What loaders loft is saying is that there is sort of a fine line when developing your loads. You will become familiar with how different powders behave in different weather. .Typically speaking, the Hodgdon powders are less sensitive to heat (H4831sc, 4350 etc) and the Reloder powders are more sensitive to extreme weather. Some guys develop a hot weather hunting load and some develop a cold weather hunting load due specifically due to this point. For Hodgdon you may be able to develop a load in 90 degree weather and see very little difference in performance in 25 degree weather, but its all relative and you should experiment in all weather conditions.
IMO testing loads in the heat is not a big deal, as long as you compensate by doing a short redevelopment period in the cold, you may find you need to either back off a grain or two, OR increase a grain or two for ‘special’ conditions. In this respect a chrony is vital.
Also, your brass will become elongated after neck sizing only for approx 3-4 firings, and will find slight bolt resistance upon chambering - this is fine, but keep an eye on your case headspace, if the bolt becomes very hard to close you should bump - if you keep good notes you will know exactly when its time to bump the shoulders again. You can get different tools to measure this which IMO is a good idea, and takes the guesswork out of it.. Some guys who neck size can get 5 or 6 reloads without body/FL sizing , but it just depends on loads etc.
One other point, you should have a target that has crosshairs on it for more exacting results, this is part of the sport of it, the type of target you have does not allow for you to hone your skills. These are all good comments, keep working and be careful,. Best of luck.
...Also w/o a head space gauge, whats the best way to measure shoulder height? I guess I could just go slow and just do it until it'll chamber easily.
Right now I'm loading 5 rounds w/ 54 gr of RL 19 at .050" off the lands to try to set up a good comparison w/ the H4831SC.
In addition to 2 rounds at each increasing powder charge (.5gr) w/ RL 19 and H4831 to find where the max is with some of my fire formed cases.
P.S. What's the reason for possible less accurate loads in hot weather? I make sure to keep my loads in the shade while shooting. It's hard to shoot below 85 deg, & nearly impossible to shoot below 80 deg in the summer
Like the other guys said, different powder will react differently in hot and cold. It's tough to make a comparison of powders in that kind of heat unless that's what temp you always shoot/hunt in. Another thing is... what is happening with your barrel in that heat??? after a few shots, your barrel temp could easilly be 20-40 degress hotter than ambient temp. I would think that might have a big affect on your groups. I personally dont like shooting in temps over 70, but where you live you dont have a lot of options other than waiting until it cools. so basically, I think it's gonna be tough to get good data in that heat.
I'll make sure to make some new targets before the next range trip. As far as shooting when it's hot I really don't have much choice, the range is only open from 10-6. Even when rifle season opens it can be in the 70's and 80's.
My goal is to try to find a good load before next month when classes start back up again. I'm going to Ga Tech and don't have much free time during the semester.
Although I do plan to try the loads again closer to season to observe the effects of the climate.
WILL THE CLIMATE CHANGES MAKE AN ACCURATE LOAD SHOOT WORSE OR WILL IT JUST AFFECT THE POI?
Large climate changes can do both - open up the group & change point of impact. I like the extreme powders too - weigh every charge (chargemaster hint hint)
The trick is to find the "sweet spot", in the middle of where groups come together, stay together, then begin to open up. That way, if it gets a little hotter, your still okay. The ladder test helps in this respect, but its quite a difficult test in my opinion, and must be done with a chrony & repeated at least once to validate the results.
There is usually a sweet spot within a few grains below the max load for your gun (not book max).
I do powder first....Look for the node. Your groups will either be getting bigger or smaller the hotter you go. I usually start somewhere in the middle and go up @ .5 increments. After I settle on a load I start with seating depth and neck tension to "Fine tune it" I always recommend using 5 shot groups. 3 will tell you a little but 5 will tell it all. Get yourself a crony borrow one if you have to. Look for extreme spread. Velocity is the key to consistency. Powder burn is the secret. Seating depth and neck tension are for fine tuning. Good luck. Warning this hobby is HIGHLY addictive!
I agree with HIGHLY addictive.
I generally shoot 5-shot groups, but I'm old now & often my vision fades enough for me to have frustrating flyers. I've gotten a couple of 3 out of 5 shots & 4 out of 5 shots .12" C-C. I can rarely get 5 shots in a small group under ½". I don't give myself any breaks & assume these flyers are all my own fault. I recently bought new single strength glasses for using only for bench shooting or handguns. Normally I wear trifocals which are lousy to shoot bench rest from. There simply isn't enough adjustment for focusing my scopes ocular lens to work well. My eyes tire quickly and lose focus. Trying to see clearly out of the top of trifocals thru a scope is an adventure in frustration for me. It's been either raining or too darned hot for the past few weeks, so I haven't had the opportunity to discover if these new glasses help.