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+--- Thread: Last Chance Sanity Check - Barrel Length (/showthread.php?tid=14349)
Last Chance Sanity Check - Barrel Length - Capt. Morgan - 10-20-2017
I have a Terminus I bolt action rifle on order with Precision Firearms, and received an email from them. My order is "up" and they wanted me to confirm the barrel length of 16" before they cut it. Either my order is somewhat unusual, or they are subtly saying "are you really sure you want to do this?"
My initial thinking was guided by numerous posts saying in effect, the Grendel doesn't give up much in the shorter barrel lengths.
Additionally, the rifle will pretty much always going to be using my TBAC 6.5 Ultra 7 suppressor. Overall handling length would then be 23".
This is pretty much a range/target rifle, under 400 yards.
Also, I am starting reloading, and would like to work up a sub-sonic load, if possible.
This is my second Grendel, the first being an AR with 16" barrel. I like that overall length and handling.
So - what say the Horde? Stick with 16" or Go Long and Prosper?
Last Chance Sanity Check - Barrel Length - BluntForceTrauma - 10-20-2017
I'd fire up a ballistics program like the JBM Ballistics Calculator and enter in my load with velocity at 16" and then add 100fps for the same load from a 20". Then examine wind drift and drop and see if they are different enough to matter to you.
If, say, your wind drift is 1/2" difference at 400 yards then maybe it doesn't matter? My general principle would be to go as short as possible and still meet your ballistic requirements.
But, yeah, PF is correct to ask that question for a bolt action, since it is unusual.
U P D A T E : Did the calculations for a 123 SMK (Litz) using velocities of 2450fps for a 16" and 2550fps for a 20", zeroed 200yds, wind speed 10mph.
200 YDS
Velocity difference = 92.3 fps
Wind drift difference = 0.2 in
Drop difference = 0 (200-yard zero)
400 YDS
Velocity difference = 85.3 fps
Wind drift difference = 0.8 in
Drop difference = 2.5 in
Last Chance Sanity Check - Barrel Length - Kilco - 10-20-2017
16" is my favorite in an AR without a doubt.
For a bolt gun? A custom bolt gun?..... hmmm if I was not running suppressed than I'd go 24", if suppressed 20" 18" minimum.
That's just me though. For 400 yard and under you wouldn't be handdycapped by a 16" at all.
Last Chance Sanity Check - Barrel Length - Troutguide - 10-21-2017
BluntForceTrauma Wrote:I'd fire up a ballistics program like the JBM Ballistics Calculator and enter in my load with velocity at 16" and then add 100fps for the same load from a 20". Then examine wind drift and drop and see if they are different enough to matter to you.
If, say, your wind drift is 1/2" difference at 400 yards then maybe it doesn't matter? My general principle would be to go as short as possible and still meet your ballistic requirements.
But, yeah, PF is correct to ask that question for a bolt action, since it is unusual.
U P D A T E : Did the calculations for a 123 SMK (Litz) using velocities of 2450fps for a 16" and 2550fps for a 20", zeroed 200yds, wind speed 10mph.
200 YDS
Velocity difference = 92.3 fps
Wind drift difference = 0.2 in
Drop difference = 0 (200-yard zero)
400 YDS
Velocity difference = 85.3 fps
Wind drift difference = 0.8 in
Drop difference = 2.5 in
I have a 20" Howa Mini and a 12" AR I don't think I would feel handicapped with a 16" especially with a 7" can. Now would I pay for a custom barrel and possibly limit myself probably not, I'd just buy a howa and have it chopped. But if the numbers are correct .08" at 400 yds isn't much and it would be much more handy to have 23" vs +27". I bet if it shoots as good as I think it will, you will never think twice once you shoot it a few times.
Last Chance Sanity Check - Barrel Length - howl - 10-21-2017
I'd go long and have it cut later if I didn't like it.
Last Chance Sanity Check - Barrel Length - Sticks - 10-21-2017
howl Wrote:I'd go long and have it cut later if I didn't like it.
+1
Last Chance Sanity Check - Barrel Length - LRRPF52 - 10-21-2017
You can get 20" AR velocities from a 16" bolt gun easily hand-loading.
Since it will be suppressed with an Ultra 7, I think your approach is sound, because you value handling and stated that 400yds and in are where most of your shooting will be done.
400yds even with a 10.5" AR15 Grendel is boring. It's extremely boring for me personally with a 16" Grendel, even shooting 2 MOA plates.
Last Chance Sanity Check - Barrel Length - Capt. Morgan - 10-23-2017
Thanks guys! Mulled it over the weekend and I'll stick with the original thinking - 16" + 7" can.
Last Chance Sanity Check - Barrel Length - BluntForceTrauma - 10-23-2017
I think you'll be glad you did. Sounds like the right decision for your parameters.
Last Chance Sanity Check - Barrel Length - Troutguide - 10-23-2017
Yes good call. I think we will start seeing more people go this route as they see the capability of the Grendel from shorter barrels.
Edit: ha ha thanks for catching that Sticks!
Last Chance Sanity Check - Barrel Length - Sticks - 10-24-2017
Troutguide Wrote:Yes good call. I think we will start seeing more people go this route as they see the capability of the Grendel from shorter barrels.Grammer Nazi, but...HOW DARE YOU!?!
Last Chance Sanity Check - Barrel Length - BluntForceTrauma - 10-25-2017
Sticks Wrote:Grammer Nazi, but...HOW DARE YOU!?!
Spelling Nazi: Grammer = Grammar. Bwhahahaha!
Last Chance Sanity Check - Barrel Length - Sticks - 10-25-2017
I just got tagged. Is my nose bleeding?
Last Chance Sanity Check - Barrel Length - js8588 - 10-25-2017
Now, now...neither one of you are Nazis. You're just AltWrite
Last Chance Sanity Check - Barrel Length - murfvol - 11-01-2017
Well done js8588.