Retumbo wont fit

My father uses h1000 in his begara hmr 300 win mag. In adg brass his load is 78 grains with a 208 eld-m at 3005 fps. That's safe in his rifle, but work up with caution.
 
New to reloading. I'm working on my first load for ELR. I'm loading for my Bergara HMR in 300 WinMag. I'm loading GunWerks brass with 215 Berger Hybrids.

From what I read the starting load is 74 grains of Retumbo. I tried loading this and the case is full up to the neck and seating the bullet to the powder leaves me at 3.745. Why is the starting load so large and not allowing me to seat a bullet enough?

I haven't been able to fire form my brass to modify it and measure seating depth to my lands yet, but I'm guessing it wont be 3.745.


What's the deal? Advice?
Try H4350 or H1000
 
Here is what ie working in my HMR
B023BF55-0FA6-4610-BB81-78098E316660.png
 
212 gr, 78.4 gr H1000, 24" AR30A1, 2850 fps...sub .10 moa
Got a Question for the HMR shooters? I just bought a HMR-PRO in the 300 WM. Has anyone been shooting one? And how do you like it? Been shooting the 300 WM in a Winchester 70 for years and use H-1000 for all my loads in the WM. All of them have been MOK. Min of Kill out to 800 yds for Elk.
 
I run RETUMBO in my 300 with 210gr ABLR at 81gr.
In Norma brass it fits with ease, in ANY other brand, it needs to be poured using a technique using a swirling motion with the powder in a funnel.
The difference in powder height doing this is quite amazing.

Cheers.
 
I loaded up 3 round sets inn .5 grain increments from 71 to 75 grains of H1000. Should I load up a few more sets higher to get to pressure? I want to have all my rounds ready when I make the long trip to the range. If I reach pressure I can pull all the rounds that are higher.

I'm just hesitant to go above burgers max load of 75 grains but it sounds like some on here are over that...?
 
I loaded up 3 round sets inn .5 grain increments from 71 to 75 grains of H1000. Should I load up a few more sets higher to get to pressure? I want to have all my rounds ready when I make the long trip to the range. If I reach pressure I can pull all the rounds that are higher.

I'm just hesitant to go above burgers max load of 75 grains but it sounds like some on here are over that...?
Different rifles, chambers, conditions, jumps, etc. If you load a few well marked in incremental increases, just be prepared to pull the bullets as soon as you get back IF you don't need them. Easy to forget and have them laying around and forget what they were. What jump?
 
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Different rifles, chambers, conditions, jumps, etc. If you load a few well marked in incremental increases, just be prepared to pull the bullets as soon as you get back IF you don't need them. Easy to forget and have them laying around and forget what they were. What jump?

Should be .020 off the lands. I used a Hornady modified case and measured 10 times to make sure I got it right. Measured the shoulder datum on my new brass and Hornady case and found they are identical. So I loaded my new brass .020 off.

I have them all in clearly labeled baggies.

Is .5 grain increments a safe jump up? Should I load up to 76? 77?
 
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Should be .020 off the lands. I used a Hornady modified case and measured 10 times to make sure I got it right. Measured the shoulder datum on my new brass and Hornady case and found they are identical. So I loaded my new brass .020 off.

I have them all in clearly labeled baggies.

Is .5 grain increments a safe jump up? Should I load up to 76? 77?
If your 75 shows no signs of pressure you should be fine at .5 gr increments. Be sure to check very closely as you go up to the next step. Your results may be different, but I had a very good node at 76 then it hit another at 78.4 gr. The 78.4 is hot and I only use it in the fall and winter. It shows the beginning signs of pressure. The 76 works very good as well. No signs of pressure at all, but best groups have typically been .3-.5 moa. Watch for your lower pressure node. It may be as far as you want to safely go.
 
D

If your 75 shows no signs of pressure you should be fine at .5 gr increments. Be sure to check very closely as you go up to the next step. Your results may be different, but I had a very good node at 76 then it hit another at 78.4 gr. The 78.4 is hot and I only use it in the fall and winter. It shows the beginning signs of pressure. The 76 works very good as well. No signs of pressure at all, but best groups have typically been .3-.5 moa. Watch for your lower pressure node. It may be as far as you want to safely go.
Once I find my load with this new brass will it change with fire formed brass? Will I have to adjust because I'd higher case volume?
 
Short answer. Most likely. I've used new Lapua brass with no change. I've used Nosler with poor initial results. After once fired, same loads were much better. Doing your own testing and documenting EVERY variable is best for knowledge.
 
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