Just wanted to get a better understanding on barrel freebore benefits. I'm looking at the 260 match reamer from PT&G that will allow me to seat the bullets out longer since I'm using a long action. Do you erode the throat faster? What are the pros/cons?
- Thread starter Reaper 31
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How hard you push it is going to be the major determining factor. Have you picked the freebore yet?
longer freebore allows your longer seating depths for the heavier higher BC bullets, gives you a little more wiggle room in setting your jump and also benefits from getting the base of the bullet out of the case for more powder volume.
ETA to add: too much freebore can cause an issue on the lighter weight bullets that are traditionally shorter (not including solids, they tend to be lighter and long-ish) creating an astronomically long jump they may not tolerate.
thats often why you see guys reference the bullet (or family of bullets) they desire to shoot and factor in their freebore on their reamer, in that order.
ETA to add: too much freebore can cause an issue on the lighter weight bullets that are traditionally shorter (not including solids, they tend to be lighter and long-ish) creating an astronomically long jump they may not tolerate.
thats often why you see guys reference the bullet (or family of bullets) they desire to shoot and factor in their freebore on their reamer, in that order.
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Cool, post the print when you can.
Yes, but to a very minor degree imo. How hard you push it is going to be the major factor.
Here's a screen shot. Hopefully you can expand it to view. It says it should have a .081 freebore which I'm still trying to learn about
According to that print, the FB is .188 and not .081.
The note in the top is referencing the fact that if you used that reamer, you would need to use either a long action or single load, as the bullets would be too long to fit the standard magazine if loaded to be near the lands.
Oh OK. To confirm i do have a long action and I have a Mc Gowen .264 blank barrel. I realize I can do different cartridges (6.5-284, etc) but this is me thinking out my project. Open to all suggestions, just don't want to buy a new action and do that again... $$$
The freebore is the area right in front of where the case neck ends but before the rifling begins to ramp up. PTG and others label their stuff backwards though so thats why its important that you know what it actually is that you are describing.
This is how most people describe it
SO on your print that would be the .188 dimension.
If your bullet is stuffed way into the case to fit in a chamber then extending the freebore would allow for more space in front of the case for the bullet to occupy when chambered.
If you go too far then you may not get enough grip on the bullet due to lack of neck-bullet contact or it could be to short to hold entirely in extreme circumstances. But the further you go the longer it gets over all and wont fit inside the confines of a short action, but you have a long action so no worry there for you.
This is how most people describe it
SO on your print that would be the .188 dimension.
If your bullet is stuffed way into the case to fit in a chamber then extending the freebore would allow for more space in front of the case for the bullet to occupy when chambered.
If you go too far then you may not get enough grip on the bullet due to lack of neck-bullet contact or it could be to short to hold entirely in extreme circumstances. But the further you go the longer it gets over all and wont fit inside the confines of a short action, but you have a long action so no worry there for you.
No. It’ll erode at the same rate. But starting that much further out. If it’s too long for your chosen bullet the above mentioned things could happen
something to consider about throat erosion. while your freebore doesn't necessarily erode it any faster. you start out with a super long throat for that specific cartridge to run the long heavy bullets for that caliber, then your already starting with a long throat so when you erode back you may run too far out. while its unlikely. something to consider. for example
my creed had the 199 FB when new. im eroded out to 240 now and wanted to switch from eldms to Atips. Atips are a finicky bitch bc they are long and the ogive seams to sit farther back than standard elds. so from what my eldms had a 60 thou jump at the same time of erosion on the barrel, my atips are now jumping 110 with the same ogive seating depth. obviously that would be much shorter if I started with a shorter free bore or started using atips earlier in the barrel life. now if I send the atip out to a jump relative close to the eldm the base of the bullet is well above the shoulder junction. so its a balance act.
my creed had the 199 FB when new. im eroded out to 240 now and wanted to switch from eldms to Atips. Atips are a finicky bitch bc they are long and the ogive seams to sit farther back than standard elds. so from what my eldms had a 60 thou jump at the same time of erosion on the barrel, my atips are now jumping 110 with the same ogive seating depth. obviously that would be much shorter if I started with a shorter free bore or started using atips earlier in the barrel life. now if I send the atip out to a jump relative close to the eldm the base of the bullet is well above the shoulder junction. so its a balance act.
D put it much more elegantly that I did.
this is what I was trying to explain.. and horribly I might add
Freebore does not change throat erosion one bit.
While a long free bore is not good for light bullets... who cares? The point of a long free bore is to run long high BC bullets.
What nobody has mentioned is how the long freebore and a long seating depth serves to align the bullet for better accuracy. Certainly the freebore diameter is also a point to consider as well.
When running a short freebore, the brass aligns the bullet to the throat and that isn't so good for accuracy.
While a long free bore is not good for light bullets... who cares? The point of a long free bore is to run long high BC bullets.
What nobody has mentioned is how the long freebore and a long seating depth serves to align the bullet for better accuracy. Certainly the freebore diameter is also a point to consider as well.
When running a short freebore, the brass aligns the bullet to the throat and that isn't so good for accuracy.
