Reloading 308

[ManrisFrack]

Yay, a gun thread!

My journey with this caliber started on a thread in the other forum and it needs to continue here.

Loading for a Savage 11 Lightweight Hunter in 308 Win.

PPU Brass
Rem 9 1/2 Primer
Hornady 150gr SP Interlok, Flat Base
2.765" OAL
Varget

Did up a ladder in .5 increments from 43.0gr to 46.5gr, 5 shots each. Primer edges were still round, no cratering and no change in bolt lift at 46.5gr. Best group was at 43.5gr - about 1.25 MOA. Hornady's max with 150gr bullets and Varget is 44.6 if I remember correctly. Hodgedon lists 47.0 max with Nosler Ballistic Tip.

Do I keep going up or be content to zero in on the node around 43.5?

I also did additional groups at 2.735 OAL and 2.800 OAL with 45.0gr. 2.800 was the best of the three lengths but still not great. I plan to load in increments of .2gr from 43.3gr to 44.1gr at 2.800" to perfect the node. The improvement I saw loading longer at 45.0gr should translate to the lower charge weights, right?

 

[RandallOfLegend]

I would consider maintaining a constant charge weight and trying different lengths. If you close gap that bullet jumps to the rifling you will find some increased accuracy. As you have seen, more powder/pressure/velocity doesn't necessarily make it more accurate.

You can find the max OAL by using an unprimed case with a loosely seated bullet. Close the bolt on that. Then back off the OAL to a safe threshold. Depending on bullet weight/nose profile, you may not be able to hit the rifling before the cartridge is too long for the magazine.

5 shots is okay. But once you find your favorite load you should try to shoot 10-20 to know that you're reloading process isn't causing variability in the accuracy/muzzle velocity

 

[Silverado1]

Set your depth at 20 thou off the lands and find your optimal charge weight. After finding optimal charge weight if your not content with the accuracy you're seeing you can start to play with other variables like seating depth, different primers, powders etc....

 

[ManrisFrack]

So I ended up going 43.3 to 44.1 and I tried the 47.0 as well - all at 2.800.

I shot Friday and the results were disappointing. With every load I'd put two close and one would open the group to 1.5" or worse. Most of the time it was the last that opened it up, but not always. I suspect the wind was a factor (NNW @ 15 gusting to 25) and I didn't feel too consistent with my head position. I think I'll settle on 43.8 for now. The loads on either side went about 1.5 MOA - good enough to hunt with for now.

The 47.0 actually had the 1st and 3rd making one hole. The primer looked good still so I might try that again.

@RandallOfLegend What about my process could be causing variability? I know concentricity can be a big deal but I do not have the tools to detect or correct for that. Likewise, I don't have a chronograph yet - hopefully a MagnetoSpeed is in the cards for Christmas.

 

[MilesTeg]

Have you ever done a ladder test? I did one on my 308 with Varget and 165gr sierra gamekings. I was surprised and found my accuracy node much lower on the powder charge than I expected. I have used these gamekings shooting steel out to 600 yds hitting a 2/3 IPSC every time I pulled the trigger. I have yet to mess with OAL of the round. I think there is a smidge more accuracy I can gain with it, I just haven't had the time to do the work. I guess my point is do a ladder test and find the node on your barrel.

 

[RandallOfLegend]

@RandallOfLegend What about my process could be causing variability? I know concentricity can be a big deal but I do not have the tools to detect or correct for that. Likewise, I don't have a chronograph yet - hopefully a MagnetoSpeed is in the cards for Christmas.

One of the best bangs for your buck is a chronograph. You 2 very important statistics (IMO) are the velocity standard deviation and extreme spread of your loadings. Lower variability in your muzzle velocities go a long way. Depending on your target range, it's hard to say what those values should be. But If you're testing at 100 yards, 50-100 FPS extreme spread may be okay, but at 200-300 yards maybe not so much. But having the data to say "The standard deviation of my rounds went from 50 FPS to 10 FPS, but I saw( increased/worse/no change) in accuracy" allows you to pinpoint what matters.

A lot of things affect velocity, which is why I like it as a measure. Some things you can control manually, others might require different dies. Velocity isn't everything, but it's an easy place to start.

Charge Weight
Primer Brand
Crimp
Neck Tension
Seating Depth
Bullet Wedge (Indicated Run-out of Bullet to Brass)

 

[ManrisFrack]

Did up a ladder in .5 increments from 43.0gr to 46.5gr, 5 shots each. Primer edges were still round, no cratering and no change in bolt lift at 46.5gr. Best group was at 43.5gr - about 1.25 MOA.

Have you ever done a ladder test? I did one on my 308 with Varget and 165gr sierra gamekings. I was surprised and found my accuracy node much lower on the powder charge than I expected. I have used these gamekings shooting steel out to 600 yds hitting a 2/3 IPSC every time I pulled the trigger. I have yet to mess with OAL of the round. I think there is a smidge more accuracy I can gain with it, I just haven't had the time to do the work. I guess my point is do a ladder test and find the node on your barrel.

Did I do it wrong? I thought that was basically what a ladder was.

