.260/6.5 CM advice needed

[Anton Chigurh]

I put together a LR 260 upper recently. 20" BHW standard profile barrel, DPMS flattop receiver and BCG. I intended it to primarily for hunting, but since have decided it's going to be too heavy for me to like for hunting.

So now I'm trying to decide whether to try it for long range target shooting (which I'm a newbie at for sure), or go ahead and sell it to fund a proper bolt action in 6.5 CM or 260 with a 26" barrel. There's a 1000 yd range 30 mins from the house and would like to get set up and start practicing soon.

I only have 30 rounds down the tube on the 260 upper, all factory federal ammo to test function. It is going to be hard on brass, I think extractor polishing and gas block tuning will help some, but I think it will eat brass much faster than a bolt gun, and I'm not sure I want to start feeding it new lapua cases. All 120gr bullets that ran 2800-2885 fps according to my chrono, so I think that will be an attainable velocity with 123 amax or smk. Good enough to reach out there effectively?

Suggestions??

 

[chevytruck_83]

1000 yard range from your house... im jealous. Put the time in anf find out for yourself. Jerk. Haha kidding. I have great results out to 750ish with my ctr-02 in 223. I say try it and build a bolt action as your abilities improve

 

[ss7]

I've seen gas guns do very well in local matches out to 1000. It can surely be done well.

My preference strongly prefers a bolt gun, but if all I had was my gasser, you'd still see me out there shooting.

In your position, if I could find a way to cash out with manageable loss and "upgrade" to a reliable bolt, I would.

 

[Ledzep]

I also suggest ditching the semi-auto if you want to shoot long range. You will get a lot more for your money shooting a bolt action.

Why?

Longer brass life
Ability to push hotter loads
No gas system or buffer weight struggle to work with
All things being equal as possible, more precision
No inertial effects of chambering bullets (pushing in or slinging out of the case)
Shorter lock times
Cleaner

Just more consistent in general. Shooting a bolt action makes things much simpler, easier, and more enjoyable for LR. I tried a LR 260 build with top quality components (Krieger, JP, etc..) and I had a 3/4 MOA rifle that opened up to ~1-1.5MOA the farther away I got (vertical dispersion I'm talking about, wind kicks my ass).

So could I use it to shoot long range fairly effectively? Yes. HOWEVER, my LRI built M700 .260 with 4" less barrel gets within 50fps of the same MV, doesn't wreck brass, and holds 1/2MOA or better vertical dispersion out to ~700, then 3/4 or so to as far as I've shot it (1300+). Within 600 it's generally the within the thickness of the reticle of my Mk6 TMR.

 

[Milo 2.5]

I also suggest ditching the semi-auto if you want to shoot long range. You will get a lot more for your money shooting a bolt action.

Why?

Longer brass life
Ability to push hotter loads
No gas system or buffer weight struggle to work with
All things being equal as possible, more precision
No inertial effects of chambering bullets (pushing in or slinging out of the case)
Shorter lock times
Cleaner

Just more consistent in general. Shooting a bolt action makes things much simpler, easier, and more enjoyable for LR. I tried a LR 260 build with top quality components (Krieger, JP, etc..) and I had a 3/4 MOA rifle that opened up to ~1-1.5MOA the farther away I got (vertical dispersion I'm talking about, wind kicks my ass).

So could I use it to shoot long range fairly effectively? Yes. HOWEVER, my LRI built M700 .260 with 4" less barrel gets within 50fps of the same MV, doesn't wreck brass, and holds 1/2MOA or better vertical dispersion out to ~700, then 3/4 or so to as far as I've shot it (1300+). Within 600 it's generally the within the thickness of the reticle of my Mk6 TMR.

Everything you said here makes sense, except the part about the gun opening up with distance, that was your load, not the gun? And the op can still have a shitload of fun with this semi, this lr stuff is fun but firing on an IPSC at 700-1K with 3 shots and after the dust settles getting 3 distinct pings, well, good luck with that using a bolt rifle.

