Conflicting info between Hodgdon and Sierra source

M

Mohave-Tec

Private
Minuteman
Jun 25, 2010
51
0
65
#1
Another brand new reloader here. My Sierra manual tells me a max load of 44.8gr with Varget and 155 SMK. The Hodgdon web sight says to start at 44 grains with this combination and maybe work up to 47 grains. I don't think I can even get 47 grains and the 155 in the same neck. I'm shooting a 26 inch 1:12 barrel.
Yesterday, first time out with my own loads I was shooting roughly bullet through bullet with 41.5 grains but I really hope to find another accuracy node at much for than 2600 ft/s. I'm looking at 800 yards and I need more speed but I don't want to blow me up. What is the truth about this common combination?
An answer or link would be great. I've searched but this sight is so freaking huge all I get is the Maytag repair man of directions to Sears.
Thanks a bunch.
 
#2
Re: Conflicting info between Hodgdon and Sierra source


Well that depends. Are you jamming the bullet into the lands or leaving some distance between the ogive and the lands? Are you loading for a bolt gun or gas gun?

I would cautiously work up the charge .2 of grain at a time and not exceed the the lowest max charge until I could measure how much (if any) expansion you are getting at the solid case head, immediately forward of the expansion groove. A good gauge is too measure a factory round right out of the box (with an accurate tool- micrometer or vernier calipher) then measure that same case after firing in your chamber.

If your loads exceed that amount of expansion; back off!
 
#3
Re: Conflicting info between Hodgdon and Sierra source

I'm a brand new reloader. I've been curious as to where my rounds are sitting in the chamber and I'm trying to make those determinations now but most of us new reloaders just cut a case to the generic 2.005 then finish out the round at 2.80 like all the books say. I like the advice for comparing a factory round before and after. I am measuring the stretch before and after my in my own rounds.
I'm shooting a bolt gun.
I don't think many brand new reloaders are are measuring the expansion in a selective section of a case, not yet. I was rather hoping I could tax the experiences of others for receipe while I gain education through my own experiences. I figure that Varget, 155 SMK and a 26 inch 1:12 barrel is probably one of the most repeated combinations in modern history, I was just hoping I could hear some powder weights from people who are or have experience shooting this combination out to 800/1000 yards.
 
#4
Re: Conflicting info between Hodgdon and Sierra source

I do have some Federal SMK in fact. I will measure these. Do you know the powder and weight used for making these?
 
#5
Re: Conflicting info between Hodgdon and Sierra source

Keep searching.

http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=323517&gonew=1#UNREAD

The 155 is more and more understood to be best at, or slightly above, the max loads listed in the Hodgdon manual. The Sierra manual is widely believed to be conservative in their load recommendations compared to other sources using comparable bullet weights in the same caliber. And. it's friggin huuuge!

I have run the 155 SMKs (2155 & 2156) and 155 AMAX at 47.3 grains of Varget in Win. and Hornady brass and am going to mover up to 47.6 in the next iteration.
 
#6
Re: Conflicting info between Hodgdon and Sierra source

It is very common to discover that a particularly slow load shoots super precision at 100-200 yds. However, if you want to shoot some distance, these loads are not gonna cut the mustard. You will undoubtedly find an equally precise load with greater velocity. Sierra is very conservative with most of their data. To get a 155 Palma or scenar cooking to 2900 (roughly the velocity required to reach 1000+), you need at least 47 gr of powder in the Varget burn rate. I get about 2900 with 47 gr of H4895. But don't just jump to 47 gr in one shot. I would start at about 44.5 and work up in 1/2 gr increments, inspecting each case after firing. If you are free of pressure signs, move to the next load. Once you get to a fast load that shows promising precision, I would move up and down from that load in about .2 gr increments to fine tune it. Once you find your money load, play with the seating depths a bit. Note that the 155s have to be seated a bit deeper than your average bullet because you need to get enough surface bearing in the neck of the case. For me, the longest I can load them is about 0.05" from the lands. I have shot them as far as 0.12" jump, and they shoot really well.
 
#7
Re: Conflicting info between Hodgdon and Sierra source

One thing you will notice if you look at your Sierra manual is that they do not list pressure. They do not have pressure barrels to measure the pressure of any of their test loads. They have a ballistician that looks at the fired case for signs of pressure and that is how they make their determination.
 
#10
Re: Conflicting info between Hodgdon and Sierra source

Another example of why it's good policy to learn to read pressure signs and load incrementally hotter for each new gun until you've found what's too hot.

FWIW, I start getting pressure signs that worry me at 47.6 grains of Varget with 155-gr Scenars.
 
#12
Re: Conflicting info between Hodgdon and Sierra source

As a new reloader you should always lean to the lower side of a charge and work your way up. Always lean on the safety side of things.

In addition make sure you are logging and keep track of your loads and any info with them so you can repeat what you have done and not have to start over.

We offer some good reloading pages to help you out!!

