My first custom in .260 is finally done - Looking for some advice as I get started loading for it and breaking in the barrel, I'm not the most experienced handloader and appreciate the help you guys have given me so far.

Rifle- Stiller Predator long action, Bartlein 8 twist 5r Rem Sendero contour at 26", HS precision stock.

Powders and bullet- I have H4831sc and IMR4451 with 142 SMKs. Can seat the 142s out as far as 2.339 base to ogive/2.939 base to tip OAL to touch the lands and still fit in the box since it's on a long action. Should give me a little extra powder room. Virgin Lapua brass.

Two main questions:
1. Which powder should I start with?
2. I have the ability to shoot at 100 yards easily, and at a different place that's a little more work out to 300-600 yards. How should I start my load development and break in? Shooting groups at 100 with different powder charges, or go through a little more effort and do a ladder at 300+?

Thank you in advance for any input you may have!

Clean the barrel, shoot 20 foulers down it, then get to load testing.

IMR 4451 is where I'd start, it's close to H-4350 burn rate, which has historically been "the" powder for .260.

Ladder test it at the farthest distance you can, up to 500 yards.

Thanks JG! I still have your info you pm'd me, super helpful!

What would you do if you could only shoot at 100 yards?

Three shot groups in the interest of saving components. Step in .3 gr increments up to Max, or beyond. Every ejected case, look for pressure signs, make note of sticky bolt lift. Stop shooting when you look to be over pressure.

The loads that shoot the best, reload, reshoot for a five shot group. After that, if you still want to tinker with it, you can play with bullet jump in .005" increments.

Both powders will work. 4451 is a great choice, and would be good first choice. If you use 4831, seat the bullet out a little further to gain some case capacity. Back in the day, I knew several 260 Rem shooters running 46-47 grains of H4831 with a 140 class bullet around 2800-2850.

Thanks Jason and Chad, just wanted to make sure I am on the right track!

Chad- do you think I can fit 46-47 grains of 4831sc in the case with a max OAL of 2.94? With either powder, I'd like to get 2800+ if possible!

Yes, you should be able to fit that much powder. Use a drop tube to help pack the powder in there. When I shot 260 Rem, I ran a 140 Berger VLD about 2.880" and chased the lands out to about 2.950", which was a long as my mag would fit. If you are running a 142 SMK, you may hit the rifling before you reach the 2.940" COAL. 2800+ fps should be attainable in a 26" barrel with a stiff load. The 4831 also helps not show pressure signs as easy as a faster burning powder. I knew guys that ran Varget, or something faster burning and would have pressure issues in inclement weather. I had a few also with 4350, but I knew I was too warm. I switched to a 130 VLD at 2960 fps, and it was awesome. But throat wear was very rapid with this combo. One of my shooting partners wore out his new 260 with 130 VLD's in 1100 rounds. Trajectory and little wind drift was great, but barrel life was very short.

Thanks Chad, I really appreciate it.

4831 sounds promising as well with as far as I can seat bullets out. Ideally I'd load up a ladder test with both that and 4451 and record velocities and look for pressure signs on both as I go.

2 small kids, a full time job, and going back to school 12 years after college is making it tough to find the shooting/loading time I would like!

Welcome! Yes, load development takes some time to do. And I do offer a load development service. I can even use your components, so everything stays the same and it cheaper to dial it in.

Thanks for the idea Chad, its crossed my mind a time or two! If I just can't get to it, I might have to call you.

IIRC 46.8 is what I'm running in my 260 with 143 ELD-X bullets for 2825 out of a 26 inch barrel. I didn't have time before deer season hit to work on seating depth, I just guessed and backed it off a couple of thousandths. Getting .5 to .6 MOA groupings out to 600 yards. Planning to work on my seating and see if I can pull it in a bit.

Thanks Texan, that makes me feel good about the velocity target of 2800 I have!

So- as of right now, the plan is to work up two ladder tests to shoot at 300 yards. One with 4831sc and one with 4451.

Two questions-

1. Should I start at the minimum charge weight listed for each powder and work up in .3g increments, or can I start 1/2 way between the min and max? Hogdon.com shows 45g as starting load and 48g as max for H4831, and 38.8g starting and 41.5g max for 4451 with a 142SMK.

2. I'm using virgin Lapua .260 brass, should I FL siz them or just load me them and shoot them?

Thanks again for all the guidance, I appreciate it!

I start in the middle, work toward max, then go past max carefully looking for pressure signs along the way. Look at Hodgdon's max charge for H-4350 in a .260 Rem, then know that they all tend to shoot between 42.5 and 44.0 gr powder charge, with no ill effects.

Since it's Lapua brass I would only size the necks, and that's probably not necessary. If it were Remington brass, I'd partial FL size them, trim, chamfer/ debur, and clean out the flash hole. But you paid for premium with Lapua, and that's what you'll get.

Awesome, thanks JG. My ladder tests were going to have 10-12+ rounds in them even before going above book max if I started at the minimum charge. Was hoping that wasn't completely necessary!

JG and Chad gave excellent advice.

As for the starting point, I never drop back to the minimum unless there is a reason for it. Such as trying for low recoil loads or such.

The 260 is a great shooter and you should get that rifle to punch 1-hole groups at 100 yards with very little effort. Just remember that extreme consistency with your powder charges and OAL measurements is the key to getting those tiny groups.

IMR4451 is a great choice for .264s and is showing great promise in some .300 chamberings also. It is quickly replacing some of my H4350 loads for my Creedmoor.

Have fun! You've got a great cartridge and rifle to work with.

Creed- thanks for the reminder, and vote of confidence, and info on the 4451! Hopefully I can get things loaded up this weekend.

The next holdup is the scope, I have to make my mind up on a Razor HD gen 2, wait on the PST gen 2 to come out, or just buy a PST gen 1 like I have on my other rifle. Tough decisions. It pains me to have a brand new rifle that's been sitting unfired this long!

Can't help any on the glass choices........all of mine say NIKON on the side.