Help a noob with some load development interpretation please.

[Centurian22]

I finally got out to the range to test my first reload work ups for my .308 and .32S&W Long. The .32 was mostly just a function and basic accuracy test that went well. The focus of my full day at the range was the .308's.

I would appreciate some help in interpreting my .308 load development. I think I know where to go but want input from others who have more experience than I do. These are 168gr Sierra Matchking HPBT loaded in once fired federal cases with CCI LR primers and the listed charge weights of IMR 4895 fired from a savage axis on bag rests. The reason for the steps changing from .9 to .5 is I was following the OCW method. I was going to have an 8th step at 45.6 but the first round I fired stuck the case hard (couldnt pull the bolt out, had to tap lightly with a wooden block to remove it). No significant pressure signs at 46.1gr. I obtained my charge ranges from a combination of Sierra, Hodgdon and Lyman with Hodgdon being the highest allowable charge.

I think that I have a 'node' around 44.1gr based on the OCW, and could possibly do some more testing between 42.7 and 44.1gr based on the ladder test. This also matches up with the 43.6 that is listed as a likely OCW load for 168gr SMK with IMR4895. I have also seen a lot of people quote 41.5gr. I have 4 of those loaded up but ran out of daylight to try them.

After fine tuning these I'll be seeing if the charges will carry over to my 165gr Sierra gamekings, then doing work ups for 147fmj, 150sgk, and 150 rem bronze points.

Thanks for any info you can provide.


OCW target with charges. The 42.7, 44.1, and 45.1 all have called fliers.


Ladder test.


'Map' of ladder test.

 

[Andrew Leigh]

Hi,

I believe you have two accuracy nodes, the one potentially better than the other. I would load up 20 rounds for the next exercise;

2 fouling rounds at any of the mentioned loads.

3 rounds each of 43.3 / 43.6 / 43.9gr. I would also preferably shoot two strings of each. i.e. two groups of each load.

3 rounds each of 40.6 / 40.9 / 41.2. Again I would recommend two strings of each. I would suggest that this could be the better of the two nodes.

If the ladder test was not done at 400yards plus I would not count on it too much.

The OCW method relies on triangulation as well. A normally distributed 3 shot group should be in the shape of a cloverleaf, be it tight, cutting each edge or loose like an isoceles triangle. Any other group shape is generally indicative of the bullet exiting the barrel as a point other than a node and or problems with the rifle or shooter like bedding or technique.

Your results are very similar / identical to what I get using the OCW method. Lateral stringing, vertical stringing, open group and then I normally get three close on the money and take the middle one.

Did you shoot on alternate targets, round robin style, as outline by the OCW method ot three consequtive shots on one target? It is important to do the round robin style. Please confirm.

0.9gr step on a .308 cartridge is too much.

 

[Centurian22]

It was all shot at 100yards, and the OCW was shot in a form of round robin: 1-7, 7-1, then 1-7 again. Only passing a bore snake once between strings. Problems with the rifle or shooter are definitely possible. It's "only" a savage axis, and I'm relatively new to center fire rifle shooting (I've fired probably 400-500 rounds of center fire rifle but thousands of .22).

My understanding of the OCW was that you're not looking for the tightest groups (as my 40.9 shows) as much as the most consistent POI over a spread of charges. I'll re-read to make sure I haven't crossed info (also very possible). This is why I think the 44.1 is a node as the 43.6, 44.1 and 44.6 all have POI's high of center. Since I was shooting in cold (35-40 degree) conditions, I'm eliminating the 45.1 to make sure I'm still safe at summer temps.

I agree that .9gr seemed too high but as I said, I was just following the OCW instructions, and with a 5 grain range, 4rds at .5gr steps would have used almost half of my 168's. I'm hoping to reach a good load while still having a box (20rds) worth left to load. I haven't looked lately but for a while 168smk's were not to be found.

Thanks for the quick reply.

Edit to add: Once the OCW node is found I am under the understanding that the tightness of the group can possibly be tuned by adjusting the COAL.

 

[Andrew Leigh]

...... OCW was shot in a form of round robin: 1-7, 7-1, then 1-7 again.

Don't reverse the order. The barrel heats equally and replicates from string to string. This would impact on the results in my opinion.

My understanding of the OCW was that you're not looking for the tightest groups (as my 40.9 shows) as much as the most consistent POI over a spread of charges.

Correct, except in my experience this apply's to groups that are triangulating. So if the groups that you mentioned were like isocoles traingle what you postulate would hold water.

