.357 max handi bore slug

[acmetim]

so i had this 16" handi rifle in .357 mag. put hundreds of rounds thru it. all kinds. .38 .357 lead, j-word. no problems ever. plenty accurate and fun. recently i rechambered to .357 max. tonite i was finally ready to load up some boolits, then i decided to slug the bore. (why now, you might ask) i had some 170 gr hard cast .358 handy so i passed one of those(with great difficulty) thru the bore. the measurements i got were .353 between the grooves and .347 between the lands. now like i said it has always shot anything i put thru it.... now i have heavy loads and heavy bullets(up to 235 gr hardcast) now i am worried about too much pressure building up. any thoughts? anybody ever heard of a .357 bore that slugged out that small? should i size the boolits down? if so how much? and do they even make sizers in .354? i will slug it again with a softer lead ball when i can get my hands on one, but i figure a hardcast would give an even more accurate reading.....

??
acmetim

[acmetim]

sorry if this is in the wrong place on the forum...wasnt sure where it went

[.22-10-45]

Hello, acmetim..try the soft ball. softer is more accurate...I have found hard lead to have some springback..although your groove dia. seems tight...Colt revolvers always had smaller groove dia. than S&W.

[acmetim]

update. just went down and redid slugging. this time instead of going thru the breech end i just drove it into the muzzle then knocked it back out. i got the same measurements with my mitotuyo digital. rezeroed it and cleaned the ends, same thing. then out of curiosity i pulled out my dial caliper. this time i got .358 and .352. i think the devil is in electronics, and i think the truth is somewhere in between the two. i did get a nice little pile of shavings at the muzzle where the bullet went in.....

[nanuk]

can you confirm the accuracy of your caliper with a micrometer?

[**oneshot**]

Soft lead that is larger that the bore will give the most accurate result. The best results for me have been using a slug that leaves a ring of lead at the entrance. But that is me.

[acmetim]

i once poured a bore lap by pouring hot lead into the muzzle over a jag. that seems like a pretty accurate way to slug a bore......

[acmetim]

but might have shrinkage as cools off....... i will test calipers with micrometer

[Whiterabbit]

if you work up your loads youll be fine. Mine shoots 250's very fast with a stiff load of h110. I didnt start there, I just ended up there.

[Goatwhiskers]

For what it's worth, machinists use a micrometer for accuracy, calipers are only for rough measurement. Also, I have never seen or heard of a Handi with a bore as tight as you found. GW

[45-70.gov]

take your slug and push it from front to back....a few times

feel for the force needed to push it

on a handi rifle....most will be tightest just forward of the chamber

fire lapp it until ...repeat with the same slug every 10 or so shots

after 10 or 20 you will notice you can use one finger soon to push it thru the mid-saction

i stop when the constriction is ''almost'' gone

the thoughts of that putty slug getting squished right after leaving the chamber
then going into a bigger barrel bugs me....[j-word bullits spring back]