300WM load development issues

[ta406]

So I'm in the process of developing a load for a new custom 300 WM. It has a fluted, medium palma 28" bartlein barrel. I'm testing 215 bergers and VV N570 powder. It was 80 degrees and sunny during testing. I shot 3 groups of 4 rounds each. Each group, the powder charge was increased by .5 grains. My testing went like this. Fire 2 rounds, cool the barrel with a small air mattress pump, then fire the next two rounds. After the third group, I noticed that the first round was about 30fps faster than the second. Then the third was 20-30fps faster than the second. Then the forth was 20 or so fps slower than the third. Something like this:
1) 3000
2) 2970
barrel cool down
3) 2990
4) 2965
This trend was consistent with all three groups that I fired. As you can see that my ES was horrible and got me thinking as how, or if I can do any type of load development with this rifle in warmer weather. I have never had this issue with any of my other rifles. I guess for load development, I will have to let the barrel cool completely between each shot. But now I'm also questioning how confident I will be using this rifle if I have to take a follow up shot or two at extended ranges in hunting conditions. I was going to test H1000 this weekend to see if the trend continues even with a different powder. I will keep all other components the same. Has anyone ran into a similar problem?

 

[L.Sherm]

I don't know how well 570 handles the heat so I would give the H1000 a try it's pretty stable. Don't be afraid to switch primers that can also help ES.

 

[ShtrRdy]

How many rounds to you have through the barrel?

 

[L.Sherm]

I helped a guy out with a 300 win. mag savage Axis using RL26 and 200 ELDx's worked pretty good speed was 2950FPS. Yesterday I tried RL23 in my 280AI 140 PRO Hunter Sierra bullets speed was 3240FPS and .400 3 shot group i was impressed clean burning and a 60FPS pickup over RL22 and was 70+ Deg. weather. I also started load developement last night in a 300 win.mag. 185 Bergers got up to 3200FPS (wow) and was just starting to see a liitle hard bolt lift and 1" group i'm gonna tune with seating depth tonight temp was about 85 Deg. So far I have been impressed with the new RL powders. I am gonna have to test and see how RL26 burnrate compares to H1000.

 

[Rick Richard]

H1000 and 215 Bergers for 300WM is like...Peas and carrots.

 

[ta406]

How many rounds to you have through the barrel?

Somewhere around 75

 

[Dosh]

406, the H1000 is a temp stable powder. The well proven "Broz" load for the 215 Berger with H1000 in 300 WM can be found here on the search. Like Rick says, they are made for each other.

 

[ta406]

406, the H1000 is a temp stable powder. The well proven "Broz" load for the 215 Berger with H1000 in 300 WM can be found here on the search. Like Rick says, they are made for each other.

I have read several of this threads and did use it for my barrel breaking but for some reason decided to try my initial load development with N570. I'm not sure why I tried to reinvent the wheel. Looks like I'll go back to what's been proven to work. Thanks guys

 

[tankgijohn72]

You have a standard deviation of 16.5 fps. Not too bad, not too great. Trying a different powder may lower the SDs. You may have a pattern for some of your loads but doubt they repeat if you take enough data. Depending on your definition of long range for hunting it may or may not matter. Put some holes in paper at your hunting range and see if you have a problem or not.

 

[dfanonymous]

what did your groups look like? if i have a high es, but my groups are solid, I disregard the ES. People will disagree, but results are results. Like someone else said, you SD is middle of the road of acceptable. H1000 really is great for heavier grain bullets, slower burn, temp stable. There so much that could make up for the sd, the powder using for that bullet, how do you prep your brass?
Also maybe bring it down or up .2 grains.

 

[BEEMAN]

what did your groups look like? if i have a high es, but my groups are solid, I disregard the ES. People will disagree, but results are results. Like someone else said, you SD is middle of the road of acceptable. H1000 really is great for heavier grain bullets, slower burn, temp stable. There so much that could make up for the sd, the powder using for that bullet, how do you prep your brass?
Also maybe bring it down or up .2 grains.