LD-CV-1.jpg


LD-S-1.jpg

 
#13
Re: Conflicting info between Hodgdon and Sierra source

I'm not quite sure I fully understand what you are telling us but the crux of it seems to be why do the two manuals differ.

Answer to that is they develped their data with different rifles; if they used the same one, the data would probably be quite simular. Point is, there's is also different from yours so you add a third large variable to the equation and your results aren't likely to match either of theirs. So, how do you find what's best - and still safe - in yours?

This is not a science in which we can say 'precisely add this to get exactly that' result. The ONLY sound rule in developing a load is, "Start low, work up slowly to book max unless you see excess pressure signs; if that happens back down a bit." NO OTHER rule can allow us to obtain safe max performance from our rigs. And, yeah, it places s bit of responsibility on the loader himself but there is no way around it.
 
#14
Re: Conflicting info between Hodgdon and Sierra source

47grs would be a compressed load. It will pretty much fill up the neck- just seat the bullet anyway, there's room in there to squish it all together! But as others have said, load up slowly and look for pressure signs. I've found this same issue loading Sierra 165gr GameKing- Sierra's max was Hodgon's min. Hodgon is your answer. Velocities were so slow with the sierra loads, it was obvious something wasn't right.
 
#16
Re: Conflicting info between Hodgdon and Sierra source

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rob01</div><div class="ubbcode-body">Trust Hodgdon. </div></div>

+1

Hodgdon makes the powder so they definitely don't want any bad information out there. In my testing I've noticed their max loads tend to be very accurate (at least in my guns) predicting where I start to see pressure signs.
 
#17
Re: Conflicting info between Hodgdon and Sierra source

... and surely whatever they publish is on the much lighter side due to liability, no?

My recommendation is start low like everyone says, maybe at 45ish grains though, work up in 0.3 gr increments checking for pressure and such as you go. Another thing to consider is the gun shooting it. You stated 26" 1:12. Is this a factory Rem by chance? If so, you will probably want to load them longer (mag-length perhaps). Those lands are a looong way away.

Get some 155 Scenars as well. Use Lapua or Win brass and I'd bet you find something sweet near mid 47grs or so.
 
#18
Re: Conflicting info between Hodgdon and Sierra source



<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Falar</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rob01</div><div class="ubbcode-body">Trust Hodgdon. </div></div>

+2</div></div>
 
#19
Re: Conflicting info between Hodgdon and Sierra source

Fantastic information all.
I missed checking this thread to be watched and lost the thread. I just found it and can't wait to get above the 45 grains I was limiting myself to via the Sierra manual. It's a good time to come back to what I believe will be my best load as well. I now have chamber gauges and Lapua brass.
Again, thanks for the precise directives. They will be very useful.
 
#20
Re: Conflicting info between Hodgdon and Sierra source

Sometimes you will also find different max loads listed. The brass cases (of the same caliber, but different manufacturers) have different internal capacities. This alters the pressure, and thus the velocity of the same bullet. Milsurp brass is often thicker than commercial equivalents. Some brass is also harder and able to withstand pressure better.

Keep in mind too the differences in chambers (same cartridge). What is safe in one rifle may be over pressure in another.

Like others have said, start low and work up a load for YOUR rifle.
 
#21
Re: Conflicting info between Hodgdon and Sierra source

Well, 46.0 grains of Varget under a 155 SMK in my LC cases (capacity at 56.0 grains water, fired cases from my chamber) are just a tad too hot, both in the first signs of pressure and the modeling of QuickLOAD. Not far over pressure, but over pressure nonetheless.

And it's one of my data points of the NON-node part of the OBT theory correctly predicting not so good accuracy. 1.5 MOA. Same for Berger 155.5s with a different powder, and 155 Scenars too. Have to back down to 2650 fps from my 22-inch barrel to get any accuracy out of that bullet weight.

Yet, the Hornady 155-gr A-Max factory loads shoot great in that same rifle, at only 20 fps slower than my Varget loads (2803 vs about 2823). Those loads use a green powder similar in appearance to Varget, too.

It's a strange world, chasing that accuracy demon.
 
#22
Re: Conflicting info between Hodgdon and Sierra source

When I am starting out with a new powder and new bullet, I do an informal pressure test by making up one cartridge in a series of charge weights ranging from published min to near published max.

I then fire them individually, working my way up through the increments. I examine each fired case carefully for pressure signs before proceding on to the next. based on pressure signs, I will make a conservative decision about where to stop, and this becomes my tested max charge for the bullet/powder combination <span style="font-style: italic">in that particular rifle</span>.

I then begin ladder testing for accuracy, working up from the lowest charge upward and ladder testing for the whole range of charges. For shorter range loads, I will use the slowest accuracy node, and for long range, the slowest node that will render good accuracy at the actual distance.

As a new handloader, you should throughly research pressure signs until they make good sense to you before you start working with loads that are near or beyond published max charges. I'll save you some time and trouble and share with you that after several decades of handloading, I have found that max loads and hot loads aren't really such a very good idea anyway.

Greg
 
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