Need some advice

[TackDriver284]

I tested the 300 Win Mag this morning, 200 ELD-X and RL26. This is my first time using Rl26 and I did not find any data on the 200 grain bullet, so I used the minimum and max loads for the 210 grain bullet. Lapua brass, fired 1X and CCI250 primers. .002" neck tension
210 grain bullet in Nosler manual shows 74 grains as middle charge and 76 grains as max, so I added 1 grain more for max charge for the 200 grain bullet. I measured the bullet touching the lands as well, and backed off .020" and OAL is 3.420" which is kind of short compared to the AccuBond 180 I used before. There was a heavy powder crunch as well.
75.6 grains - 3,070 fps average 3 shot group
76.0 grains - 3,120 fps average 3 shot group
76.4 , 76.8 and 77.2 grains - Stopped shooting after using 76 grains due to high velocity , no pressure signs was visible.
If you see the picture, the 200 ELDX was seated wayyy deep in those cases, and its only .020" off. Would that be a reason the velocity is so high?
The 3 shot group with 75.6 grains is excellent for hunting, 76 grains as well, but the speed is insane, its why I stopped shooting, because I want to keep all my fingers.

75.6 grains - 3,070 fps

76 grains - 3,120 fps

Conclusion, I will pull all bullets, redo at 75 grains up to 75.6 grains. I noticed there is a lot of bearing surface as well, could have been a reason for high velocity.
What do you advise? Any opinions on why the speed is insane? Are the data that I used correct from the data on the 210 grain bullet, since I used that data on a bullet that is 10 grains lighter.

 

[JD338]

Mark,
Looks like you are on the right track. The speed increases isn't enough to worry about and the lower pressure will help with longer case life.
The 75.6 gr load pushing a 200 gr bullet at 3070 fps is a freight train.
That load is a shooter!

JD338

 

[Guy Miner]

Great shooting as well as darned good work at the loading bench.

I'd throttle it back to that 75 - 75.6 level you mentioned. Try it again, and figure on hunting with it.

Guy

 

[Ridge_Runner]

I don't get it, with no pressure signs why would a bit of extra velocity hurt? I have rifles that shoot faster than they are supposed to, and some that shoot slower. I was the same place once with my STW, was shooting 3550 with a 140, called the folks at sierra. Was told with no pressure signs that I was not over pressure with that rifle, even if I experienced flattened primers with the 215 federals to disregard that because the 215's have a soft cup, with no ejector marks, sticky extraction/heavy bolt lift, or case head expansion, just keep shooting.

 

[xphunter]

I typically figure 100 fps per 10 grains of bullet weight in general
Ditto JD

 

[gerry]

It's good to be careful. There may be no traditional "pressure signs" but lots of extra speed is a pressure sign that we should be aware of. I would be happy with the 3070 fps load especially with RL 26 and it's reputation of being a bit squirrely when you get up to high pressures. great shooting by the way.

 

[DrMike]

Cartridge          : .300 Win. Mag.(SAAMI)
Bullet             : .308, 200, Hornady ELD-X 3076 G7
Useable Case Capaci: 79.175 grain H2O = 5.141 cm³
Cartridge O.A.L. L6: 3.420 inch = 86.87 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : Alliant Reloder-26 *C

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.0% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step    Fill. Charge   Vel.  Energy   Pmax   Pmuz  Prop.Burnt B_Time
 %       %    Grains   fps   ft.lbs    psi    psi      %        ms

-10.0   88    69.21   2699    3235   44595  12191    100.0    1.412
-09.0   89    69.98   2729    3308   46248  12258    100.0    1.389
-08.0   90    70.75   2760    3382   47967  12318    100.0    1.366
-07.0   91    71.52   2790    3456   49757  12378    100.0    1.343
-06.0   92    72.29   2820    3531   51606  12436    100.0    1.321
-05.0   93    73.06   2849    3606   53518  12494    100.0    1.299
-04.0   94    73.82   2879    3681   55498  12550    100.0    1.278  ! Near Maximum !
-03.0   95    74.59   2908    3757   57551  12606    100.0    1.257  ! Near Maximum !
-02.0   96    75.36   2938    3833   59682  12660    100.0    1.237  ! Near Maximum !
-01.0   97    76.13   2967    3909   61893  12713    100.0    1.217  ! Near Maximum !
+00.0   98    76.90   2996    3986   64187  12765    100.0    1.197  ! Near Maximum !
+01.0   99    77.67   3025    4064   66569  12816    100.0    1.178  !DANGEROUS LOAD-DO NOT USE!
+02.0  100    78.44   3054    4142   69043  12866    100.0    1.159  !DANGEROUS LOAD-DO NOT USE!
+03.0  101    79.21   3083    4220   71612  12915    100.0    1.141  !DANGEROUS LOAD-DO NOT USE!
+04.0  102    79.98   3111    4299   74282  12962    100.0    1.122  !DANGEROUS LOAD-DO NOT USE!
+05.0  103    80.75   3140    4379   77058  13008    100.0    1.105  !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 5% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 5% relative to nominal value:
+Ba     98    76.90   3059    4156   72045  12497    100.0    1.144  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 5% relative to nominal value:
-Ba     98    76.90   2918    3780   56429  13092    100.0    1.260  ! Near Maximum !

