Silly question about min/max loads

[colt933]

I've handloaded for about 12 years with great results.

I just got a new .300WM rifle (700P 26").

I'm using 190SMK and 4831SC, new Win cases, REM mag primers(all I could get at the time).

The Hodgdon manual states 69.0 and 73.0 as min/max charges for this combination.

Lots of data just gives a max load and says to start 10% below max.

But the Hodgdon manual's min load is only about 5% below max.

I have found an accuracy node at 69.6gr for my rifle (cloverleafs at 100 yards). I did not experience signs of over-pressure until 73.9gr, .9 above max.

Most people say they find their accuracy node somewhere near the middle of the min/max range.

But I have found it at near the MIN from the Hodgdon manual, but it would be near the middle of the range if I had started 10% below the max.

Thoughts???

 

[ChadTRG42]

Re: Silly question about min/max loads

There's a lot of factors that go into what each company will publish for min/max loads. Some listed max loads are watered down for legal reason's, and some are pretty close to actual max.
So, if they post a max of 73.0 grains, and you are using the same components and bullet seated to the same COAL, then you "should" be fine.
On your low end charge, you have found the low end accuracy node in your rifle. There will also be another node at the high end near max (and maybe one in the middle). Most shooters/reloaders want fast and accurate, so most of us load near max, or just over book max. I would work around (above and below) the 73 grains in small increments, and see what your rifle likes. Just stay under your 73.9 grains. There will be another node there, I promise!!!

Chad

 

[colt933]

Re: Silly question about min/max loads

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ChadTRG42</div><div class="ubbcode-body">
There will also be another node at the high end near max (and maybe one in the middle). Most shooters/reloaders want fast and accurate, so most of us load near max, or just over book max. I would work around (above and below) the 73 grains in small increments, and see what your rifle likes. Just stay under your 73.9 grains. There will be another node there, I promise!!!

Chad
</div></div>

Yes, 73.3 is another accuracy node for this rifle.

 

[ChadTRG42]

Re: Silly question about min/max loads

You should be fine!! It's under your known max, and shoots well. Does it shoot better than the low end node? The high-end node should also give you tighter ES/SD numbers than the low one. Did you chrono them?

 

[colt933]

Re: Silly question about min/max loads

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ChadTRG42</div><div class="ubbcode-body">You should be fine!! It's under your known max, and shoots well. Does it shoot better than the low end node? The high-end node should also give you tighter ES/SD numbers than the low one. Did you chrono them? </div></div>

Accuracy is pretty similar at both loads - haven't picked a clear winner yet.

I haven't chronoed them. I was using the OCW method for the first time. I've put together some 3-round batches at 69.4,69.5, 69.7, 73.2, and 73.4 to further refine if possible and will chrono these, hopefully this weekend.

 

[ChadTRG42]

Re: Silly question about min/max loads

That will work!

 

[colt933]

Re: Silly question about min/max loads

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ChadTRG42</div><div class="ubbcode-body">
On your low end charge, you have found the low end accuracy node in your rifle. There will also be another node at the high end near max (and maybe one in the middle).
</div></div>

So might my 69.6gr accuracy node actually be in the middle?

It is pretty close to the middle if you started at 10% down from 73gr .

If 69.6 is not the middle accuracy node, then if there was an accuracy node between 69.6 and 73.3, there would only be about 2 grains difference between low and middle and another 2 grains difference between middle and high. That doesn't seem like much difference (2 grains) in that gigantic case.

Thoughts???

 

[ChadTRG42]

Re: Silly question about min/max loads

I don't know without shooting it, but I would think you found the 2 that are there. I don't think there would be one in the middle though.

 

[Fuzzball]

Re: Silly question about min/max loads

Book "min-max" loads have nothing to do with accuracy nodes. What they recognise is that powders need to burn consistantly to have a good chance of shooting well and that means near the "normal" top pressure range. Loading below suggested min.s simply indicates the pressure may be insufficent for the powder to do well with that bullet weight. Over max has its own set of problems.

Accuracy nodes occur where they occur. Anyone making statements about where it's most likely to occur simply doesn't have a lot of reloading experience. Or has been very, very lucky.

 

[colt933]

Re: Silly question about min/max loads

Nevermind - questions answered.

Thanks to all who participated.

 

[308isgreat]

Re: Silly question about min/max loads

The only answer I can come up with is to go out there and try it.

 

[Unsichtbar]

Re: Silly question about min/max loads

http://practicalrifler.6.forumer.com/viewforum.php?f=4

You may have looked at this site, people that us OCW post there test ask questions. You might find it of interest to look at post of targets any cal or serach for ( 300 win mag )see if you can see scatter groups, loads with a common POI which is what you are looking for. Shoot those 3 or 4 at 300 yds to prove then pick middle load refine by ajusting seating depht.

 

[MitchAlsup]

Re: Silly question about min/max loads

A typical cartrige in a typical barrel with have 4 to 6 accuracy nodes at least 3 of which are near OCW loads between the min to max spread.

Most reloaders have an intimate understanding of why not to go (much) over max loads (Kabloomo). But few understand that there are a raft of really bad effects when underloading under min. Once the bullet starts to decelerate in the barrel when the pressure drops the supersonic blast wave runs into the back of the (now slowing) bullet, this causes a reflectionoff the base of the bullet. This new shock wave flows back down the tube detonating any unburnt powder, often raising pressure far above the limits of even the best steel (RSI shows 120K PSI) . This is known as secondary pressure and can cause lots of shooting problems and enve blow up guns.