Thinking about building a 260 rem and wanting to know if it's easy to tune.
I've read that getting the gas right is important and accuracy is excellent if you hit on a good load.
Got Fed and Win 308 brass and 6.5 bullets to use.
Got a Grendel but want to try 130 VLD's and 140 A-max's.

I would suggest asking over at the precision rifle/ semi auto section.

More info there. Good luck.

Easy to tune?  Biggest challenge is finding a load that provides .260 Rem performance, without hitting the gas port so hard.

Accuracy is a combination of common accurizing techniques, a concentric barrel that is tempered well, and a good load.  My current .260 Rem. has a Bartlein barrel, was squared up by GA Precision, bedded, gas block secured with sealant, and it shoots better than most bolt guns I've owned or shot. It consistently shoots 5rd groups into .4-.6" at 100yds, and printed a sub-MOA group at 1000yds the very first time I shot it at 1k.

Don't start with .308 brass unless you like neck-turning, because when you size down the .308 brass, the neck material becomes very thick.  There are plenty of sources for .260 Rem brass on the market.  Lapua lasts the longest.

would you mind to explain what you mean by the hitting gas port to hard comment?just trying to learn.thanks

Is there a factory 260 load that will usually work in a gas gun?

The .260 Remington generates longer pressure curves with the lengthy bearing surfaces of most of the projectiles, especially everything 107gr and higher.

The AR10 RLGS was developed around the characteristics of the 7.62x51, with faster powders and shorter bearing surface 147gr FMJBT pills.  You could have the same peak pressure with both, in one example, but the slower burning powders behind long shanked pills will leave a higher pressure down the pipe compared to the same distance with a faster burning powder and a short shank pill.

If the gas port gets hit with higher pressure, the reciprocating parts retract to the rear more violently, which isn't a good thing for reliability of longevity of a gun.

Some of the factory 120gr loads work ok, because they use faster powders.  I personally would never shoot a factory load in my current .260 Rem AR10, but I have buddies that have tried it.  Shorn extractor rims, brass flow into the ejector slot, and really harsh treatment of the brass is typical with 139gr, 140gr, and 142gr factory ammo-all of which was designed for bolt guns.

There are some small loading companies that have run specific gas gun loads for .260 Remington, especially with the number of guns GA Precision has put out with the GAP-10, but I only hand load for the .260 Rem. in the AR10.

does this mean it only functions well with handloads in a ar frame?

With the common hunting and target pills with long shanks, yes.  If you read JP's website about these calibers, he will outright tell you the same thing.  It will cycle factory ammo, but the brass will be trashed in most cases, loose primer pockets, shorn extractor rims, ejector channel brass flow and shear, pierced or cratered primers...

.260 Remington, 6.5 CM, 6.5x47 Lapua are basically a reloader's game in the AR10 frame rifles, and that has been my experience, as well as the experience of scores of shooters I know in the competitive long range shooting circles that I run in, ranging from here in the West, to Europe.

Think I'll wait for now.
Starting to think a 22 inch bolt gun in 65 creed might be better in the long run.
Probably a 700 action with a Lilja or Bartlein tube.
What do you mean by a tempered barrel.

If you are going to go bolt gun, I would look at the Tikka T3 in the Whiskey 3 chassis.  It smokes the Remington 700 hands down. Rem 700 takes way too much effort to make it right, whereas the Finns make rifles right from the start.



Even with a bolt gun, I personally would still be hand loading for it, but that's just me.  I'm a stubborn fan of the precision auto-loader, but I do find a bolt gun easier to shoot after having driven gas guns more often.

Tempering and heat treating of barrels can be done in different ways.  I buy quality barrels from the top end, because they have these processes down.  A lot of rack-grade barrels are garbage, when it comes to seeking accuracy from them.  When they heat up, POI will walk all over the place.  They usually aren't concentric as a rule, not on the OD to bore, threads to bore, or chamber to bore.

Damn, that looks pretty sick...likely the nicest B/A competition rifle I've seen for a while !

It would do quite nicely with a 22" tube in a short action .260 Rem. or a 6.5x47mm Lapua Cal., etc.

damn.i have a home built ar10 and a factory m&p10 and was hoping to change the home built gun over to a different caliber.no particular reason other than wanting something different.my reloading skills aren't exactly ninja quality,however ive managed to load some nice shooting 556 and 308....maybe ill take on the 260 challenge.does varget work well in 260 or maybe 4895?

There are quite a few reloading handbook loads for Varget, but it isn't the most ideal powder for the .260 Remington.  Density and burn rate don't work out so well as far as performance goes.

Your medium-to-slow burning powder ranges are what makes a .260 Rem sing with 123gr-142gr pills.  It's a hard hitter on steel because of retained energy.

Between the .260 Remington and 6.5 Grendel, I have no reason to own .308 Win. anymore, which is why I don't.

ok,thanks for your knowledge.

No way would I spend the time working .308 brass to 260REM spec
to be used in a gasser while having a demand for sub 0.5MOA accuracy.

1)  I can buy LAPUA brass cheaper than my labor/time to rework 308 brass

2)  260REM is not the way to go in a gasser for a ton a reasons besides:
    A) 6.5 Creedmoor
    B) 6mmXC

Best to you.

