6.5 mm short action round choice

[Garycrow]

Here is a 6.5x47 Lapua with the same 130 VLD seated to where the junction of the boattail is even with the neck/shoulder junction. The OAL of this round is 2.675"



Here is that same 6.5x47 L round in an AICS magazine, notice that there's plenty of room. Someone stated earlier that an AICS magazine is 2.880".



Here's the 2.930" 260 remington dummy round in the AICS magazine.

 

[Garycrow]

If you seat the bullets so the length is 2.880", or any other length you desire, in both cartridges, the 260 will have a capacity advantage.

 

[brant89]

I just finished a .260 AI built on a Savage LRP platform. I can easily seat the 140AMAX into the lands with almost 1/8" of room left over in the factory mag box. No feeding issues at all and no modification to the mag box was needed. I'm not getting the velocities some people are claiming out of my 28" criterion barrel (I get heavy bolt lift around 2930fps with IMR4350) but the accuracy is astounding. Shot 1MOA groups at 600yd while fireforming Lapua brass which hasn't needed trimmed yet after four firings. Best group to date with the 140's was three shots inside 1.5" at 585yd (I will probably never shoot a group that small again. Haha).

 

[stomp442]

2930 is right where you want to be. You can do just about anything you want with a 140 at 2930fps.

 

[brant89]

My current loads are running about 2870fps which is my best accuracy node. A different powder (H4350/RE-17) might produce different results, but IMR4350 is readily available and I refuse to sacrifice accuracy for velocity. I will say that in my experience 4831 will not produce good velocities in the 6.5mm cartridges in this powder capacity range. I have heard of others that have had success with it but it hasn't worked for me in 260 Rem, 260 AI, or 6.5 CM.

And before anyone else says it, yes I realize that I can get very close to those velocities out of a standard 260 but I will also be trimming every 3-4 firings. At the rate I'm going my brass will probably fail before I ever have to trim it. I've thought seriously about running an AI reamer down my .223 also (I find myself trimming constantly) but I can't bring myself to alter a barrel that produces 1/2 MOA groups.

 

[brant89]

So in response to the original question, 260AI all the way. I love mine.

 

[Mateo]

6.5 Sherman Shortmag. 140's at 3300 fps, or at 3050 with 55'000 psi (or less) for great barrel life. VLD's seated to the lands fit in an AICS mag no problem. Easy to make the cases. Built off of the SAUM case with shoulder pushed back .1". I just built mine. It's alot of fun if you enjoy this sort of thing. YouTube 6.5 SS and you'll see how easy brass can be done. Almost exactly the same ballistics as the popular 6.5 saum but it fits in a proper short action

 

[Jud96]

I may do a .260 once my .243 barrel is fried. What powder charges are you guys using with IMR 4350 and 140s with a 26" barrel? I know H4350 is a go to powder for this round, but I never see it on the shelves around here. Everywhere I go, there's always a few pounds or more of IMR 4350 so this will probably be my powder of choice. Not Trying to hijack the thread, but has anyone had success with a case full of slow burning powder such as 7828ssc, Retumbo, or H1000? Thanks

 

[brant89]

I've had excellent results with IMR4350 in 260 Rem and 260 AI. Consult your reloading manual for starting loads and work your way up watching for pressure signs. I was able to get to 2830fps with 140's in my 26" 260 Rem but I don't recommend pushing it that hard as I started seeing ejector marks once I pushed past 2800fps. Many cite temperature sensitivity as a reason against using IMR4350 but I have yet to see any significant velocity variation. I probably just aided in selling all of my choice powder off the shelves but hopefully it works for you.

P.S. See my previous post about my results with IMR4831 if you are thinking about trying slower powders.

 

[Jud96]

I've had excellent results with IMR4350 in 260 Rem and 260 AI. Consult your reloading manual for starting loads and work your way up watching for pressure signs. I was able to get to 2830fps with 140's in my 26" 260 Rem but I don't recommend pushing it that hard as I started seeing ejector marks once I pushed past 2800fps. Many cite temperature sensitivity as a reason against using IMR4350 but I have yet to see any significant velocity variation. I probably just aided in selling all of my choice powder off the shelves but hopefully it works for you.

P.S. See my previous post about my results with IMR4831 if you are thinking about trying slower powders.

The reason I ask is because my Nosler Manual shows IMR 4831 and IMR 7828 giving the best velocities. My buddy was using H4350 in his 6.5-284 and he wasn't getting the velocities he was looking for so he gave Retumbo a try and has never looked back. He gained 100fps by switching to Retumbo. I know the 6.5-284 is a larger case than the .260, but was curious if it would benefit from slower powders. Thanks for the info. I would like to reach 2850fps in the .260, but not sure if I will be able to do that without going to the Ackley Improved case.

 

[brant89]

The Hornady manual also shows IMR4831 giving good velocities with the 140 AMAX, but I had a hard time even getting to 2700fps. I realize each barrel is different, but I have tried it in three different barrels and none of them produced acceptable velocities. I will save it for my stepdad's 30-06 and my future 300WM build.

 

[C Mahoney]

Thanks for all the advice, it's been very helpful.

 

[Jud96]

The Hornady manual also shows IMR4831 giving good velocities with the 140 AMAX, but I had a hard time even getting to 2700fps. I realize each barrel is different, but I have tried it in three different barrels and none of them produced acceptable velocities. I will save it for my stepdad's 30-06 and my future 300WM build.

I got good velocity with IMR 4831 in my .300WM with a 190gr SMK out of my 26" barrel. Average MV was 3112fps.

 

[brant89]

Good to hear. I was afraid I was going to be stuck with 8lb of powder I couldn't use.