I need a refresher on load development.

[Guest]

I have a new box of Hornady SST 140gr and on a recommendation from the 1000yard guy at the gun store I picked up a box of match grade magnum primers.(Why didn't I think of that.) And I have a jug of 4831sc xtreem. I am pursuing a more accurate hunting load for my .264 win mag improved bench gun.
I'll start by just bumping the bullets up aginst the lands.Fill with a light load,fire 3 shots,chronograph,record group and conditions,check for pressure. Increase by 1 grain and repeat.Keep increasing untill I have pressure or the group falls apart.Once I find the best load I can pursue fine tuning with the seating depth or, if the best group is terrible I can abandon this combination all together.
Please feel free to offer opinions.I am trying to learn. AND I realize there may be more that one method which works.
Thanks.

 

[milanuk]

Not too much wrong here, other than I'd venture the opinion that 1gr increments are bit steep, even for a larger case like the .264 Win Mag. 1/2 gr steps are plenty.

Some people pick a powder from the loading manual w/ the bullet they choose to work w/, start at the manuals recommend minimum load and start working their way up. Not entirely a bad idea, and probably the safest overall. Just may go thru a butt-load of components getting from the min load to what ever maximum is in your gun (may be more than what the manual shows).

Another one I use a lot, and the normal disclaimer here, I'm not necessarily saying its a good idea, just that it is what I do. I pick a powder from the manual for the bullet I have on hand, see what the max listed load is, then back down about a grain to a grain and a half and start there, working up in 0.3gr increments, up to and perhaps a little over the listed max, depending on the gun. Your mileage may vary (YMMV).

Finally, try doing a search on 'OCW' or Optimal Charge Weight on the forums at www.accuratereloading.com, www.snipershide.com, among others (can't remember if the guy has a thread here on it). Probably a bit into the 'advanced' load development, but it might float your boat anyway.

HTH,

Monte

 

[Brent]

I use the ladder method too.

1/2gr step up per round to max load with ten rounds while plotting impact spot for each shot on paper to see which loads group together and at what velocity.

This is how you can target the sweet spot in your rifle. If a rifle has a stable load range with this powder, it should produce at least a promising 3 shot group from this test which can be confirmed and fine tuned with OAL and charge wt variations to better match barrel time.

This is alot faster and uses less ammo to find the spot too.

 

[Guest]

Brent,ladder method huh? If this works it is WAY superior to what I usually do.Looks like I may have a new way of testing loads.
Thanks a lot.

 

[BountyHunter]

go to date 12-19-02 on this sight under bullets, ballistic etc and see a link for detailed explanation of audette/ladder method. "Best explanation" you can find. About 20 pages with photos.

 

[BountyHunter]

frankg

Think I would try fed 210s also. Most have found they give better ES than 215s or other mag primers in that size case, especially with 4831 sc.

Good luck

BH

 

[Brent]

Something to look at along the way while testing too. The ladder method works very well, you will get workable results. The way you have been doing it will work, just take much more ammo and at 1gr steps you "could" miss a good load.

Link that BH refered to

 

[Guest]

Well I have some results I like. I already had some rounds loaded up when I read about the ladder method so I just went with what I already had.I have a couple of groups that look like they would have been 1/4 inch had I done my part better and had a better rest.The fliers opened the gorups to 1/2 inch.
Now I am wondering something.These new groups were shot with sst bullets,magnum primers and with me holding the stock pretty hard.These are all new components. So is it the bullets or the magnum primers or me pulling the stock in tight? I'm sure enough testing will tell,but does anybody want to venture an educated guess.
.264 winmag,sleeved 700 action,27 inch Kreiger,Lone wolf bench stock,muzzle brake,timney trigger(for now),16 lbs,Nightforce 5.5x22.

