Powder burn marks on shoulder


Well-Known Member
Hi All,

Well, I finally got a chance to try out the new rifle yesterday (more about that later!) with a range of homeloads. 243, N140, 87gr bullet.

From the lightest loads right through to the near maximum I was finding burn marks not only on the neck but also on the shoulder of the case.

I know this can be a sign of low pressure, but the primers were fine in all cases, no cratering, no backed out primers etc.

There were no burn marks at all on the sides of the cases.

Oddly, with the starting load the burn marks stop neatly 2/3rds of the way down the shoulder. With the heavier loads it was all the way down the shoulder.

The cases are new winchester never fired. I full length resized, trimmed etc before loading.

I did not crimp the bullets.

I was also zeroing at the same time, the groups were around 2 inches at 100 yds - shots taken from a not very comfortable position I might add, in the rain.

What are your thoughts on this shoulder burn issue?


Well-Known Member
Try posting a pic or two. I use 140 and get carbon marks on the necks and sometimes shoulders . Neck sizeing is better as your cases are now fire formed to the chamber of your rifle.
If you have a new rifle it can sometimes take up to 200 rounds before the rifle shoots well.
What rifle is it ?


Well-Known Member
It's a Ruger Hawkeye. The fireforming issue had occurred to me, I also wondered if there was crud in the chamber that was preventing a proper seal. There is now I suppose!

Unfortunately, the organised side of me chucked the cases into a cleaning solution so I could check for splits. cracks etc - never thought to take pics - doh!

The heaviest load I fired was 36.3 of 140. The max is 38.3 so I do have some room for manouevre if it is low pressure.

But as the lightest load - 34.3, sealed the first third of the shoulder and after that it got worse, I'm not sure if it's an under-pressure issue at all.


Well-Known Member
How many of each powder weight did you load ?
What were the increments of powder weight ?
Did you get a measurement of each group/weight ?

Most importantly use a good rest/sandbag !
You will only get a good load IF you work at it.

Do NOT worry about where the bullets hit the target . you are working a LOAD you can zero after you have a 1/4 " group .
Good luck


Well-Known Member
Hi Splash

I have kept all the data, targets etc and I am reloading to a plan.

It's the burn marks on the shoulder I'm worried about.



Well-Known Member
you say you were shooting in the rain, one point is the ammuntion and chamber must be dry, if it was not then this maybe the explantion for the burn marks, the rain will increase chamber pressures



Site Staff
I have just reread this thread, and I would like to get a couple of things sorted for my own benefit. Do you mean the cases are actually burnt or are they sooty? as in a lack of obturation? You mentioned in your initial post of this thread that you realise these marks could be as a result of low pressure, but the primers were not cratered at all all fine, if they were not fine this could be an indication of High pressure not low.

If these are the rounds that you used when you were out with wadas, they seemed to be OK. If I were you and they did the job, I would not worry too much about a little soot on the cases. However if you wish to play a bit and try to eliminate them by varying the load / pressure then it can only add to your experience. Remember the load you develop for your rifle is unique to yours and yours alone, it may or may not be safe in other rifles.

Have fun



Well-Known Member
Hi John

Sorry for not being clear - it was soot, it just washed off no problem afterwards rather than the brass being scorched.

I'm now making up some loads in the midway to the 3/4 of the way up the loads in the table and I'll see how they go. The tables list 34.3 - 38.3 as the range, I'm stopping at 75.5 no matter what. Until I have more experience with it I'm staying away from the max load. I doubt it will be the most accurate anyway. In truth, even the lightest loads grouped OK.

The rifle was proofed before I got it, and I am wondering if there was residue left in the chamber from that which prevented a good seal. I dont know how many rounds are used t proof a gun. I checked every case after it was fired and the primer condition was perfect - I wouldn't have continued otherwise.

I have cleaned it now. We'll see how I get on and I'll report back.



Well-Known Member
What a plonker I am - of course I mean 37.5!

Exceeding the maximum load by 100% is not a good idea!

Yes, it's 243 but regular flavour.


Well-Known Member
burn rates

i loaded some .243 win using N140.but mine were using 100gr hornady sp. N140 is a pretty quick powder for .243 (IMO). i got soot on the necks and shoulders. I have now loaded with nobel rifle powder 0. (the same data applies for Vectan tu7000) which is very close to IMR 4350. these powders are a lot slower burning. i got far better accuracy and no sooting on the cases. it might be worth slowing down the powder you are using.



Well-Known Member
The answer to your question is the fact that your cases are new and a little small for the chamber.
Once you have fired them dont full length resize but just try to resize the neck/shoulder only. This is easy by spacing off the shell holder with a small coin (10 cent). Remember to remove the decapping pin.
Once the case has been fire formed a couple of times to your chamber you will get batter obturation.