Rough Load workup

[hounddawg]

I see a lot of threads wondering how to do a load workup, here is a step by step rough 4 X 4 workup. This is designed toi get me in the ballpark and fine tuning is still needed

Fist step was researching the load. It is meant as a long range load up to 800 yards. The BC of this bullet is too low for 1000 yards, it drops below 1350 FPS at 1000 and would probably be OK but I would prefer the 142 SMK for 1000 shooting

Once I determined what range I plugged numbers into a ballistics calculator to see what FPS would be needed to get 1350 or better at 800 and researched the powders I have on hand. H4350 is the popular choice for a lot of shooter for 6mm as well as 6.5, gives great speed and I have about 7 pounds on hand so that was the powder choice.

The Sierra manual does no list H4350 so it was off to the Hogdon site where it listed a minimum of 43.5 to a maximum of 46.5. I like to have at least two load data sources and looked at the Nosler 120 CC data. In my experiance the SMK and Nosler CC bullets are very similar and almost identical in in ogive shape. They listed 44.5 to 48.5. Ken Waters Pet loads book is a good reference to check and see also but I would warn against using it as the sole data source, but he had 43.0 and the SMK listed as a very accurate load

Now to actually load the test ammo on post 2

 

[hounddawg]

part 2

After doing the initial research to determine a safe load range I decided to start with a low of 43.0 and a maximum of 44.5 which I thought would give me plenty of velocity at 800 yards. If I had a opportunity to shoot at 1000 I might see if I could find another good node that would give me 3100 or 3200 FPS but why waste powder and barrel life with more than what is needed to get the job done.

edit - cases were Lapua on 2nd reloading, primer pockets were uniformed before first firing and cases were trimmed, chamfered and deburred. No annealing. Charges were weighed thrown on a Johnson Quick Measure then hand trickled to the milligram on the $20 Smartweigh scale. When I say hand trickled I mean hand trickled, I use a empty yogurt cup of powder and my thumb and forefinger. I have done a previous primer test with six different primers using H4350 at 90% plus case fill with a different bullet and knew the H4350 seemed to like the Remington primers best so no further primer testing needed

I am attaching 3 files. The first is a spreadsheet showing velocities followed by the rough depth of seating test and finally a rough charge workup. As you can see the H4350 give great consistency across a wide range with low SD's and ES's. The minimum charge gives me a speed of 2975 when seated on the lands which is plenty for 800 yard shooting. Notice the increase in velocities with the various seating depths.

I first fired 4 rounds as sighters and to foul the barrel. I also increased each by .5 gns to a maximum of 44.5 to check for pressure signs. If I had decided to push the charge to the maximum load I would have started decreasing the increments to .3 and .1 as I neared maximum. That was followed by 20 rounds with a charge of 43.5 gns seated at .073 from lands, .050, .035, then on the lands. The ones on the lands had great velocity numbers and grouped well so the 20 that I had loaded at home with various charge weights and left seated at .000 from lands were not reseated. I did have my seating die in a Lee hand press along with calipers in the event the bullet wanted a "jump"

At the end the 43.0 charge and the 43.5 charge had a average velocity only 8 FPS apart and the groups are fairly tight. Next week I will fine tune the depth working away from the lands in .005 increments using a 43.3 charge weight to see if I can get grouping below .5 and hopefully into the .3 to .4 range

Anyway this is how I start a load test, I would be interested in how others do it and any critiques on my methods. Please use detail and pics of groups are always of interest

 

[F. Guffey]

I built a rifle, I loaded 120 rounds with 12 different loads that consisted of 12 different head stamps, bullets with different powders and different wrights of powder and then headed for the range. When I finished firing the 120 rounds I knew what the rifle liked. The groups moved around but did not open up and there were no flyers. Some groups shared the same hole and no group was larger than a quarter. That would be 10 holes in one group and I was not there to show off.

I loaded another 120 rounds of 12 rounds of 10 rounds each and took the rifle to the new owner. I instructed him to determine what the rifle liked, For him life is much simpler; he went to the range, fired one round and then zeroed the scope and put 9 holes on top of the first hole. I had to call him to determine what the rifle liked. He said it did not matter; all he had to do was zero the scope when changing ammo. He did not like the trigger so I suggested he purchase one he liked and I would install it.

I purchased a new rifle with 4 boxes of Federal GMM 300 Winchester mag ammo' I headed to the range. The rifle required work and adjustments. The 74 round went through absolute zero; I moved over and then handed the rifle to the new owner with the last 5 rounds. He put the last 5 rounds through the same hole.

At the same time I started on another 300 Win Mag; it was a Winchester model 70 in 300 win mag. It did not shoot groups, it shot patterns like a shot gun. Winchester and I had words, the warranty shop sent the rifle back to Winchester and things got worst. Time past, they sent the rifle back to the Warranty shop in a new box. That had to be 16 years ago, last year I loaded another 120 rounds thinking I should get over it and then I got over it. I sent the ammo to Alabama to be fired in the other 300 Winchester Mag. The old owner said he replaced the scope and needed the ammo so he took one box to zero the scope.

F. Guffey