Pressure problems ADG brass

[bob_dobalina]

I am struggling a little with new ADG brass. I know it is thicker and has less capacity, so I did a ladder from Nosler book load for my 300 WSM of RL17, 180 NAB, REM 9/12M primer starting at 62. I made it to 63.2 and say pressure signs - ejector mark, heavier bolt lift. I saw a velocity plateau at 62.6 - 62.8 so loaded up 62.7 and it shot great. However, I started seeing the same pressure signs with this load. I thought there was oil somehow involved so I did a thorough cleaning but still see pressure.

This is a 20" barrel, and I did a rough water measurement of a once fired case at 81g of water. I am trying Gordon's Reloading Tool, and it looks like I'm on the cusp of pressure but it also shows higher speeds than I am getting. However I don't know if Gordon's Tool is expecting the fresh brass water capacity or the once fired. I am shooting fresh brass, and I will say it's a tight fit in my chamber.

Now my velocity measurements are not great because I'm shooting through an old PRO Chrono at ~ 12 feet, because this gun has a suppressor and my MagnetoSpeed won't work. But I have them posted below. I'd think you'd add ~ 15 fps for being downrange.

300 WSM - 20" barrel - RL17 - ADG - REM 9 1/2M
62 - 2721
62.4 - 2732
62.6 - 2777
62.8 - 2783
63 - 2772
63.2 - 2795

Gordon's shows my 62.7 gr load around 2800 so it seemed sane that I'd be safe shooting 62.7 at ~ 2780 - 2800. Anyways, I'm hoping you all can offer advice or maybe double check my data with QuickLoad? Thanks

 

[Blkram]

Just remember that the reloading data should always be used with starting 5% less than max and working up in your firearm, and when you experience any pressure signs, you will be over pressure in your firearm and need to back off, regardless if you have reached their published max or not.

Another point is that you need to use specific water (do not recall the exact term at this moment) for testing case capacity ( you cannot just use plain tap water) as it will affect your measurement.
DrMike can provide more detail here as he explains it better than I could attempt to. I will let him do so when he checks in.

 

[bob_dobalina]

I just measured 6 shell's water capacity with RO water on my better scale and came up with an average of 81.3gr. Low - 81.2, high 81.5.

I measured a WIN case I had no problems with 64gr RL 17 and it had a water capacity of 82.4.

I would sure appreciate if someone could tell me what QuickLoad says for my data? 300 WSM - 20" barrel - RL17 - ADG - REM 9 1/2M, 81.3gr water

 

[bob_dobalina]

Just remember that the reloading data should always be used with starting 5% less than max and working up in your firearm, and when you experience any pressure signs, you will be over pressure in your firearm and need to back off, regardless if you have reached their published max or not.

Another point is that you need to use specific water (do not recall the exact term at this moment) for testing case capacity ( you cannot just use plain tap water) as it will affect your measurement.
DrMike can provide more detail here as he explains it better than I could attempt to. I will let him do so when he checks in.

Thanks Blkram, what would you back off to?

 

[NYDAN]

Another factor may be the thickness of brass neck. I believe ADG has a thicker neck than other brass. You may want to check your neck clearance. Compare the brass neck diameter of a fired round to the diameter of the neck with a bullet seated. My understanding is that minimal neck clearance could result in higher pressure before reaching full velocity. Good luck on figuring it out. Dan

 

[bob_dobalina]

Any factor may be the thickness of brass neck. I believe ADG has a thicker neck than other brass. You may want to check your neck clearance. Compare the brass neck diameter of a fired round to the diameter of the neck with a bullet seated. My understanding is that minimal neck clearance could result in higher pressure before reaching full velocity. Good luck on figuring it out. Dan

My fired brass is .345. With bullet seated, .342. A WW shell with bullet seated is .336, for comparison.

I wonder if I should just full length resize or use a lee neck collet die on the fresh brash. Some of these seat and feel like they have hardly any neck tension.

 

[Blkram]

Thanks Blkram, what would you back off to?

Perhaps DrMike can run the QuickLoad for you and that will help...but other than that, at what point did you start to experience the ejector mark and sticky bolt lift?
Back off a half to a whole grain from there, and hopefully you will still see decent performance (velocity and accuracy wise).

 

[NYDAN]

My fired brass is .345. With bullet seated, .342. A WW shell with bullet seated is .336, for comparison.

I wonder if I should just full length resize or use a lee neck collet die on the fresh brash. Some of these seat and feel like they have hardly any neck tension.

So, it sounds like you have total neck clearance of 0.003" (.345"-.342") (or a little more due to brass spring back). I am NOT an expert on neck clearance but that sounds a little low for a hunting rifle. I was recently told I should have 0.005" or more total neck clearance for a hunting rifle.

Hopefully, there is another member of the forum who can voice an opinion on neck clearance and provide some guidance. Dan

 

[bob_dobalina]

Turns out it may have been an out of spec chamber. It's a SAAMI chamber now. I would still appreciate if anyone could run my numbers in quick load it sure would be helpful for new brass and a short barrel

 

[hunter24605]

I am struggling a little with new ADG brass. I know it is thicker and has less capacity, so I did a ladder from Nosler book load for my 300 WSM of RL17, 180 NAB, REM 9/12M primer starting at 62. I made it to 63.2 and say pressure signs - ejector mark, heavier bolt lift. I saw a velocity plateau at 62.6 - 62.8 so loaded up 62.7 and it shot great. However, I started seeing the same pressure signs with this load. I thought there was oil somehow involved so I did a thorough cleaning but still see pressure.

This is a 20" barrel, and I did a rough water measurement of a once fired case at 81g of water. I am trying Gordon's Reloading Tool, and it looks like I'm on the cusp of pressure but it also shows higher speeds than I am getting. However I don't know if Gordon's Tool is expecting the fresh brass water capacity or the once fired. I am shooting fresh brass, and I will say it's a tight fit in my chamber.

Now my velocity measurements are not great because I'm shooting through an old PRO Chrono at ~ 12 feet, because this gun has a suppressor and my MagnetoSpeed won't work. But I have them posted below. I'd think you'd add ~ 15 fps for being downrange.

300 WSM - 20" barrel - RL17 - ADG - REM 9 1/2M
62 - 2721
62.4 - 2732
62.6 - 2777
62.8 - 2783
63 - 2772
63.2 - 2795

Gordon's shows my 62.7 gr load around 2800 so it seemed sane that I'd be safe shooting 62.7 at ~ 2780 - 2800. Anyways, I'm hoping you all can offer advice or maybe double check my data with QuickLoad? Thanks

GRT uses fired brass H2O capacity. Make sure to calibrate it with your known velocity and you should get pretty close results. I used your 63.2 velocity and adjusted Ba to match and it showing 52505 psi. looks like you've got plenty left on the table

 

[NYDAN]

Turns out it may have been an out of spec chamber. It's a SAAMI chamber now. I would still appreciate if anyone could run my numbers in quick load it sure would be helpful for new brass and a short barrel

I am glad you got it sorted out.

 

[bob_dobalina]

GRT uses fired brass H2O capacity. Make sure to calibrate it with your known velocity and you should get pretty close results. I used your 63.2 velocity and adjusted Ba to match and it showing 52505 psi. looks like you've got plenty left on the table

I am glad you got it sorted out.

Yes sir thank you for the help. And @hunter24605 got me sorted out with the GRT software which is amazing so disregard my QuickLoad requests.