for proper functioning most importantly.

 

[MSTN]

The JP bolt is a safe bet.

Be aware any firearms engraving with your NAME-CITY-STATE must be done by an FFL, according to the ATF.

 

[JR1200W3]

thanks, just looking for y’all to check over my parts. And make sure I’m ordering thr right stuff for proper functioning most importantly.

Instead of using a conventional upper and lower and then going ultra lite on the handguard and grip, why not go with a high end lightweight upper and receiver from a company like VSeven? That way you can use more durable handguards and buttstocks. Click on @MSTN username and follow his builds for inspiration.

 

[chadwickz71]

Thanks I’ll look them up and check weight savings, reason why I put the noveske on here was purely because it was in stock locally and I know they are good quality. Besides the obvious major brands I’m not very versed on ar manufactures like v7. Thats why I’m here asking for help, so thank yall. I don’t want to find out later I should’ve done something different that was obvious.

 

[chadwickz71]

Looking at the v7 handguards they are about same cost and weight as smoke, I assume you guys might say that alloy handguard might be more functional and stronger then the composite?

 

[Redlion]

The JP bolt is a safe bet.

Be aware any firearms engraving with your NAME-CITY-STATE must be done by an FFL, according to the ATF.

I second the JP bolt assessment.

 

[chadwickz71]

Sort of thinking now to go the V7 receiver set, with their hyperlight handguard.
Get all the receiver pins/parts from them too.
stick with the JP BCG and buffer system

Then source the triggertech, smoke stock, and 12.5" barrel

 

[JR1200W3]

Sort of thinking now to go the V7 receiver set, with their hyperlight handguard.
Get all the receiver pins/parts from them too.
stick with the JP BCG and buffer system

Then source the triggertech, smoke stock, and 12.5" barrel

SLR Sentry adjustable gas block, JP Lo mass BCG, JP silent capture buffer system for law tactical folder, Trigger Tech single stage duty trigger, CGS Hyperion K with vented end cap, Acro P2 on a Reptilia 1.93" mount.....Barnes 115gr TAC TX as fast as you can make one shot brass with Ramshot TAC....*chefs kiss

 

[ut755ln]

First build here so ignorant to some of this stuff so bare with me. rifle is for thermal hog hunting, already us some heavy 308s and want to try a ultralight 6.5 grendel. If all works well i'll basically give this to my 69yr old dad and build a second for myself as we would like to transition out of the heavy 308s.

6.5 grendel 12.5" 100% suppressed. Keep light/compact as possible

I'd like to stay as "top of the line" as possible, but some of these choices like the billet matched set are purely because they are in stock local for me in Dallas where i can also file my tax stamp for it being a SBR.

Noveske gen 4 matched set "in stock at Riflegear in dallas" but would entertain other options that are in stock i can get
JP lower parts kit
JP Full mass bolt carrier
What 6.5 grendel Bolt should i get ????????????
charge handle Noveske or radian both in stock at riflegear
Triggertech Trigger
JP JPSCS2-15H2 buffer system
Smoke composites buttstock (looking at short pull vs Rifle length) need some opinions here...
Smoke handguard "Need some help with what length im thinking 10" ????
smoke pistol grip "not sure if that saves much weight, maybe more for matching furniture than actual weight help"
Forward assist / dust cover "do i need this, looks like the Noveske comes with it ???
precision firearms barrel 12.5 bartlein/kreiger "can i get a way with a pencil profile here on the 12.5" figure i would talk to these people for advice
SLR adjustable block and gas tube, titanium Block
Should i go a ASR brake or direct mount to save weight?
I have omega 30s, and 36m suppressors with ASR brakes on my heavy guns and i like them but not a necessity.

Does this look pretty solid?
Need some opinions on this.... Can i save weight anywhere else that would mean a lot?
Durability of the Smoke furniture? ya'll have good luck with it,,,

Hoping LRRPF52 will circle by and check my parts, as i've been reading lots of his work with a 12.5" grendel, and lots why i wanted to go this route.

Some specific comments, I have not used everything that you listed.

1) The JP Bolt Carrier and their 6.5 BCG are good to go. I just bought my second BCG from them for my 6 ARC.
2) Pencil Barrel - How rapid are you going to shoot and how important is accuracy?
3) I tried a really light build once and hated it, I would ditch all the carbon fiber furniture. It just does not save that much weight.
4) You do not need a forward assist.
5) Noveske makes good stuff but that is a lot of money for a roll mark that does not make the gun any better.
6) I have tried several adjustable gas systems, the winner going away is rifle speed.