The minute you cannot get a group to triangulate within the boundaries of the three shots i.e. the point at where all the perpindicular line meets then you have one of two problems. Your shooting is poor or the load is poor. Your shooting is not that poor so I am assuming it is the loads.



I used to replicate my targets in a spreadsheet. Above are an actual OCW exercise.
Target 1 - Horizontally strung, open group
Target 2 - Vertically strung, open group
Target 3 - Kind of cross between targets 1 & 2 slight triangulation, open group.
Target 4 - Group tightening up, slight triangulation
Target 5 - Group also tighter, triangulation
Target 6 - Group opening up, triangulation
Target 7 - Group identical to target 4, coincidental?
Target 8 - Group now open again

So the groups start poorly and end poorly. The three groups of interest were found on targets 4, 5 and 6 with the middle of the three being the load settled on. This load shoots 0.75MOA without me having to take extraordinary care when shooting. What is happenind is that the groups outside of these three are at some point on the antinode while the three in the middle are centred around the node.

What you will also find is the the POI does not move significantly as you postulated BUT the group pattern is different.

Hope this makes sense.

Once the OCW node is found I am under the understanding that the tightness of the group can possibly be tuned by adjusting the COAL.

This is true but I tend not to play with this too much. I am a hunter, my three rifles are all generally well sub MOA so that is more than good enough.

My Sierra's tend to like a longer jump and typically all my Sierra's are in the order of 0.10" from the lands. This on the advice of an experienced loader, never questions this and for the same reason my Accubonds are about 0.03" from the lands.

Maybe I should start playing with the jump.

Remember playing with the jump does alter the chanmer pressure so it is not a case of finding the load and then moving the bullet back and forth. Use a chrony and keep the speeds the same, this will mean altering loads slightly.

 

[Centurian22]

I believe if I had done my part better the groups would have "triangulated" better. As I mention in the original post three of my groups had called fliers that I know I pushed. My axis is primarily for hunting as well but I'm curious just how far I can stretch its and my own accuracy. Once I am dialed in at 100yards I'll start working at 200 and keep going as far as I can withing the restrictions of my area (hard to find long shots) my equipment and my abilities.

I have tested and found that my magazine will hold rounds that touch the lands. I will eventually play with it but will definitely keep an eye on pressure / safety and try that 0.010 off first as I'm using mostly Sierra's right now. I do not have a chrono yet though it will be on my wish list soon. Thanks for all the help and input. I was really expecting to hear from more people by now. Maybe over the weekend.

 

[Andrew Leigh]

The disclaimer that Dan Newberry makes on his OCW method is that you are able to shoot sub MOA groups for the method to work.

Don't second guess the results. When I first started the OCW method I used to, with poor results and lot's of wasted ammo. The sequence of targets I included was specifically from very shortly after I had bought my first rifle, a 30-06, and I had developed a flinch which lead to flyers.

I included this sequence as I was in the same boat as you, new to the method and unable to interpret the results due to apparent flyers.

I stand by my recommendation. You need to get one load that you can measure your rifle against. Then get clever and play with the loads and load up if you want.

Don't forget that an inability for the group to triangulate may have nothing to do with you but the fact that the bullets are exiting the muzzle on the antinode. This is diagnostic for a poorer load.

Subsequent load development with a 6.5mm and a .375 would reveal that the same group patterns are typical, vertical and lateral groups, open groups with a couple in the middle that are closer. This assume that you have started around a node. I have had it that I started at the wrong point and the loads started coming together on the last target bit I had run out of loads and needed to go back and start higher.

 

[steve4102]

I would load 5 at 44.3gr and test.

 

[Andrew Leigh]

Please share what the technical / statistical basis for that comment is?

 

[steve4102]

44.1gr and 44.6gr have almost identical groups size at identical Points of impact. A charge right in the middle may also have identical POI and group size. If it does, then the OP will have identical POI and group size with a charge weight +/- .3gr.

 

[Andrew Leigh]

OK thanks,

would agree with the reasoning but from personal experience no group vertical / horizontal or cross between the two has been close to a node.

Waiting to see what the OP does next and what the outcome is.

Cheers

 

[Centurian22]

OP here, I'm not quite sure where to go, I was hoping for a better 'turnout' of the experienced reloaders I've come to see around here and possibly get a consensus from them. I work away from home so its unlikely I'll be doing anything before December. I have 4 each of 43.6 and 41.5 loaded from before, that I didn't get to shoot. I may try those for group size just to see how they do.

