260 Starting Seating depth

[deadnbrkn84]

I'm beginning load development on my new .260 and I'm wondering what a good starting seating depth it. I searched on here and couldn't find anything. I'm shooting 140gr Nosler Custom Comps out of a Rock Creek 22" 1:8.5 barrel. How far off the lands should I start? Any info would be awesome. Thanks so much for the help in advance.

 

[jrob300]

Re: 260 Starting Seating depth

The CC's are tangent ogive so distance to the lands should not be critical. If you can get them within .005" to .020" that would be a good place to start and then you can take a nap while your buddies with VLD's are fretting about chasing the lands.

John

 

[Fester47]

Re: 260 Starting Seating depth

You might try the Berger Hybrids. I have had good luck with the 230gr in my 300WM. I have a 260 being built by AJ Brown and I have 200 of the 140gr waiting for it. I think they will shoot. Just have to wait and see.

I load test into the lands to find max pressure loads. Then I can back off the lands and lower pressure if the nod is on the high end.
But usually my nod is lower than max pressure. Then I tweak for more accuracy with OAL.

 

[deadnbrkn84]

Re: 260 Starting Seating depth

Well I'm not gonna try another bullet unless I absolutely cannot get these to shoot as I have 2,000 of them. I have high hopes though as they have performed flawlessly in my old .308. I just didn't know if these was a good.260 starting point for how far off the lands

 

[deadnbrkn84]

Re: 260 Starting Seating depth

Well I'll try .010 off to start with and see where that gets me. I had them in the lands for the initial firings and it seemed inconsistant at best. Some would bug hole then others not at all. That being said I have a feeling the seating depth was not consistant because the bolt often felt different when closing.

 

[427Cobra]

Re: 260 Starting Seating depth

I would start off with at the lands, then move away in .010 steps, in my 260 139Scenars shoot best at the lands, 140Amax .015 off, 142SMK do about the same from at to .060 off