My lightest rifle is actually 16". From tip to butt (for the Navy). Direct thread to save weight for the can or A2 flash hider. Proof Research Carbon Fiber barrel. Rifle Speed adjustable gas block. BCM 13" mlok rail. I did the battle arms upper and lower without a forward assist. BCM mod zero grip, Magpul CRT stock. I went with a Rubber City Armor titanium bolt carrier group and the JP Silent Capture Spring. I am pretty sure I bought a titanium barrel nut to save an ounce or two. I did not go skeletonized anywhere or full carbon fiber anywhere.

It shoots fine but I didn't actually like it because it was too light ironically and I ended up selling it.

 

[RedDirtRifleman]

I built a light, not ultralight and definitely not premium, 12.5” Grendel for deer hunting. I will make a couple recommendations based on that experience.

Don’t do ASR on this build. You want 100% suppressed and lightweight? Why do a heavy locking QD system. Direct thread all the way. Lightweight taper mount if you’re dead set on using a mount. (Edit: hell you’re paying for a titanium gas block, why would you pay more money for more weight further down the barrel)

I’ve got a Hanson profile barrel and it doesn’t drift too bad at my 200 and in hunting distances even if I dump a mag at the range. Instinct, not experience tells me not to try much more than that.

I’ve got an 11” handguard on mine. I like it ergonomically. A loss of one inch would be a mild annoyance but not a deal breaker.

 

[cas6969]

JP Full mass bolt carrier

Then you're not all in on the Ultralight thing.

 

[Cascade Hemi]

Looking at the v7 handguards they are about same cost and weight as smoke, I assume you guys might say that alloy handguard might be more functional and stronger then the composite?

Magnesium is not as strong. BCM used to sell magnesium handguards but stopped due to durability issues

 

[JR1200W3]

Don’t do ASR on this build. You want 100% suppressed and lightweight? Why do a heavy locking QD system. Direct thread all the way. Lightweight taper mount if you’re dead set on using a mount. (Edit: hell you’re paying for a titanium gas block, why would you pay more money for more weight further down the barrel)

Spot on, right here. QD systems that consist of a suppressor adapter and a muzzle device are fun to use but just add unnecessary weight. I direct thread just about everything. Lighter and shorter.

 

[chadwickz71]

Wanted to drop this out there... Shot a message to V7, got a response same day. I asked them if they would be interested in building a 12.5" ultra-lightweight 6.5 Grendel. Rep said, "yes we can help ill have one of the main guys reach out to you in a day to discuss what you want."

They build a 6ARC 16" check out the specs so i assume they'll want to drop the 12" grendel in this system: https://www.vsevenweaponsystems.com/16-enlightened-6mm-arc-rifle/

My semi-ignorant self added up most of the parts from their list and broke through $3200 and i know i didn't get everything... So yeah they're at $3700 full gun

Expensive piece of machinery here, but geez i checked some prices on other brands parts and it adds up, and it aint cheap going light...

Biggest difference i see is their Titanium BCG and h1 buffer vs JP bcg with Jp h2 buffer which is what everyone seems to say I need to use for running correctly...

 

[chadwickz71]

guess my question on the above post is

would you give up some weight savings and go a JP BCG and bolt or go the titanium units V7 runs and heck for that matter go your own precision firearms kreiger/bartlein barrel? Or just get all ther lightweight parts? Im more asking this pertaining to the actual function of the rifle.

 

[Cascade Hemi]

guess my question on the above post is

would you give up some weight savings and go a JP BCG and bolt or go the titanium units V7 runs and heck for that matter go your own precision firearms kreiger/bartlein barrel? Or just get all ther lightweight parts? Im more asking this pertaining to the actual function of the rifle.

Depends, but looking at your parts list you can have the same end result and weight with each. You have light(er) weight carriers but then use H/H2 buffers. The Ti carrier is 2oz lighter than the JP steel LMOS carrier. If you went with a 1oz traditional buffer/spring, SLR AGB, and steel JP LMOS you would have the same overall weight as the Ti carrier and H buffer.

All of the silent capture spring buffer systems weigh more than just a traditional buffer and spring of the same buffer weight and spring rate. Frankly, it doesn't make any sense to use a low mass carrier but then pile the weight back into the buffer. You may as well use a mil spec carrier and run a light weight buffer if you need the overall weight with H2.

 

[chadwickz71]

That makes total sense. I was just under the impression that I should use the full mass carrier for the best function of the rifle versus the low Mass…. Is that not correct to say it that way?