Next work up will be smaller steps probably from 42.5-45.0 and possibly the 40.6-42.0. I need to see how I'm doing for components. If I have enough I'll probably try the 20rds that you (Andrew) recommend or at least something similar with .3gr steps. Then I'll be seeing if the load carry's over well to the 165gr Sierra Gamekings hopefully it will which will save me a lot of components.

 

[Andrew Leigh]

Those 165gr. Game Kings are awesomely accurate bullets. 3/165 = 1.8%. You probably will need little to no compensation.

Having a chrony would help immensely.

Alternately, you could contact someone on the forum who has Quick Load. You will need to give them some information so they can calculate the accuracy node. I have dispensed with the OCW method as it simply takes to long and is too expensive, I now get a friend to calculate me a load on Quick Load until I can scratch the money together to buy a copy.

The information required will be;
- Primer type.
- Powder type.
- Bullet type preferably with catalogue number.
- COL when bullet is just touching the lands
- COL when the bullet is seated with the jump you require.
- Capacity of H2O in grains of the cases you are using. Take 10 cases, weigh them and number them, fill them with water and weigh them again. Subtract weight 2 from weight 1 and divide by 10 to get the average.
- Two existing loads (using the above components) and what the average speed for each load was.
- Length from the closed bolt face to the muzzle.

All the above is easy and you can do the measurements at home except the speeds. Beg steal or borrow a Chrony, shoot those other loads of yours over the Chrony and then your data will be complete.

 

[ArchAngelCD]

I think you're laboring here for no good reason. You said your 43.6gr group was @ .75" and as we can see the pattern is correct. You might want to go .3gr on either side to see if you get a better group BUT, .75" with a $350 entry level Savage Axis hunting rifle is outstanding results IMO. Results like that from a hunting rifle were unheard of as little as 20 years ago from such a rifle.

One note, you are shooting 168 Sierra MatchKings right now. I would load up a few sets of 165gr GameKings to be sure they shoot the same. I use MK's for practice and GK's for Deer and my results are the same. (but in a 30-06) My final test are usually done with 4 rounds over 3. I feel the added round, even though only a 1 round addition gives you a lot of information.

Seriously, for the rifle you're shooting 3/4" @100 yards is outstanding results, stop laboring. with a 3/4" group that would put you in the kill zone of most Deer @1000 yards. (not that most hunters would do that) @400 yards that would put you right about a 3" group if you do your part and a Deer has a kill zone well past twice that.

 

[4895]

If you have a .22lr consider shooting a round with the high power rifle and set it aside for a couple minutes to cool. Then shoot your .22lr single shot style. Remove any magazine, load one round manually, etc. This will give you time to focus and concentrate on your shooting, and keep you shooting, keeping your heart rate steady, and save a bit of $$ as well. After say 5 or 6 rounds of .22, should be a few minutes, you are ready to shoot the centerfire with a new, relaxed calm and steadiness.

 

[Centurian22]

Arch: glad you weighed in! I think you mixed posts I never gave measurements of the groups because I hadn't taken any yet. But I just checked and the 43.6 gave me 1.1" and 40.9 a bit tighter at 0.8". As you said neither is anything to sneeze at from an entry level hunting gun. I just want to squeeze what I can from it within reason and more so I want to have a load that is insensitive to slight variations as the OCW's claim to be. This will help when I use different brass, primers (I would still do a safety work up don't worry), temperature swings in Maine from 20-100 deg F.

4895: That's almost exactly what I was doing. I had my .22's with me but never shot them I was having too much fun shooting some clays between rounds of load dev. Nice way to kill time between shots while cooling. I like the single load idea for .22 though thanks!

 

[4895]

I like the single load idea for .22 though thanks!

It works for me especially when I shoot a boomer. I've never heard of OCW loading until today. This gives me a new insight into loading for "cold bore" hunting rounds. I have since written down some new loads to develop based upon your experiment and hope to have good results. Thank you!

 

[Muddydogs]

Here's my opinion. Your rifle is shooting well at 100 yards but I would load up some 40.9 grain loads and put 100 or so down range. Why you ask? Well looking at the target out of 7 groups it appears that 5 groups have flyers which leads me to believe that a few more rounds down range will help your shooting and what better way then with a light powder charge to save a couple bucks. With 4 groups spread across 4 grains that appear to be about the same size but different configuration its really hard to say. Any of the 4 tightest groups would be fine hunting loads if they hold.

 

[DRYHUMOR]

This is why I think the 44.1 is a node as the 43.6, 44.1 and 44.6 all have POI's high of center.

Don't worry about where the groups end up, once a load is more or less finalized, you will be adjusting the scope to POI.