I have a 260 reamer and was wanting to make an upper for my AR10.

Was unaware of the gas system drama. What about just making a longer gas tube and moving the GB further out?

Most reloaders use .243 Win. brass or .260 Rem brass from the start, with the right powders there is no problem
getting the AR-10/AR 308 gas rifle to run properly...If not using a good powder that works well in the .260 Rem
then there is a adjustable gas block that can help solve that Issue...

The 6.5 CM use pretty much the same powder range as the .260 Remington AFAIK, but it is another option one can
use...

Good luck.

After having great results with a .260 bolt gun I seriously looked into building a .260 AR.  I've been disappointed with what I have read about other shooters experiences with them.

IMAO unless you know you are going to be consistently shooting beyond 500-600yds often there just is not much justification for building a .260 AR over the much more common and proven .308 AR.  Now I think I even prefer the 6.5 Grendel over .308 for those purposes in an AR.

FWIW I have found Varget not to have great results with my .260 loading, 4895 has produces some nicely grouping loads but with a significant sacrifice in muzzle velocity.  My best overall results so far have been with RL-19 and 4350.

I have had great results sizing .243 brass to .260 in the bolt gun, don't know how those results would be with an AR.

   
Bingo!  Don't know why people don't concider this.  David Tubb did this when he built his 6XC SR-25.  Get a copy of Quickload and plot pressure v. distance for the bullets/powder you want to use.  Pick the distance where press is 19200 as this is the pressure that Eugene used when he designed the gun.  For the .260 about 2.5" longer than std. rifle length if memory serves me.  This solves the problem at it's root and eliminates heavy buffers, adjustable gas blocks, etc. as bandaid fixes.  You'll just have to tell your barrel maker where you want the gas port/gasblock area machined and make your own gas tube.  Use stainless aircraft brake tube for this.

Oh I have and love Quickload! Use it all the time to get port pressures by telling it the "wrong" barrel length!

And since I AM the barrel maker, I can put it wherever I want....

That has been done, but you can work out good loads with hand loading using a standard RLGS, as I have with H4350.  The gas system drama also exists with .308 and the 175gr SMK, Hornady Superformance loads, and any long bullet shank/slow burning powder combo.  It's why I only hand-loaded for .308 AR10's as well.

This is the same boat I ended up in.  There is no reason for me to own .308 with the capabilities of the 6.5 Grendel, and every single piece of 6.5 Grendel ammunition has been manufactured specifically to function in the gas operated AR15, unlike most of the .308 Win. ammo.

For the times throughout the year when I need .260 Remington performance, I can crank out 150-200rds of .260 Rem hand loads for that event.  The rest of the year sees a constant diet of 6.5 Grendel.

An adjustable gas block will eliminate many of the potential issues with port pressure and cycling. I've added an SLR to my 20" 260 and have no issues with it using H4350 and 139/142gr bullets. The rifle also shoots and cycles 260 Gold Medal Match fine, with and without the adjustable black. Not sure what powder they're using in that. The 123 Scenar at 2850 is a pretty darn good gas gun load. When the Berger Hybrid 130s come out they'll be the next thing to try, assuming they can be loaded to mag length.

I love the 260, but for pure gas-gun performance the 6 Creed seems to be the winner.

Even in .308 the Hornady Superformance ammo was noticeably harsher on the G2 Hunter and my shoulder. It just didn't feel right to shoot it much, like something would break on an AR if you shot a lot of it. Just my take.

I'm not trying to pick an argument, but for the sake of discussion I'll take the other side of some of this.

1- the gas block doesn't effect pressure.  Boyles law.  It will restrict gas volume, which somewhat alters pressure to the bolt for a very short period of time, but after enough volume has reached the gas key, your final pressure should be about the same.  The difference in volume will make a marked difference in recoil, bolt speed, etc, which should be able to slow cycling enough that pressures have dropped by the time the bolt unlocks and the carrier moves.
If you are having trouble cycling, a gas block is not likely to help, it only limits volume.  Very few problems are caused by excessive volume, but some shootability traits are improved with less gas.

2- also to be considered is dwell time.  If you have a lot of barrel forward of the gas block you will have the bolt/carrier pressurized longer.  

3- slower powders (lots more than burn rate at play here though) will increase the amount of gas in the system, primarily because you get to use more of it.

4- I own two Creedmoors, but I really don't see an advantage to the CM over the 260, nor do I see an advantage the other way.  They use essentially the same powders, bullets and basically the same amount of powder.  Other than the CM maybe fitting in a mag better, it's not really an improved caliber for the semi imo.

now to do more research, 6mm has been my go to bullet for a while and @ $215 the A/P receiver set is calling

Do it.

24" Lilja .260 Rem. 1/8 T

Loves 142 SMK's over H4350 in Lapua brass

Great looking set-up Bhart89...Bet is shoots great...How much did the Lilja barrel set you back ? Did you get that new NiB .308 BCG to
run smoothly that you bought a while back ?

I had to do quite a bit of gunsmithing adjustment/polishing on both of mine to remove all the rough spots, and the bolt was still tight
with the barrel extension...

Good luck with it...