I've seen seen the method where you just do one round at each weight, fire them all at the same target and see which 2 or 3 have the lowest vertical. I shied away from that because it doesn't seem to allow any shooter error and keeping track of which charge hit where gets tough unless you are by yourself and can run down to the target when you need to.

I'm still pretty new to reloading. If I've made over 200 rounds so far, I'd be surprised. As such, I don't have a full compliment of equipment or components. I'm just trying to get MOA out of the basics.

 

[MilesTeg]

I did miss read your post. I personally do the ladder test on one target and see where the point of impact start to group up. To me it sounds more like you did a group comparison (there's a name for it but I can't remember it right now). If you don't have access to a 200yd range a ladder test might not work for you. First one I tried for my 308 was 100yds and didn't tell me much. Someone suggested to shoot at a greater distance and it made all the difference in the world.

 

[ManrisFrack]

I did miss read your post. I personally do the ladder test on one target and see where the point of impact start to group up. To me it sounds more like you did a group comparison (there's a name for it but I can't remember it right now). If you don't have access to a 200yd range a ladder test might not work for you. First one I tried for my 308 was 100yds and didn't tell me much. Someone suggested to shoot at a greater distance and it made all the difference in the world.

I do have access to 200. I'll try that out, thanks.

 

[meketrefe]

The ladder system is popular but it has limited value.
One ends up shooting a lot more test rounds than necessary.
I might do a ladder testing but becase so many calibers and developments, more times than not I do the following:

A) Segregate brass by brand /year but w/o being paranoid.
B) Prep & trim brass all consistent. If max accuracy is required then make sure necks are consistent and turn them if needed.
Same thing with flash holes and primer pockets. When using military brass this might be done after beveling the primer pocket.
C) Measure bullets and weight for consistency. If max accuracy is not the goal then just make sure you check for consistency randomly.
D) First find the max COAL dictated by the chamber or magazine whichever comes first unless one single feeds the the magazine is not an issue.

So having all the above into consideration one comes to the actual loading and seating.

Performance Load testing

A) take note of the primer maker, model, year and batch them if you can.
B) Same thing with the powder.
C) Check for the max and min loads according to reloading manuals. Might want to check based on case used (volume) and also
double check with the bullet manufactures load info for the specific load. Specially for that specific bullet and COAL tested.
These information might give you a good idea of the virtual max loads for the given COAL.
D) You might pick up a load in the middle of that range for the COAL you want to test with your chamber. you might want to
back out lets say 15 thousands from you max COAL and then start in the middle of the table. If the COAL you have is
larger than the COAL in your reload data and you are not jamming against the lands this should not yield more pressure.
Test a couple of loads like that and take note of accuracy, speed if you want, dimensions.
I would read the delta using a bullet gauge vs. measuring from the tip that is not that precise.
E) If primers look good and no cratering or stretching is apparent and you want to keep going pick up a load between the last load
and max load but do not change COAL. Only change one thing at the time.
F) Test a couple of loads and check for primers, craters, swipes, etc... Also write down accuracy and speed if you want.
G) If everything checks you might be in the sweet spot for most loads that is below 100% density. Here you can do two things,
increase slightly like 1/2 grain with the same COAL or stay where you are with powder and change COAL.
This is the time you might want to take three shots with the same load looking for accuracy.
Regarding primers if you just see slight flattening then this might or might not be a sign of over pressure. Some primers are
soft and flatten out faster than harder primers like military primers. Also the flash holes impact primer pressures.
Also only cratering alone is not a sign of high pressure for the same reasons above.
Most times pressure signs come in two or three so look for swipes, extrusions of any kind following primers and necks.

Performance load testing for hunting.

Once you follow the three jump above you might find yourself a sweet spot pretty quickly that you like for accuracy
but lets say you want to trade off a bit of that accuracy for speed and power for a less accurate more powerful
hunting load. The hottest loads will rarely be the most accurate for several reasons but they might be plenty accurate
and you should take the same approach but approaching or exceeding the 100% density. It is not unusual to have
compressed loads for hunting. The only consideration is to do 2 shot tests and small increases when approaching
the red zone.

It is ok to get a slight flat primer for a hunting load. The thing is brass will not last that long and might reserve
a batch of brass for that purpose. Some might even get lost in the snow or mud so who cares anyway.

In Summary:
When you get information online take and validate to get an idea but also take it with a grain of salt.
Everything starts with knowing your own chamber and because chambers, barrels, rifling are different what is ok for one person might not work at all for another. Reloaders and manufactures give us very limited information about all these conditions so a lot of the load data is a bit arbitrary. The first thing is to know your own chamber.

Eventually you will get to the accuracy by finding the loads
and then being very consistent. This means from prepping to charging to seating and crimp every round is
a carbon copy of the previous and next round.

Alternatively one can take some commercial match ammo or other ammo one likes and test it and then everything
possible to make a precise replica of that round. For this it might be nice to know the speeds at the muzzle
so we can look for fuel to reproduce the speed with the same cases and COAL.

the ladder testing has some value for some people but there are many ways to skin a cat.

I hope this makes sense.