I would like a precision match gun chambered in .260 Remington with a collapsible stock, 15 in free floating for end, and a stainless steel bull barrel 16-20 inches in length depending on the weight of the rest of the firearm to try and create a good balancing point. I do not have the time to build my own rifle and below is what some of the local builders have told me.

"The AR series in 260rem is problematic and takes a lot time to get working correctly. We can build and get it to work right but not without careful selecting the perfect parts. This makes the research and labor costs higher.

 

1. The bolt is a simple 308 bolt but the 260 has very different characteristics.                                      

     A. It can puddle primers                                                                                                                                                      

     B. It stretches brass casings which makes it harder to extract.

     C. The bolt has to have a to have totally flat face with no recess as the shell may bounce  when fired.

 

2. The barrel needs to be at least 20 inches or more long in order to make the gas system work right.  

     A. this caliber was designed in a bolt action not a semi auto.

     B. The shorter the barrel, the sooner the gas gets out. This unaffected with a bolt gun

     C. The semi auto is gas operated and requires 20k+ psi. If the gas gets out too soon or too fast, it will have cycling issues.

     D. 22 inches would be a better start.

                       

3. The barrel needs to be custom made with a matching pre head spaced bolt.  

4. The buffer tube should be full length and not carbine to give it the maximum spring return. Therefore, no collapsible stock."

 

Has anyone else experienced or heard of these problems with the .260 Remington cartridge in an AR?

Yes.  Answered each item above.

It isn't plug-and-play from .308 parts and assumptions when looking at bolts, carriers, springs, and buffers.

Things that help:

* Reduced size firing pin aperture on the bolt.  JP calls this a high pressure bolt.

* Correct gas port diameter for the barrel length, loads you are shooting, and dwell time.  Too large of a port will really cause you problems.

* Correct gas port location.  RLGS is actually close for comfort with much higher port pressure than the AR10 was ever meant to run on.

* Quality, reputable manufacturer BCG, not cheapo parts with whiz bang coatings claiming to be better.

I personally just had GAP build mine, and it runs.  I've bent several firing pin retaining pins due to firing pin rearward acceleration from hotter loads.

I love the performance, but there are several penalties to pay with .260 Remington.  I have owned 2 of them, first a DPMS LR-260, and then my GAP-260 built on DPMS receivers and BCG, with a Bartlein pipe.

I haven't shot it in a long time.  Most of my long-range sessions are filled with 6.5 Grendel in the AR15.  Factory ammo support for a gas gun is a huge factor in that, as is compatibility with AR15 parts.

LRRP, why is the .260 in a more precarious gas tuning area than the .308 and .243 AR10's?  You probably recall that I had an Armalite 20" .243 and still have the Armalite 20" .308.  The .243 ran flawlessly and of course, so does the .308.  I remember you saying that Armalite did a .260 AR10 some time back.  Did it run reliably?  Some of the things I see listed appear to be possibly load related.

Totally different propellant and projectile characteristics working together to increase port pressure.

You use slower burning powder with your 140gr loads in .260 Rem, more like what you would see in some of the magnums.

Combined with a smaller bore and a lot of bullet shank, the pressure curve lasts longer and stays higher farther down the pipe, which hits the port with much higher pressure.

This is the main challenge with .260 Remington in a gasser, and why I like using 123gr - 130gr projectiles vs. 140gr.

The lighter bullets do better with H4350, which is kinda fast for .260 Rem.  Gas system runs better.

I've had loads with 140gr where I could feel the buffer trying to break the extension tube out of the back, with substantial increases in recoil and abuse of the gun.

My DPMS 260 ran great and was very accurate. You just needed to maintain your gym membership to be able to carry it.

LRRP summed it up pretty well.

I run a Larue Tobr in 260 and it's a blast to shoot. I do load on the lower end in regards to powder, but have had amazing luck with the 139gr Lapua Scenar bullets over 4350. I do run it suppressed with a Saker, so the larue gas block is run on the suppressed setting and I'm now trying a heavier buffer as well.

Just have to be careful with the factory ammo that's out there because it's loaded much hotter for bolt guns. I typically use my reloads, but when new stuff comes out (Like the more recent FGMM) I do try it. There's been an occasion or two when I've seen blown out primers, so again something to be careful about if you're only shooting factory stuff.

LRRP is probably tired of hearing me comment on lusting after a 260...LOL!  To me it seems like the 260 is a reloader's rifle.  I think if I were going to go with off-the-shelf ammo, I'd go with a 6.5C.  I've recently gotten back into reloading and am already playing with about three calibers right now.  Still, the 260 looks very appealing to me.

