Developing loads over winter...bad idea due to pressure?

[Bigeclipse]

if you do the typical load work up where you shoot until pressure signs and then back off a grain, do you need to worry about catastrophic failure of those loads in summer or will you most likely just encounter a heavy bolt lift?

 

[Creedmoor shooter]

You should be able to notice any pressure signs as it gradually gets warmer. Unless you developed a load in 10 degrees then decide to take it out 4 months later on a 80 degree day then it shouldn't be a issue. I have a winter load and a summer load. My winter load is always loaded with a very temp stable powder as here in the northeast we have huge temp swings from fall to winter and from the end of winter through the end of spring.

 

[Mike 338]

IMO, flirting with "max" pressure as a regular load is generally ill advised. We almost never do that with anything else we own and if we do, it breaks. Pick a caliber that normally operates at the speeds and pressure you prefer and there is no need to max it out.

 

[HARPERC]

Yes you can get yourself in trouble with extreme temperature swings. As always the Devil is in the details, components, and actual environmental parameters.

"Typically" I find a load that meets all needs before any pressure signs are visible.

 

[Bigeclipse]

Yes you can get yourself in trouble with extreme temperature swings. As always the Devil is in the details, components, and actual environmental parameters.

"Typically" I find a load that meets all needs before any pressure signs are visible.

Yeah. I've just read a lot of people on here who load rounds in half brain intervals and keep upping until they hit some sort of pressure sign (cratered primers, sticky bolt lift...etc). Personally, I have never done this and always stuck to book max values while watching for those signs. I NEVER achieve published values though so far as far as velocity so I was thinking about trying this technique while closely watching for pressure signs.

 

[Pdvdh]

I doubt the gun will blow up. Might scar the head of the bolt if being reckless and careless. The brass case head is the weakest link in mix.
I doubt you'll be either... So proceed if you desire a bit more velocity / pressure. The Hodgdon extreme powders I've used are less temperature sensitive in cold weather, based on my Alaskan experiences. Can't speak to the hot temps. Never happens here.

 

[memtb]

I "always" do load development on hot (90+ F) days. I usually push to max or near max loads, so...I don't want to cross the "pressure ceiling" if shooting on a hot day. memtb

 

[dok7mm]

I used to like to develop my loads in weather that is consistent with hunting season temperatures and then back off and work up to a summer load, for practice.

Now, I tend to do my load work more in moderate summer conditions and run that load year-round, using only proven temp stable powders and avoiding temperatures above 85*.
I also compare my loads to a given hunting altitude on JB Ballistics and my phone apps to make dope cards for possible situations.

In spite of the fine ballistic calculators we now have access to, you can't beat shooting your actual drops in your hunting area, if possible. I try to shoot one each at 400 & 800 yds to compare to my apps.

 

[Bigeclipse]

I used to like to develop my loads in weather that is consistent with hunting season temperatures and then back off and work up to a summer load, for practice.

Now, I tend to do my load work more in moderate summer conditions and run that load year-round, using only proven temp stable powders and avoiding temperatures above 85*.
I also compare my loads to a given hunting altitude on JB Ballistics and my phone apps to make dope cards for possible situations.

In spite of the fine ballistic calculators we now have access to, you can't beat shooting your actual drops in your hunting area, if possible. I try to shoot one each at 400 & 800 yds to compare to my apps.

I'm running IMR7828ssc, IMR4064 and varget mainly. Are these temp stable?

 

[DocDoc]

Typically, the Hodgen extreme line, which includes Varget, RL-16/23, an enduron, have the lowest variation with temperature. At least, these are the ones I have easy access to.

 

[longrangehunterII]

Yeah. I've just read a lot of people on here who load rounds in half brain intervals and keep upping until they hit some sort of pressure sign (cratered primers, sticky bolt lift...etc). Personally, I have never done this and always stuck to book max values while watching for those signs. I NEVER achieve published values though so far as far as velocity so I was thinking about trying this technique while closely watching for pressure signs.

Pressure and velocity are one in the same and you should load to the expected velocity unless you see those signs. By that I mean most manuals are off these days, and for a given bullet weight in the cartridge you're using just stick to the average expected velocity range for that powder and barrel length you're using and you'll be fine.

Most nodes are not right at max, and you'll find a accurate load that's safe in all conditions. I rarely find the only option is at or near max, and do a lot of load development in the winter. Just keep your ammo, and your gun at a more normal temp i.e. like in your car/truck...... I do mine at home and have a indoor shooting bench where I can shoot out the window.

I've found IMR 7828, and VarGet to be both temp stable.

 

[jrock]

I do most of my load workup in the late fall and late spring. Not the dead of winter. I have not found issues with most powders and most guns going from a cooler work up temp (40 to 50 deg) to summer temps (95+). Sure there is change but not enough to get to pressure. I work up to the first max pressure sign and then make sure I stay at least 1 grain away from it. I always seem to find a node short of maximum. I have had problems with ball powders in 223 and 204's going from cool to hot weather. IMR powders in my book are not stable as compared to the extreme series powders. About 1 to 2 fps per degree of change in my guns.

 

[Pdvdh]

I'm running IMR7828ssc... temp stable?

No, not even close to temp stable compared to Hodgdon H1000 or Retumbo.

 

[longrangehunterII]

Ok, well the data I have from 10/21/03 @ 6,000' using 59.0 IMR-7828 F210M Rem FF brass behind a 175 NPT in a 280 AI at 75 degrees:
Hi-2807
Lo-2779
Avg-2798 @ 20' muzzle
ES-28
SD-11

Same ammo/load on 11/22/03 @ 6,000' 18 degrees:
Hi-2812 #4th shot
Lo-2774 #2 shot
Avg- 2795 @ 20' muzzle
ES-37.39
SD-14.17
Ammo brought to temp for 2 hours prior to testing.

I used this ammo/load throughout a lot of hunting seasons in Montana, and whenever I retested it I got close to the same velocity unless I was at a totally different elevation, and back in those days I had no Idea what DA was or how to get it....... that's temp stable IMO, but maybe the powder IMR made back in 2000 is different then what's being used today?

Don't know, but I just used the last of that lot powder this year in the same rifle/load and the ammo I made produced almost the same velocity (+25 fps) avg over what I have written above. My only mistake was not breaking/cracking the old seal from the powder residue around the bullet from the old ammo I made back on 10/21-10/24/2003 which I thought might have contributed to the velocity swings I was seeing on paper at 750 yards.