 

[Michael Eichele]

Frankg,

It helps ALOT if you clean your barrel before trying a different powder even if only a few have been fired from the previous. Also, some loads will need 1 foul shot and others may need 3. Give everything an equal opprotunity by starting at ground zero if changing powders or even bullets if the type of bullet is much different. Also some loads can be shot 100 times and no cleaning neccessary, and others will loose accuracy after 20. So it is best to clean often when developing a new load to make sure you get the best out of it.

 

[Brent]

Consistancy is key... Time will tell though.
I'd work up and down around that load to see if things get better or worse then play with oal on the best load to improve it more, being consistant the whole time.

I don't know if you switched powder or not, but I've started to shoot a few foulers when I switch powders too. I have seen a new powder upset a good load too many times for the first couple rounds out of the gun, so I know it happens. It may be worse with some more than others though.

 

[moosehunter]

I gave this method some thought and have a question or two. Near as I can figure a .3 gr. increase will give my 300 win. mag. maybe 10 or 15fps. increase. At 300yds this will be maybe 1/4" elevation increase. So ideally I will be looking at a vertical rip in the paper about 6" long at 300yds. Any feelings on this? Id sure like to give this a go but Im sceptical about blowing 20rds of 240gr. MK's down range if this is all Im going to get.

 

[RBrowning]

The premise of the ladder method is that you will find areas in your incremental loading progression that have clumps of holes and areas that have few holes. This is caused by a combination of the bullet velocity and the amplitude of the vibration. If it was velocity only you would have a vertical string of evenly spaced holes. But because the two interact you get groups of three or four as shown in the graph above. If you load in the center of these groups it makes the load less sensitive to powder measure and case capacity variations.

If I remember the article correctly the powder increment is not necessarialy a fixed amount, but it is the range of measure that you want to test divided by 15. If your manual reccommends loading your favirite cartridge with somewhere between 68 to 73 grains of powder, you would take the 5 grain range and divide it by 15 to get an increment of .33 grains. If the math is easier or the weight increments are awkward, you can use more steps than 15. This will make the groups even easier to see. If you go to fewer increments you might not see a group where there really is one.

[ 01-17-2003: Message edited by: RBrowning ]

 

[Guest]

The 'ladder method' is an interesting academic exercise, but very consuming of time and resources. To get to a load that works, it is much easier and quicker to fire several rounds to determine where max pressure is with a particular lot of powder.

Once you know (for example) that 102 grains is max for that bullet and powder, back off about 2.5 percent, and then work a short ladder in about 3/10 grain increments. If the gun bullet powder combo won't hole up in the top 2 percent, switch powders, or switch bullets.

The principles behind the ladder system do exist, but what most don't tell you is that the ladder is not made of equally spaced rungs. Almost all rifles shoot better when loaded near max pressure, The standard deviations in velocity will be smaller, and the ignition is more consistent. Also the faster a bullet is moving, the larger the standard deviation it can have, before barrel harmonics manipulate the vertical stringing the same amount as a slower load, as the barrel frequency and amplitude will not increase at the same rate as bullet velocity.

 

[Brent]

I finally have "some" results with the 220gr SMK over RL25. First trip to the range was with 88.5 - 93gr in .5gr steps at 3.75" oal. Well guess what... 88.5 was 67,000 psi already! So much for that starting load. I had them seated into the lands .005" while I broke in some new brass.

I fired the 89 and 89.5gr loads too and was up to 71k psi that fast. No psi signs besides primers spreading out some. My factory ammo tested normal psi so I headed home.

When I got home I loaded some back up at 86.5 - 89.5, begining slightly lower, just in case psi was still high, seating them and the unfired remaining loads deeper to .050" off the lands just to see if psi would come down some.

Next, I loaded up some at a little lower range, 84 - 88.5 seated into the lands .005" like the first ones.

Just for kicks and giggles I loaded up some at 86.5 - 93 seated .105" off the lands that would fit in the magazine. As you can see, I didn't want to come home with a cold barrel again.

Stay tuned... I'll post results when I wake up in the mornin. I'm beat.