Tips needed for quality load development

Sounds like your on the right track ,I start at the bottom and even go lower some times. A lot of my rifles have two sweet nodes .( One for cast and one for jacketed ) I'm lucky I don't have to leave the yard to test my ammo .

CC

When sizing, verify that the cartridge headspaces off the shoulder (not the belt). A collet die will extend brass life. RL22 is a good pick, IMO. 4831 would be okay, if RL22 got scarce.
You didn't indicate what bullet weight you're working with. 140s work well for deer, and shoot nice and flat. Retumbo would be another powder option for these.

Good luck on getting to the lands on newer Rem. The last one I setup was +.15" longer than the magazine. My Rem 7mm Mag is one of the older ones (1970's) where getting to the lands are easy. I get my best groups in the 0.020"-0.030" jump.

Like you, I have a long drive to the range so when I am working up a new load, I start from the starting load recommended in the load data and then go up 0.1 grain for pistol and 0.2 grain for rifle and load ten rounds each. When I get to the range, I shoot those ten rounds, starting with the lightest load in strings of five shots.

• The first string is shot over a chronograph and each case is collected and inspected for any abnormalities. The impact of the rounds on the target is noted and each target is noted with the rounds shot into it, but since the sight picture is distrubed by pausing after every round to inspect the case, this really doesn't tell me a lot about accuracy or repeatability.
• The second string is shot with the focus on hitting the target and so is what I base my judgements about accuracy on.

When I'm at the range, I concentrate on gathering data for the initial strings and shooting consistently for the second string. I don't worry about analyzing the data until I get back home because I know that it's going to be another 8 to 12 weeks before I get back and that gives me plenty of time to do it at home.

The last "new" cartridge I started reloading was 9mm. I didn't even own a 9mm pistol but had been given a bunch of 9mm brass. Of course I took that pile of brass as a challenge to pick up the new caliber and that meant I had to have a gun to test fire it in and you can guess the rest. My process on the 9mm has been a little different because I was having to learn how to shoot the pistol, get it sighted in and all that while trying to learn how to reload for it so I've had lots of iterations with several different powders and that just increased the factors to consider geometrically. I think you were prudent to settle on one powder to start.

I like to take my reloading gear to the range with me. Gives the rifle time to cool while I'm loading. I can also make any adjustments I find need without having to pull a bunch of ammo down. Starting that close to the lands you might run into it quick. I'd suggest only going in .2gn steps & looking for a range of at least plus or minus .2gn doesn't effect the group. This might not give you the tightest group you sit that day but probably the most repeatable.

Start at magazine length and go shorter as needed. You will probably not find a .005 off load that will fit the magazine. Don't worry about it, load em and shoot different powder weights until you get good groups, then shorten your COAL until it shoots better. Try .005 at a time until you are happy. I like 4350 4831 and 7828 in those big magnums.

I agree with kingmt about taking the gear (limited reloading setup and enough components) to the range with you. That is why I purchased a Lee Hand Press. For the 7MM though you might want to take your regular press or a rugged spare one and figure how to mount it to a bench or use a B&D Workmate to hold a 2X6 with the press mounted on it. Primers, a bunch of brass, different bullets, and a couple different propellants and you are in business. Add a CRONY and some good weather, take your time and it will be FUN. Don't forget a range report.

I take two wood clamps to fasten a 2x8 I have predrilled to mount my press to. There is a power inverter in my vehicle that runs my scale. If your using beams first I'd suggest switching to electronic but at least have a box to put your beam in to keep the draft away.

I'm lucky that one of my ranges is my mom's old homestead. I go in the old house to reload.

For commercial sporting rifles, I think it's a waste of time working up loads with charge increments smaller than 2% of charge weight. And the more recoil they have, more shots per test group are needed. There's only one accuracy node for any barrel that's a few grains of powder wide. Shoot at least 30 to 40 shots per test group and you'll agree.

Seat bullets as needed to feed reliably from magazine. Forget increments of a few thousandths to find that sweet spot. 7 Rem Mags' throat erodes down the barrel .001" for every dozen shots.

Bart B. said:

There's only one accuracy node for any barrel that's a few grains of powder wide. Shoot at least 30 to 40 shots per test group and you'll agree.

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Grains? Or did you mean tenths of a grain?

