How far off pressure are you loading?

[wind gypsy]

I find this interesting. Would like to understand better what you think is going on.

I'll type out a longer explanation if I think it's warranted, but I think I do believe in nodes so I'm curious about your school of thought.

Rokslide discussion of the podcast Harvey linked. https://rokslide.com/forums/threads/your-groups-are-too-small.290821/

I wouldn't argue with the best benchrest shooters in the world about nodes but I'm pretty damn confident most of us run of the mill dudes trying to hit animals or steel are at an overwhelmingly net negative when we get into the weeds thinking we're finding a node vs using that time to improve our field shooting abilities.

 

[Gstew1930]

I go till I start popping primers then I let er eat . I usually look for heavy bolt lift or ejector marks then back down 1.5 grains

 

[Vern400]

I usually don't go over book Max. There are a few cases where one book doesn't agree with another.

I use federal primers which tend to be a little soft.
As the corner radius of the primer begins to sharpen, meaning the radius gets smaller I know I'm within a half grain of a fully flattened primer. I stop at the slightly sharp radius. I rarely get more than book velocity except with 26-in barrels and slow burning powder.

I almost always see minor primer flattening before I get the click when the bolt opens, or get ejector pin swipe. Stiff bolt raise... I'll pull bullets. For reference, I'm using Rem 700 trued actions with 4000+ shots.

I always validate my cartridges at 90° or above.

 

[ckleeves]

This is Rokslide buddy. I run redline +1-3 grains. Carry a mallet in my shooting bag for opening the bolt. If I’m consistently blowing primers then I back off .2 and let her eat. Thought this was what everybody did?

 

[Gstew1930]

This is Rokslide buddy. I run redline +1-3 grains. Carry a mallet in my shooting bag for opening the bolt. If I’m consistently blowing primers then I back off .2 and let her eat. Thought this was what everybody did?

Hell yeah!

 

[Bowfinn]

Good deal! I forgot to check the delivery.

I now find heavy bolt lift or ejector marks, back off 2-3 grains, spray a light mist of water on the case and shoot to check for heavy bolt lift again. 2-3 grains off pressure signs has seemed to work. I sometimes have 1 or 2 out of a 10 shot test that requires primary extraction with the sprayed cases but nothing that fights me running the bolt.

With the wet case you are getting 1-2 cases out of 10 that has a slightly increased bolt lift force?

 

[T_Widdy]

With the wet case you are getting 1-2 cases out of 10 that has a slightly increased bolt lift force?

Yes, it seems to depend on case size magnum cases are worse than standard case head

 

[seand]

I typically make the assumption the velocity the book lists under the max charge weight is at max SAAMI pressure. Adjust up or down 25fps/in of barrel of course.

Typically I run at least a grain or two below max pressure in hunting loads (one grain is approx 50-60 fps and 3ksi in my creedmoors). I’ve also run right at max for NRL hunter but generally wouldnt do that for hunting.

 

[pbroski]

I do load development whenever it's convenient. That's usually in spring or early summer when the temps are cooler. I like to avoid heating up the barrel too much, so fire 3 to 5 rounds, then let the temp drop down until it's cool to the touch.

I first do a pressure test to find how high I can go with powder. When I find max, which is the max velocity that the cartridge is supposed to get, I load that powder charge, then go down from there in 1% increments for a 5 or 6 steps. I load 10 of each and shoot at distance. Usually over 500 yards and on a calm day in the early morning.

I look at the pattern of how the shots impact on paper, mostly looking at vertical, but horizontal is important too. Most times it's pretty clear where the load is most happy. Sometimes it's near the top and sometimes it's near the bottom.

I take the best powder charge and do a seating depth test at .003" apart for 5 or 6 increments loading 10 of each and also shoot them at distance. Usually there will be 2 or 3 adjacent cbto lengths that shoot better. I pick the longest one and call it done.

The velocity that the finished load is getting is the velocity I try to keep the load at regardless of ambient temperature. To do that I tweaking the powder charge up or down depending on expected temperature trends. Less powder in summer and more powder in fall and winter. I figure if the velocity stays the same, the load stays in tune and never goes over pressure.

 

[Harvey_NW]

I do load development whenever it's convenient. That's usually in spring or early summer when the temps are cooler. I like to avoid heating up the barrel too much, so fire 3 to 5 rounds, then let the temp drop down until it's cool to the touch.

