Sooty Shoulders - What's causing this?

[KMart]

This helps a great deal. Thank you.

Given this, what would you suggest to eliminate the sooting? Faster powder? Increasing the charge? (I'm still inside of Hodgdon's data but at or above others).

This advice given by 243winxb in post 9 would be my starting place.

Increase neck tension/bullet hold, so bullets don't move to soon. A faster powder or magnum primer may help. The long jump to the rifling, makes it worse

Another very good suggestion in one of the posts is to get a F/L bushing die and only size 1/2 to 3/4 of the neck length. The unsized portion of the neck will be at chamber neck diameter and help to seal off the blow by.

 

[Pinnah]

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The main reason for this post is to advise caution when increasing powder charge in these old guns. They weren’t designed to shoot at modern pressures. My Hornady book has this advise, which I will include.

Thanks, yes I have that data too.

Most sources I've read suggest max CUP for the reloading the Swede somewhere in the 46,000 range. Hodgdon's data asserts it is at or below that pressure.

One of the challenges with this round is how much the published data disagrees.

 

[joshb]

Thanks, yes I have that data too.

Most sources I've read suggest max CUP for the reloading the Swede somewhere in the 46,000 range. Hodgdon's data asserts it is at or below that pressure.

One of the challenges with this round is how much the published data disagrees.

Good. Having lots of data can help and confuse. My summation was to start low using the Hornady data and look for an accurate node. You can see mine did well at a medium charge weight. Getting that tight of a group at 100 was better than I had hoped for!

 

[Pinnah]

A quick follow up bump...

Two things to report.

1) I tried some faster powder - Varget. The Hodgdon data goes from 34.0 - 37.5

My ladder was:
Load: 35.1, 35.4, 35.7, 36.0, 36.3, 36.6, 36.9

There was no soot on the brass but nothing even close to MOA.

2) I tried Magnum primers with IMR-4831.
Load: 42.6, 43.0, 43.4, 43.8, 44.2, 44.6, 45.0, 45.4, 45.8, 46.2

The brass was all clean and the primers showed no sign of problems. I've not explored this range for accuracy yet. Time will tell.

 

[Flouncer]

Hornady makes a 160g roundnose that may be easier to source than Norma or Lapua projectiles.....

 

[Gun Nut 1]

I have read this thread with interest and have a question. If you found a jackpot accuracy load that you are happy with in every way other than the soot issue, why not live with it? Might require some additional cleaning of the gun and the spent brass but I don't see that as a big deal, am I missing something? Gun Nut 1.

 

[rwj]

I have read this thread with interest and have a question. If you found a jackpot accuracy load that you are happy with in every way other than the soot issue, why not live with it? Might require some additional cleaning of the gun and the spent brass but I don't see that as a big deal, am I missing something? Gun Nut 1.

I get concerned from a safety perspective when hot/high pressure gasses are moving into areas where they’re not supposed to be close to my face…

 

[Pinnah]

I have read this thread with interest and have a question. If you found a jackpot accuracy load that you are happy with in every way other than the soot issue, why not live with it? Might require some additional cleaning of the gun and the spent brass but I don't see that as a big deal, am I missing something? Gun Nut 1.

I view the soot as an early indicator of the potential for secondary explosion effect. Low (in the book) charges of slow H4831 in this gun have caused dented shoulders, blown primers and a stuck bolt.

For some gun/powder/bullet combinations, low charges can be as bad as high charges.

I view soot in the same way I view flattened or cratered primers - as indicators that something ain't right.

 

[mikecr]

I believe very quick sealing (low sooting) provides lower SD.