I usually find two nodes that shot constant on different days that works +/- .2gn & at most .4gn but none so far hold a group above that.

Whole grain increments.

If you shoot 5 or less shots testing a load, that's not enough to be meaningful. .

20 or 30 is better.

Benchrest winners see a 4X or more spread from smallest to largest across several 5-shot groups. Their first one fired each day is not always the smallest; the smallest is just as likely to be the last one. The rest of us are no different.

The largest groups shot best represent accuracy; that's what one can count on all the time. They happen just as often as the smallest ones do. There's no limit on the size of big groups; small ones won't be smaller than zero.

I guess I don't have the correct powder. I have to hold mine much tighter then that on the scale.

I'm talking about two 7 mag loads with charges 1.5 grains apart. Spread for each is 3/10 to 4/10ths grain. Not a 1.5 grain spread for each load.

Bart B. said:

I'm talking about two 7 mag loads with charges 1.5 grains apart. Spread for each is 3/10 to 4/10ths grain. Not a 1.5 grain spread for each load.

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I hope this isn't hijacking the thread & still useful to the OP as it seems it would be.

I guess I'm not quite fallowing your statement. Are you saying you get the same POI over a 1.5gn spread? Or the stay in a straight line in windage as they climb up the target.

Ether way I don't get ether. My groups usually tighten in both diminutions once I got a node & I can hold the same POI for about .6gn spread before they open up again. I then make my load in the middle & try it on different days to see if it shoots the same. Which usually it does. This usually isn't my best group but usually the best group one day shoots like crap another day.

What he is saying is that a powder dispenser will throw ± 0.3 - 0.4gr deviations. With the powder charge of 2 loads 1.5 gr apart form each other ( example 60.0 vs 61.5g)

Post 16 says all the right stuff.

I never use smallest group as the accuracy of a load. 99% of the time, they're mostly luck as the variables pretty much cancel each other out. Biggest groups show what all the variables do when they add up in all directions.

The smaller the biggest groups, the tinier the littlest ones will be. So, you need to shoot enough shots to ensure the groups are as big as the ammo makes them.

kingmt, are you shooting at least 20 per group?

After I decide on a load then yes. Other times it depends. If I get at 4"group after 3 shots I move on if it's shooting well I'll do 5 & move to the next load looking for same POI for 15 rounds then I load the middle load of those 15 & shoot more. Then I'll move on up looking for another node.

How do you separate your errors from that of the ammo and rifle?

I know where my sights were when the rifle fired on the rear case I don't know where they were I don't count that round. I don't judge groups by where they are related to the centre but rather where they group.

Personally I can hold under 1" probably under half that at Two Hundred yards. I use enough magnification that I can see exactly where I was when the rifle fired.

What about the human repeatability errors not related to aiming and calling the shot?

,,,

A chronograph. Target rifles and chronographs go together like peanut butter and jelly. The only problem with a chrony is that your son will be peppering you with even MORE questions, and GOOD ones LOL

Bart B. said:

What about the human repeatability errors not related to aiming and calling the shot?

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Well I had a rifle once that with a certain factory ammo I could shoot a hole that you couldn't tell more then one of the 17 caliber bullets went through @ 100 yards on a calm day. I hunted squirrels out to 100 yards with it.

I'm only out to 200 yards as of now so I've yet to find my mistakes. Maybe when I get out to 300 I'll find them.

I've always been pretty good with a rifle & had one in my hand since I was about 7 years old. That was about 35 years ago. I went through a spell that I strived for same hole accuracy but that left me about 2 or 3 years ago. I still like to shoot small groups but I'm pretty happy if at 100 yards my autos shoot under an inch & my bolts under 3/4 now because the groups that shot the smallest on one day never seemed to on any other day. I look for the nodes now.

I'll let you know when I start finding problems with my forum. I tried to talk to a member about this type of thing when I'm able to get out to 800 yards but they let me know they wasn't interested in helping me so I'll just wait & see when I get there & teach myself.

Good bullets make the biggest difference. If your shooting junk you can't expect much.

kingmt said:

I still like to shoot small groups but I'm pretty happy if at 100 yards my autos shoot under an inch & my bolts under 3/4 now because the groups that shot the smallest on one day never seemed to on any other day.

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That's been normal with everyone; me included, for few shot groups since rifled barrels were invented.

20 to 30 shot test groups stay about the same size from day to day.