Need Help....Heavy Powder Residue On Case...

[IDelkhunter]

Hey folks,

Hoping someone can help me. I have attached a couple of pictures of cases from load development on my Defensive Edge 7mmSTW. I was doing an OCW load test and all cases from min load to max load exhibited this level of residue. I could smell powder after each shot and decided to stop after 7-8 rounds. I have never seen it any of my other guns....wondering if it is a safety issue or if something is wrong? Here are the specifics:

Carlock Defensive Edge 7mmSTW
Virgin Nosler Brass sized with .311 S Bushing die giving me .002" neck tension
CCI250 Primer
H1000 loads from 72-76 grains
180 Berger Hybrids
.020" off lands leaving me only about .140-150" bearing engagement with the neck

Any thoughts on cause/corrective action?

Thanks for your help,

Marcus

 

[IDelkhunter]

Should have added....

There is residue all down the case, with heavy deposits in the web area....

 

[IDelkhunter]

Better pic

 

[IDelkhunter]

Another pic....the first 6 are once fired 8mm Remington necked down to STW loaded at 75 grains of H1000. Same CBTO. I shot these in the same session to zero the scope. You can clearly see the change from the Remington brass to the Virgin Nosler....I'm stumped?!

 

[Sully2]

Dont know why your cases are getting sooty,,,but..

"020" off lands leaving me only about .140-150" bearing engagement with the neck" aint nearly enough neck for anything I load.!!!

 

[IDelkhunter]

I agree with you....I usually always follow the one caliber engagement method, but previous owner had luck at that length and I thought I would start there.....I was mistaken about the 8mm cases, they are actually Nosler, not Remington....

 

[Lefty7mmstw]

anneal your brass I'd guess... I'd say to run your charge up but hodgdon is already showing a 74.5 grain top load using h1000 for a 180 with the 7stw. I'd say to ditch the h1000 and cci250 also in favor of other choices, but that's just me. I'd think rl25, retumbo, or rl33 and a 215 would do you better.

I've been shooting the heck out of my new stw barrel the last couple of months with ww and rem brass and rl25, rl26, and rl33 (with a bit of rl50 and h50bmg tossed in) and never had a sooty case.
Sully2 is correct too that you want the bullet to fill the neck in a case like this... It's a hunting round and the pill needs to stay square to the world.... Half way in isn't enough IMO...

 

[IDelkhunter]

Thanks for the response. I will try other brass and powder....but what doesn't make sense to me is the difference between the two loads....one being a Nosler 8mm and other being Virgin Nosler STW, both loaded with H1000? Just can't figure out what's going on?

 

[FearNoWind]

Couple of things I'd check.
Shoulder set back - if it's too long it'll let base escape toward rear
Neck tension relative to neck wall thickness. If necks don't open up an seal when fired it can cause that - especially if the head spacing is sloppy
Bullet not seated deep enough in the neck
Powder charge too low
Loss of neck sealing at throat area due to hardened brass (May need annealing)

 

[IDelkhunter]

Thanks again for the response. I did a little more measuring and discovered that the headspace difference between virgin and once fired is .017". I've never done a lot of before/after comparison to see how much shoulders "grow", but that seems like a lot? Thinking next steps will be to reload the once fired and see if it goes away? I'll try the Retumbo/215's Lefty mentioned. Do any of you STW guys shoot N570 in this cartridge?

 

[dok7mm]

I had this same problem [ for the first time ever ] on my son's 7mm RUM a while back. After a lot of head-scratching, I found it to be the amount of reduction in neck diameter of brass fired in his chamber - .319 nk. - to the .313" bushing I was using for .002 neck tension on 168 Berger Classic Hunters. It finally dawned on me and I checked some more brass by resizing 10 more pieces of the new Nosler brass I was fire forming. Six outa ten had necks measuring .002" less than my target neck of .313". Basically, my one stage reduction was giving me .004-.005 neck tension and coupled with the different case neck thickness of the high $$$ Nosler brass, the case necks were not sealing consistently. To prove my theory, I changed to a two step bushing setup using first a .306 bushing, then my final .313 bushing, while measuring case neck diameter after each step. Perfect, I sailed thru the rest of the brass with no more sooty cases. You didn't mention your die set-up or fired case neck diameter, so this may not apply to your situation. +1 on the possibility it is a headspace issue.

 

[dok7mm]

Meant to say I used a .316 intermediate bushing, SORRY

 

[jjmp]

Sounds like the above poster nailed it great job, nothing wrong with h1000 or cci -250 primers in the stw .

 

[Jerry M]

Great information!