308 load question about Max charge

[p5200]

I have some rounds loaded to the Hornady 10th edition load book. Everything is to the book specs for Varget powder except, the powder charge is .3 grains over the max. This is for 168 grn. Hornady A Max. Should I pull the bullets or, should they be safe to fire? I've got 8-10 rounds loaded like this. Thanks again!

 

[rijndael]

What are the details of your load? brass, charge, coal, etc.

 

[p5200]

Winchester brass, 44.3 gr. Varget, 2.800" COAL. 168 gr. A max.

 

[rijndael]

Your Winchester brass may have more internal volume than what's listed below, mine did. If it does, pressure would be a little lower.

Here's the defaults in GRT.

 

[Straightshooter1]

Winchester brass, 44.3 gr. Varget, 2.800" COAL. 168 gr. A max.

Here's some numbers from QuickLoad that you might find helpful (based on Winchester brass volume of 57.3 gr H2O:

 

[Jager]

I have some rounds loaded to the Hornady 10th edition load book. Everything is to the book specs for Varget powder except, the powder charge is .3 grains over the max. This is for 168 grn. Hornady A Max. Should I pull the bullets or, should they be safe to fire? I've got 8-10 rounds loaded like this. Thanks again!

So, how did you arrive at this load? Did you run a ladder, starting at some lower charge? Did someone give you the load, and you found out later that it was hotter than Hornady's max?

The load is one thing. How you got to that load is every bit as important.

 

[p5200]

I started at a lower load three different loads all together I labeled each baggy tried the first two loads with no problems. A few days later, I was going to use the max load but, when I read the label on the baggy I thought it didn't sound wright so I re-checked my Hornady load book and it said 44gr. for max charge. This is the rifle I'm using. https://remingtonarmsusa.com/remington-model-700-tactical-aac-sd-308-winchester-heavy-barrel-rifle/

 

[rijndael]

Well, I'm not going to be the guy to tell you it's fine to shoot.

I will say that if these exhibit pressure signs, you may ruin 10 pieces of brass. It's not super easy to replace these days. And, it's pretty easy to pull down 10 rounds and re-load them, it's not like you have 100 of them.

 

[p5200]

I don't blame you, and I'm thinking the same thing I'll just pull them.

 

[dsinfour]

Just shoot them. I shot them with 45 grains

 

[Straightshooter1]

I don't blame you, and I'm thinking the same thing I'll just pull them.

I've used more than 44gr of Varget pushing 155 SMK's and no problems with cases having less less volume than Winchester brass (see pic below). If I was using Winchester brass, I'd have less pressure and velocity than I got. But, it's ALWAYS wise to start low and work your way up.

 

[Charlie-NY]

Today, I shot several 168TMK bullets with 44.0 Varget in Lapua cases. No signs of pressure whatsoever. Your brass probably has greater volume than the Lapua brass. I'd shoot them without worry but that's just me. A load of 44.4gr is only a 1% increase in charge.

 

[rijndael]

No signs of pressure whatsoever. Your brass probably has greater volume than the Lapua brass.

And, he's got a factory throat. The bullet won't hit the lands until 10" down the barrel.

 

[Ned Ludd]

SAAMI MAX pressure for .308 Win is 62K psi. The pressures predicted by responders to this post using your listed specs and either QuickLoad or GRT range from 55.1K to 57.7K psi. You're probably OK to shoot them, but only you can make that decision. You can easily go ahead and pull them (there aren't very many). That is the safest alternative. At the other end of the spectrum would be to go ahead and just shoot them all. A "middle ground" alternative might be to shoot one, record velocity, and make an estimate from velocity and/or the presence/absence of pressure signs on the brass whether you're willing to shoot the rest.

 

[p5200]

Well I fired three rounds don't see any obvious signs of over pressure or anything. Funny thing though, The brass measures the same before and after firing?

 

[p5200]

When closing the bolt on the 3 rounds fired it seemed to have quite a bit of resistance. Maybe they fit the chamber tight to start with? Only thing I can think of that would cause them to measure the same before and after firing.

 

[p5200]

I believe I will try bumping back. .002 on the 3 fired cases and see how well the bolt closes on them. My loaded rounds must not have been bumped back any, from their expanded state from previous firing.

 

[Straightshooter1]

Well I fired three rounds don't see any obvious signs of over pressure or anything. Funny thing though, The brass measures the same before and after firing?

You need to be more specific as to what you measured.

When closing the bolt on the 3 rounds fired it seemed to have quite a bit of resistance. Maybe they fit the chamber tight to start with? Only thing I can think of that would cause them to measure the same before and after firing.

That resistance very likely could be due to just the lengthening of the case from base to shoulder; where to keep it from having that resistance would be to bump back the shoulders. But again, it's a matter of the specific measurements before and after firing.

BTW: it'd be helpful to know what kind of velocity your getting with that load.

 

[p5200]

I used the Hornady comparator. 400 gauge on the unfired and the fired cases both. I don't have a chronograph but hope to get one.

 

[Clark]

308 win is saami registered at max average peak pressure 62kpsi.
Here is an overload work up I did while measuring extractor groove expansion.
The measurable change was between 73kpsi and 78kpsi quickload.