What is the lightweight setup I should use from JP but keeping function in mind? I don’t want to fight fixing a gun with cycling issues…. I don’t know enough about this area yet to completely understand what actually works and doesn’t work…

 

[CaptArab]

I'd probably just buy the $550 PSA 12" kit and make sure I liked it before spending a couple mortgage payments on a rifle for shooting pigs.

 

[chadwickz71]

Good point, but I have used these heavy guns here long enough to know what I want. That’s really our only gripe with off the shelf weapons these days

I just want to get my parts right so I don’t come back here in three months telling you guys the gun won’t function good and y’all say something like “well it’s because of the parts you bought you should’ve got x part that is more dependable.”

 

[JR1200W3]

That makes total sense. I was just under the impression that I should use the full mass carrier for the best function of the rifle versus the low Mass…. Is that not correct to say it that way?

What is the lightweight setup I should use from JP but keeping function in mind? I don’t want to fight fixing a gun with cycling issues…. I don’t know enough about this area yet to completely understand what actually works and doesn’t work…

This is where I'd make weight concessions. Especially when you're talking about a few ounces. I would choose performance and function over weight when it comes to the BCG and buffer system.

 

[Cascade Hemi]

That makes total sense. I was just under the impression that I should use the full mass carrier for the best function of the rifle versus the low Mass…. Is that not correct to say it that way?

What is the lightweight setup I should use from JP but keeping function in mind? I don’t want to fight fixing a gun with cycling issues…. I don’t know enough about this area yet to completely understand what actually works and doesn’t work…

Low mass is less forgiving of ammunition changes and requires gas regulation. Titanium carriers, if not done right, are hard on Aluminum receivers. My preference is low mass steel carriers but V7 has a good reputation. KAK sells a reduced buffer combo with three buffers at a super low price. You can then try SprinCo white, blue, and red springs. None of this is hard but you need to be willing to try a couple of setup changes initially to get it right.

 

[Bakwa]

Just some motivation.
My 12.5 Grendel.

 

[LRRPF52]

For weight, I would look at overall system weight and balance once the thermal is mounted and make sure you’re not too light, where torque could negatively affect sight picture or if you plan to tripod-mount at night while standing and scanning.

Work outwards from the critical core parts, starting with barrel/bolt combo:

Barrel
Money no object, unless you’re planning on cutting 10 and X rings with it, there isn’t a need to go up to Krieger or Bart, but it won’t hurt. Criterion will group plenty fine for hogs, but if you want your dad to giggle when you confirm zero and shoot groups, you can do Krieger or Bartlein from PF. For a 12” always suppressed, I would think about MLGS instead of CLGS, maybe a .068”-.072” port?

Have Mark pin the gas block with a tight seal to the journal. If I could, I would want the KAC Mod 2 gas system. Q actually uses something similar/same on their Honey Badger. Riflespeed is another adjustable gas option that has 12 settings, but you will need to figure out which regulator length you need.

Bolt carrier
I’m a big fan of the Bootleg adjustable gas carriers running suppressed, which is what I have done and I think is part of my success formula for having superb reliability and consistent ejection for the past 7 years with my 12”, and the other one I built using the same core parts.

For bolts, get a Rexus bolt.
A true Mil-Spec firing pin or if you can find one, the Alexander Arms tri-lobe shaft firing pin.

Receivers/Handguard
Noveske receivers sound great, especially the ones with the blended transition to the handuard.

Pick your trigger/LPK/CH. I like polymer ejection port doors now.

Suppressor
For lightweight suppressors, it’s hard to beat TBAC. My Ultra 5 doesn’t even feel like it’s there. I would go with one of the newer, larger diameter cans from them like the Magnus-K CB (9oz), which didn’t exist when I put my 12” together.

For the stock, I would think about balance and cheek weld ergonomics more than just going for rock bottom on weight.

Of all my ARs, I really like my 12” Grendel the best. It’s better for close-in work than any of my 14.5” -16” 5.56 blasters, and better than 20” 5.56 for mid-long range work as well.

 

[Bakwa]

Hey friend,

For some context I wanted something similar to you and this is the route I went,

Barrel and GB
I have a Noveske barrel. It produces consistent sub MOA groups, sometimes sub half MOA groups. I'm pleased with its accuracy. My first choice was going to be a PF barrel as well, but on a whim I jumped on the Noveske.
The GB is pinned by Noveske and it seals tight, even when suppressed.
BCG
JP Bolt works great. Reliability is 100%.
Bootleg adjustable carrier. This was a must for me as I run mine suppressed and unsuppressed. Again, it's 100%.
Upper
I had it setup with a VLTOR MUR upper but I found out that didn't fit on my MARS lower, so I made the switch to a FCD forged upper. It still shoots just as good, has not wobble on my MARS lower. Both have been GTG for this barrel.
Handguard
I wasn't as weight conscious as you are but I didn't want a short pig of a 6.5G either, so I initially used a Noveske MLOK 9" HG which was lighter weight and can be seen is in the pictures I posted above. When I changed the upper, I took the opportunity to put a longer HG on to mount other devices. It now sports an 11" FCD MLOK HG. It's still not a pig but it's not as light when I put a can, LAM, MPVO, WL, bipod etc, on it.

