Home Forums Hunting & Shooting Ask The Gunwriters How do 'you' work up a new load for a new rifle?

One of my most accurate rifles is a 7-08 with a magazine that limits how far out I can seat bullets. IME, it takes a little more work experimenting with different bullets to find one that shoots well with a jump in your particular rifle. Mine happens to like 120 ballistic tips, and even with a thin barrel, it stacks 'em.

I'm jumping Scenars 0.084 in my 260 with good juju, but do start at the lands with everything knowing I only have one direction to go.



Except NPT's and mono's...

Same here.

Crow Hunter,

I didn't say "all chronographs aren't accurate." In my experience Pro Chronos are, but not all brands are. I have seen another brand off by 100 fps or more, shooting the same load under varying light conditions.

All Nosler manuals since the introduction of the 260 Partition have listed the same data for the three powders mentioned, IMR4064, IMR4350 and RL-15. There's a velocity spread of over 80 fps for those powders, which isn't even roughly the same.

Since powders normally vary in burning rate from lot-to-lot by up to 3% or so, AND from how much they've dried out since the container was opened, I wouldn't be surprised at 200 fps difference between three powders already listed with an over 80 fps difference. The powders from some manufacturers can vary even more.

I am NOT saying loading data is infallible, by any means. A big problem with some data (and one which drives me nuts) is the practice followed SOME companies of working up loads in a pressure barrel, then chronographing the velocities for publication in a factory rifle. Sometimes they explain this and sometimes they don't, but the usual reason is to provide "velocities in a typical rifle." Since there ISN'T any such thing as a typical rifle, the velocities can be wildly misleading.

Speer is one example. In one of their 13th manual they published a sidebar with the .308 Winchester data:

"We've had many callers ask why the .308 velocities shown are equal to or better than some of the .30-06 velocities shown... First, a compact case and a higher pressure limit give the .308 the edge with bullets up to 150 grains. Things are about equal with the 165 grain bullets, but the .30-06 case's ability to hold a lot of slow-burning powder gives it the upper hand with heavy bullets.

"The second reason is the sporting rifles we used to record final velocities. Both have 22" barrels and were bought at the same time. The .30-06 sporter posted velocities about 50-100 fps behind the pressure barrel. That's normal. On the other hand, the .308 sporter was consistently equal to or slightly faster than the pressure barrel. Like we've said several times, all sporters are different!"

The first part of Speer's statement, that the .308 is equal to the .30-06 with lighter bullets, is flat wrong, since no other source of data shows it. The second part demonstrates why working up pressures in one barrel and then recording velocities in another can be very misleading. (It used to be even worse when many companies used the SAME rifle for shooting velocities long after the throat had developed considerable wear.) I wish ALL reloading data sources showed velocities from the barrel used for working up pressures. It would be far less confusing.

I also wish they'd all use piezo-electronic equipment, but understand why some don't. It's expensive, but it also provides more accurate than strain-gauge pressures. Many handloaders put a lot of faith in strain-gauge results, but even many supposed professionals don't understand the variables and limitations in strain-gauge results.

But that's somewhat beside the point here. Despite those limitations of even professional equipment, their tests are all done under much more strictly controlled conditions than those of 99.9% of handloaders. Temperature is one. SAAMI ballistic labs work up loads at 70 degrees--or at least all I've been in do.

The temperature reaction of different powders is all over the place, and I only know one handloader who has an indoor range kept at a constant 70. The rest do their testing at whatever the temperature is at an outdoor range, which can easily vary 50 degrees or more.

This affects some powders more than others, and even the same powders will react more to temperature changes in certain applications than others. As an example, in one temperature test I did with various cartridges at both 70 and zero, IMR4350 lost twice as much velocity in the .30-06 with 165's as it did in the .375 H&H with 300's.

Neither IMR4350 or IMR4064 is particularly temperature-resistant. Reloder 15 is much better, or at least is has been for about 15 years now. Before then it was pretty temperature sensitive, but was changed when the U.S. military wanted to try it out. So even the "same" powder can react differently depending on various factors.

Then there's how powder is stored and used. Leaving a powder container open for a while, especially on a warm dry day, will change the burn-rate even more than the 3% most manufacturers try to maintain. Which is why ballistic labs are also careful about storing powder under controlled conditions.