Thought I'd throw up a projection with the parameters you gave. I do believe that the advice you've been given is correct. No pressure signs? Enjoy the gift of velocity with the great projectile.

 

[PJGunner]

I agree with what Guy and Dr. Mike said. My pet load for the .300 Win. Mag. uses Winchester Magnum Rifle powder (WMR) which hasn't been available in years. I reached a comfortable max load that came very close to 2900 FPS using either the 200 gr. Speer Hot Core or Nosler 200 gr. Partition. Only game shot with the Speer was a cow elk at a lasered 530 yards. One shot and done. Haven't shot anything but paper so fr with the Nosler. The really cool part is the load is accurate in five rifles, a Winchester M70 and four Ruger Number ones, a "B" and three "S" models.
Paul B.

 

[jimbires]

Mark ,if you want ; give me all your specs . bbl length , fired case water capacity , COAL measured off the tip, and about what outside temp you were shooting in . also give me powder charge and velocity for the ones you've shot . I'll play a little bit .

when I first started using RL26 in my 7 rem mag I did the same as you , I thought no way is this safe , but it was .

 

[300WSM]

It's good to be careful. There may be no traditional "pressure signs" but lots of extra speed is a pressure sign that we should be aware of. I would be happy with the 3070 fps load especially with RL 26 and it's reputation of being a bit squirrely when you get up to high pressures. great shooting by the way.

This ^^^^^

Couple things of note...
The only purpose of a chronograph with loading ammo is to give a point of reference. With all the data out there its great to compare it with other printed data. Maybe it's a trajectory you're trying to achieve....
But it's an even better tool to suggest something is within parameters oro outside of....
To which you're definitely doing the right thing by looking

The why...who knows.

But...

Couple things of note.

Chronograph accuracy?

Have any factory ammo to compare to try and gauge both your chronograph and rifle?

 

[RL338]

I question your chrono readings. 76grs seems like a good spot to stop. The only rifle I’ve seen RL26 hit pressure is my boys 257 Wby. As charge weight goes up velocity will level off and wham sticky bolt (Weatherby brass).

 

[TackDriver284]

Mark ,if you want ; give me all your specs . bbl length , fired case water capacity , COAL measured off the tip, and about what outside temp you were shooting in . also give me powder charge and velocity for the ones you've shot . I'll play a little bit .

when I first started using RL26 in my 7 rem mag I did the same as you , I thought no way is this safe , but it was .

Hey Jim, thanks for the offer. Here are the specs, H20 capacity 92.29, barrel is 26, COAL is 3.420, 75 degrees, powder weight 75.6 grains, 3070 fps. Let me know what you found. Thanks

 

[TackDriver284]

Couple things of note.

Chronograph accuracy?

Have any factory ammo to compare to try and gauge both your chronograph and rifle?

A couple of weeks ago, I have compared the 3-5 fps ES for the 6BR and the 6.5 Creed with my P35 and a Magnetospeed. My buddy checked my speeds and ES with his MagnetoSpeed and both chronographs was spot on.

 

[300WSM]

A couple of weeks ago, I have compared the 3-5 fps ES for the 6BR and the 6.5 Creed with my P35 and a Magnetospeed. My buddy checked my speeds and ES with his MagnetoSpeed and both chronographs was spot on.

Well...

if something fails remember there is always a time it happens and a time when it was perfect.
In other words you checked it before and it was ok...and odds are it still is accurate...
But...
As I said if something goes amiss it wasn't always that way.

If you're using a "chrony style" they can be battery sensitive...
light sensitive...
good or bad.....

Again from your comparisons weeks ago it's unlikely your chronograph is acting up but the only way to be sure is shoot it through another chronograph...or check a factory load with a published velocity the same time you're shooting your reload.

I'd try that first.
You could be all worked up for nothing.

