stinkyduck13
Well-Known Member
How is freebore measured? Factory OAL measurement plus distance to lands? Thanks
Free bore measurement?
- Thread starter stinkyduck13
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Mikecr
Well-Known Member
Are you filling out a new reamer print, or just curious about an existing chamber?
stinkyduck13
Well-Known Member
No just curious about how it is measured, as a lot of talk here about it and thinking when I did some load development on my tikka 300wm. Thinking I had .188 of free bore. But now realize it's a bunch more. Have a 6.5 prc to load up soon and always want things planned out ahead. Thanks
CBTO
Cartridge Base To Ogive
If you need more info send us a PM and I'll explain.
We can also make you a Modified Case for free. You just need to get the Modified Case Tool.
Thanks
Len & Jill
Easiest way is with one of these. Well worth it when handloading for new bullets.
Hornady Lock-N-Load Overall Length Ga Bolt Action
The Hornady Lock-N-Load Overall Length Gauge is one of the best kept secrets to accurate reloading. This tool allows reloaders to quickly and easily...
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ntsqd
Well-Known Member
Which raises the question of what freebore would you specify for any particular bullet, and how would you determine that?
Technically its the other way around, you pick your bullet based on your chambers freebore.
Experience and personal preference.
I like to start my load development at -.020" off the lands. But this is dependent on the length of the bullet I want to use and what the actual freebore in the chamber was machined to by the gunsmith or mfg. A longer bullet needs a longer chamber freebore. If your chambers freebore isnt long enough for the bullet, it will stick too far inside the case limiting your powder charge and its not really ideal to use.
ntsqd
Well-Known Member
I was looking at it from the other end, ordering a new barrel not working with an existing one. If I'm ordering a barrel then how much freebore do I want for some particular bullet? Just accept SAAMI or ask for something custom?
But, I'm realizing that such a question threatens to derail this thread, so I'll ask this in it's own thread.
But, I'm realizing that such a question threatens to derail this thread, so I'll ask this in it's own thread.
You pick your bullet and seat a dummy round so its not protruding into the case past the case shoulder. Take that sample to your gunsmith and have him ream your freebore to whatever distance to the lands you want. I suggest he sets it so your .020" off the lands.
If your building a rifle you can get the freebore needed to shoot long bullets. Works both ways.
MagnumManiac
Well-Known Member
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It is measured from the end of the chamber where the clearance for the neck is back down to nominal bullet diameter, including clearance for the bullet. This dimension is almost always .040" or .050" longer than max case length. It is then measured to the full height of the rifling.
There is actually 2 dimensions to a throat, the true throat, coned or parallel section, and the leade. Most reamer prints denote the difference, but do not specify which is what.
Cheers.
