Verticle Spreading and load development help - where to go from here?

[vancewalker007]

Hi All,

So I have a Bergara Premier Highlander in .300 Win Mag that I am working on some hand loads for. I am using Berger 215's, H1000, Norma Brass, CCI 250's, and Redding Type-S Bushing Dies. Gun will be primarily used for elk hunting out west.

I followed Berger's starting point of 70.5 grains of H1000, and shot .015, .020, and .030 off the lands.

See the first imagine below - the .030 off the lands shot the best (by far). (Image without a circle)

So, 70.5gr is pretty light for H1000 in a .300 WM, and decided to bump the powder charge up to 74gr (imagine with the red circle). This caused the groups to open up. This had zero pressure signs.

Question is, from here, do I bump up to say 75 gr and keep going until I see pressure - then tweak the seating depth again? Was hoping that the powder increase would not open the groups that much. I am new to this precision reloading.

If you have not shot at least a velocity ladder, you will not know if your on a boundary of 2 velocity nodes. You can get big velocity jumps if you are which can cause vertical issues. For example if you measured velocity in a ladder it you will see a pattern like the following (contrived example). Your see small velocity variations then you'll move up a little more and the velocity will jump. You need to stay away from those jump points unless you like pulling you hair out.

I do this test when first developing a new load. I'll pick a safe CBTO like 40 off, then load a single round per charge weight starting 10 shots below max and stepping up a little at a time to book max. For bigger cases you can use larger steps, I like .2 gr because is gives me very good resolution on the node points. This is a velocity test, not an accuracy test so I don't usually even shoot it on paper. There is a method that you shoot similar ladder loads on paper at say 300 yards that gives around the same information, its just harder than using a chrono.

Either way you will safely find you rifle's pressure max and your pressure/velocity nodes to load in. So using the example below 74.4gr will give very similar results to 74.5gr or 74.6gr. So if your a little off on you measuring or if you run in super cold or hot weather your load has some flexibility. Once I pick a powder load then I use seating depth to fine tune groups. I seem to use up less components doing it this way. If you are shifting powder weights and seating depth at the same time its hard to really track what is causing changes and you use a lot of components.

73.6gr - 2905fps
73.8gr - 2900fps
74.0gr - 2950fps <<-- jump point
74.2gr - 2970fps
74.4gr - 2980fps
74.6gr - 2975fps

BTW - These velocity nodes will shift a little in speed once your barrel hits its speedup. So a speedup will usually not change the load jump points the velocity will just be a little higher. So 74 will still be a jump point but the velocity might be say 30fps faster.

 

[CONatureBoy]

I agree with the comments about the hybrid-ogive bullets shooting accurately while seating well off the lands. Much of their virtue is this ability, which makes it easier to load them deep enough that (a) they fit in your magazine and (b) you have at least one full diameter of shank inside the neck (which is another accuracy rule of thumb I learned back in the day, and which helps the neck tension hold the bullet at the desired seating depth while you're out in the field, bouncing your bullets around in a plastic box). On the other hand, seating deeper than necessary has its own set of problems. (Find out why elsewhere on this forum.)

Don't play with several variables at the same time. Stick with a fixed COAL, or better yet a fixed length-to-ogive (see https://www.reloadingallday.com/post/do-i-measure-by-o-a-l-or-ogive) while you change the charge weight. Fix the charge weight while you change the length. If you play with both simultaneously, the number of possible combinations makes for a much harder search problem. It's quite possible to send enough rounds through the barrel to change the chamber dimensions modestly, while trying to work up a load on the assumption that the chamber dimensions are fixed. But if you're methodical, you should be able to find and verify a very good (if not best possible) recipe within 20 rounds. If you're very methodical you can do this while also breaking in the barrel, as someone else in this thread suggested. (Again, I bet you can find some good barrel break-in recipes elsewhere on this forum.)

 

[Upsidedownjack]

Supprized that your starting with such a light load in the 300 WM. I have a HMR-PRO 300 WM. 79.0 gr H1000 LRM primers , 180 gr SST pills,and set just off the lands. So far, no pressure signs, good speed and dead nuts at 200 yds. Even tryed H1000@ 80gr. Opened up, a lot! Went back

 

[fnlights]

Supprized that your starting with such a light load in the 300 WM. I have a HMR-PRO 300 WM. 79.0 gr H1000 LRM primers , 180 gr SST pills,and set just off the lands. So far, no pressure signs, good speed and dead nuts at 200 yds. Even tryed H1000@ 80gr. Opened up, a lot! Went back

I just followed what Berger said in their manual to start at

 

[Roughrice]

Supprized that your starting with such a light load in the 300 WM. I have a HMR-PRO 300 WM. 79.0 gr H1000 LRM primers , 180 gr SST pills,and set just off the lands. So far, no pressure signs, good speed and dead nuts at 200 yds. Even tryed H1000@ 80gr. Opened up, a lot! Went back

HOLY CRAP!

 

[fnlights]

If you have not shot at least a velocity ladder, you will not know if your on a boundary of 2 velocity nodes. You can get big velocity jumps if you are which can cause vertical issues. For example if you measured velocity in a ladder it you will see a pattern like the following (contrived example). Your see small velocity variations then you'll move up a little more and the velocity will jump. You need to stay away from those jump points unless you like pulling you hair out.

I do this test when first developing a new load. I'll pick a safe CBTO like 40 off, then load a single round per charge weight starting 10 shots below max and stepping up a little at a time to book max. For bigger cases you can use larger steps, I like .2 gr because is gives me very good resolution on the node points. This is a velocity test, not an accuracy test so I don't usually even shoot it on paper. There is a method that you shoot similar ladder loads on paper at say 300 yards that gives around the same information, its just harder than using a chrono.

