18" or 16" on M5 Build Pro's Con's input?

[rockchalk06]

Looking for recommendations on barrel length for my M5 build.

This will be .308 with a 15" rail. The plan is run a 1-10 power optic with an RMR on an offset mount. Break with be YHM to run my can on it.

Barrel will most likely be from Aero and I'm looking hard at the stainless fluted.

I don't see myself pushing this past 500 meters anytime. Realistically 300ish is what I'm thinking. I have a 20" bolt gun for distance.

How much will the extra 2" matter in terms of accuracy? 1-10 twist and will probably run 175 or 168 grain bullets. Never run anything shorter than a 20" with .308 in my life.

Thanks in advance OSA

 

[undeg01]

You do not need to worry about a loss of accuracy with a shorter barrel 308. If built right, the only thing you will lose with a shorter barrel is some velocity. At the ranges you are talking about, the loss of velocity will be negligible. If you start pushing your range out to 800 yds, and especially 1000 yds, you will find that you will not have enough barrel to get the amount of burn you need to get the velocity for those ranges.

I’ve got a DPMS Gen2 in 308 with a 16” barrel and a Remington 700 PSS 308 that I cut down to 16”. Using 168 gr FGMM ammo, I would put either of rifles up against any 18 - 26” rifle at 300 - 500 yds.

 

[JEVapa]

What's its purpose? A cbt carbine role? - 16" 25m-500m all day. Or an intermediate range/recce rifle? - 16"or 18" 25m-7-800m all day.

Make a carbine light...less rail length IMO - 12"-13.5" 1-8x/1-10x DVO
Recce - longer rail for NVDs; bipod; 2.5-10x/4-12x DVO

Either length, run a midlength gas. Either will run 175 SMK (GMM; 118LR; AB39) just fine. If you can get a 1-8 twist (there are a few out there), it's even better.
BTW, we regularly engage steel-people out to 1000m-1200m with 18" 308 gas guns out west. But most are out to 500m-1000m.

 

[swampratt]

I ran a 24" savage heavy barrel and then cut it to 20.5 and the accuracy node widened.
And way less finicky if the temps changed.
Was my 2nd most accurate rifle.

Some guy I let shoot it at the range just had to have it.
I sold it to him and bought another Savage heavy barrel but in 18" and it is even better.
I will not sell this one.

 

[rockchalk06]

You do not need to worry about a loss of accuracy with a shorter barrel 308. If built right, the only thing you will lose with a shorter barrel is some velocity. At the ranges you are talking about, the loss of velocity will be negligible. If you start pushing your range out to 800 yds, and especially 1000 yds, you will find that you will not have enough barrel to get the amount of burn you need to get the velocity for those ranges.

I’ve got a DPMS Gen2 in 308 with a 16” barrel and a Remington 700 PSS 308 that I cut down to 16”. Using 168 gr FGMM ammo, I would put either of rifles up against any 18 - 26” rifle at 300 - 500 yds.

Thank you for that first hand. That's exactly what I was hoping for.

 

[rockchalk06]

I ran a 24" savage heavy barrel and then cut it to 20.5 and the accuracy node widened.
And way less finicky if the temps changed.
Was my 2nd most accurate rifle.

Some guy I let shoot it at the range just had to have it.
I sold it to him and bought another Savage heavy barrel but in 18" and it is even better.
I will not sell this one.

I replaced a Savage 24" 308 with my Bergara in 20" and noticed my nodes were much wider. Granted, higher end barrel etc, but running everything over my Chrono told me it was a good decision.

 

[swampratt]

I fought with my 24" barrel for 2 years before a friends words finally sank in .
CUT THAT BARREL DOWN!
I have been hooked on short barrels after that

 

[Bocephus123]

Built my old buddy from childhood an AR 10 16" .308 hope he likes it . gave it to him yesterday. just ran into each other a while back. my 16" is great for no farther than i shoot.

 

[rockchalk06]

Last second, I ended up going 18". I appreciate everyone's input. I got a really good deal on this one.