300 RUM and 230 Berger Hybrid project

barefooter56

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Nov 10, 2014
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913
Did my second ladder test yesterday evening. After these 12 shots, made about 63 shots fired since the barrel was cleaned. I started seeing some ejector swipes in the 92.8 to 93.6 range. I guess this pressure is coming from the barrel getting fouled? I can see a noticeable difference in the bore of the barrel from before this last test to after it. The temperature was around 70 and overcast with a steady 3-7 mph wind from my 10 o'clock getting up to 10 mph at one time i'm guessing. This kept the barrel at a good temp without me having to cool it much at all. I dialed left 1 minute for most of the test and 1.5 when the wind got a little stiffer to keep them all on paper which turned out pretty good since I was just guessing wind speed and hold and never having feedback on my correction till all 12 shots were fired. After my first two 4 shot ladders I dialed down 1 minute to get my last four shots on the target because the wind folded the top half of my target over. I was just glad all 12 shots made it on there lol. Right now I'm thinking of going with 89.2g and shooting that some to see how it does. I can't help but like the very top three shots and their velocity, but being as I was having some pressure signs there I would like to stay away if I can reach one mile without it. The results:
F7A2094E-8E2F-41C2-9C55-80ED0B0EA35F_zpslqitaesh.jpg

108DC732-81C9-4AE7-A899-E7520BE360D4_zpsmynwmudm.jpg

3EBDBCEC-C914-4C6C-B5DA-0AF9C3446A31_zps2tahmacr.jpg
Cratered primer and that's a rather large ejector mark. This isn't due to barrel fouling. Its due to an over pressure load . I would suggest retesting the 89.6, 89.2 and 88.4. The 88.8 load MAY be out of the line due to shooter error because it is down and right. That is usually caused by a right hand shooter "snatching" the trigger as the cross-hair of the scope passes the aiming point. Retest that one also. A mile is nice but accuracy is nicer. Let the rifle tell you what IT likes.
 

ajridgedell

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Jan 22, 2011
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85
Location
Louisiana
Cratered primer and that's a rather large ejector mark. This isn't due to barrel fouling. Its due to an over pressure load . I would suggest retesting the 89.6, 89.2 and 88.4. The 88.8 load MAY be out of the line due to shooter error because it is down and right. That is usually caused by a right hand shooter "snatching" the trigger as the cross-hair of the scope passes the aiming point. Retest that one also. A mile is nice but accuracy is nicer. Let the rifle tell you what IT likes.

All my ladder tests are done in a gun vise that allows the gun to recoil similar to how it recoils when shoulder fired. The gun is mechanically aligned to target and remotely fired by an air diaphragm inside the trigger guard. I have absolutely no doubts that the sights are on target when the striker hits the primer. I didn't know what else would cause these pressure signs to start showing up at those powder charges when they have not previously shown up earlier in my test. I believe even though the brass didn't show those ejector swipes at the same charges earlier and at even higher air temperatures, they still very well may have been over pressure, possibly just random that these pressure signs showed up now, or something else maybe contributing?
I will still take your advise and work the 88.4 to 89.6 range, but I find it interesting that the velocities are slower for that range of power charge then my previous ladder test. I think I have the base model shooting chrony so I don't know how much faith to put in those numbers.
 

barefooter56

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Nov 10, 2014
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913
All my ladder tests are done in a gun vise that allows the gun to recoil similar to how it recoils when shoulder fired. The gun is mechanically aligned to target and remotely fired by an air diaphragm inside the trigger guard. I have absolutely no doubts that the sights are on target when the striker hits the primer. I didn't know what else would cause these pressure signs to start showing up at those powder charges when they have not previously shown up earlier in my test. I believe even though the brass didn't show those ejector swipes at the same charges earlier and at even higher air temperatures, they still very well may have been over pressure, possibly just random that these pressure signs showed up now, or something else maybe contributing?
I will still take your advise and work the 88.4 to 89.6 range, but I find it interesting that the velocities are slower for that range of power charge then my previous ladder test. I think I have the base model shooting chrony so I don't know how much faith to put in those numbers.
ajridgedell,
IF you can find a buddy with a Magneto-speed chrony. Try running the loads over that and just look at the velocity and SD. Not the group on the target just to get a reading you can trust. If you want. What I do with my CED-M2 is to assemble the unit and measure up about 4 inches on each sky screen support and wrap orange electrical tape around the supports ( all 4) at that point. I use these to bore sight the rifle on then pan the rifle left to right to center it in the screens as best I can. Then I place a white piece of paper across the rear screens and fire some rounds though the chrony to see how high the rounds are above the sensors and how centered the rifle is. One shooter had the idea of using a laser bore sighter to do this that looks like a real good idea. Lasers don't put holes in Chronographs lol ! Your rifle MAY like running in the danger zone. Who knows. Usually though another lower velocity accuracy node can be found and hopefully will meet your needs without having to beat your rifle and yourself to death. I have one like that and cant wait till it wears out the barrel!!! lol !
 

