old bore, not pitted bore leading.

[fffffg]

drilling loads 8.7x 72r are comming along great.. finnally got plenty of help and used 21 grains 4198 and 200 grain bullet.. got what felt like decent velocity.. lead hardnessis 30/1, lead tin ratio.. velocity 1300 to 1500 feet per second im guessing... used wax check under bullet..  large chunks of leading in bore comming out easily  with tight patch..  looks like gauling.. several has said its coused by a rough bore.. my gunsmith says to use more lube and harder lead..  the bore looks like it was cut with lots of mill marks, then lapped enought to make it shoot good with jacketed bullets (1926).. .. the rifling looks a littly wavy not rough to me, but what do i know??  ive got some 20/1 bullets comming in about 10-14 days to try.. the bullets im using only has one grease groove lubed, i rubbed some spg on the out of case groove..  the lead came out of the bore  easily .. and i gave it a jb comnpound treatment tonight..  will thes old riflings that was made rough (not pitted) work out with cast bullets?.. any suggetstions welcome..  dave

[Leftoverdj]

Dunno, Fffffg. No way to tell without seeing the bore. More lube and a harder bullet sounds pretty sensible to me. I've gotten decent accuracy out of some peppered barrels, but never tackled one that was really rough from the factory.

My major leading problems have always come from undersized bullets or pushing PB bullets too hard.

Did you have leading trouble with the 10 grains of Unique load?  If that did not lead, it's unlikely the trouble is the barrel.

[John Traveler]

fffffg,

I'd try what your gunsmith suggested, harder bullet and more lube.

I'd make up some linotype bullets and switch to an Alox-beeswax lube mixture.

For those velocities you are getting, and that soft alloy, you may be getting some base burn from your non-gaschecked bullet.  Yes, the rough bore can contribute to leading, but so does pushing soft bullets with marginal lubrication.

[fffffg]

i got some leading but not anywere near as much with 10 rounds of 8,9,10 grains of unique.  the leading was chunks, gauling as i said..  i think this soft lead would bump up with either of these loads so probabably not under sized.. the bullets i did recover did not have bad bases or cutting one one half, the other half was destroyed by the dirt bank.. but i recoverd three and those halves were fine..  the 21 grains 4198 was worse in the center of the bore.. maybe.. hard to tell  .. im going to see if it improved with jb lube today and will post back here tonight..  tocompound the leading problem the bullets were sized .006 inches and this reduced the groove and increased the nose diameter to bore size.. a lot of lead ridding with little lube...  half way down the bore does sound like a lube problem..  hardness/velocity could be following if bullets are under size when the hard bullets arrive.. i also have some of veril smiths blue lube, i think ill try that tommorow.. its solveed severe leading problems for me in the past.   dave.

[John Traveler]

ffffg,

What is the chance that you have a tight spot in mid-bore in addition to having that rough bore and rifling?

If carefull bore slugging does show a tight spot, I'd consider lapping the bore with a cast-in lapping slug...but NOT "firelapping".  As fare as I am concerned, "firelapping" is a desperation measure.

[fffffg]

i talked to  a drilling smith today..  he said the gun probably had ratchet rifling that was for paper patches..  with your info i did a constriciton tests and found that the muzzel is larger than the center..  i couldnt figure this out and then it all came together.. the shotgun shot high, the rifle shot high. the bore has an enlarged muzzel..  this all points to a black powder gun.. the smith said the germans were making black powder guns into the 30s..  i dont now if the muzzel larger was on purpose to make the paper pathche bullets have maximum velocity, or it wasnt an issue becouse paper patch pure lead  bullets have a hollow base..  ill probably figuure it all out sometime,, but im committed to finding what  this thing was made to shoot without making alterations..luckily someone hasnt already altered the chambers on the 2 1/2  16 gauge so its pretty much orriginal..  everyone is saying that when the barrels allign is when iv found the loads.. dave

[Lloyd Smale]

since your using smokeless powder why dont you try tumble lubeing the bullets in addition to your wads. I dont know about everyone else but ive had good luck fire lapping handgun barrels. Done 5 of them and never had a problem allways had less leading and accuracy has improved in a couple of them and never did the accuracy deteriorate.

[fffffg]

i cleaned the gun very carefully tongight after using 8 1/2 grains unique..  8.7x72r.. very light load.. like a 38 special rifle.. shot a 1 1/4 inch group at 36 yards..  1/4 inch  horizontal spread,,, 1 1/4 verticle spread.. leading in breach moderate..   bullets are 30/1   here is the big but,,, but they were swedged down from .366 to .361 ..  will this ruin hardness? or caouse stripping in a long lead bore with all the loads i used, black powder and the like???  i smeared on blue  lbt lube today and couldnt believe i still got leading, it has to be stripping..  dave.