DPMS LR in 21 inch barrel?

[fmsniper]

I put my 20 inch POF for sale its a great gun, but it shoots as good as may DPMS 24 inch, so I figure I can use the money for a SCAR17 in the future, anyway, so 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?

my 24 inch

[98Z5V]

I like it!  <thumbsup>

[imschur]

fantastic

[survivalshop]

I don't see anything in the photo !  <laughs>

Nice rifle & can't wait to hear how a 21 " bbl. shoots.

[fmsniper]

Hoping it does well, I haven't seen one in21 inch  so I figured I would try it, seem s like an all around good hunting length

[Jgun]

fmsniper,

Maybe I'm confused, You say that you already have the 24" pictured and plan to use the lower and bolt carrier from that one, Correct? I've also had multiple uppers that I use by sharing one lower, but I go with dedicated bolt carrier groups so all I have to do is pop the pins and install the upper. You can even have dedicated optics,  But do I understand you correctly that you will have a setup that will require you to switch bolts in your shared carrier in order to go back and forth with your lower and carrier?

[survivalshop]

The reason I'm interested is how that length bbl. will perform.

There are reasons bbls. are kept at certain lengths , but its not writen in stone .

[fmsniper]

Yep I know 18, 20 24, but why not 22 or 21, normal hunting rifles are 22 inch, any how It will be done  <thumbsup>

barrel should be here today then I will get the Lathe later today or Tuesday, when I cut it I will put a recessed 11degree crown on it as well

Jgun; I do plan to use the lower and bolt carrier from my 24 inch I also use dedicated bolts as they can conform to the barrel trunnion of each individual barrel so it its not wise to keep transferring them, but why spend the extra $$$ for a carrier and parts when they can easily be changed, as you only shoot one gun at a time?

and each of my guns have their own optics, my 24 inch has a Burris XTR on it now and the 21 inch will us a 2.5 X 10 Vortex Viper

[survivalshop]

M14/M1A have a 22" bbl. .STD.

Like I said ,nothing written in stone , but it will have some thing to do with performance & accuracy.

Is the twist of the BBL. 1-10 ? We are talking about a .30 cal bbl. ?

[fmsniper]

Roger, 1-10, 308, stainless Heavy Barrel, I carried the M21 in 22 inch barrel last tour in Iraq, did very well, well bottom line is if it does not perform I slap it back on the lathe and pop off 1 more inch down to 20.

[survivalshop]

Ya , most don't have a lathe or the expertise to do that , nice to have that option .

I will be waiting for a range report, for sure .

[fmsniper]

where I am stationed is a machine shop near by my office I use it and the Bridgeport often, to make muzzle brakes and face receivers, as well as cut new threads on barrel I am working on, so yep it is nice to have the toys available:  wife wants me to take a NATO assignment to Northwoods that Branch is offering us  next  but I really am not interested in going to a country I cant bring my guns.

[fmsniper]

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

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

[fmsniper]

just got back from the lathe, barrel is cut 21 inch 11 Degree crown, will mount it tonight and shoot it tomorrow

picked up 168 grain American Eagle Factory OTM for testing

top is the 24 inch

bottom 21 inch

11 degree crown

[98Z5V]

where I am stationed is a machine shop near by my office I use it and the Bridgeport often, to make muzzle brakes and face receivers, as well as cut new threads on barrel I am working on, so yep it is nice to have the toys available:

I miss that, more than just about anything - I had two phenomenal guys back at Ft Lewis.  They could work wonders, make anything, modify anything.  I hung out in there as much as possible.  They were magicians.  They'd let me take anything in there, and it didn't matter what it was - they could make it better. 

picked up 168 grain American Eagle Factory OTM for testing

That ammo has worked very, very well for me.  <thumbsup>

[fmsniper]

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

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

[survivalshop]

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

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

Do you have something against 20" or this all experimentation ?

I assume this is shot @ 100 yrds., why not try this length out farther , 200,300 yrds. , after you break it in of course.

I'm curious , ya got my attention, but I believe this has all been done before or documented some where .

What is your goal , more accurate , lighter ?

[fmsniper]

I already have a 26, 24, 20 and 18,  in 308 just wanted something different, will shoot 400 yards this weekend, no goal, just having fun, and may use it for hunting this year, if I sell my 20 inch POF

I sold my 26 it was too long, and sold the 18, too short

I have kept the 24" DPMS  and the 20" POF, I think I may be on to a good barrel length for a hunting rifle in SEMI, but that's just me

[survivalshop]

18 " too short ,why ?  For hunting you would think a lighter shorter bbl. would be the ticket .

Unless real long range would be the goal.

Interested in the out come of range session @ 400 yrds.

[fmsniper]

my shots here are out to 725 meters

[Jgun]

I have a question for you regarding the 21" vs the 24". I see that the 24" has a muzzle brake. None of my AR's are crowned barrels without any muzzle device. Since both of your uppers are very similar other than the 3" difference and the brake on the 24, I was wondering if you could give me your subjective opinion on how much difference it makes having a brake vs a bare barrel? does the recoil of the unbraked one feel a great deal heavier than the 24"?

[fmsniper]

not a great deal no but enough to get me back on target faster, I would say it makes a 3006 feel like a 308, thats the best way I can explain it

Hope this helps

[survivalshop]

All barrels are crowned in some way ,threaded or not. Look closer next time you have your muzzle device off .

His bbl. is crowned all the way out to the full bbl. dia.. Most are just crowned at the bore opening.

[Jgun]

I'm aware that all barrels are crowned (or should be). I guess I didn't word my post clearly. What I was trying to state was that I didn't have an AR with just a finished unthreaded barrel without some sort of muzzle device. Since both of his uppers appeared to be almost identical, with the exception of the 3" extra length and the brake on the 24" I thought he'd be able to give me some good feedback on just how significant the effect of the comp was.  This may be more a matter of my not being very perceptive when it comes to the effects of different brakes, but I often have a hard time telling if one is clearly more effective than another. I just picked up a comp (threaded for a .223) that I want to test on my 300 as soon as I bore it out for .30 cal and rethread it 5/8-24".  This seems to be an area where  there doesn't seem to be a great deal of scientific documentation to back up the claims that the mfgs make. Every one says that theirs is the most effective.

[fmsniper]

heading out to the 1000 Yrd range tomorrow if it does not rain