The thought of shooting factory ammo through my .260 gasser is so foreign to me, it borders on blasphemy.

My rifle has never seen a single factory load, nor will it unless someone duplicates my 130gr VLD hand loads.

I have seen some 6.5 Creedmoor rifles shoot the Winchester 140gr BTHP load run flawlessly, using a Fulton Armory 24" barrel.

The brass exited without a sign of abuse or primer flow as well.

Have an aero m5 upper and lower, would like to build a 260 as I have a bolt gun and reload for it. Can you suggest components that would work or should I stick to 308 ?

Getting a good barrel, bolt, bolt carrier, and buffer are critical to making a .260 Rem run well.

For reloading, the Lapua brass will take abuse better than others, but the case capacity is less than Remington brass.

I have had great results with Winchester 7mm-08 brass necked down.

A bolt with a smaller firing pin aperture will help prevent any primer issues.

Correction, they just went up on the website for pre-sale, I had one in my cart but just have too many bills right now.

Who makes a good barrel, bolt and buffer for a 260?

JP HP bolt, full mass or low mass BC, and their silent capture spring.

Is 6.5 creedmore more reliable?

LRRP, I think I recall you saying you used 7mm-08 cases for your 260.  Is there a reason that necking up the .243 won't work equally well?  

I saw that Wikipedia stated that it can, so I guess that's the ultimate source right there...LOL!  But seriously, do you know any reason one couldn't go that route?  I'm heavy into .243 cases is the reason I ask.

I know those who do the 6mmX45 neck up the 5.56 case about a half millimeter with no issue, and if I'm counting right, that's going to be about the same for .243 to .260.

Necking up .243 Win. works, and that's what a lot of people used to do with Lapua brass before there was Lapua .260 Rem brass.

You have to turn the doughnut out though inside the neck.





The Case for the .260 Remington

Good grief, LRRP...I've been doing quite a bit a reading about donuts and other evils.  I thought strict adherence to case sizing, trimming, COAL, and other more mundane reloading practices would be all that was reasonably required.  Some of this with exotic cases sounds a bit like building drag racing engines...LOL!

Pretty interesting stuff, but it puts me off a little if the .260 is going to a highly labor intensive commitment.  I like mechanical challenges to a degree, but I'm looking for a little more pleasure in my shooting than intricate work and more tools.

I really enjoy such endeavors in my motorcycle/automotive efforts in the area of engines, suspension, ignition, fueling, etc.  The good thing in that arena is that you don't have to constantly perform the tasks to achieve some real performance reward to enjoy over some time.  

Reloading involves a lot of tedious, repetitive tasks to achieve performance for a just a few cases.  I don't mind and rather enjoy the level of work in the reloading I do now.  I could do case turning, neck reaming, and similar tasks, but I'm not looking for a career.

And I'm with you on not wanting to go off-the-shelf with a .260...and frankly all my better ammo in .223, .243, and .308 is personally reloaded.

If you have piles of .243 Win brass, the easiest thing to do is universal de-cap them, tumble-polish, and sell them.

Take that money and buy some Lapua .260 Rem brass, or Winchester 7mm-08 brass.

I learned the hard way that no matter what, I have to full-length size new brass for my .260 Rem gasser anyway.

I was in the middle of a competition using new unfired Lapua cases, and I had several failures to go into battery, and failure to extract.

I never had that problem with 7mm-08 necked down, because I of course had to full-length size all my 7-08 cases to make them into .260 Rem, which is very easy.

Another thing about Lapua brass is that published load data for .260 Rem is almost always based on Remington brass, which has a lot more case capacity than Lapua, at least with the cases I have.

You will build pressure faster with Lapua brass, so charge weights need to be lower.  It's the toughest, most consistent brass out there though.

I also never shot factory ammo when I was shooting .308 Win.  I settled on the 155gr Lapua Scenar in Lapua brass, going 2820fps from 22" and 24" AR10s.

LRRP, being that before now I only dabbled in .308 and .243 reloading for bolt guns, isn't it common for semiauto .308 and most other semiauto applications to need FL sizing?  Yes, I've read lots of material about the issue, but it seems to yield more opinions than Hillary's lost e-mails.

Yes.  You need to FL re-size for gassers, otherwise your case walls will jam into the chamber walls.

There isn't enough strength from the action spring or inertia from the BCG to close on a neck-sized case like you can with a manual turn-bolt action.