 

[Ledzep]

It's probably velocity difference from shot to shot causing it to open up further out, combined with increase wind effects. It happens to an extent in my bolt-action, too.

So if you want to try to work up a load that has <20fps ES and single digit SD in a semi-auto, be my guest.

Admittedly, I'm not OCD about reloading. I don't turn necks, I don't uniform pockets, I don't weight sort brass/bullets, I don't anneal every firing etc.. etc.. 1/2 MOA is "good enough" for what I do so I quit after finding that load, instead of shooting 100+ rounds finding the perfect seating depth etc.. etc.. Set it at mag-length and forget it.

ETA: It is my belief that no matter what you're shooting, the angular cone of fire opens up as range increases. Unless you have exactly the same shot every shot.

 

[Milo 2.5]

Not going to take you up on the ES-SD on most semi's, but I did just do load development for a friends Gap 10, 6.5 creed, I think we were under your posted numbers.
I have a number of C Dixon built rifles, most have shot a 1/4" group at 200 yards, so yes our load development is quite diff, worst was 3/8".
I've shot a 2 1/2" group at 1320, a 6" group at 1650, ad 2 shots at 1850 going about 2" just couldn't fuck it up with a 3rd. I totally agree that wind messes up groups at distance, and who knows, the wind could've blew a botched shot back into my groupings, hence I usually don't pat myself on the back!

 

[FCS]

I put together a LR 260 upper recently. 20" BHW standard profile barrel, DPMS flattop receiver and BCG. I intended it to primarily for hunting, but since have decided it's going to be too heavy for me to like for hunting.

So now I'm trying to decide whether to try it for long range target shooting (which I'm a newbie at for sure), or go ahead and sell it to fund a proper bolt action in 6.5 CM or 260 with a 26" barrel. There's a 1000 yd range 30 mins from the house and would like to get set up and start practicing soon.

I only have 30 rounds down the tube on the 260 upper, all factory federal ammo to test function. It is going to be hard on brass, I think extractor polishing and gas block tuning will help some, but I think it will eat brass much faster than a bolt gun, and I'm not sure I want to start feeding it new lapua cases. All 120gr bullets that ran 2800-2885 fps according to my chrono, so I think that will be an attainable velocity with 123 amax or smk. Good enough to reach out there effectively?

Suggestions??

Make buffer as heavy as possible. 260s run a slower burn rate powder so you are seeing higher port pressures, you benefit with heavier buffer by keeping bolt locked up longer.
Get an adjustable gas block, turn gas "OFF".
Develop load with rifle in "single shot mode".
Open gas block just enough to get 100% reliable function.

Go with 140gr bullets, LR you can not push a 123 fast enough to overcome the BC difference. 139 Scenar, 140 SMK, 142 SMK, 140 Amax would all be reasonable choices though I'd favor the 139 / 142 given you most probably have a SAAMI spec chamber.
Gas guns will eat brass faster then a bolt rifle, that is true. You can minimize the differences but can not make a functional gasser as easy on brass as a bolt.

 

[Anton Chigurh]

Thanks for all the replies so far. I'm following most of what has been said..

LedZep, how long a barrel did LRI put on your m700? I've seen some of their work over at Predatormasters and they put together some nice sticks for sure..

FCS, I appreciate all those tips and did some of them already, and will try the single shot mode if I decide to run this thing. The BHW barrel is a 1 in 9, which might screw me on the 140s. Again, I was thinking hunting rig when I ordered the barrel not LR, so I didn't worry about the slower twist. I'm not sure though, it might run the 140's.

I just got back from running some test loads at 100 with my 20" 6.5 Grendel (123 amax), and my semi custom 243 (105 amax). I think I have both of these shooting well enough to load up some rounds and start stretching my range out some while I think on this 260 issue.

Any and all feedback is appreciated.

 

[LawnMM]

Go with the bolt action, you can put a nice auto loader together, BUT...

