I'm shooting a WSM cased wildcat with an epic bullet that is 20 grains heavier then anything else commercially available in this caliber, while I'm not ready to reveal any numbers for this bullet yet I am looking for a bit of knowledge regarding any advantages there may be to having a bullet seated low in the case.
Here is a teaser pic of this cartridge with the bullet loaded to the optimal length that puts the junction of the boat tail right at the base of the neck of the case. (pictured with 6mmbr) OAL was 3.2" and nearly perfect for a long action. (Looking hard at the Norma Blaser Mag case with this bullet but that is a different discussion)
Of course this bullet has a bit longer bearing surface and a little longer length then normal (less then .100" longer though in each regard to the next heaviest commercial bullet of this caliber) which means I am seating the bullet deeper in the case then might be optimal due to the standard length of the throat of the chamber.
I am shooting this WSM in a long action so there is no worry about mag length restrictions.
I have considered reaming the throat a bit longer but I'm not sure if I should.....
When loaded to max OAL the junction of the boat tail of this bullet is sitting .190" below the base of the neck taking up what QL determines to be 2 grains worth of powder. In my testing of this bullet I am getting only 20 FPS gain per grain of powder yet es numbers are very low.
So...... should I ream the throat almost a 1/4" longer or keep it the way it is? Is there any advantages to keeping it the way it is?
Sure the advantage to seating a bullet longer is greater case capacity but in my case only maybe 40-50 additional FPS?
Maybe I can operate at lower PSI by extending the throat but.... maybe the additional pressure may help with better ignition with the slow RL-33 powder? I have found in every caliber I have loaded RL-33 it likes the bullet to be touching the lands and near max pressure for best accuracy. Maybe the slight additional pressure helps with this powder?
Having an extra .190" worth of throat to chase should certainly extend the life of the barrel but yet.... I'm shooting these heavy bullets no more then 3000 fps with very slow powder so I should do OK with barrel life for a little while but if I ream the throat a bit longer I would get the barrel Nitride processed and that would extend the life too. Once you Nitride a barrel there is no more fooling around with reaming anything.
Maybe a longer throat would ensure less runout between the bullet, case and barrel with the bullet engaging the rifling more true? Or I suppose you could screw up the throat reaming process too imparting possible runout in the throat and/or rifling???
Of course if I reamed the throat the barrel would basically be paired with these long bullets and any bullet lighter/shorter would have a heck of a jump, yet I'm OK with that.
The argument is pretty clear to the advantages of seating a bullet longer "out" of the powder column of the case but I have been racking my brain trying to think if there is any advantages to seating the bullet deep in a case while still having no jump of the bullet? You guys have any knowledge to share about such ideas? Kind of like the research that must have gone into the 300WM in it's development back in the day with deep seated bullets and short necks?????
With the limited testing I have done so far I am getting very good accuracy with 1/2 MOA at 600 yrds and reasonable pressures.
in this pic it shows the first and only group so far at 600 with these bullets, first shot sighter was slight low and right, next three rounds went 2.75" with 5-10 mph varying winds. This wasn't even a "tuned" load yet.
I'll post more data about this bullet later after more testing has been done, for now I am really interested to hear any knowledge or ideas on any potential benefits there may be of seating a bullet this deep with the slow buring RL-33 powder vs. extending the throat of the chamber?
Good shooting and Swage on!
BT
Here is a teaser pic of this cartridge with the bullet loaded to the optimal length that puts the junction of the boat tail right at the base of the neck of the case. (pictured with 6mmbr) OAL was 3.2" and nearly perfect for a long action. (Looking hard at the Norma Blaser Mag case with this bullet but that is a different discussion)
Of course this bullet has a bit longer bearing surface and a little longer length then normal (less then .100" longer though in each regard to the next heaviest commercial bullet of this caliber) which means I am seating the bullet deeper in the case then might be optimal due to the standard length of the throat of the chamber.
I am shooting this WSM in a long action so there is no worry about mag length restrictions.
I have considered reaming the throat a bit longer but I'm not sure if I should.....
When loaded to max OAL the junction of the boat tail of this bullet is sitting .190" below the base of the neck taking up what QL determines to be 2 grains worth of powder. In my testing of this bullet I am getting only 20 FPS gain per grain of powder yet es numbers are very low.
So...... should I ream the throat almost a 1/4" longer or keep it the way it is? Is there any advantages to keeping it the way it is?
Sure the advantage to seating a bullet longer is greater case capacity but in my case only maybe 40-50 additional FPS?
Maybe I can operate at lower PSI by extending the throat but.... maybe the additional pressure may help with better ignition with the slow RL-33 powder? I have found in every caliber I have loaded RL-33 it likes the bullet to be touching the lands and near max pressure for best accuracy. Maybe the slight additional pressure helps with this powder?
Having an extra .190" worth of throat to chase should certainly extend the life of the barrel but yet.... I'm shooting these heavy bullets no more then 3000 fps with very slow powder so I should do OK with barrel life for a little while but if I ream the throat a bit longer I would get the barrel Nitride processed and that would extend the life too. Once you Nitride a barrel there is no more fooling around with reaming anything.
Maybe a longer throat would ensure less runout between the bullet, case and barrel with the bullet engaging the rifling more true? Or I suppose you could screw up the throat reaming process too imparting possible runout in the throat and/or rifling???
Of course if I reamed the throat the barrel would basically be paired with these long bullets and any bullet lighter/shorter would have a heck of a jump, yet I'm OK with that.
The argument is pretty clear to the advantages of seating a bullet longer "out" of the powder column of the case but I have been racking my brain trying to think if there is any advantages to seating the bullet deep in a case while still having no jump of the bullet? You guys have any knowledge to share about such ideas? Kind of like the research that must have gone into the 300WM in it's development back in the day with deep seated bullets and short necks?????
With the limited testing I have done so far I am getting very good accuracy with 1/2 MOA at 600 yrds and reasonable pressures.
in this pic it shows the first and only group so far at 600 with these bullets, first shot sighter was slight low and right, next three rounds went 2.75" with 5-10 mph varying winds. This wasn't even a "tuned" load yet.
I'll post more data about this bullet later after more testing has been done, for now I am really interested to hear any knowledge or ideas on any potential benefits there may be of seating a bullet this deep with the slow buring RL-33 powder vs. extending the throat of the chamber?
Good shooting and Swage on!
BT
