Pew pew: 1st post, 6.5g barrel question

[gedeon]

I have run the numbers and it appears either a 14.5" (pinned FS) or 16" grendel, either threaded for a TU7, is my next build to fill the out to 1k duty.

Looking at the numbers and how they would work with my reticle and the probable distribution of shooting distances for this upper, this is what I came up with:

14.5" 123 Scenar, 300 yard zero

D MV E T MOA MILS
100' 2266 1403 6.1 -5.9 -1.7
300' 1967 1056 0 0 0
500' 1694 783 -42.3 8.1 2.4
675' 1481 599 -119 16.8 4.9
800' 1346 495 -202.8 24.2 7
950' 1210 400 -343.5 34.5 10

This would leave me supersonic with 9mm energy at 1,000 yards and far more energy/flatter trajectory than the 5.56/7.62 on the way there.

I started shopping for a 16" barrel to enjoy it sooner rather than later and I was ready to pull the trigger on a BSF with the Opticsplanet 10% discount, but the 16" is not available through them. It looks like the wait times for all BSF barrel lengths is a while, so I am back to square 1 and all options are on the table in consideration of having to wait unless I drop barrel quality.

It does not look like PR does a 16" 6.5G, so there's that option crossed off. So, if I was going to order a SS 6.5G barrel from someone, what would you buy if I was to have it cut down to 14.5" and the FS pinned on it out to cross 16"? Or, would you custom order a 14.5" and send them the TBAC FS? If the latter, who would you buy the barrel from? I like to try and do things right once rather than 80% three times, so fit and finish as well as style points like fluting/dimpling (pitts) are factors.

The rest of the build looks like this:

Swaro Z8i 2-16x50
KAC SR-30 complete lower
Radian Weapons Complete Upper w/14" Handguard
KAC/LMT Enhanced BCG
JP Adjustable GB
KAC 45 degree offset w/Holosun 503GU or Aimpoint T2

Comments and critiques are welcome.

This lower is going to be NFA-stamped to be swapable with a KAC SR-30 9.5" or a tbd .458 SOCOM upper also.

 

[TexLuke]

I bought a 16” Grendel barrel from Craddock Precision. They’d make you one 14.5” also if you want.
It’s a criterion blank, SS, mid length, I sent my bolt in so they could verify headspace when chambering it.

It took about a month to make. Still in the safe as I haven’t had time to put this upper together, much less to shoot it.

 

[Greg Langelius *]

Midway/AR Stoner. I know the price point looks ridiculously low, but my Buddy and I have been cautiously trying them out (16" lightweight 1:7" Wylde/me, 24' 1:8" stainless bull Wylde/ him), and their barrels shoot.

18", 20", and 24" ship tomorrow. For 1000yd, I'd suggest the 24" one. Maybe some of this stuff could make your job simpler and quicker, my lightweight 16" Wylde came in as part of the nearly identical upper shown here.

Greg

 

[Lonestar1027]

Why use a 300 yard zero outside of a hunting application?

 

[gedeon]

Thanks to the replies.

The reason I am looking at a 300 yard zero is because of how the 123 scenar, 14.5" 6.5 grendel distances fit into my MIL reticles (k16i sm1/z8i 2.-16 skmr3). I am looking for this to be a swiss army knife setup and will build a 6.5 creedmoor bolt for dedicated long range out past 800y.

0, 2.5 mils, 5 mils and 10 mils are quick adjustments to make on the reticle without touching the turrets. The bullet apexes on the 300y zero around 150 yards at a maximum of <8", so that is within acceptable parameters for a swiss army setup.

Here is what the 100 yard zero chart looks like:

D MV E T MOA MILS
100 2338 1493 0 0 0
300 2034 1129 -17.1 5.4 1.6
400 1890 976 -37.7 9 2.6
500 1754 840 -68 13 3.8
600 1625 721 -109.7 17.5 5.1
900 1294 457 -323 34.3 10

14.5" 123 Scenar, 300 yard zero

D MV E T MOA MILS
100' 2266 1403 6.1 -5.9 -1.7
300' 1967 1056 0 0 0
500' 1694 783 -42.3 8.1 2.4
675' 1481 599 -119 16.8 4.9
800' 1346 495 -202.8 24.2 7
950' 1210 400 -343.5 34.5 10

 

[gedeon]

This will have hunting duty in long wide open spaces over 1 mile altitude.

