Thread: First attempt at reloading. Thoughts please.

Just ran your setup through Gordons reloading tool for a ballpark reference. It seems like you are on the money with the range of loads you have tested. Chasing more speed might be a pointless exercise, as the pressures are starting to get up there.
(I just went with the default bullet seating depth from the tool)

What distance did you shoot the targets at? Looks impressive

Greetings @Blackfern,
You certainly have done your homework. I recently loaded 42.5 grains of AR2208 behind the 140 grain Remington Corelokt which is below max in the Hodgdon data for the 139 grain Hornady Interlock. The BT, Corelokt and Interlock are all soft projectiles so the Hodgdon Data is relevant. The load chronographed 2,710 fps average in a 19 inch barrel so your result of around 2,600 fps looks about right for your 42.5 grain load. My chronograph is a 35P with a 4 foot screen spacing. This validates your chronograph results.
Load data needs care in selection. The ADI data of 42.2 grains for the 140 grain is for a harder projectile and the 43.5 grain max for the 139 grain is more relevant for the BT that you are using.
To me the chronographed velocities you got for the 41.5 grain load look high. With the 7mm-08 you would normally expect around 50 fps more velocity per grain of powder added and your other data supports that. Primer appearance is a very poor (i would say practically useless) indicator of pressure. There is much to learn so will post again later in the day.
Regards Grandpamac.

Shoot groups of 5 or more, 3 is just too small a sample size to get an idea of how well it performs. Be sure to count outliers and not ignore them as 'fliers' after the fact.

Shoot all rounds in a string, don't wait too long between each subsequent shot.

Other things to try:

Size cases according to the chamber, not a random measurement. Removed the firing pin and get a feel of how much you need to size the case, a slick bolt operation with no hangups is the target.

Don't weigh every charge, use the scales (beam is nearly always better than electronic ones for consistency and accuracy, unless you spend thousands) to set your powder measure and get a good idea of how accurate your powder throws are. Anything under 0.5 grain extreme spread in 20 throws is excellent. Look up 3D printed baffle designs that go in hoppers to ensure consistent metering.

Get a set of pin gauges or a measuring tool to determine 'neck tension' after sizing. Very difficult to measure brass hardness at home, so settle for measuring the ID of the sized neck.

Also worth getting primer pocket gauges, putting a primer in a loose pocket can end badly (etched bolt face or locked up rifle).

Record ambient temp when you first try a load, then go out on a day that is much hotter/colder. I've had loads that grouped perfectly on one day develop hang-fires when temps dropped, or pressure spiked on a hot day to where case extraction was difficult. But then again you have that lovely, temperature-insentive, ADI made powder that Europe banned...

Greetings again,
Had a fossick in the Hodgdons data. In their pistol section they list data for the 7mm-08 with a 15 inch barrel. Their load for the 139 grain Interlock is the same 43.5 grains of AR2208 with a velocity of 2,610 fps at a pressure of 50,000 CUP. Over the years I have placed more weight on velocity as an indicator of pressure than powder charge. There is a long list of variables in components and rifles that effect the velocity that we get from a given load as well as the pressure that it develops. Munching the data together leads me to a velocity of around 2.600 fps with a 7mm-08 in a 15 inch barrel with the softer 139-140 grain projectiles. GRT seems to be the outlier in the data sets in this case. In your rifle and with your components 42.5 grains of AR2208 looks like a reasonable max.
Regards Grandpamac.

Originally Posted by 7mm Rem Mag

What distance did you shoot the targets at? Looks impressive

All at 100mtrs at the Taupo deerstalkers range.

I think all of those loads probably shoot just as well as each other.
One thing I have learnt from reloading is people are very willing to chase the statistical noise endlessly and a lot of advice is essentially to do this and it's wrong.
I quite like the data and info coming from Brian Litz who seems like the only person doing enough testing and controlling for variables to actually definitively learn anything about what actually matters in internal and external ballistics.
The reality is you don't have enough data to say there's a velocity drop anywhere in your load ladder. Velocity nodes disappear when you shoot enough to give a statistically relevant amount of data.
You also don't have enough data to say any of your groups are better than each other.

In accepting the reality that our load testing doesn't have enough data points to actually find the "best load" you must flip your thinking and look for the worst loads and discard them because big groups and wide velocity spreads are reliable indicators, smaller groups and small velocity spreads are not.
The reason you must think like this is that groups can't get smaller if you shoot more, and velocity spreads for a single load likewise can't get smaller, but with more testing they can always get bigger as you add more data points and the true spread distribution of the load reveals itself.

