Home Forums Reloading Big Game Rifles Apparent High Pressure with Book Loads ?

I was getting over book velocity for that load, but lower than max velocity according to the book and ejector marks on the cases.

...Sounds like you need to load less than "book max." ...

This.

Why would you load near book max without working up to it while watching for pressure signs?

You don't happen to load a .277-caliber with 140 Partitions, do you?

You might take a look at dims across the board. First thought comes to mind is a tight chamber and/or thick case wall in the neck.

Only if the box was miss marked.

Sounds like you need to load less than "book max." It happens. Velocity is the best indicator as long as your chrono is accurate. But I've gotten funky chrono ouputs in changing light near dusk.

Ejector marks on the case head are IME some of the best pressure indicators.

Known rifle we've had for years that never gave a problem before.

Only if the box was miss marked.

How does one test for thick neck wall?

Just a Hunter - from what I saw in your first post, I think you have two separate problems, neither of which has been mentioned yet.

#1 - get rid of the WLR primers. They have been cracking and leaking like that for at least the last 10 years, it's a known problem that I think Winchester still hasn't fixed, because people keep using them anyway. I have several pitted bolt faces because of them, and it's not related to high pressure, just bad primer cups.

#2 - You need to measure the headspace on your sized brass, especially with new brass, don't just guess and turn the size die in 1/4 turn ( or whatever) past touching. I'd bet lunch you'll find headspace is a little too short with that new brass and is causing false pressure signs. Measuring headspace is easy if you have a digital caliper, and while it's easier with the right tool, you can do it with just an empty 9mm pistol case inverted over the rifle case neck. Compare to your fired brass from that chamber (with primer removed!) and set headspace back .001-.002".

I'm

I'm reading what you are saying about the Winchester primers. Man I have a lot of those.

The headspace might be right. I have a .284 that gives false high pressure signs too with new brass, but it hasn't shown an increase in velocity or bad primers so that confused me.

Thank you Mule Deer. The bullets go into the fired cases so that must not be it.

antelope sniper

I may have to do just that. Also I am thinking of trying a lighter load or reloading the fired cases and seeing if the headspace has been corrected by the firing. Sound idea or stupid?

I'm reading what you are saying about the Winchester primers. Man I have a lot of those.

The headspace might be right. I have a .284 that gives false high pressure signs too with new brass, but it hasn't shown an increase in velocity or bad primers so that confused me.

It sucks about the Win primers, I hear ya; I've got a couple cases of them myself that I won't use. Too bad, cause I liked them before they had problems.

Excess headspace will show false pressure signs, guaranteed. It's really simple to measure though to be sure, just compare to fired brass in that chamber, as long as it's not from a really mild load with the primer backed out. (When the primer is backed out in a mild load, the shoulder is bumped back.)

Here's picture to show what I mean. Zero the caliper on the fired case, then measure the sized case. The measurement is between the case head and the middle of the shoulder. This one is adjusted correctly, the caliper measurement shows the shoulder has been bumped back .002". You can use a fired 9mm case, something like a Hornady headspace comparator, or make your own like I did.

Sounds like you need to load less than "book max." It happens. Velocity is the best indicator as long as your chrono is accurate. But I've gotten funky chrono ouputs in changing light near dusk.

Ejector marks on the case head are IME some of the best pressure indicators.

I was testing loads for my wife 6.5x55 Ruger MK II the other day and got high pressure signs with under max Nosler book loads. The powders tested were H1000, RL-22 and H4831SC. The other component were Nosler Brass, 140g Nosler PT and WLR primers. I only shot one round from each load because I was getting over book velocity for that load, but lower than max velocity according to the book and ejector marks on the cases. This has never happened before. One primer appears to have leaked and one was almost pierced. At least it looked that way. Bolt lift seemed fine. I pulled the bullets and reweighted the powder and in all loads it was correct. Wondering what could be the cause?

I thought of too short of throat: Nope plenty long and well over what they were loaded.

Improper head spacing maybe that allowed the brass to slam back into the bolt, but again not a problem before. However this was new brass, but a brand I have used before.

Bad primers maybe, but again that higher velocity with a shorter barrel.

I thought my scale was off, but used the same scale right after these were loaded to load .257 Roberts that were spot on velocity and no pressure signs.

Any ideas would be helpful.

Have you checked the water capacity of the nosler brass. Then compared it to a different brand?

Thanks guys.

I think the first thing I'll do is try factory stuff (Question: I imagine the factory stuff is really light due to old rifles they are fearful of.)

Because of the Primer issue I think I will try some CCIs and see if that is a problem.

The soft case issue. That's a new one for Nosler as far as I have heard, but I think Norma makes brass for Nosler and have heard of some Norma brass being soft.

Also see what the Nosler brass water capacity is.

[quote=Just a Hunter]That said, the reduced case capacity should be enough to give you pressure problems with minimum loads.

Is that should or shouldn't give pressure signs?