I've had loads move left right up down. I try to concentrate on using the same point of aim at a target(s). I then look at how a load group looks, minimal horizontal and tighter vertical is what I'm looking for.

When I think I have something I want, I reload and re shoot the load to verify. I tend to load 5 rounds of each charge weight, with .3 grain increments separation. When I get close, I drop down .2 and go over .2 along with the original charge. Slight seating adjustment may or may not follow, depending on what it looks like.

 

[ArchAngelCD]

Arch: glad you weighed in! I think you mixed posts I never gave measurements of the groups because I hadn't taken any yet. But I just checked and the 43.6 gave me 1.1" and 40.9 a bit tighter at 0.8". As you said neither is anything to sneeze at from an entry level hunting gun. I just want to squeeze what I can from it within reason and more so I want to have a load that is insensitive to slight variations as the OCW's claim to be. This will help when I use different brass, primers (I would still do a safety work up don't worry), temperature swings in Maine from 20-100 deg F.

4895: That's almost exactly what I was doing. I had my .22's with me but never shot them I was having too much fun shooting some clays between rounds of load dev. Nice way to kill time between shots while cooling. I like the single load idea for .22 though thanks!

Yes I did cross up two different posts, sorry...

 

[Centurian22]

Muddy: I definitely plan to get lots more trigger time with this and my Mosins to refine and improve my shooting skills and abilities. Resources permitting I could re-run some tests after more practice but at this point it will likely be with a different bullet style.

Dry: I am aware of shifting my scope to the POI when all is done, I'm just hoping to find a load that is tolerant to slight changes in pressure from charge weight variances, brass differences, temperature etc.

4895: You're very welcome! Have you found and checked out the original page about OCW dev? http://optimalchargeweight.embarqspace.com/ In case you have not there is a lot of great info, instructions and examples. As stated I'm a complete noob and I was able to follow it lol.

Thanks again for everyone's input. Because of working away, and with holidays fast approaching I may or may not get to any further development for a while but when I do I will defiantly post the results.

 

[ArchAngelCD]

Muddy: I definitely plan to get lots more trigger time with this and my Mosins to refine and improve my shooting skills and abilities.

Just a note on the Mosin Nagant, as you well know the trigger just terrible on those rifles. If you are trying to train using a trigger that bad could cause you to develop bad habits. Timney Triggers has a direct replacement for just a hair over $100 and turns that rifle into a great shooter. (1.5lb to 4.0lb)
http://www.timneytriggers.com/index.php?option=com_wrapper&view=wrapper&Itemid=45

I put a similar Timney Trigger in my Model 1917 Surplus rifle and it made a world of difference. (and for only $55 too!)

 

[Centurian22]

I've looked at those but couldn't bring myself to pay as much (or close to it) for a trigger as I did the rifle. I have however done my own work on it and polished the trigger and sear bringing it down to a smooth almost crisp 4lbs. Very good point about the different triggers not equalling exact match training.

 

[ArchAngelCD]

Wow, if you really got that trigger anywhere near 4 lbs you did a great job. I know what you mean, I couldn't bring myself to spend as much on a trigger as I did the rifle with the Mosin Nagant either. I just wanted you to know it was available. I feel the 1917 Enfield was a different story. I paid $170 for the rifle which was sported slightly and the trigger was only $55 so I did that one... I really like the rifle at the range because it's heavy and soaks up a good bit of recoil off the bench and the barrel is still 26" so it's fun to see my velocities match the reloading manual velocities too! lol

 

[Walkalong]

Throw out the ladder test and the OCW method. Test at around .3 increments, starting at just over the minimum load. Shoot three or four groups at each charge weight. As you go up in charge weight you will find sweet spots, probably two, but maybe three in the data if you test a big enough spread.

Reload some more of any charge weight that shot well, as in more than one decent group. See if it repeats the groups. Tweak from there if you want. You want to try to find the middle of the .3 or .4 Gr spread that shoots well. were you using wind flags, or at least watching wind? The evening or morning in calmer conditions are best for group shooting, but even then there are gremlins out there.

 

[Centurian22]

Thanks! Yea I don't have a 'real' trigger gauge but using a fish scale and repeated pulls it averaged 4lbs +/- 1/2lb which could have been my reading or the trigger. Then about an hour with 600grit paper, some metal polish and q-tips. Couldn't be happier. I have a second Mosin now so I can get a side by side comparison at the range before I fluff and buff the new one. My first, a 42tula is staying original, my second 43izzy is getting a Boyd's featherweight thumbhole stock and long eye relief scope on the rear sight base hopefully.