Have not reloaded in years and not familiar with 700X and its corrosive properties. I do know black powder can be very corrosive and should be cleaned often and then cleaned some more. I always thought the so called modern powders would not harm the barrels. Yep they might be dirty but maybe not harmed by the residue. I am always amazed when looking at used guns at even some high end gunshops and the barrels are sometimes dirty.

Having a dirty gun even overnight gives me the willies.

It's my understanding that it is corrosive primers (no longer in use), not the powder, that is the problem

Hard to tell looking at the bore if residue is burned or unburned powder . Make a patch out of a blue shop towel. 1/4 about right for a 12 G. Light lube with oil and push it through the bores.

Take the patch outside and light it with a match. Unburned powder grains will fizz. Dirty bore won’t

William

Hmm, have not heard that before. Maybe something to it as a combination. Whatever the problem was I think they might have cured it in modern load components. I don't know that much about black powders from back then to ones made today but would like to think they are not near as bad as they were from 1800's with quality control and corrosive properties. Probably wrong on that assumption as well.

Also agree with William as test but my guess its burnt powder residue. Some powders have the different burn rates. Learned this the hard way shooting right handed semi-autos as lefty and having some slow burning powder slung in front of your eyes. Also saw some poor college kid at a KA Old South party use modern slow burn powder instead of black powder in a canon, and even standing half way beside canon but downwind got burned very badly. God sometimes does not take care of drunken children.

700X isn't the cleanest burning powder but I shot it for years with no problems. It's only as dirty as the last shot. Every gun could pattern the same load differently. The wife's little 28ga Beretta wouldn't pattern 8 1/2's worth a darn, but 8's or 9's were just fine. I don't know what the pressures were, but you could try a 1/2gr more of powder and see how it patterns/burns. Good luck.

Low P loads with 700x? I inherited a large tin of it and have never used it because I've not seen low P loads for it. I recently loaded up 1000 9mm with it just to use it up. I hope it doesn't gum up my HPower too badly.

15 grs 700-x 7/8ths oz shot 209p primer sts hull at 1150 fps 5700 psi
lots of loads fron 7/8ths oz to 1 oz with psi under 7000

The 209p might be the issue. I always have 10,000+ WW209's in stock and don't use loads that don't use that primer. Could be I've just not found a low P load using a 209 primer. For the size of the tin I have it would be worth buying some p's to use it up. I think I have the same issue with large jugs of WST and 800-X.

with most of the primers, 209a,win 209,and others except the mag. primers, should be no problem to find data with 7000 psi and under for 700-x. I load from 20 ga 3/4 oz to 10 ga. 1 1/4 oz all lead loads.
scott

If you're loading at 8000psi or less any of the mild primers will work without a lot to worry about. I'm looking at 16grs of 700X in a Rem hull and 3/4oz of shot and with a Rem, Win, or Cheddite primer and they all have 9300 to 9900psi. If you go down to the 14gr loads they show pressure in the 7000psi+ range.