Okay so Ive just returned from testing my latest loads. I cant remember who wrote it but it dealt with the amount of soot left on a fired case and it had to do with pressure. All of my fired cases showed soot down to around half of the shoulder junction. What does this tell me? Thanks for the help.

PS i shot these open sights prone with the set trigger and at 25m I shot a group of just under an inch. 2 went into one hole! Should I leave the load as is? Upto 100m shots on bushbuck and bushpig with open sights. Took the scope off.

You're gettin soot because the pressure in your load it a bit too low. I would increase the charge until the "sooting" stops. I also think you should better groups once the pressure comes up. Might help to know what bullet weight, powder charge and what type of shooting/hunting you want the load for?
The 7x57 is fast getting to be a favorite cartridge for me.
Paul B.

The help desk at Somchem advised a start load of 36gr S335 with the max being 39gr. I loaded 37.5gr I didnt bother starting at the recommended start load of theirs. They said I should seat the bullet to a OAL of 75.1mm. I seated to 77.5mm. My rifle is a CZ 550 and at that length they are 4.35mm away from kissing the lands. Increase OAL and try 38gr? Any ideas please. Will want to load tomorrow. Thanks.

You are probably 2 or 3 grains away from the soot stopping if your cases are not real old or work harded.
I like to work up loads with known good fresh brass or at least annealed to about 6.5mm below the shoulder. With a cartridge that I am plinking with I like to load until the body quits being sooted. Another check I make is to make sure there are no a lot of unburned grains (zombies) left in the bore. (I use mostly extruded powders) This results in a low pressure load that gives long case life but low velocity. I am not sure what your powder burn rate is or what your goal is.

Be very careful changing 2 variables at the same time. I like to start with the bullet at or touching the rifling if:
1. They are securely seated and will feed without problems
2. They fit the magazine and will feed with out problems

If I do not like the bullets seated out that far I can always seat them deeper.

lal, I have a burn rate chart here from the GS Custom web site that puts S335in the Reloder 12 ballpark and just faster than H4895 and if it was me I would thing your powder choice is too fast ( depending on the bullet you are loading of course)

I would much sooner go down to S365 if you are loading the 150 - 160 gn bullets which is in the same burn range as the IMR 4350 H4350 and just faster than the Reloader 19 that many more will be familiar with.

If you are loading the 140gn weight I would much sooner use the S355 which is in the same range ( on the chart it is between ) Varget and H414.

With those different powders, and a bit more information on your load you may get a more detailed answer from the knowledgable on the forum.

Hey Bud,

Hmmm?

Sorta depends on what you're trying to do here; get rid of the "sooting" on the necks? This may be inconsequential if the bullet weight is appropriate (you didn't mention the specific bullet weight) and accuracy & pressure (you do not want too little pressure, either) are normal.

This "case sooting" is normally an indication that the case neck is not sealing itself quick enough in the chamber to avoid gas & particles from blowing out of the case and down around on to the neck & shoulder of the case and (don't forget) also into the chamber of your rifle (which will have the same amount of soot in it).

It could mean that there is not enough pressure at the optimal moment and it could also imply that you've an oversized chamber in that any case, powder & bullet combination will never seal correctly, too.

My initial solution would be to try a "quicker" (relative) powder OR a heavier bullet with a reduced or similar charge depending on what charge range would be appopriate for another bullet weight.

The OAL is completely within range for a 7x57 cartidge but I would also imagine that you'r not ever going to get too close to the lands in your chamber for this cartidge which are mostly based on a huge amount of freebore or "leade" for the old round nosed 7mm (.284") 175 or 177 gr. bullets.

The normal immediate action resolution for a powder related "case sooting" is to use a quicker (relative) powder to increase the chamber pressure more rapidly.

Thanks all. Bullet is 175gr Hornady interlock. I want to know if it will be safe to go up half a grain and crimp with the LEE factory crimp die which is said to give it the initial pressure increase. According to a Somchem technician the start load is 36gr and max 39gr. Am I still in the safe zone? 37.5gr caused the soot problem but I did not crimp the bullet.

quote:

Originally posted by lal:
Thanks all. Bullet is 175gr Hornady interlock. I want to know if it will be safe to go up half a grain and crimp with the LEE factory crimp die which is said to give it the initial pressure increase. According to a Somchem technician the start load is 36gr and max 39gr. Am I still in the safe zone? 37.5gr caused the soot problem but I did not crimp the bullet.

Probably safe -- that's why data is published. O nly you can find out. "Brunos" are nice and strong so don't be overly cautious in your testing. A couple other thoughts. If the chamber is a little generous you will be chasing something elusive (trying to reduce sooting). Crimping is not done to seal the chamber against over-pressure, but to keep the bullet in place instead of shifting around due to recoil, etc. The long bearing surface of the 175 grainer is enough to keep that from happening, especially in a 7x57 class/size. I'd switch to S365 as has been suggested...

Lekker dae

Barry van Clute, Texas af