It's not cheap and it's not quick. You have to shell out cash for premium components and then spend a lot of time diagnosing and resolving issues that will likely come up as you tune the gun and ammo to work properly and reliably. Frankly it's probably more of a task than the average enthusiast is up for, so a smith is a better option.

Or just put a bolt gun together...

 

[FCS]

Thanks for all the replies so far. I'm following most of what has been said..

LedZep, how long a barrel did LRI put on your m700? I've seen some of their work over at Predatormasters and they put together some nice sticks for sure..

FCS, I appreciate all those tips and did some of them already, and will try the single shot mode if I decide to run this thing. The BHW barrel is a 1 in 9, which might screw me on the 140s. Again, I was thinking hunting rig when I ordered the barrel not LR, so I didn't worry about the slower twist. I'm not sure though, it might run the 140's.

I just got back from running some test loads at 100 with my 20" 6.5 Grendel (123 amax), and my semi custom 243 (105 amax). I think I have both of these shooting well enough to load up some rounds and start stretching my range out some while I think on this 260 issue.

Any and all feedback is appreciated.

What powder are you running with the 123s?

 

[Barrel Nut]

Or buy an LRP-07....almost best of both worlds. ...

 

[Anton Chigurh]

What powder are you running with the 123s?

I haven't evened opened the box of Lapua Brass or the redding dies. I have only shot 30 rds factory ammo thru it so far, after I saw how bad it was chewing up brass I thought I'd stop and think on whether I want to run it or not. It's too bulky for my hunting needs, so it comes down to will it make a good range toy.

I could still send the brass back and exchange for creedmoor brass (I already have 1 CM for hunting) or save the components for a bolt gun..

I was planning to try IMR and/or H4350

 

[LRRPF52]

You can tune a non adjustable gas block gas gun to treat brass very well, while also getting extreme accuracy.

The same approaches to the bolt, as well as bedding the barrel extension into a trued/squared receiver face will tighten the gun up very well, using a concentric barrel and bore.

130gr is where I find the happy place for a gas gun .260 Remington. The speeds you are getting will be way more competitive than a .308, even if you stick with 123gr, but again, I recommend 130gr. The 130gr VLD is great when you go fast with it, compared to the 139-142gr 6.5mm's.

 

[FCS]

130s are great bullets, though I don't think I'd run a 130 VLD in a gas gun with a SAAMI 260 chamber. 9 twist is going to be a bit slower then I'd like for a 130 VLD also, personal preference.
130 Norma might stabilize in a 9 twist, be a better overall match to a SAAMI chamber than a 130 VLD, given OAL constraints of AR magazine.

123s I'd be looking to a step faster burn rate powder then any of the 4350s, lower your port pressure and keep from tearing up your brass.

Picture of brass, show what is being tore up would be helpful.

 

[LRRPF52]

The new IMI 7.62 mags allow for longer COAL. My chamber is cut for the 139gr Scenar, but it works so well with 130gr VLD's, I didn't look back. My "plinler" load is 41.0gr of H4350 behind the 129gr SST, and that load is very accurate as well. I have a Bartlein barrel though.

 

[FCS]

I've not handled the IMI 7.62 magazine, what OAL is possible?

 

[FCS]

123 in a 260, 20" barrel, standard rifle length gas system, I'd be looking at Varget. One of the 4350s might get you more velocity but port pressure is going to be high, brass going to get beat up. Varget will get you reasonable accuracy, reasonable velocity, drop your port pressure and be easier on your brass.

Worth what you paid for it.

 

[Anton Chigurh]

Thanks for the info. I will look into varget as an alternative, I have plenty of it. How about re-15?

It does gave an adjustable gas block, which I have turned down to just cycle. That helped a lot of course.

Being that the factory loads I tried we're pushing 120s to 2800-2885, I think maybe they were on the verge of being too hot for this rifle. Looking in my nosler manual, that's mid level speed on their 24" test barrel so it's be top speed on a 20", right?

I polished the extractor also, lightly as I haven't messed with one before. I might need to do a little more. what is your take on radiusing the corners to minimize chew marks on the rims?