 

[jimbires]

Hey Jim, thanks for the offer. Here are the specs, H20 capacity 92.29, barrel is 26, COAL is 3.420, 75 degrees, powder weight 75.6 grains, 3070 fps. Let me know what you found. Thanks

Mark , I can't get the two velocity points to align . I can get 75.6 grain to show 3079 FPS . I can get 76.0 to show 3118 FPS , but I can't get both to show actual velocity at the same settings .I'll contribute this to a pressure spike at 76.0 grains . what I'm seeing on quickload , I'm going to say that 75.8 grains 3086 FPS is your MAX, 63956 PSI , it's rated at 64000PSI . another thing that's telling me this is the huge velocity gain you show with only adding 0.4 grains of powder , I'll say this is a pressure spike , they also show up when working around max pressures . my gut tells me your 75.6 grain load could be problems when the temp goes up ,I feel it's right on the edge at 63393 PSI . I'd bet if you started a ladder from around 71.0 and worked up you would see the velocity go flat for a couple powder increments before the 76.0 grain load , then 76.0 spikes up .

some guns will work well at higher pressures , others won't . I'm going to say it's just this combination of powder and bullet in this rifle . you was smart to stop where you did .

 

[RL338]

Mark , I can't get the two velocity points to align . I can get 75.6 grain to show 3079 FPS . I can get 76.0 to show 3118 FPS , but I can't get both to show actual velocity at the same settings .I'll contribute this to a pressure spike at 76.0 grains . what I'm seeing on quickload , I'm going to say that 75.8 grains 3086 FPS is your MAX, 63956 PSI , it's rated at 64000PSI . another thing that's telling me this is the huge velocity gain you show with only adding 0.4 grains of powder , I'll say this is a pressure spike , they also show up when working around max pressures . my gut tells me your 75.6 grain load could be problems when the temp goes up ,I feel it's right on the edge at 63393 PSI . I'd bet if you started a ladder from around 71.0 and worked up you would see the velocity go flat for a couple powder increments before the 76.0 grain load , then 76.0 spikes up .

some guns will work well at higher pressures , others won't . I'm going to say it's just this combination of powder and bullet in this rifle . you was smart to stop where you did .

I tried his numbers also , but burn rate has to adjusted way off from each other. Lapua brass tends to hide pressure.

 

[jimbires]

I tried his numbers also , but burn rate has to adjusted way off from each other. Lapua brass tends to hide pressure.

I adjusted weighting factor , Ba , and shot start trying to get things to align , I couldn't do it . has to be a pressure spike at 76.0 . yes , Lapua brass is tough stuff , it hides pressure well .

 

[RL338]

RL26 is hard to align in my Wbys. That .4gr sure had a velocity jump for him. Maybe chrono error?

 

[TackDriver284]

Mark , I can't get the two velocity points to align . I can get 75.6 grain to show 3079 FPS . I can get 76.0 to show 3118 FPS , but I can't get both to show actual velocity at the same settings .I'll contribute this to a pressure spike at 76.0 grains . what I'm seeing on quickload , I'm going to say that 75.8 grains 3086 FPS is your MAX, 63956 PSI , it's rated at 64000PSI . another thing that's telling me this is the huge velocity gain you show with only adding 0.4 grains of powder , I'll say this is a pressure spike , they also show up when working around max pressures . my gut tells me your 75.6 grain load could be problems when the temp goes up ,I feel it's right on the edge at 63393 PSI . I'd bet if you started a ladder from around 71.0 and worked up you would see the velocity go flat for a couple powder increments before the 76.0 grain load , then 76.0 spikes up .

some guns will work well at higher pressures , others won't . I'm going to say it's just this combination of powder and bullet in this rifle . you was smart to stop where you did .

Thanks Jim. I'll work up some loads from 75 to 75.6 and test again. I like this speed at 3070 fps, and that 3120 fps load was a bit too much for my liking for a 200 grain bullet especially at 75 degrees, imagine when temps gets to 90 degrees, its reason I stopped shooting because of common sense. I was using the 180 Accubonds at 3150 fps with RL22 and it was not a max load, just 1 grain shy of max. It was an accuracy load because the faster speeds was not giving me the accuracy I wanted. I was pushing it to 3260 fps when I was seeing some mild ejector marks.
Hopefully I won't see any velocity / pressure gains once the hot dog days of summer comes. I like this 200 ELD-X bullet.

Would seating the bullet too deep in the case cause pressure? I was surprised to see that I was .020" off the lands and bullet is so deep. I don't think seating longer another .010" will help much. I read that seating a bullet too deep can reduce case capacity, and raise pressure as well. I was heavily crunching powder for those charges.

 

[TackDriver284]

I adjusted weighting factor , Ba , and shot start trying to get things to align , I couldn't do it . has to be a pressure spike at 76.0 . yes , Lapua brass is tough stuff , it hides pressure well .

What weighing factor did you use? What shot start numbers did you use? I have never played with shot start.
I used .4 weighing factor and see that I'm approaching the max line. If using .5 weighing factor, I'm over the max line.