300 rum loads

[stxhunter]

went out and chrono some loads today had been shooting 95 gr retumbo 200ab and getting avg of 3085 fts and 3/4 inch groups. im not sure on the sd but i think it was 29ft don't remember es this is out of my 700p 300 rum.today i loaded 10 with 94.5 grs shot 10 shot group 3/4 inch velosity was avg 3114 sd was20 es 59 .then i shot 10 with 95.5 grs that went into a group about 5/8s inch avg velosity was 3135 sd was9 and es29 this is the one i'm going to shoot now but i don't understand how the 94.5 gr load had a velosity higher than the 95 gr load almost as high as the 95.5 load if it would group as good i would use it

 

[Sendero_Man]

Was there a temperature difference between the days you shot the 95 and todays temp ?

I am guessing if you loaded 5 of each 94.5, 95, and 95.5 and shot on the same day, you would have better data to compare.

Just my guess...

 

[stxhunter]

same temp pretty much 89 when i chrono the 95gr load chronoed 10 shots and it was 91 when i chronoed the other two loads yesterday also 10 of each load

 

[jmden]

I'm no expert, but it may be that the powder settled a little differently in the case of the 94.5 g loads right before you fired. Some folks have found large differences in velocity if each case isn't handled similarly. Just a poke at an explanation here but I'm not sure this theory applies to such a large case that's nearly full with powder.

It might also be that you've just found a range of powder charge that shoots at nearly the same fps. This may be a 'sweet spot' in which to look at developing your load further within. You may want to take it out long and see what happens.

Just a couple of ideas (probably wrong).

Good luck.

 

[Skidly_50]

300rum

mine did the same thing!

 

[BillR]

Lots of differant results between guns

I'm also shooting 95 grains of Retumbo with the 200 Grain AB. I have seen a lot of differant results on here using that load for some reason. I have crono'ed my load twice now and got the same results. 3200 average with an ES of 30. I'm trying to get it down below at least 20 ES. What can also give a person variations in results is neck tension. Seems that as the necks work harden it can affect your results. Too much spring back when resizing. I also use a brush and scrub the insides of my case necks good before I resize and I'm annealing about every other loading and the problem has been lessened. Little things you can do can make a big differance in results. I'm not sure Retumbo is the perfect powder for the .300 RUM or not but at least its as good as I have found for volocity and presure. H1000 gave good ES but I was lucky if it got over 3000 with the load the gun liked and if I tried to move up in load I started loosing cases. (Primer pocket)