260 rem problems

[JanSmit]

I got a 260 rem and have some issues.

shooting same hand loads, some of the cases show pressure and some not.
new lapua brass
the chroni speed does not change dramatically 3-5 ft
the barrel does have some chatter marks

We have tried different loads and cases and the problem still remains.

grouping nothing under 1" at 100

 

[Greyfox]

What is your load and velocity? I have seen similar issues with random sticky cases, after 1-3 reloads using neck sizing with recent lots of Lapua. My accuracy is very good though, .25MOA. I'm using 45gr of H4831sc with a 142 SMK. Velocity is 2800. I'm suspecting a problem with the brass, since FL sizing only gets some of the tight cases back down to size. I have tried two different FL dyes set to max. I also thought that this load may be too hot, but there are no visible pressure signs with any of my fired rounds. My rifle is a Savage LRP.

 

[J E Custom]

Shorten the loaded length by about ,020 just to see if you are to close to the lands. (Some chambers
have little or no free bore. Also check a fired case neck diameter and then a loaded neck diameter (
you should have .004 difference or more.

If you know someone that can do a "proper" lapping job, the barrel needs it badly (This should not cause pressure but it could effect accuracy and fouling).

It could be many things , but these are a few to try.

J E CUSTOM

 

[trigger puller]

+1 on the barrel and the length I load for a 260 and I can go up to 48gr of 4831sc before I see flattened primers. GOOD LUCK

 

[JanSmit]

Shorten the loaded length by about ,020 just to see if you are to close to the lands. (Some chambers
have little or no free bore. Also check a fired case neck diameter and then a loaded neck diameter (
you should have .004 difference or more.

If you know someone that can do a "proper" lapping job, the barrel needs it badly (This should not cause pressure but it could effect accuracy and fouling).

It could be many things , but these are a few to try.

J E CUSTOM

1.lands are clear
2.the chamber is not to tight checked neck size
3.speed 2812 our powder is different in south africa to yours but the load data on quick load shows the load as being fine(a friend shoots 1gr more powder on his 260 and no problems with speed of 2860)
4. Used new lapua brass and norma that was resized after fired

 

[Jinx-)]

What are your pressure signs, can you be more specific? Can you take a picture of the crown, does it look like this one?

 

[JanSmit]

flattened primers on some others blowout primers and some just have ejector pin shine
spots on the rear

will post pictures tomorrow
i am going to shoot it again tomorrow

 

[Jinx-)]

you might have to adjust your firing pin, sounds like cratering... What action are you using?

 

[Beluebow]

Make sure you remove all resizing lube off your cases.And your chamber is clear of any cleaning solvents.