Either way you will safely find you rifle's pressure max and your pressure/velocity nodes to load in. So using the example below 74.4gr will give very similar results to 74.5gr or 74.6gr. So if your a little off on you measuring or if you run in super cold or hot weather your load has some flexibility. Once I pick a powder load then I use seating depth to fine tune groups. I seem to use up less components doing it this way. If you are shifting powder weights and seating depth at the same time its hard to really track what is causing changes and you use a lot of components.

73.6gr - 2905fps
73.8gr - 2900fps
74.0gr - 2950fps <<-- jump point
74.2gr - 2970fps
74.4gr - 2980fps
74.6gr - 2975fps

BTW - These velocity nodes will shift a little in speed once your barrel hits its speedup. So a speedup will usually not change the load jump points the velocity will just be a little higher. So 74 will still be a jump point but the velocity might be say 30fps faster.

Great example, I appreciate it! So in your example if you were going to start reloading, you would probably pick the 74.4 because if you fluctuate in either way, you should achieve a similar velocity? What powder charge should I start this at? If I start at 72.4, I am talking about nearly 30 reloads just in this test.

 

[fnlights]

HOLY CRAP!

Agree lol, here it is from Berger

 

[fnlights]

You should load 30 thou jump and shoot a ladder from 74 to 76 grs at .2 increments look for a speed node, a flat spot, a spot where the speed stays the same. And look for pressure. A good node is were the fps ES is less then 20 fps across .4 grs/ 2 shots or more. Load the middle of that node/powder charge. And then test your jump again at 5 thou increments and since 30 thou jump was best before go up and down from there, 20, 25 30, 35, 40. When you shoot these you should see a pattern to follow to the best load. See ocw and Satterlee load development videos.

Leaning towards this - From what I have seen online, you can expect pressure between 76-79 grains - I wish I would have disregarded what Berger recommended @ 70.5gr and followed this from LRO: https://www.longrangeonly.com/300-winchester-magnum/

 

[fnlights]

I did a load development on a 300 WinMag last summer for a friend. Are use the 210 grain berger bullet. I got as high as 79 g of H 1000. Slight cratering to the primer. So I backed off and use 78 gr. I like a big slug for hunting but a 180gr bullet might perform better in a 300 winmag.

See this is also the issue - if I run a velocity test and start at only 74 grains, I am talking about 21 rounds in order to find this, in a time where it took 4 months to get H1000 and Berger 215's lol. I agree I think this is probably the best option because there are no short-cuts, but wow I did not expect this to be such a long (rather expensive) process haha

 

[Tulsa Reiner]

I have a chrono - I just have not set it up yet because I saw no sense in putting it together and taking it down with a starting load of 70.5 gr of H1000 - which from a .300 WM is a charge that I do not think anyone would shoot because its probably only 2,500 fps - not ideal from a .300WM.

Developing a load is tedious work. If you really want accuracy, you need to put the time, and powder into the small, stepwise development.
There really aren't any shortcuts, and the chronograph is one of the tedious components of the work. The extra time put into using your chrono will save you powder in the end.

 

[fnlights]

Developing a load is tedious work. If you really want accuracy, you need to put the time, and powder into the small, stepwise development.
There really aren't any shortcuts, and the chronograph is one of the tedious components of the work.

Yeah I am gathering that rather quickly - I have no doubt at the end of this I will have an amazing shooting rifle

 

[GrayCreed]

Hi All,

So I have a Bergara Premier Highlander in .300 Win Mag that I am working on some hand loads for. I am using Berger 215's, H1000, Norma Brass, CCI 250's, and Redding Type-S Bushing Dies. Gun will be primarily used for elk hunting out west.

I followed Berger's starting point of 70.5 grains of H1000, and shot .015, .020, and .030 off the lands.

See the first imagine below - the .030 off the lands shot the best (by far). (Image without a circle)

So, 70.5gr is pretty light for H1000 in a .300 WM, and decided to bump the powder charge up to 74gr (imagine with the red circle). This caused the groups to open up. This had zero pressure signs.

Question is, from here, do I bump up to say 75 gr and keep going until I see pressure - then tweak the seating depth again? Was hoping that the powder increase would not open the groups that much. I am new to this precision reloading.

Once you find the seating depth you like you need to do a staterlee ladder test with 10-15 shots. Each shot has a different powder charge (you are not shooting groups). Shoot all shots from the lightest to the hotest being very careful to let the rifle cool an equal amount between each shot ( I usually set the timer for 1 min). Also I like to aim before I chamber the round. (So it goes like this: set timer, wait, timer is about to go off place round in weapon and aim, then timer goes off- push bolt forward and squeeze the trigger). Do worry about accuracy, you are trying to see the velocity curve rise as you go up in powder charge. When you are all done you plot the velocities as points on a graph-chart. This will show you the slow/rapid rise in velocity as you add more powder. Look on your chart for "flat spots" which are places where even with charge wieghts .2- .5g apart the velocity changes very little. Also this test will show you your primer/powder relationship and if the like each other.

This way saves you alot more powder, bullets and primers than the traditional way of loading 3-5 round groups at different powder charges. Once you find the flat spot you only need to load for groups in the flat spot and you can "re-tweak" your seating depth at that spot.

 

[camodave7]

Realize that the new World Record non typical elk was shot near where I live at 18 yards.

 

[camodave7]

Yeah I am gathering that rather quickly - I have no doubt at the end of this I will have an amazing shooting rifle

Wrong. There are lots of shortcuts. How much accuracy is required for example on a moose with a 2 foot square kill zone?