 

[b6graham]

you don't even have a MV yet. that scope isnt a BDC. it's set up the way it is on purpose. Not to be a dick, but i think you're a long ways away from ethically taking game at 500, 675, or 950 yards with a 6.5 Grendel if you're asking these questions

 

[gedeon]

See attached for muzzle velocity.

14.5" 6.5 grendel = 2405
+ TBAC U7 = +20fps
2425 MV

Ordinary use will range from 4000 - 8000' elevation, so my FPS will be better and the data will be better than I got out of the hornady ballistics calculator.

From my original post:

"Looking at the numbers and how they would work with my reticle and the probable distribution of shooting distances for this upper "

Where have I mentioned taking game at 1,000 yards with this upper?

What I have said is that this will be a swiss army knife build. This could be used for anything from coyotes to WOLVES or deer and pronghorn, if you must have more details. Similarly, I would like to have the capability to shoot out to 1,000 yards supersonic with 9mm type energy at that distance.

Do you have a barrel recommendation?

re: reticle, swaro offers the BRX-i.

For ordinary use, the z8i BRX-i is the optic it will have on it. If it was HD, it will have a K624i SKMR3. The weight savings is significant.

 

[gedeon]

At 5280 elevation the energy is .45acp level

D MV E T MOA MILS
100 2294 1437 5.9 -5.6 -1.6
150 2230 1359 7.2 -4.6 -1.3
300 2045 1142 0 0 0
400 1926 1014 -14.9 3.6 1
525 1785 870 -47 8.5 2.5
700 1600 699 -121.2 16.5 4.8
1000 1326 480 -351.2 33.5 9.8

 

[b6graham]

And I'll bet you go to the reloading depot and you find 100fps spreads

And there will very likely he a big difference in drops at 4k and 8k elevation

Picking a zero based on drop data for a gun that isn't yours isn't logical. Using a 300y zero isn't super logical either especially using any new FFP scope

 

[hoop12]

I’ve got an 18” Barrel on my grendel from AR Performance. Tack driver. I know it’s longer than what you’d like, but you might check their website out. It’s down from time to time, as it’s basically a one or two man show for the most part, but I absolutely love my barrel from them. You might go check out the Grendel forum. 65grendel.com

 

[gedeon]

@b6graham

You have to start somewhere, right? Adjusting my zero is the easiest adjustment to make. Maybe I will decide on a 222.2 yard zero when I get my swiss army knife assembled. Thanks for your concerns though.

@hoop12

I have lurked 65grendel for a while also. The 12.5" /12" faxon is the fashion there. I am going to do some additional homework this week and will report back when I have made decisions and have a functional piece of hardware.

Thanks to everyone who took the time to read and reply!

 

[hoop12]

@gedeon , I’m on there as well, I know the 12, 12.5 and 12.7s get a lot of love over there, but recently there were a few threads on the possibility of 13-14.5” group buys and people experimenting with the 14.5”, didn’t know if you saw them!

 

[gedeon]

@gedeon , I’m on there as well, I know the 12, 12.5 and 12.7s get a lot of love over there, but recently there were a few threads on the possibility of 13-14.5” group buys and people experimenting with the 14.5”, didn’t know if you saw them!

Thank you for the heads up on that. I will check that out as I have not.

I was originally going to build this lower as a pistol with a KAC sr-30 9.5" .300blk and do a 12" build, but the lower transferred in as a rifle and so my plans had to change. I'm going to stamp it, but starting out with all options available I think the 14.5" would be perfect with a pinned FS. If I didn't want to suppress it, I would have already ordered a 16" barrel and moved on with life. Since I want to suppress it and I have to custom order a barrel, I am investing more time into the build specs as I do not have a 14.5" 5.56 and this would all but eliminate my interest in that rifle setup. The 6.5G is not the right tool for moose, grizzly or very long range, so I do not have an interest in a barrel beyond 16". I have a 7mm RUM for those tasks, but I am interested in a 6.5CM for long range target shooting.