Let's look at your .375 H&H "problem" again. Aside from each of the powders possibly varying 3% from the lots Nosler used, did you shoot at 70 degrees each time you tried any of the loads? Were the powders all equally fresh, or had some been sitting around in containers that had been opened a number of times, perhaps containers that sat open on your bench for a while?

Believe me, despite anomalies like Speer's .308/.30-06 data (which they've since fixed), modern loading data is far more consistent than the results from any home handloader.

When the obsession with warp speed subsides, shooting is a LOT more fun. Assuming two loads capable of the same accuracy, anyone claiming that 100 FPS makes or breaks a load is full of schit.

In a new rifle I start with working over the rifle. Usually bedding, floating, and trigger work and a good cleaning. I clean all oil off the bolt with break cleaner inside and out then put a very light coat on the outside making certain not to get any on the bolt face. I then wipe off any excess. I also make certain to remove all oil from the chamber and swab the barrel as dry as possible.

Just as an example......My cousin has a 270 Remington that he shoots factory Core loct 150s in. He was getting around 2 1/2" groups at 100 yds and requested assistance to get better groups. We cleaned the bolt, bore, and chamber of any fouling and oil.

"The next trip to the range netted under 2" 300 yd groups" I have also personally noted in my own firearms that oil in the chamber or on the bolt face is deteramental to accuracy.

I like to start load development using my most prefered bullet and several powders.

I load to .010 off the lands or mag restraint whichever comes first.

I load 3 1 grain under max book.....3 at max book....and 3 1 grain over book in both powders for a total of 18 rounds.

Then head to the range with a Chronograph in hand. The Chronograph is my safety tool. If I ever see velocity that is unusually high over book max velocities I will stop right there. So far I haven't encountered this.

I don't neccasarily choose the most accurate load. I look for acceptable accuracy and velocity and fine tune with seating depth.

Shod

According to the study done by Brian Litz, the handloader can get accurate velocity data from a Magnetospeed. A nice recent advancement in my opinion. I wish the books used 22" barrels for the short action cartridges such as 308 win or 338 Fed. That is worth ~50fps right there. Once I factor that in, I find most books agreeable with what I see. With the possible exception of Nosler. I find their loads anemic at best. I find Hodgdon's and Barnes' data to match mine pretty well.

I test from 600 and 1000 yards and if they deliver the right performance from these two lines.....good enough!!

I try and save on both components and barrel life and I believe my method does just that.

If it's a new gun, i'll break-in the barrel with about a dozen+ rounds; 1/2 dozen singles, cleaning between to get the copper out then 2 sets of 4.

I'll then take a starting charge or a charge i'm familiar with and load up 4 sets of 3 rounds each; .005" off, .045" off, 085" off and .0120" off the lands. I do this to get an "initial" OAL. One or several of these will show a preference. I then move on to this.

http://www.longrangehunting.com/for...detailed-article-video-42881/index3.html

From there, I might refine the OAL in smaller .005" increments and/or a primer test.

If the rifle is a quality built rifle, I'll almost always find a sub moa load, usually a sub 1/2 moa and the occasional 1/4 moa load; 5-shot groups.

Alan

I pretty much go the same route, but I always bed mine first. They always need to be properly bedded. I've seen it every time, so make it a habit to just do it before I even pull the trigger on a new rifle. I also generally shoot a box of corelokts thru a new rifle and use the fireformed brass to work up loads. I always load bullets .020" off the lands and call it good. I will generally start a little above mid range with powder charges, load 10 rounds for each powder charge up to max book load. I shoot 1 fouling shot for each charge wt and then shoot 3 3 shot groups. When I find something that is shooting sub moa, I then shoot some 5 shot groups to make sure the loading is consistent. Loading for and finding 1 good load for 1 rifle is exceptionally easy. Loading for 4 (or more) rifles of the same chambering in one outing and finding a good load that works well in all 4 is a little more complicated and requires the use of a calculator and figuring averages.

As an example, here's 4 targets shot with 4 different 30-06's. Ammo was taken from the same box, it wasn't the best load for 1 rifle, but the best average load for all 4 rifles:



5 shot groups, even the upper left target that only looks like 3 shots...