Marble

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Joined
Jul 19, 2012
Messages
362
Location
Shasta County
All my ladder tests are done in a gun vise that allows the gun to recoil similar to how it recoils when shoulder fired. The gun is mechanically aligned to target and remotely fired by an air diaphragm inside the trigger guard. I have absolutely no doubts that the sights are on target when the striker hits the primer. I didn't know what else would cause these pressure signs to start showing up at those powder charges when they have not previously shown up earlier in my test. I believe even though the brass didn't show those ejector swipes at the same charges earlier and at even higher air temperatures, they still very well may have been over pressure, possibly just random that these pressure signs showed up now, or something else maybe contributing?
I will still take your advise and work the 88.4 to 89.6 range, but I find it interesting that the velocities are slower for that range of power charge then my previous ladder test. I think I have the base model shooting chrony so I don't know how much faith to put in those numbers.

Just to elliminate temperature variations, you can keep your ammo in a small ice chest. I've done this before in 90+ heat to keep my rounds at the approximate temp. If it's going to be warm outside, I will place the cartridges in my ice chest with a piece of cardboard over the top of them. On top I might stick some cool bottles of water there or an ice pack depending on what I expect to encounter while I am there.

Prior to doing this, if I was out in the heat for several hours, my velocities would slowly climb up. They have stayed more consitant since doing this in cool weather.

If you were shooting in cool weather before, and now in hot weather, I would imagine the extra heat may give you a different pressure or velocity. Do you have your velocities still from when you shot in cooler weather? Be interesting to see if they have creeped up.
 

Marble

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Jul 19, 2012
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Shasta County
And I like ho wyou are taking your time and doing one thing at a time. I'm a little jealous as my gun is still out getting rebarelled. It will be a few months before I get it back...
 

ajridgedell

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Jan 22, 2011
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Location
Louisiana
I appreciate all the input, the only other time I recorded velocities was on my first ladder test from Sunday when it was 87 and in general everything was warmer, so that may explain why I got a little slower velocities for the same powder charge on the second test. I'm getting anxious to head up to my honey hole and put my target out there just over a mile. I plan to take some video of everything when I go.
 

ajridgedell

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Jan 22, 2011
Messages
85
Location
Louisiana
Wow, didn't mean to drag this out or start and not get to the finish for so long. It's been hot as crap and work has kept me busy all summer but I finally got back to it and have finished up my load work and drop data and zero and all that stuff. I shot several groups at 89.2g and wasn't super impressed, so I shot some a 93.1 and they were definitely worse. Cleaned barrel very good and shot a few more groups at 89.2. It's not quite as great as I was hoping but I feel confident that with this powder, bullet and gun, this is the best I am going to get. My groups have been averaging .6 to .75 Moa off a bipod and rear bag from bench and prone.
94C72F2A-8207-4E1F-86BA-8A739419DD55_zpsswyeu9fj.jpg

Here is my last two 3 shot groups to confirm zero and confirm my hold to 600 yards. The shot low right from 100 yards was my cold bore shot, but in all my other testing I have kept track of my cold bore shots and they have been right in with the wrest of the groups. I don't think I've mentioned it but I am shooting with a silencer.
My next step is to find time to go to my honey hole and connect with my steel target at one mile. I plan to record the event, hopefully it turns out good.
 

Lrt307

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Nov 8, 2012
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262
If you are shooting group sizes different days that is inaccurate data Imop. Different days temp and different station psi will net you fifferent results ice chest or not. It doesn't take much to skew a shot when shooting groups. Thise are just a few of the variables not to mention the guy driving the gun. I have some 300 rum 230 berger data I will dig up. I ended up in the 92.0- 92.5 .095 off lands if I remember right. I also shot H-1000 which shot better but can't remember my charge without looking? I wanna say 89.5 - 90.5 grains????? I will check. Both loads were tunning in the 3025 fps range without psi signs. .095 was the majic. Good luck on your hunt.
 

geo4061

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Jun 25, 2014
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Location
Southern Oklahoma
Lrt please check your data. That is 4 grains over Berger max. I am a little over max and loading .010 into the lans. At high temps and low elevation I am getting pressure signs. Thanks
 

Lrt307

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Nov 8, 2012
Messages
262
Lrt please check your data. That is 4 grains over Berger max. I am a little over max and loading .010 into the lans. At high temps and low elevation I am getting pressure signs. Thanks

I will check my data and post but keep in mind you will lose a ton of pressure comparing .010 off lands to .095. I was running .030 off lands getting psi but would not fit in mag so I started pushing bullet in case to fit mag. I lost a ton of psi with more jump. I had to load 2 more grains to get back what I had lost to match my target load.
 

ajridgedell

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Jan 22, 2011
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85
Location
Louisiana
Well I'm planning on going to give it a shot this weekend. If I am successful enough then that itch will be scratched, if not then I'll try different powders I guess.
 
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