Additional freebore ?

[Axkiker]

So I am building an F-tr rifle and was unable to get one of the 2013 team USA f-tr reamers that I was after. I rented a .308 Lapa / match reamer from 4 d rentals which I have used very successfully in the past along with a throating reamer. The biggest difference I see between the f-tr reamer and the rented one is the freebore is drastically different. I believe the rented reamer is .115 and the f-tr is upward of .170.

So my thought is to chamber like normal and just use the throating reamer to get up to that .170 area to make up the difference.

Seem legit or a horrible idea? Im not a gunsmith but I've chambered several barrels and have been pretty successful. Just curious if there are any hidden aspects I'm not aware of.

Thanks

 

[swd]

Throating reamers work great. It do it pretty regularly. Go easy and check often. I slit a case neck with a little tension on it and use my desired bullet in to check OAL. You have to play with tension a bit to get it right but it works great once you do.

 

[LVLAaron]

FTR guy here... go for it. Read through the "not enough freebore" thread that's currently at the top of the pile. Just be careful with the throater, you can cut a lot really quickly

 

[SKWERLZ]

So I am building an F-tr rifle and was unable to get one of the 2013 team USA f-tr reamers that I was after. I rented a .308 Lapa / match reamer from 4 d rentals which I have used very successfully in the past along with a throating reamer. The biggest difference I see between the f-tr reamer and the rented one is the freebore is drastically different. I believe the rented reamer is .115 and the f-tr is upward of .170.

So my thought is to chamber like normal and just use the throating reamer to get up to that .170 area to make up the difference.

Seem legit or a horrible idea? Im not a gunsmith but I've chambered several barrels and have been pretty successful. Just curious if there are any hidden aspects I'm not aware of.

Thanks

Yep.
Easy to do, like mentioned in the other FB thread just remember the throating reamers cut very easily so be cautious.

 

[Axkiker]

Okay good deal.. seems like I'm on the right track.

What's your alls method for measuring. Being I know the freebore of the reamer I'm using I was thinking I could setup an indicator to measure how far in I cut with the throating reamer after I finished the initial chamber. This is a hand reamer but figure I'll still do it while in the lathe.

Or as mentioned above is it maybe better to chamber then use a bullet in a case to measure the difference before / after using the throating reamer. I could measure the bullet with a headspace gauge incrementally as I cut. I think I have one of those Hornady things you thread on a case used for checking jam that might work.

Anyways something is happening this weekend lol.

 

[Sniperhandle]

A foolproof way of doing it for someone that doesn't have experience using a Uni-Throater would be to take the piece of barrel you cutoff the muzzle end and chamber the stub, It doesn't need to be a full chamber, Then throat it slowly until you achieve the depth you want being sure to tighten the stop collars. When you reach the point you have the freebore you are looking for your Uni-Throater will be set for the depth you need and will be ready to use for when you get your barrel chambered.

 

[ELR LVR]

Or as mentioned above is it maybe better to chamber then use a bullet in a case to measure the difference before / after using the throating reamer. I could measure the bullet with a headspace gauge incrementally as I cut. I think I have one of those Hornady things you thread on a case used for checking jam that might work.

Here is a method that is nearly fool proof - if you are throating deeper than the chamber reamer
Once chambered to fit your FL sized brass case, be sure your headspace is correct etc
1) screw action onto barrel
2) close bolt - insert cleaning rod with flush tip into muzzle until it bottoms out against boltface
3) mark the cleaning rod at the end of your muzzle
5) Open bolt and insert the bullet you will use into the chamber,
lightly tap it against the lands just to seat it.
6) re-insert cleaning rod until it just kisses the meplat of the bullet
7) mark this new postion on your cleaning rod at the end of the muzzle
8) measure the distance between these 2 marks on your cleaning rod
This will give you the OAL where the bullet touches the lands
---
Make a dummy round with the bullet to have this OAL
Now you can gauge how much of the bullet is seated into the case and take a measurement of how much further you want to throat.
---
Don't rely upon land markings engraved into the bullet as a gauge for how much the bullet is in the lands
this is a false type of reading due to the 2 angles of the Leade and Ogive nearly matching.
IE: what looks like .020" land engravement on the bullet can actually be just touching.
---
Go ahead and throat maybe .020" and set your stop on the throating reamer
repeat above steps 1-8 to measure a new OAL of a dummy round
This is to ensure you know you have throated as much as you expected
if all is good, reset or adjust your reamer stop for the additional amount you wish to throat.
---
You are ensuring an exact throating depth by using this method where the bullet kisses the lands with the very bullet you are throating for.
I would sort 3 or so bullets for this purpose having the same OAL and BTO due to bullet variations

 

[Axkiker]

Here is a method that is nearly fool proof - if you are throating deeper than the chamber reamer
Once chambered to fit your FL sized brass case, be sure your headspace is correct etc
1) screw action onto barrel
2) close bolt - insert cleaning rod with flush tip into muzzle until it bottoms out against boltface
3) mark the cleaning rod at the end of your muzzle
5) Open bolt and insert the bullet you will use into the chamber,
lightly tap it against the lands just to seat it.
6) re-insert cleaning rod until it just kisses the meplat of the bullet
7) mark this new postion on your cleaning rod at the end of the muzzle
8) measure the distance between these 2 marks on your cleaning rod
This will give you the OAL where the bullet touches the lands
---
Make a dummy round with the bullet to have this OAL
Now you can gauge how much of the bullet is seated into the case and take a measurement of how much further you want to throat.
---
Don't rely upon land markings engraved into the bullet as a gauge for how much the bullet is in the lands
this is a false type of reading due to the 2 angles of the Leade and Ogive nearly matching.
IE: what looks like .020" land engravement on the bullet can actually be just touching.
---
Go ahead and throat maybe .020" and set your stop on the throating reamer
repeat above steps 1-8 to measure a new OAL of a dummy round
This is to ensure you know you have throated as much as you expected
if all is good, reset or adjust your reamer stop for the additional amount you wish to throat.
---
You are ensuring an exact throating depth by using this method where the bullet kisses the lands with the very bullet you are throating for.
I would sort 3 or so bullets for this purpose having the same OAL and BTO due to bullet variations

I think I gotcha... Seems like the moral of story is to use a bullet you will be shooting as your gauge of sorts.. You want to measure the bullet and its forward movement as you cut.

 

[ELR LVR]

I think I gotcha... Seems like the moral of story is to use a bullet you will be shooting as your gauge of sorts.. You want to measure the bullet and its forward movement as you cut.

Yes, you are correct