18 VS 22 Barrel Advice

[TwoStrokeTyrant]

I am planning a build using JP Enterprises upper, bolt, bcg, and of course, barrel. However I am torn between the 18 inch and 22 inch barrel lengths. I was initially gonna go 22 to get the most out of it but I am not convinced the added size/weight will really be worth the performance gains. It will primarily be a range/hunting gun within 500 yards but I would still like to have 1000 yard capability if I ever get the chance to take it out that far. So what would be the better choice?

PS: I am wanting consistent sub-moa capabilities out to 500 yards

[VASCAR2]

A Friend has an 18 inch barrel he was shooting at 950 yards and getting consistent hits in the Ft Campbell area of Kentucky. The main issue he encountered was not enough elevation on his scope. I put 20 MOA mounts on my 6.5 Grendel rifles because at my elevation above sea level my scopes max out around 800 yards. I have one Aadmount 30 MM mount and several Warne one piece 20 MOA mounts.

A Friend and I chronographed several loads with a Magnettospeed chronograph on 16, 18, 20 and 24 inch AR-15 6.5 Grendels.



Here is a list of the tested ammo by average velocity for each barrel length.

120 Grain HP BT PPU

16" 2392

18" 2455

20" 2480

24" 2559

110 grain FMJ PPU

16" 2510

18" 2570

20" 2614

24" 2683

123 grain A-Max Hornady

16" 2419

18" 2464

20" 2505

24" 2568

123 Grain SST Hornady

16" 2430

18" 2493

20" 2511

24" 2583

Hand Load 123 Grain Nosler CC, 31.0 grains CFE223, CCI 450

16" 2449

18" 2471

20" 2526

24" 2619

100 Grain FMJ Wolf

16" 2507

18" 2571

20" 2615

24" 2695

Hand Load 107 Grain SMK 28.5 IMR8208XBR, CCI 41 Hornady cases.

20" 2658

24" 2729

Here is the difference between the 18” barrel compared to the shorter 16” barrel which was slower with every load.

120 grain PPU HP BT

63 FPS difference

110 grain PPU FMJ

60 FPS difference

123 grain A-Max

45 FPS difference

123 grain SST

63 FPS difference

Hand load 123 grain Nosler CC

27 FPS difference

Wolf 100 grain FMJ Steel cased

64 FPS difference


Difference between 20” and 18” barrel 6.5 Grendel

120 grain PPU HP BT

25 FPS difference

110 grain PPU FMJ

44 FPS

123 grain A-Max

41 FPS difference

123 grain SST

18 FPS

Hand load 123 grain Nosler CC

55 FPS difference

Wolf 100 grain FMJ Steel Cased

44 FPS difference

[FLshooter]

I always get the heaviest,longest barrel that I can shoot for what I am using it for.

PS if you are wanting sub moa capabilities at 500 yrds,call Mark at precision.I am sure he will give you the same advice I gave you.And he will probably recommend a Krieger or Bartlein 24 inch heavy barrel.I have the Bartlein.It does sub moa at 600.

[Wethepeople]

Kind of an old thread but thought I'd share my thought process when making a decision to buy my JP barrel. My use is pretty much the same as the OP's.

Unless I have some messed up inputs in the ballistic calculator, should be close.

Used 123gr SST, G1 BC .510 with a hopeful 2450 fps intial velocity. Input a 90deg 5mph wind velocity at avg atmospheric conditions here at 4600 ft altitude. Shooting angle 0.

-403.05 " bullet drop at 1000 yds.
38.49 moa or 11.2 mils come up.
40" Wind drift or 3.84moa/1.12 mils
TOF 1.68 seconds.
1324 fps at 1000 yds.

Looks very doable from 18" barrel based on VASCAR2s post. So I bought the 18" barrel. Plenty of elevation, 17mils, on my optic. Someone could sanity check these estimates. No range time on my barrel yet to compare to actual DOPE.

This bullet starts exceeding velocity of my 18" WOA .223 Wylde barrel shooting 77gr OTM pills beginning at approximately 975 yards. That rifle is very consistent at 1000 yds under the same conditions. Requires 9 mils elevation dialed.

[LRRPF52]

If you're at 4600ft elevation, the 18" is more than plenty in my experience.

123gr SST isn't a .510 BC as stated, but was found to be more like .462 G1 region.

If you want to shoot more TGT shooting with it using a bullet that also doubles as a hunting bullet, you can also try the Sierra TMKs and TGKs, Berger hunting VLDs, or Hornady 123gr ELD-Ms.

[nuthead]

ive been using a 0.239 G7 bc for the 123gr amax.... its spot on out to 500m for all temps and air densities (I use a 0.8fps/ degree celcius for MV variation with 8208)

havent pushed it any further only because you cant really use it for hunting past 400m or so

[Harpoon1]

I?m rarely happy with a ?one size, do it all? gun. End up compromising on everything and inevitably wishing I hadn?t.

There?s ?hunting?, and then there?s ?hunting?. Riding a four-wheeler up to your blind and sitting there all day, is one thing. Throwing a gun over your shoulder and ?still? hunting up and down through the mountains for days on end is another. Just saying.......


18? is slightly better for hunting, the 22? is slightly better for the range. Hunting season is couple of months long, you can go to the range year round. What?s more important to you?

[Wethepeople]

Hey 52, do you have the actual G7 BC for the 123 SST? I can only find the published data as you pointed out. Thanks, Jeff.

[CJW]

Interesting post Vascar

[LRRPF52]

Hey 52, do you have the actual G7 BC for the 123 SST? I can only find the published data as you pointed out. Thanks, Jeff.

The main reason we would be using a G7 BC is for beyond 600yds, and I'm not sure the 123gr SST would be the bullet for beyond 600yd shooting unless that's all you have.

[Wethepeople]

Thanks. Yep, I know. Just looking to update my list of G7 BC's from a more reliable source than manufacturer published data. I use Litz's custom drag profile data from his second addition book or those added since then on AB library.. I couldn't find 123gr sst G7 data from AB but have found .232 as opposed to the .230 you show since I posted the question. Close enough for now.

My new rifle doesn't like the 123 sst so far, at least in the Hdy factory loads. So far, 120 gr. hpbt in the PPU blue box, 123 eld m Hdy and 130gr Berger in FGM loads are shooting best. I haven't been rolling my own loads yet as I only have 60 rounds thru the new pipe. Just getting some early velocity data for each of those factory loads this far. Will be working our LRP public range days this coming Thurs. and Sun., so should get some good trigger time and more baseline DOPE for those 3 bullets.

I'm really enjoying my Grendels soft shooting characteristics. Can only go 400m at home so looking forward to getting on the LRP range in a couple days. Lots of different bullets yet to be tried.