The end product is a very useable 100% reliable hog getter.

 

[chadwickz71]

Both you guys above are going a standard gas block but adjustable carrier Vs an adjustable block and fixed carrier.

Is there a reason that is better for these Sbr’s in particular or just a personal preference?

 

[Cody S]

Just some motivation.
My 12.5 Grendel.
View attachment 8408345View attachment 8408344

that is way too cool not to sbr it

 

[Bakwa]

that is way too cool not to sbr it

Check post 26.

 

[LRRPF52]

Both you guys above are going a standard gas block but adjustable carrier Vs an adjustable block and fixed carrier.

Is there a reason that is better for these Sbr’s in particular or just a personal preference?

I hate fiddling with set screw adjustable gas blocks where the tiny little set screw gets carbon-seized. Especially for CLGS where port pressure and temperatures will be higher, that little set screw gets blasted with pretty intense heat and worn-down on the front end, which then needs to be chased with additional turning-in. This is more true if you shoot high-volume, so might not be a consideration.

With the Bootleg carrier, I just dialed it down to fully-suppressed and it runs great on 2x 12” Grendels with the same barrel/bolt. It’s the most user-friendly adjustable gas that I’ve seen because you just insert a small flathead into the ejection port to turn the valve between its 4 detent click-retained positions until you see 4:30 ejection, and you’re done.

This keeps my bolt locked longer, since I’m using a high-efficiency Ultra 5 .30 cal suppressor. I went 30 cal instead of 6.5 because I didn’t want too much back pressure and ejection port pop.

I’m also using heavier action spring weight and a standard buffer weight at 2.9oz. Runs like a raped ape and has done so for 7 years now. It goes out every month.

I also de-edge, blend, and polish my feed ramps if the barrel extension hasn’t been tumble-polished.

Ejector gets radiused/chamfered to eliminate any chance of right side cartridge presentation binding, which is a thing with 7.62x39 or PPC-based cases in the AR-15.

Gas tube gets aligned properly with the carrier key to prevent binding or clipping.

 

[Bakwa]

For me the Bootleg adjustable carrier has become my go-to.

I used to be all in on the Superlative Arms adjustable GB's. That 16" rifle to the right of my 12.5" Grendel in the picture above was my go-to DMR comp rifle and it had a SA on it too. I've never had a SA seize up or carbon lock on me, but I have experienced that with other quality GB's, so it's always a thought in the back of my mind.

The adjustable carrier is just so much easier to adjust over any adjustable GB that I've used, and I can visually verify where it's at [which is a huge value in itself]. By just looking at it, I don't have to shoot and find out that I forgot to adjust it for how it's set up in that moment.
I'm all about low maintenance in general.

I used to have a number of rifles with SA gas blocks, now all of my gas blocks are pinned and all of my carriers are enhanced carriers of sorts [LMT, KAC, LWRC] or Bootleg adjustables.

Cheers

 

[chadwickz71]

Need some input here after calling around this is what I have being held for me untill I make a decision here by the day.

12.5” Kreiger I can build how I want it
Or
11.5” bartlein carbine+1 gas with tube included

Both are .750 gb size barrels

Most likely be a 11” handguard from v7 I think

This is my first Grendel what barrel would you go with.

 

[chadwickz71]

The 11.5” was a special run and oddball I guess, they had to order the gas tubes so people and use them.

 

[Cascade Hemi]

What gas length for the 12.5? If Carbine I'd go with the 11.5" +1. You didn't mention, what profile for each?

 

[chadwickz71]

I have the option on the 12.5" to go Carbine or Mid. Mark at PF recommended the Carbine but could do either. for now that choice is over my head.

LRRPF52 recommended MID i believe with his experience

 

[91Eunozs]

The JP bolt is a safe bet.

Be aware any firearms engraving with your NAME-CITY-STATE must be done by an FFL, according to the ATF.

