16" Vs 18" barrel, can't decide...

[LRRPF52]

I've had 2 different 16" Grendels, currently have one, and I'm losing track of the 18" guns replicating with barrels from various sources.

My first Grendel I built using one of the older ER Shaw Alexander Arms barrels ordered from Midway in 2009, when you had to be on an email notification just to have a chance.

Anyway, I've chrono'd a lot of different Grendels since then.

What I've seen is that the 16" and 18" numbers often overlap, or are within 18-40fps of each other thereabouts.

Here are some examples:

17.6" Lilja 318 barrel:
123gr Hornady SST factory 30JUN2015
2441
2467
2477
2489
2481

120gr Scenar-L Precision Firearms Load
2505
2504
2532
2518
2498

123gr AMAX, 31.2gr CFE 64˚ F, 17MAY2016
2507
2492
2477
2496
2477
AVG: 2490fps

17.6" Lilja 318
120gr Federal OTM 11MAR2017
2485 (5 shot average)
2454 (5 shot avg)
2487 (5 shot avg)
2510 (5 shot avg)
2484 (20 shot avg)

18.5" Lilja barrel:
123gr Hornady SST factory 30JUN2015
2468
2441
2421
2495
2453

16" AA/Shaw barrel:
123gr Lapua Scenar (Moly) Precision Firearms factory 03APR2012
2447
2451
2454
2450

123gr Lapua Scenar (Moly) PF load, hot day
2522
2484
2582
2518
2503
AVG: 2522fps


123gr Hornady A-MAX factory 25MAY2013
2365
2470
2422
2470
2460

These were all shot over the same Beta Chrony 15ft from the muzzle. A common thing I've noticed is that everybody that ends up building an 11.5-12.5" Grendel that also owns 16" and 18" Grendels shoots the short barrels more often.

I think I might be leaning in the direction of having the 12" for a utilitarian blaster/HD/plinker/800yd LR, 18" for hunting in the mountains, and 22" for most of what I used to use .260 Rem for.

12" will be set up as a 21st Century PDW/LR blaster, suppressed.