What am I doing wrong

[Gun nut]

Headspace issue?

 

[OU812]

Like others have said, do you have a different scale to try? Maybe try different brass?

 

[C.Smith]

So I do have a beam scale I'm not a big fan of electronic. I have tested it by weighing different weight bullets and it seems to be right on. I have actually seen florescent lights cause a magnetic field that will effect a scale. I do not have those but have LED. I did think of that and shut them off and used a regular bulb with no issues one way or the other.

And my rifle will shoot factory rounds just fine, that is why I'm so sure it is my handloads.

Corey

 

[super-7]

Not being smart but I would get a good beam scale and weigh one load at a time electronics are nice but I don't trust them I guess I'm just too old school.

Yep this is kinda what I thought upon reading the OP!! Verify your scale readings..
Also is there another rifle you can chrono a couple of your original reloads with, that would rule out something with the fire arm.
With H-1000 and a 160 gr AB I would believe you should be closer to 68-70 grs to get 3000 fps.. Just saying .

 

[C.Smith]

I was getting over 3050 fps second. Way to fast for the 62 grains of H1000.

Corey

 

[Polaris]

I think the only plausible option we haven't ruled out is the accubonds. Have you tried a different bullet, perhaps a common cup and core design to see if the problems replicate? If they do not, I would contact Nosler and send them a sample for lab testing.

I'm not a metallurgist, but wondering if something could go haywire with the bonding process or the alloy that would spike pressures and velocities. Kind of like the Speer Deep Curl, which was quietly withdrawn for this reason.

As a range master, I've seen many different causes of excessive pressure, a couple leading to firearm damage, and yours has me stumped. Generally a carbon or metallic fouling ring will cause sticky extraction, but not severe overpressure. If it is in the throat, it can spike pressure, but generally not velocity. An oily chamber will cause excessive breech pressure, but not chamber pressure. Extreme temperature can cause both pressure and velocity spikes. I've seen this on closed bolt full autos with ball powders, when a round was chambered for a prolonged period in a smoking hot rifle.

 

[OU812]

I would try some different brass, may have got a bad batch.

 

[C.Smith]

Well you guys have given me some good ideas. My buddy dropped off some other bullets to try. I also have some older Partitions (the machined kind) I may try as well.

Corey

 

[muleman]

Is your chrony set correctly? I once had problems like this and ended up being the chrongraph. It was a folding type that was opened up to completely flat causing an artificially high reading.

Scott

 

[BF375]

What kind of rifle/barrel is this?

 

[C.Smith]

Its the stock barrel, and yes the chronograph was set up correctly. I been talking to people today that know more about reloading than I. Apparently the factory rounds were showing slight signs of over pressure as well, flattened primers. I've come to the conclusion that either I take it to a gun smith to figure it out or change the barrel. I'm opting towards the barrel, as I bought this rifle years ago as a donor. I'm actually thinking I will make it into 300 WM.

Corey

 

[C.Smith]

Just an update I've decided it has to be my barrel. I bought this rifle years ago as a donor action that I've decided to do just that. Ordered a McGowen barrel for it yesterday and I'm selling all my 7mm RM stuff.

Corey