I defer to your experience, but my understanding is that if you’re Form 1 SBRing the receiver, you’re now the manufacturer…engrave it with a Dremel, or hell, a hammer and chisel if you want. Just be sure to follow the ATF’s technical guidelines for placement, minimum font size, and depth to avoid any crap from LE if stopped…though technically only a treasury agent can ask for your SBR paperwork.

That said, I‘ve taken all of mine to Grey Laser engraving who is local(ish) to me down here near San Antonio. There’s likely someone near the OP in the DFW area as well, but I’m pretty sure he can accept FFL items via mail too.

—


edit: all of ours simply say:


Xxx Family Trust
City, State

…with actual name, city, state listed of course, LoL. The serial number, and the rest of the required markings are as delivered from the original manufacturer (various for our SBRs), and simply filled in on the various Form 1s when we submitted them.

More details re: engraving starting on page 6 (section 479.102): https://www.atf.gov/resource-center...n-guidebook-firearms-verificationpdf/download

 

[Cascade Hemi]

I have the option on the 12.5" to go Carbine or Mid. Mark at PF recommended the Carbine but could do either. for now that choice is over my head.

LRRPF52 recommended MID i believe with his experience

12.5 Mid

 

[91Eunozs]

Also, are you 100% sold on the 6.5 Grendel?

It’s a fantastic pig round for sure (though I went 6.8 for various reasons), but if I were starting fresh on an intermediate round for pigs, I’d seriously consider the 6 ARC, or the new 6 Max.

The latter is particularly appealing since it uses the same bolt as a standard .223/5.56 rifle, just like 300BLK.

 

[91Eunozs]

Re: Smoke Composite stocks, they’re gtg. I have a couple, and really like them for lightweight builds. Get whatever ‘fits’ the primary shooter…non-adjustable of course.

I prefer rifle-length for my ape-like appendages, and put one on my light(ish) weight AR10:

…but put a carbine length on my wife’s “matching“ AR15. I pre-paid for 2A Arms Xanthos, and the original Balios Lite receiver sets with specific (and matching) serial numbers…waited over a year for them to come up in the production cycle! LoL

I even put one of their rifle length stocks on my uberlight no tax stamp build (wanted to see how light I could go without resorting to a SBR build):

…3# 4.4 oz with an empty 10-rd aluminum GI mag:

…3# 9.1 oz with a loaded 10-rd mag +1 in the chamber (using True Velocity’s polymer-cased/steel based ammo):

I wouldn’t trust my life to it, especially for any sustained strings of fire, but if I had to carry a rifle on a 100-mile run or something, and then take a few shots at reasonably close range, it’s actually pretty cool. Feels like a toy gun.

Edit: Smoke Composite’s hand guards and pistol grips are gtg too…but there’s lighter stuff out there if weight reduction is your primary objective. Here’s one I built up for my daughter-in-law…still pretty light, but more focus on reliability and accuracy:

This one needed to have an adjustable butt stock though, so it has V7’s lightweight buffer tube and a SI Viper Mod stock. Would probably have picked the MFT Battlelink minimalist stock to save another 1/2 ounce or so over this one if I could have found it in stock back when I did this build; pretty much at the height of the Covid silliness.

 

[LRRPF52]

I have the option on the 12.5" to go Carbine or Mid. Mark at PF recommended the Carbine but could do either. for now that choice is over my head.

LRRPF52 recommended MID i believe with his experience.

I’ve been using CLGS with the 12” and shooting exclusively suppressed. I think the farther forward you go with the port, the better for a dedicated suppressed blaster.

Mine runs great because I use the Bootleg to limit how much gas flows into the expansion chamber in the BCG, and I’m using extra power action spring weight.

 

[LRRPF52]

Also, are you 100% sold on the 6.5 Grendel?

It’s a fantastic pig round for sure (though I went 6.8 for various reasons), but if I were starting fresh on an intermediate round for pigs, I’d seriously consider the 6 ARC, or the new 6 Max.

The latter is particularly appealing since it uses the same bolt as a standard .223/5.56 rifle, just like 300BLK.

Hornady’s 100gr ELD-VT 6.5 Grendel load, along with 105gr Blitzking and 107gr SMK loads perform like 6mm in the real world, only you can shoot 100-110gr faster from Grendel than 6mm AR or ARC, so the ballistics overlap/are indistinguishable from when I compared real-world 1000yd results to Hornady’s Doppler data for 6mm ARC.

None of the other alternate cartridges have 124 factory ammo options either ranging from 85gr to 140gr, so it’s kind of a moot point now anytime I look at the latest cartridge.

There’s a whole range of projectile weights that haven’t been explored yet in 6.5 Grendel as well, that will blow the socks off everyone when they see the numbers.