I just seen where BROZ tested N570 in his 300 Win Mag. He was getting higher velocity than when using H1000. I use N570 in a few guns and like it. Just don't like how it meters out of the powder scale.

 

[barefooter56]

So I'm in the process of developing a load for a new custom 300 WM. It has a fluted, medium palma 28" bartlein barrel. I'm testing 215 bergers and VV N570 powder. It was 80 degrees and sunny during testing. I shot 3 groups of 4 rounds each. Each group, the powder charge was increased by .5 grains. My testing went like this. Fire 2 rounds, cool the barrel with a small air mattress pump, then fire the next two rounds. After the third group, I noticed that the first round was about 30fps faster than the second. Then the third was 20-30fps faster than the second. Then the forth was 20 or so fps slower than the third. Something like this:
1) 3000
2) 2970
barrel cool down
3) 2990
4) 2965
This trend was consistent with all three groups that I fired. As you can see that my ES was horrible and got me thinking as how, or if I can do any type of load development with this rifle in warmer weather. I have never had this issue with any of my other rifles. I guess for load development, I will have to let the barrel cool completely between each shot. But now I'm also questioning how confident I will be using this rifle if I have to take a follow up shot or two at extended ranges in hunting conditions. I was going to test H1000 this weekend to see if the trend continues even with a different powder. I will keep all other components the same. Has anyone ran into a similar problem?

ta406,
With only 75 rounds down the barrel its not even close to being broken it. It takes usually around 250 rounds before the rifle will settle down . Are you seating this bullet to magazine length or have you done some seating depth testing? If you have not and may want to give it a try I suggest you start at .015 off the lands and work back towards the cartridge case in .005 increments at the lowest powder charge listed for the bullet/powder/cartridge combination you are testing. Once the bullet seating depth accuracy node is found. Work the load back up slowly checking for pressure signs and accuracy until your highest velocity accuracy node is found. If you want to try all your load testing at magazine length you may want to work the load up in 1/2 grain increments until you get to 2 grains below maximum then drop to .2-.3 tenths grain increments until you get to 1 grain below maximum then drop to 1 tenth grain increments. You dont want to make big moves (1/2 grain) all the way up to maximum. You need to get finer as you go up so you don't miss something . Right now just looking at your velocities you should have an ES around 30 so your SD ( standard deviation , which is the more important than ES in my opinion because it is an indicator of vertical dispersion which is what you dont want) should be around 15 or so. That's not too bad but you should be able to get it to around ten , maybe less. You are close where you are at so you may want to test to either side of the load you have now (.2-.3 tenths grains). Any load testing should be done with the barrel fouled by shooting at a practice target until the bullet strikes stop their vertical movement and begin to cluster . Load testing can be tedious and frustrating at times so only make one change at a time and test it . And keep good notes in your reloading log book! A little patience here can pay big dividends. You can contact the BERGER BULLET techs at 714-441-7202 from 8am to 4:30pm EASTERN time MON thru FRI . We are always glad to help.
Thanks for using our bullets!
Take care,

 

[ta406]

what did your groups look like? if i have a high es, but my groups are solid, I disregard the ES. People will disagree, but results are results. Like someone else said, you SD is middle of the road of acceptable. H1000 really is great for heavier grain bullets, slower burn, temp stable. There so much that could make up for the sd, the powder using for that bullet, how do you prep your brass?
Also maybe bring it down or up .2 grains.

Groups were horrible. Probably close to 2 inches at 100 yards.

 

[ta406]

I just seen where BROZ tested N570 in his 300 Win Mag. He was getting higher velocity than when using H1000. I use N570 in a few guns and like it. Just don't like how it meters out of the powder scale.

Thats where I got the idea. Since I had a pound of it I figured I would give it a try. I saw 3170 fps before I got stiff bolt lift. Groups were bad to say the least. And I agree with you about poor metering. It was a pain in the rear trying to use my chargemaster