I first do a pressure test to find how high I can go with powder. When I find max, which is the max velocity that the cartridge is supposed to get, I load that powder charge, then go down from there in 1% increments for a 5 or 6 steps. I load 10 of each and shoot at distance. Usually over 500 yards and on a calm day in the early morning.

I look at the pattern of how the shots impact on paper, mostly looking at vertical, but horizontal is important too. Most times it's pretty clear where the load is most happy. Sometimes it's near the top and sometimes it's near the bottom.

I take the best powder charge and do a seating depth test at .003" apart for 5 or 6 increments loading 10 of each and also shoot them at distance. Usually there will be 2 or 3 adjacent cbto lengths that shoot better. I pick the longest one and call it done.

The velocity that the finished load is getting is the velocity I try to keep the load at regardless of ambient temperature. To do that I tweaking the powder charge up or down depending on expected temperature trends. Less powder in summer and more powder in fall and winter. I figure if the velocity stays the same, the load stays in tune and never goes over pressure.

I'm way too lazy for that, I either get lucky or play barrel roulette

 

[Harvey_NW]

I think some tests and logs on new barrels going through load development would be extremely interesting and I'll join you on the next one I do too.

Pictures and velocity data sets from temp testing process I explained earlier in the Painless Load Development thread, post #1,041.

 

[Ramem7mm]

on the last rifle which is a 25 creed I loaded up lets say 8-10 rounds with increased powder charges and chronoed each shot. I had read what others had perceived as max charges and used that as a stopping point and check each case for signs of pressure. when I got near what a max load was supposed to be I did see the ejector marks showing up on the brass(never a sticky bolt). I backed off . 5 grains and luckily the powder and bullet length combo were shooting great so I left it there. over the course of 2 months of PRS and NRL I shot all 400 pieces of brass that I had and the barrel sped up maybe 50-70 FPS after all rounds were fired. I resized the brass and shot it. FPS was faster than what I wanted so I backed off 3 tenths of a grain to get back to what velocity was shooting good and it shoots sub 3/4" groups or better pretty consistently. I did mess with seating depth a little bit but it wasn't picky at all. by far easiest gun I have loaded for.

 

[SloppyJ]

on the last rifle which is a 25 creed I loaded up lets say 8-10 rounds with increased powder charges and chronoed each shot. I had read what others had perceived as max charges and used that as a stopping point and check each case for signs of pressure. when I got near what a max load was supposed to be I did see the ejector marks showing up on the brass(never a sticky bolt). I backed off . 5 grains and luckily the powder and bullet length combo were shooting great so I left it there. over the course of 2 months of PRS and NRL I shot all 400 pieces of brass that I had and the barrel sped up maybe 50-70 FPS after all rounds were fired. I resized the brass and shot it. FPS was faster than what I wanted so I backed off 3 tenths of a grain to get back to what velocity was shooting good and it shoots sub 3/4" groups or better pretty consistently. I did mess with seating depth a little bit but it wasn't picky at all. by far easiest gun I have loaded for.

It's nice when you get one that easy. When it feels too easy I always struggle with the "what ifs" in my mind that would make it even "better". I've found .223 to be like that. Almost all of my .223 loads for different bolt guns are damn near the same load. Seems like the creedmoor family are similar as well.

Did you notice the return of pressure signs when the barrel sped up? You had to be right back on that line of ejector marks or slightly over.

What's your sample size when testing groups?

 

[Ramem7mm]

It's nice when you get one that easy. When it feels too easy I always struggle with the "what ifs" in my mind that would make it even "better". I've found .223 to be like that. Almost all of my .223 loads for different bolt guns are damn near the same load. Seems like the creedmoor family are similar as well.

Did you notice the return of pressure signs when the barrel sped up? You had to be right back on that line of ejector marks or slightly over.

What's your sample size when testing groups?

I didn't notice any signs of pressure after first firings. sometimes you get lucky I guess.

 

[Speedy7722]

Similar to some others, I end up having time for load development in the spring and summer.

I measure everything and utilize GRT to anticipate max charge. I go 1-1.5 grains less than modeled max and shoot 5 rounds to gather velocity data. I true up GRT and then load 10 rounds across the 50-60k PSI range. I shoot the 10 looking at velocity, POI, & group size. I haven't had an issue with getting into significant pressure this way.