the continuing saga of the used 30 br bbl

M

mike in co

Guest
i built a 700 based 30br on a third hand krieger bbl.
the cost was correct and worst case,, just rechamber it.
it shot well for a couple of months, a club win at 198/200,and
a third 199/200.
i tried tried a new bullet and it shot 1" groups. several attempts to get it to shoot
and no luck.
discovered a hard carbon ring where i thought the throat was. it had
grown and was now pushing bullets back into the case.
no cleaning would get it out..used a throater to break it up.
gun goes back to shooting BUT the lands are now 100 thou past
where i thought they were.( this was not the throater..no netal removed)
ok new length, and ok shooting.
at the best of the west, lou gave me some lt30 to try.
two trys and no luck....
so today. i set the bullets back 100 thou and reduced the charge and went out
to see what would happen.( this is the original length the gun shot well at)
two 1's, two 2's.......ave is .178 with a mid velocity of 2973...
100 thou jump!....( berger 115's and 34plus of lt30).

'splain that to me ??
 
in the original config...yes a ruff ring around the bullet.
no cleaning moved the ring, i bought a throater and the first "touch" was a black ring on the throater.
at the first touch it them only moved the bullet back .020 from the .050 it was moving them back.
one more very light touch and i was done..no bullet movement.
but no more....well not since the throater...i guess only time will tell
the brass that came with the bbl is very short. i am guessing blown out blue box.(1.470!)
i use gold box fire formed with no bullet...i can see the chamber neck end at 1.540 on my brass.
their brass left a giant gap to form a carbon ring in...i am guessing there was a ring when i bought the bbl.

ALBULLET said:
Will this carbon ring leave a mark on the bullet jacket when it seats the bullet deeper into the case...?
Click to expand...
 
Last edited by a moderator:
i shot again with 35.2/4/6 and all showed vertical, so i may try 35.8 and 36...
lou said 36!
i re-shot 34.6 and it looked good for score shooting.. a little horizontal, no vert.
 
I have been a proponent of carbon cleaning from the early days of moly coating.
been there done that
 
Lou had said that 36 gr of lt30 should work in my 30br with 115's.
my first couple of tries were not successful, but when i went back to the .100 jump,
accuracy came back.
today i shot 35.8 and 36..simple three shot groups.
35.8 was a .4 and 36 was a 0.141.....damn that guy is good.
so will shoot some more and see how consistent it is.
just shy of 3100 fps from a 24" bbl.
club match this weekend....
 
mike in co said:
....two 1's, two 2's.......ave is .178 with a mid velocity of 2973...
100 thou jump!....( berger 115's and 34plus of lt30).

'splain that to me ??
Click to expand...

I worked with a couple of .30's that would shoot great when the jump got between .050-.100. So did some pals.

.30 barrels like this aren't to be trusted. -Al
 
today i reshot the 36 gr load.
3 foulers/sighters
and 5 x's..
time to try 20 or 25( we only shoot 20)
 
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