why not 21 inch 308 DPMS for hunting

fmsniper

1st Sergeant
Full Member
Minuteman
I decided to build a DPMS LR 21inch barrel by taking a 24 inch stainless HB and cut it down to 21 inch then re-crown it, I already own a 24 inch DPMS LR, so I will use the same lower and bolt carrier but a new bolt, I already have all of the parts and just ordered the barrel, should be interesting having a 21 inch barrel. primary purpose is hunting rig while walking, deer hunting out to 600 yards. My 24 inch has taken deer out to 725 yards so I figure this 21 inch should be fine?
I got the barrel in today will hit the lathe in the morning;
here is the upper its painted the same as my other, this one was in .243 I sold the barrel

DSCN4976.jpg

this photo shows where the 3inches is going to be cut
DSCN4977.jpg


Thoughts?
I am thinking recessed 11 Degree crown?

 
Re: why not 21 inch 308 DPMS for hunting

Fmsniper,

What is your purpose in wanting a 21" barrel? weight savings? having a handier rifle?

If your intention is to save weight, I hope u realize that you will not save a noticeable amount of weight by shaving off 3 inches of the barrel. i'm talking like 4-6 ounces...

If your goal is to lighten up the rifle, you should get the barrel reprofiled to about a .750 profile. You will save about 1.5lbs to 2lbs off the weight of the rifle.

If however, your goal is to just make the rifle more manageable, a 21" barrel is handier a 24inch barrel, but not by much...you should really make it handy by opting for a shorter barrel length...say 18inches.

Just my $0.02 cents.
 
Re: why not 21 inch 308 DPMS for hunting

Mine started out a 24 and quickly cut it back to a 20. Its a personal preference for me. The 24 felt front heavy and it now feels more balanced. It is still a 14lb rifle!!!
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Re: why not 21 inch 308 DPMS for hunting

had 18 inch felt short, currently own a POF 20 inch always wanted to try 21 inch would be little more manageable in and around brush, and slight velocity increase, not by much but some, besides if the 21 inch does not shoot, then I can can always cut it down to 20, 19, 18.

and gives me something to do on the Lathe
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and I like doing things others are not..have not seen a 21 inch yet, I am sure they are out there but would be fun to try, and I own a 24 inch 308 DPMS still
 
Re: why not 21 inch 308 DPMS for hunting

I have used 308 AR rifles with 18", 20" and 24" barrels. I liked the 20" the best. I liked the thinner profile. I felt the barrel contour of my DPMS SASS was too thick. The barrel was too short to get the velocities I wanted. My 18" DPMS was still 20" long. I would have prefered to dump the 2" flash hider in lew of 2" more barrel. It seemed to work fine on the MK11 Mod 0, I used in Afghanistan. I think the short barrels and mid length gas systems don't exploit the full benefits of the 7.62 cartridge. The 24 inch AR10T I used for a while was very unweldy getting in and out of vehicles, but performed well out on the range. I think your 21" barrel should work out well. I would be curious to see the velocities before you cut the barrel and after.
 
Re: why not 21 inch 308 DPMS for hunting

Greetings from Florida everyone.. I am new to this site (joined 20 min ago)..

I am curious to hear about your experience with your 24" DPMS. as well as feelings on having a flash hider. I bought a somewhat complete lower (minus the buttstock) at the gun show 2 days ago and today just ordered ((DPMS 24" A3 Stainless, Free Float, Fluted, Threaded Barrel Upper with Forward Assist, Dust Cover and Smiths Vortex FH)).
Thanks
 
Re: why not 21 inch 308 DPMS for hunting

Doc, my 24 inch is a very accurate rifle, I have a brake on it, ( No reason ) just put one on, the rifle shoots .25 to .5 MOA with 168 Grain Hand Loads from a bench, I am actually getting om average .5 to .75 with American Eagle 168 OTM Factory ammo, great barrels for the price, only thing I do is true the upper and a good trigger. Now I shoot for a living in the Army but the rifle has allot to do with it.
 
Re: why not 21 inch 308 DPMS for hunting

I have a 20" Krieger "AR10"- .820" to the gas block and .750" to the muzzle. It balances well, is easy to maneuver, and I still get 2600 fps from a 175 grain sierra. It shoots .5" or better groups.

I think 20" is about the perfect length in this application, and would work great for hunting. I've hunted with a 26" bull barrel rifle, and it sucks. My old FAL had a 21" barrel and a 3" flash hider, which made it too long. You might even consider 19" if you will run a flash hider or brake.
 
Re: why not 21 inch 308 DPMS for hunting

Thanks for the feedback.. Damn. 26" BBL must have been HEAVY. I will have to upload my pics as this come together. I should have the upper this monday. Still need to find a nice buttstock.. not opposed to a used one if anyone is looking to sell and upgrade
 
Re: why not 21 inch 308 DPMS for hunting

As far as going to 21in from 24, I think you'll be happy. I just got a 21in N6, but I keep looking at it and thinking about cutting it down to 18. I think you did right by trying 21 first. You can always cut some more off, but once it's cut, you can't add it back.
 
Re: why not 21 inch 308 DPMS for hunting

I just picked up a Bushmaster 308 orc with 16" barrel. I plan on using this gun strictly for deer and hogs. First Black rifle for me and the fact that it was threaded 5/8x24 was the nail in the coffin. I was wanting a short rifle to use suppressed. Even with a 24oz can on it is still balanced well and maneuverable. Still have yet to take it to the range.
 
Re: why not 21 inch 308 DPMS for hunting

well 1st 15 rounds down the new barrel 1 and clean for the first 10, then this 5 shot group with American Eagle 168 OTM factory ammo, bottom shot was a called pull on my part.

center to Center .763, I am sure it will get better as the barrel brakes in

DSCN5275.jpg

So over all not to bad; room for improvement, will leave it for a few and see if it tightens up, if not, will go to 19 inch
 
Re: why not 21 inch 308 DPMS for hunting

I've had a couple rifles cut down to 21", but they were both bolt guns. Shot great and handled much better; balance was good, especially on a bipod.
 
Re: why not 21 inch 308 DPMS for hunting

I expect .5 MOA out of my 308's I will work with that
when I build a AR I true the receiver, polish feed ramps, check lug contact, and I use a 4 jaw chuck on the lathe and zero of of the bore not the out side of the barrel when I cut the crown ensuring accuracy. So I expect it to shoot.

I may pull it apart and bed the barrel extension, that I did not do this time?