Over pressure. Safe load ?

[dvdt]

I'm a new reloader.

I started my voyage of load development over the weekend. I was using CCI large rifle primers, virgin lapua brass, 168 gr AMAX seating to 2.810 COAL. I used Varget powder.

My rifle is a bone stock 700 SPS-Varmint.

I loaded exactly what was in my Hornady book. I started at 32.6 and ended at 44.0.

I noticed lifting the bolt on the shots from 44 were a bit harder than others. It wasn't a "holy shit that's hard" but it was certainly noticeable. To me, that means I'm reaching the limit of a safe load very very quickly. The primers were certainly flattened but looked identical to the factory loaded Hornady 168 grain MATCH ammo I have.

Now, the thing is these guys shot F'ing AMAZING! 3 shot group measured 0.510. I say 3 shot as I was shooting 5 shot groups and know I pulled 1 (little scared to shoot a max load). All 5 measured right at 0.979 (100 yards).

I did not chrono this load. My book says this should be about 2600 ft/sec. It was 34F outside.

Is this a safe load for me ? They shot so damn well. If I hadn't pulled that 1 shot (and darn near froze my ass off) this thing would have shot right at 1/2 MOA. That's outstanding in my opinion! Either way, I just loaded rounds that will shoot 1 MOA and I'm just plain tickled pink.

I'm looking for words of wisdom. I'm concerned about the hard bolt lift.

Am I an idiot for not shooting these through a chrono ?

 

[RTH1800]

Re: Over pressure. Safe load ?

Sir,
I would offer the folling thoughts. Accuracy is good, but you can likely acheive the same result with several loads.
I am not overly concerned about the pressure at this point, but when it warms up you could have problems. I would back off about 1 grain and try that. You will get longer brass life, similar or better accuracy and most importantly, a confidence in your saftey.
JMO

 

[Victor N TN]

Re: Over pressure. Safe load ?

I agree about the powder difference when it warms up. Varget is one of the better powders. But there may still be a difference when the temps outside get up around 90*F. Just because a max load is listed, doesn't mean you have to run it that hot. I tend to run a slightly cooler load in most of my loads.

 

[Fuzzball]

Re: Over pressure. Safe load ?

" It wasn't a "holy shit that's hard" but it was certainly noticeable. To me, that means I'm reaching the limit of a safe load very very quickly."

Normal looking primers are not a valid indication of normal pressure and a noticably stiff bolt lift isn't a "mild" indicator of approaching safe pressure limits, it's already well over the normal limits. You're getting your warning, reduce the charge or take your chances playing Russian roulette.

 

[308sako]

Re: Over pressure. Safe load ?

Deleted in protest!

 

[Swan]

Re: Over pressure. Safe load ?

... and what grain increments did you load with each group? I'm surprised you only found that one accuracy node at max load.

If the 44gr load rendered heavy bolt lift, try 43.9, 43.8, 43.7, etc. I'm guessing you will find one almost as accurate at lower load. But, maybe not.

 

[former naval person]

Re: Over pressure. Safe load ?

44 grains is not a max load for my rifles. With the 168 gr my rifles like 45.5 or so...check the other things that .308 Sako mentions. You may be getting false feed back...or, you have a tight dimensioned rifle/barrel that won't tolerate the higher loads. All rifles/barrels are unique...just like you! JMHO

 

[Downzero]

Re: Over pressure. Safe load ?

The max from Hodgdon's website is 45 grains and I've found that to be safe even in a gas gun.

Why would you start at 32 grains? Standard reloading practice is to back off 10%...no more.

And don't fear a max load. Nothing you'll find in a book from 2010 is even near a max load, as evidenced from your Hornday book, which lists a max load a whole grain below what the manufacturer of the powder lists.

Work up a safe load in your gun, watch for pressure signs, and use your chrono so you know where you're at.

 

[AUJohn]

Re: Over pressure. Safe load ?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: dvdt</div><div class="ubbcode-body">
I noticed lifting the bolt on the shots from 44 were a bit harder than others. It wasn't a "holy shit that's hard" but it was certainly noticeable. To me, that means I'm reaching the limit of a safe load very very quickly. The primers were certainly flattened but looked identical to the factory loaded Hornady 168 grain MATCH ammo I have.


Is this a safe load for me ? They shot so damn well. If I hadn't pulled that 1 shot (and darn near froze my ass off) this thing would have shot right at 1/2 MOA. That's outstanding in my opinion! Either way, I just loaded rounds that will shoot 1 MOA and I'm just plain tickled pink.


Am I an idiot for not shooting these through a chrono ?

</div></div>
Hard bolt lift is a sign you need to drop down a bit. Virgin brass makes it more difficult to tell where you are really at though. 3 shot groups don't give you a real idea, once you think you have some accurate loads load 20 of each and shoot 5 shot groups. then pick the load you want.

Chronographs are not "that" important. Load for accuracy. IF you are shooting out past 800mtr's then you may need a speed check. Even if you have a Chronograph you still need to shoot your ranges and confirm your drop, you could just shoot them, calculate your speed if you need to and if not just not worry about it.

I would run some of the loads again with fired brass and double check for pressure signs. Dont load ANY higher than you are now until you are SURE you are not at the limit.

 

[AUJohn]

Re: Over pressure. Safe load ?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Downzero</div><div class="ubbcode-body">
And don't fear a max load. Nothing you'll find in a book from 2010 is even near a max load, as evidenced from your Hornday book, which lists a max load a whole grain below what the manufacturer of the powder lists.

Work up a safe load in your gun, watch for pressure signs, and use your chrono so you know where you're at. </div></div>

You do know how they work max loads out right? and why the loads vary? If they find this much variation you would think "we" can also see it

In some rifles listed max loads ARE exactly this and it's not some pretend limit for legal reasons. You also get large pressure peaks once you are in the hot range. These can come on very very fast. Changing brass can put you well into the danger area. Max loads are exactly this and most reloaders should stick below them.

Load for accuracy and look for pressure. Speed is not important for most shooters AND no way to judge pressure. I'm getting 2800fps from one of my guns while others can push for far more. I get pressure signs a bit above this and if I ran 100% I have no margin for hot days or a dirty bore. I find the hottest accurate load with safety and keep there. If this load is not sufficent for what I need I find different powder or projectiles.

 

[sambo3006]

Re: Over pressure. Safe load ?

Just curious if the load data is for the AMax bullet or another 168. Bearing surface of bullets can make a big difference in pressure. I would definitely shoot through a chrony. Shooting each load through as you go up will tell you lots. If you are getting uniform velocity increases then get a big jump with the next load (shoot a couple to ensure that it isn't just a big ES), you may be at an unsafe pressure. Lapua brass is tough enough that you won't get loose primer pockets until you are way over saami max pressures.

 

[Quicky06]

Re: Over pressure. Safe load ?

The front of a tub of varget says 46 gn max with a 168 smk. This shoots well in my rifle with no pressure signs in 60 degree weather will have to wait until warm weather to varify. I havnt gone higher but this is in well used hornady brass which had greater case capacity than lapua.


Were your lugs greased?
This makes a big diffrence