load development??

[dragman]

when developing a new load for a big caliber gun just curious how many people always stay under the book's max??? Is it safe to add powder slowly until the primer or brass shows signs of pressure?? I just would like to see how everyone else does it?

 

[bheadboy]

all the big calibers have more than enough energy to kill most anything in class you are after, thus to me the concern is not to squeeze the max out of it but to get to the accurcy node that my particular rifle has.

This is as often near max as it is 100fps under max, just depends on the rifle, bullet combo.

i always start down 5% with 2-3 powders and the bullet i am most intereted in then work up to see velocity, sd, es, accurcy eliminate powders as i go and stop when i have good velocity, accurcy.

Bob

 

[mikecr]

I wouldn't go beyond YOUR max, and that should be when brass measurements depart from YOUR sizing plan.

Always working up, the brass will tell you when it's time to stop.
And you can expect that a little 223AI's stopping point will be higher in pressure than a 7STW.

 

[dragman]

working up a load on a 338 lapua. I want to use reloader 25 with 300 grain berger hybrids. only 300 grain load I could find in my books was in a lyman book and it said 85 grains was max I am using Federal 215M primers. I read were a couple of guys were using up to 91 grains I worked up to the 91 grains and haven't seen any sign at all of pressure. should I stop or see if I can get more snot out of them???

 

[DennisH]

I will post the link to this info:

BE CAREFULL, I have a 338Edge and I always recommend starting low and working up! Watch your primers, first sign, sticky bolt lift, second sign. In fact if you have a sticky bolt, I would STOP immediately!
I couldn't find any info on Bergers! Maybe this will get you started.

Link to the below info:

http://www.reloadersnest.com/frontpage.asp?CaliberID=140

338 Lapua
Bullet Sierra Match King
Bullet Weight 300 grs
Powder Reloader 25
Powder Weight 91.0 grs
Primer CCI 250
Brass Make Lapua
Barrel Length 27 (inches)
C.O.L (inches)
Velocity 2738 fps
Group 100 yds .708 (inches)

 

[DennisH]

PS: Certain people found there node using larger loads.

I found during my ladder test, the lower the charge, the better the groups were! Backing off the lands was also a major factor in accuracy with my 338 Edge!

Long story short: A recommended load from Shawn Carlock which was just above the recommended starting load for my gun ended up being the ACE in the hole!

Don't use the numbers shown on my target, but set up right, the 338 will shoot! I know several who have them, and all shoot very accuratly. Remember, I am shooting a 338 Edge which is very close to a 338 Lapua!

PS: Lapua site - reloading info http://www.vihtavuori-lapua.com/pdfs/Rifle-Reloading-Data-2006.pdf

I worked up to the 91 grains and haven't seen any sign at all of pressure. should I stop or see if I can get more snot out of them???

Per your above post, I am posting my target just to show you how a few grains of powder will affect your groups, even on the big calipers! It's a LOT of powder, again BE CAREFULL, never go more than .3 grains up during your load development. Every bullet I tried, even Berger's, all liked being off the lands at least .050 and more. I never shot a good group with any bullet set closer to the lands. Again, this is my gun stats, every gun is different.

 

[dragman]

great information thanks all.

 

[DennisH]

I shot a 338 Lapua today just to compare this gun to my 338 Edge. There almost one and the same! Both very accurate. We were shooting 600 yds in 12mph erratic crosswinds. The wind had little effect on the 300grain loads! We were shooting everything from a 223 up to the 338's. The 338 without any doubt shot the best in these windy conditions!

I also talked to a person who several months ago was doing a ladder test devolping a load for his 338.

He stated he was uping his charge 1.0 grain per load. Another words, 91.0 - 92.0 - 93-0 -94.0 ; He didn't think there would be any problems doing this.

Long story short: He almost blew the gun up! I don't know what charge it happened on, but the next step up on his ladder loads, this next step up load blew the case up in the chamber and damaged the bolt! Brass came apart around the primer pocket area and the first 1/2" of the brass. He also stated he is lucky to be here! Stated he was told this by many people, and was lucky the barrel didn't blow up!

Good part: A new bolt assembly and a trip to the gunsmiith restored the gun!

Also stated there were no pressure signs on "any" of the previous loads! Even in a 338, 1.0 grain of powder is a lot for any gun!

Just a thought!

 

[mikecr]

Dennis, I will guarantee there was a sign -that he wasn't watching.

Bring calipers to the range when working up to find max. Pick a spot nearest the webs that you can consistently measure at(I use the webline ~.2 forward of extraction groove).
As you go up in pressure this datum will step change to a larger diameter that represents chamber minus springback. It'll hold at this diameter for further increments, but at some higher charge will step change again another .0005"(1/2thou). This represents brass yielding and the point where FL sizing will be required. Barely above this you get popping extraction as the brass is left at an interference fit, because the chamber sprung back fully, while the brass did not(yielded).
That 1/2thou step change was the sign your friend should have stopped at, and of coarse it's easier to nail with smaller increments.

Primers,,,bolt turn,,, could do anything, or nothing, through the range.
But your chamber is your best die, and you are sizing in it(upsizing).
That's what you wanna watch.

 

[DennisH]

MikeCr, Thanks for the info, I will pass it on!