My .260 Build

[gdcpony]

Here is a thread the I will track a build I have been dreaming of for a few years now. I will only update when something changes or to reply to you guys. Hope you enjoy as it may take a bit for all the parts to come in.

First is the starting point. I bought the upper rifle a couple years ago just for this build. figured I could shoot it while waiting to do this. At the time it seemed we might lose them (yeah I got a little panic and bought the last on the shelves the day after the shooting before prices went up)

Now, I can finally start the build! I deliberated quite a bit over the caliber as you can see here:
.260 or .257 - THR

Finally the .260Remington won the rights to be fired out of what I hope will become a master piece of a build. I have the following ordered:

Barrel- .260 Rem caliber 24" length
A 24" standard profile from BHW threaded with no fluting. I shall see how it shoots.

Handguard- JP Rifles
The longest JP piece I could get.

Brake- JP Rifles
I just need to figure out how to get proper washers for it.

Gas tube- JP Rifles
I want to be able to tune this rig so I got one I could adjust.

Buttstock- I picked a Magpul PRS up off Craiglist for $165

A few misc parts and I should have everything for it. For now I wait impatiently for my orders to arrive. As they arrive I will give my impressions and finally assembly. Then at long last, I will give a range report with factory and reloaded ammo for you all.

 

[Win.308Stealth]

Tag. To follow the build.

 

[Deleted member 48126]

Tag. To follow the build.

Me too

 

[gdcpony]

All of the parts are in except for the barrel. That I have to wait 8-12 more weeks for. I might do some testing with the other components while I am waiting. I do have a few 308 rounds left around.

 

[woodnut]

You will love your decision to build a 260! Two things you should consider:1) get an adj. gas block.2) think suppressor instead of brake! My 260 loves the 140ish bullets. Have yet to try 123s though. I have a Grendel that uses those so I doubt I'll change.
The adj. gas block allow you to dial in the right amount of gas to efficiently operate the rifle without undue recoil and battering. Makes it much more accurate too.
Hope the barrel comes soon!

 

[kimba]

I would love to do a 260, but hate the fact that ar10 uppers are not standardized so parts a hassle. You will love the 260 - out of my savage with 24" I shoot the 140 at low 2800 fps and just did a 100 grn amax load that does 3499 and is crazy accurate. Not sure you can get those out of the ar chamber, but the round is a great one. It makes the 308 look like the sister in law from the mountains of West Virginia. You should be able to throw the 100's at 3200fps and prob the 140 at mid 2700's.

 

[gdcpony]

Here we are so far. I Got the old gas block to fit under the JP guard and went shooting. Oh boy does it make a difference! I was bursting milk jugs at 400 like no body's business.

 

[gdcpony]

You will love your decision to build a 260! Two things you should consider:1) get an adj. gas block.2) think suppressor instead of brake! My 260 loves the 140ish bullets. Have yet to try 123s though. I have a Grendel that uses those so I doubt I'll change.
The adj. gas block allow you to dial in the right amount of gas to efficiently operate the rifle without undue recoil and battering. Makes it much more accurate too.
Hope the barrel comes soon!

I have the adjustable GB already, just a pain to swap out the tubes on them. The suppressor is not something I am into. Looks horrible (personal opinion), and if I shoot against someone, I want them to know I am there, which the brake does really well. I tried a couple shots with it on and man did the rifle tame down.

I would love to do a 260, but hate the fact that ar10 uppers are not standardized so parts a hassle. You will love the 260 - out of my savage with 24" I shoot the 140 at low 2800 fps and just did a 100 grn amax load that does 3499 and is crazy accurate. Not sure you can get those out of the ar chamber, but the round is a great one. It makes the 308 look like the sister in law from the mountains of West Virginia. You should be able to throw the 100's at 3200fps and prob the 140 at mid 2700's.

The DPMS parts are pretty easy to use. Uses alot of AR 15 parts, so that makes it easy. You should try it out. I love building my own and the AR platform allows that better than my other favorite (Mausers).

 

[kimba]

what velocities you getting? and is that a carbine length gas tube? If so, turn the gas way down

 

[gdcpony]

what velocities you getting? and is that a carbine length gas tube? If so, turn the gas way down

I had the old GB inside the tube so no adjustment. Muzzle velocity is 2650fps with 150gr FMJ's. this is still the .308 barrel. I can't wait to put on the 24" 260 and see what I get with it and 123gr SST's.

 

[kimba]

my guess with a 24 inch barrel is about 3000 if you push it. I get 3500 using 100 grain amax in my bolt 260 which is a 24" criterion barrel. am getting 2800-2850 using the 140 . I did shoot the 129 sst at around 2900, but did not push it as was in a rush that first season to get the rifle set up for first hunt with it - it was a 26" shillen. Took a mule deer on a front chest shot and it did not move an inch.
I just built a Grendel and am load deving it with a 24 inch bull and am getting 2750 with 100 and buddy that I bought barrel off was shooting the 123 amax ( duplicate to 123 sst) at 2600. I am going out in a bit to run a few down the tube and adjust the gas block. I think the 120 class is the way in Grendel due to case capacity and velocities, but the 130 or 140 is the bomb in a full 260 ar - or drop all the way to the 100 and shoot for 3300-3400fps.
Might sell my bolt 260 to do a ar10 260 soon or 6.5 x 47 lapua as love those small primer pockets

 

[woodnut]

KIMBA, I wouldn't think you can safely run the 123s to 2600 in an AR. Be very careful and slowly work up. With the adj. gas block, yeah you may do it. But be very careful! When I got to 2500 I was seeing pressure signs. Temp. rise can make a safe load not so safe,too. You may find 2300 to 2400 to be optimal speeds. I am like you in wanting more speed; if Hornady can get 2500 so should I kinda mentality. I found accuracy fell off when speed went up. Just do the right thing and slowly work up ! It's a great cartridge and works fine at 2300 to 2400 with the 123s.
Oh, and my rifle loves the factory AMax but the factory SSTs are just a tad slower and not quite as accurate. But they will get the job done!

 

[kimba]

KIMBA, I wouldn't think you can safely run the 123s to 2600 in an AR. Be very careful and slowly work up. With the adj. gas block, yeah you may do it. But be very careful! When I got to 2500 I was seeing pressure signs. Temp. rise can make a safe load not so safe,too. You may find 2300 to 2400 to be optimal speeds. I am like you in wanting more speed; if Hornady can get 2500 so should I kinda mentality. I found accuracy fell off when speed went up. Just do the right thing and slowly work up ! It's a great cartridge and works fine at 2300 to 2400 with the 123s.
Oh, and my rifle loves the factory AMax but the factory SSTs are just a tad slower and not quite as accurate. But they will get the job done!

documented 123 load using 28.3 grn xbr all day you do not know what you speak of - bear in mind a 24 " barrel not the 20 or even 14 inchers you see in books. I just wnt out with my ar gen using 100 grn amax and just 30 grn of tac and got 2797 with es 24 and sd 12 with no pressure.

 

[kimba]

the gren can do 2600 all day with 123 loads, but it takes a long stick. I hear folks say the 260 can only do 2700 with 140 bullets all the time yet folks that know get mid 2800 easily.