Powder Charge

[Jim Hundley]

I have been loading H-1000 with the 168 TSX out of a .300 Win.mag.with great success.Decided to try the new 165 Accubond with the same powder,primer,and brass.Worked up to 83 grs. of H-1000 for a velocity of 3163 fps.I was hoping for 3200 fps. as with the TSX load.I called Hodgdon and they said go to 84 grs. of H-1000 with the 165 Accubond and that the compressed load would be well within their safe pressure limits.Anyway,loaded the 84 grs.of H-1000 and the velocity didn't even reach what was attained with 83 grs.(84 grs.,3148 fps.).What gives???The temperature was 97 degrees,but the barrel and ammo was kept at room tempts.Can anyone help me out or should I retest the load?
Jimmy

 

[sewwhat89]

Sounds like you have hit your max load.

Are you looking to use a temp insensitive powder or just what you have on hand?

 

[Jim Hundley]

Hoping to use a temp.insensitive powder.My question is why the 165 Accubond has less velocity than the 168 TSX with an equal or greater powder charge(1 gr. over the TSX load)?I have had the desired velocities with the TSX,but can't obtain it with the Accubond.Could it be a greater bearing surface with the Accubond?83 grs.of H-1000 results in 3195 fps with the TSX,the same load with the Accubond is 3135 fps.

 

[skip AI]

Do you think that is enough velocity to be stressing over?

I mean 60fps is stuff all IMO.

 

[sewwhat89]

Well, I am getting 3216 with Hornady Interbonds with 77 gr IMR 4831. Maybe you could try working up to that and check your velocities. I was getting 3190 at 50F and 3216 at 85F. Not sure what part of the country you are in to know if that matters, but on the other hand, is 60 fps significant? I suspect the bc of the NAB is better than the TSX, and by 500 yards exceeding the TSX's ballistics. JMO

 

[Jim Hundley]

Thanks.I am not all that concerned about 60 fps,but was trying to get some insight as to why the varience exists.It seems to me that the 165 would have at least the same velocity as the 168.
Jimmy /ubbthreads/images/graemlins/confused.gif

 

[royinidaho]

Compare the bearing surface of the bullets. The longer bearing surface'd bullet may be slower. Jacket type is also a variable. Also you my want to try shooting through about a yard square piece of paper about 4 or 5 feet ahead of the muzzle to see how much powder isn't buring in the barrel.

Just some tho'ts....

 

[Jim Hundley]

Thanks,Roy!That is just what I was thinking.
Jimmy

 

[Roll-Yur-Own]

Jimmy, it doesn't make sense that you went up a grain and went down in velocity.

Did you shoot both these loads same day?

I would shoot a 5 shot group of each and measure velocity.

I would also alternate since you are not shooting for group size but rather velocity. In other words shoot 10 shots 83,84,83,84,83,84 etc. and measure velocity on each shot.

Then I would compare results. If you do this I would like to see the results myself.

When you started seating the AB's did you have to raise or lower the seating die from where it was shooting barnes?

I wouldn't worry about the 60 fps as others have said - the AB does have a much better bc.

I really like the hodgdon extreme powders. How did the AB's & Barnes group with it?

 

[sewwhat89]

Had you cleaned the rifle before shooting the NABs after shooting the Barnes? Could have been due to the Cu from Barnes left in the barrel causing the problem too.

 

[Jim Hundley]

Thanks for the response.I was not trying for groups,just experimenting with powder charges to see if I could get to 3195 fps.Every load that I have shot at or close to that velocity has grouped very well.The last two times I have loaded with Ramshot Hunter with excellent results.The word is that Hunter is temp.insensitive like the Extremes.No way to tell when it is 103!My load of H-1000 has been great and super consistant with the 168 TSX.

 

[Jim Hundley]

Yes,I always clean when changing bullets and/or powders,plus I fire at least 3 foulers before getting down to the nitty-gritty (same load as the testing is going to be done).