 

[White Mamba]

My 14.5 ran 2450fps when new with the 123amax, its a hunting machine.
I run with a 100yrd zero but while on the move I just set the turrent to .5 mil for a approx. 50/200yrd zero in case something happens fast.

 

[gedeon]

What elevation are you at, if you don't mind me asking? What barrel and what kind of MOA did you see out of the box? I assume it is not as accurate as it started by your wording, so when did you start to notice the shots widen? How does it handle 1 second breaks between a run of 10-15 rounds?

Your experience is one confirmation of what the calculators have been telling me and I don't think I need the terminal benefits that additional inches would provide. At the same time, shorter I think I give up accuracy and practical FPS/E. I spoke to Zak at TBAC recently and the Ultra5 is not going to do anything meaningful for me on the 6.5G. With a 14.5" barrel, I do not have NFA requirement to use on another lower and I'm at ~20" suppressed or unsuppressed, scary loud and very manageable.

The ~7" apex @150y on the 300y zero is acceptable in the context of a SD scenario where the target would be center mass and anything shorter or longer would be accurate; beyond that it is arguably not going to be a self defense scenario. In a pinch/SHTF scenario, the mental note over 300 would be just to aim for head or hat instead of center mass. Past 500 and there is conceivably time to take range and consult dope card.

Swiss army knife/Multi-tool

 

[White Mamba]

What elevation are you at, if you don't mind me asking? What barrel and what kind of MOA did you see out of the box? I assume it is not as accurate as it started by your wording, so when did you start to notice the shots widen? How does it handle 1 second breaks between a run of 10-15 rounds?

Your experience is one confirmation of what the calculators have been telling me and I don't think I need the terminal benefits that additional inches would provide. At the same time, shorter I think I give up accuracy and practical FPS/E. I spoke to Zak at TBAC recently and the Ultra5 is not going to do anything meaningful for me on the 6.5G. With a 14.5" barrel, I do not have NFA requirement to use on another lower and I'm at ~20" suppressed or unsuppressed, scary loud and very manageable.

The ~7" apex @150y on the 300y zero is acceptable in the context of a SD scenario where the target would be center mass and anything shorter or longer would be accurate; beyond that it is arguably not going to be a self defense scenario. In a pinch/SHTF scenario, the mental note over 300 would be just to aim for head or hat instead of center mass. Past 500 and there is conceivably time to take range and consult dope card.

Swiss army knife/Multi-tool

I am at sea leavel. 28.5 gr 8208 and 123 amax for a handload or Hornady factory amax . The upper is a old Sabre defense mid length which are rare to find. Carbine gas length will cost you speed. When it was new It would frequently shoot 3 round bughole groups and was one of the most accurate ar15s I ever shot. Under 1/2 moa was the norm for 3-4 round groups. Ive never shot a string of 10-15 rounds through it withoutt a break.
It probably started to slow down velocity wise after 4k rounds I would guess, never kept a log on it. I need to bump up the charge weight , buy new brass and retest it. It was rode hard as a hunting rifle - rain, creeks, falls , dirt and blood were the norm. I still have it but have switched the Fix rifle for hunting now

 

[LRRPF52]

I would recommend Precision Firearms if you want a 14.5" made. Go with a Criterion or Bartlein. I do a lot of altitude shifting as well where I'm at, with baseline being 4400ft, other areas 6600ft, with hunting up past 9000ft. For those reasons, I use 100yd zero, otherwise you'll be all over the place with a 300yd zero.

Precision Firearms 6.5 Grendel Criterion Barrel

I'm using the TBAC Ultra 5 on my 12" Faxon group buy barrel build. I went with a 30 cal Ultra 7 because these are extremely effective cans at suppressing, so shooter's ear noise is actually louder with a 6.5mm can because of supersonic venting through the carrier.

The Ultra 5 is a great can on Grendel AR15s, super pleasant at shooter's ear even on the 12" pistol.