This does beg the question how do you decide on a load. This relies on having goals for velocity, velocity spread, and accuracy. Find loads that meet those goals, if in testing they ever exceed those parameters, discard them. If all exceed them then look to make sure the goal is reasonable. Then look at rifle and components. This way you're not constantly searching for the best groups and going down rabbit holes only to be disappointed when further testing reveals the true realities of a single load.

The above post by Makros reflects my views in every respect and is better written than I could achieve so has saved me some time in making a mess of repeating the same content.

Originally Posted by dannyb

you state its a bush gun ? will the 41.5gn load do what you need it to at he max range you are likely to use it out to ? if so why waste projectiles and primers etc ? end of the day it's your load, do what you want but i think your already onto a pretty good load there.

well buggamesideways........ we agree on something LOL..... AND if your going to twiddle n fiddle with the dials on your scope,even getting another 300fps cough cough wont matter a flying fig unless your trying to do 7mmswm feats with the 7mm08

why on Gods green earth would he need to fire a 10 shot group?????
my eyes arent as good as they once were but even I can see a 21shot group of around an inch or less with a 150 extreme spread......what I cannot see is any problem here??? given that there is a 2.5grn difference in powder weight to achieve that....again where is any issue for a sub 300 yard rifle???
load up 5 of the 41.5 5 of the 42 and 5 of the 42.5 if you really really really feel the need to waste some more components, go shoot them again minus chronic graph and make your decision based on whats most accurate...then STICK TO THAT LOAD....

and here is another free observation for you... @RUMPY may like to confirm this as seeing his targets with multiple loads made it plurry obvious to me. this is really easy to see for yourself as you look to have used a sticker for aiming point.
wait for it
wait
wait
wait
ok here it is
ALL of your groups are same size or smaller than your aiming mark!!!!!!!!!
nah stop,look again..let it sink in,look again....
unless you have huge magnification and can cut that orange dot neatly into 4 bits like a pizza there is simple NO WAY IN HELL you POSSIBLY CAN shoot a smaller group...you cant as you arent asking rifle to do so,youve asked it to shoot into the dot,and it has.

Yep if hunting just use the 41.5gr load, the deer aren't going to noticed a slight tweek here and there job done.

If shooting compitition then you could play around a bit however most shooters would be envious of your results.

Yeah what @Micky Duck said about target size makes sense. The target I was shooting at was about an inch and a half black circle drawn on paper. A wobble half an inch either way and I was still "on" target.

Greetings again @Blackfern, @Makros has made some very good points echoed by @Puffin. One three shot group tells you little if anything about the accuracy of a particular so I prefer to test loads for accuracy in the velocity range that I am hoping to achieve. I note that you started with 1 grain increments and then smaller increments closer to max so you already know this. Earlier this year I worked up some loads in a 7mm-08 for 600 yard F Class shooting. 145 grain Speer projectiles and AR2206H powder were used (what I had on hand) in Lapua cases that have been fired twice. The rifle is on a Rem 700 action with a 26" heavy barrel. Hodgdon has data for that projectile and powder in a 24" barrel so allowing for the extra barrel length 2,800 fps looked possible at reasonable pressure from their data. The rifle, scope and cases were on loan from my son so the scope was mounted and some start loads of 39 grains of AR2206H were assembled for zeroing and initial chronographing. This took 6 rounds. Measured velocity was in line with the Hodgdons data once the extra barrel length was factored in so the next loads of 2 each of 40, 40.5 and 41 grains (max) were chronographed. The top load of 41 grains chronographed 2,795 and 2800 fps. At this point seating depth and other items could have been played with but the 600 yard shoot loomed (my first ever) so a batch was loaded. The rifle shot better than should have been expected with a creaky jointed novice behind the butt and components are limited so more testing will need to wait, perhaps for some time.
I think the point here is that small to medium capacity cartridges like the 7mm-08 and .308 mostly shoot well with any reasonable load if the loading technique and components are up to it. Not all cartridges are that well blessed.
Regards Grandpamac.

41.5 or 42.2 would be my picks of the bunch, I'd be looking at the 42.2 and going with that. Mentioning things like a slightly flat primer almost makes me think light load case not sitting back fully before the pill is engaged into the lands or some other weirdity...