johan teughels
Member
so i need help
30x 47 more info needed
- Thread starter johan teughels
- Start date
Dusty Stevens
Hollow Point Dispenser
Seat a bullet long, measure it then close the bolt on it and remeasure. If its shorter then thats your jam length and your zero starting point
johan teughels
Member
that is wat i do normaly but it does not work for thise thing i get a round mark before it touche the grooves
M
mks
Guest
Johan,
Looks like you have slightly fat bullets and/or a tight free bore. The fact that you can force a reversed bullet in about 0.3" suggests that the bullet is not much larger than the free bore, if at all. But the leading edge of the free bore is scraping the carbon off the normally seated bullet, which means that the diameter of the bullet plus the carbon is larger than the free bore. This might be the cause of your accuracy problems. Bullets should be a few tenths smaller than the free bore.
Hope this helps,
Keith
Looks like you have slightly fat bullets and/or a tight free bore. The fact that you can force a reversed bullet in about 0.3" suggests that the bullet is not much larger than the free bore, if at all. But the leading edge of the free bore is scraping the carbon off the normally seated bullet, which means that the diameter of the bullet plus the carbon is larger than the free bore. This might be the cause of your accuracy problems. Bullets should be a few tenths smaller than the free bore.
Hope this helps,
Keith
R.G. Robinett
"That'll never work."
Or, the free-bore should cut several 1/10,000Ths " larger than the bullets!
Never order a .30 cal. reamer with a free-bore diameter of less than 0.3085" - it is very desirable that the free-bore diameter be large enough to, "clean-up" the grooves, and leave not the slightest vestige of lands! Think H-322(Extreme), or, N-133. RGP.S. According to tolerance Specs. (+/- 0.0004"), this reamer COULD actually be anywhere between 0.3081" - not so desirable
- and .3089" - very desirable . Again, always Spec., "NOT LESS THAN", and allow the maker to use the tolerances range above there.
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johan teughels
Member
can ot post a pic from the inside ofthe barrel but i inspected it and the frebore cleand the grooves there is no trace of them when i look into the barrel with my ttol (brass tube with magnifiing glass) i will try the same proces wiht some other bullets i got l.dit some more testing last WE and i have a better accuracy with less neck tension (only .001"smaller busshing then full dia) and less powder (125 gr bullet with 40 gr of N135 ) i will messure speed hopfully next WE
what is a desent speed for the 30x47 and 125 gr bullet ?
what is a desent speed for the 30x47 and 125 gr bullet ?
johan teughels
Member
got my new toy working
speed mesurements is fun to play with
got some deasent 3 groeps with 41 gr of n 135 sierra pro hunter 125 gr at 2750f/s
the 40 gr of 135 N got a speed of 2700f/s
wil do some more testing with 41.5 gr of 135N but change the seating depth
speed mesurements is fun to play with
got some deasent 3 groeps with 41 gr of n 135 sierra pro hunter 125 gr at 2750f/s
the 40 gr of 135 N got a speed of 2700f/s
wil do some more testing with 41.5 gr of 135N but change the seating depth
Nice to hear that you're getting promising results! I don't know about the art/science of rifling and chambering barrels as some other here do. There are lots of ways to determine seating depth relative to the lands and it looks like you explored most of them. I tried those methods too, but eventually got a Sinclair seating depth tool. It is consistent after a bit of practice and since every different bullet requires a measurement, a tool like the Sinclair saves time. Once you have your base-line "bullet to the lands" number, you can easily adjust seating relative to this.
btw, I'm fighting with getting a shortened 308 to shoot too, so I feel your pain!
btw, I'm fighting with getting a shortened 308 to shoot too, so I feel your pain!
johan teughels
Member
will sierra 125 gr fb (2121) work ?
can not find info on use ofthat sort of bullets inthe 30x47 configuration i got
any idea on the lenght /ogive seems i can not find it on the sierra site
can not find info on use ofthat sort of bullets inthe 30x47 configuration i got
any idea on the lenght /ogive seems i can not find it on the sierra site
Pete Wass
Well-known member
If you can get
some Speer 125 TNT bullets you will probably like them a lot. 125's should work fine.
Pete
some Speer 125 TNT bullets you will probably like them a lot. 125's should work fine.
Pete
johan teughels
Member
to mutch realy bad flyer (nearly no wind and some 5-6-7 scores )
took the barrel of to do some desent measurements
dropped in a bullet placed a rod in the barrel from the front till it hit the bullet then marked the depht on the rod
took a case seated the bullet till it had the same depht reading on the rod
is the free bore not way to mutch (compaireto reamer specs )
seatted bullet is the same as the one on the top
got a sierra 150 gr 2190 HPBT on the bottem to compaire the lenght
that thing is driving me nuts lost 4 matches and more then 300 testing shots
took the barrel of to do some desent measurements
dropped in a bullet placed a rod in the barrel from the front till it hit the bullet then marked the depht on the rod
took a case seated the bullet till it had the same depht reading on the rod
is the free bore not way to mutch (compaireto reamer specs )
seatted bullet is the same as the one on the top
got a sierra 150 gr 2190 HPBT on the bottem to compaire the lenght
that thing is driving me nuts lost 4 matches and more then 300 testing shots