Lengthen throat? Cost? DIY?

entoptics

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Jan 16, 2018
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617
I have two barrels, which are Savage prefits, that have throats considerably shorter than I'd like (0.15" - 0.19").

FYI, these are a 264WM, and a 7mm Rem Mag, which will be exclusively shooting ELD-M/X bullets (perhaps some other VLD types, but nothing lighter than 143/175 gr). They both shoot pretty decent as is, but they come in right around SAAMI max length when 0.020" off the lands, so there's a heck of a lot of bullet below the neck/shoulder, and I have 3.5" of magazine to work with.

I've got access to a pretty solid lathe, and am pretty handy, but not sure I'd want to buy a reamer, then screw it up and be out a barrel and a reamer...

I don't have any smiths nearby, but since these are prefits, I assume costs would be somewhat lower if I were to send the barrels off to have it done? What's the "best guess" for what it would cost for a single barrel?
 

entoptics

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Jan 16, 2018
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617
This might help:
Very helpful. The thread at LRO seems generally positive, but I've heard few reports that PTG tools can be sketchy.

I found them at 4D Reamer Rentals for $32, which I'd be happy to pay if I was certain I could get good results. I actually have a 7mm RM take off Savage barrel I could practice on too. I also have a bore scope, so I could inspect my results and get before/after images.

If I were to go this route, would there be an advantage to using a lathe? Anyone have tips/tricks for getting perfect alignment?
 

tobnpr

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May 30, 2013
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248
Why are you concerned with SAAMI "max length"?
Modern VLD bullet designs have pretty much rendered them useless.

I don't even measure OAL unless I'm concerned about mag length- and most of the time I'm not in a target rifle.

If you've got the bullet seated at least as far as the top of the boattail being even with the neck/shoulder junction- you're fine. Some don't even care if it exceeds mag length if they're ok with single-loading.

It's when you've got too much bullet in the case due to too short a throat- limiting your case capacity- that you'd want to lengthen it.
 

entoptics

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Jan 16, 2018
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617
Why are you concerned with SAAMI "max length"?
Modern VLD bullet designs have pretty much rendered them useless.

I don't even measure OAL unless I'm concerned about mag length- and most of the time I'm not in a target rifle.

If you've got the bullet seated at least as far as the top of the boattail being even with the neck/shoulder junction- you're fine. Some don't even care if it exceeds mag length if they're ok with single-loading.

It's when you've got too much bullet in the case due to too short a throat- limiting your case capacity- that you'd want to lengthen it.

...They both shoot pretty decent as is, but they come in right around SAAMI max length when 0.020" off the lands, so there's a heck of a lot of bullet below the neck/shoulder, and I have 3.5" of magazine to work with.
;)
 

tobnpr

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May 30, 2013
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Sorry- wasn't following.
So ya have plenty of mag length to work with, but a SAAMI spec chamber. Got it.

I use the same micrometer reamer stop that I use for chambering, with a 1/4" adapter for the throating reamer.
Whenever possible, I do it in the same setup after the chamber is cut to depth.

Some guys with a really light touch can do it freehand, but I'd never try it. You can dump 20 thou like a hot knife through butter before you know it.

The spare takeoff would be ideal IF the chamber were cut the same- but given it's a 700 takeoff there's zero correlation in chamber depth to the Savage. Still, could use it just to get a "feel" for it.

Disclaimer: I've not used the Uni-throater. If it were used as part of the original chambering setup I'd do it in the lathe. Since it's not, you'd need an indicator rod with a correctly fit pilot just to dial in the bore (do you have them?).
Even then I don't see an advantage in taking the time to setup in the lathe.

Call 4D and talk to Fred- he'll either confirm what I said, or tell you I'm dead wrong :)
 

Ckgworks

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Mar 6, 2018
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I have lengthened the throat on a 6.5 Grendel by hand.......I posted about it on here a while back. It was pretty easy, and I have been very happy with it. I drilled out the primer on a piece of fired brass and used that to help keep it centered up. A nut on the back side to control depth. Now that I have a lathe, I'd probably do it in that, but as others said it is VERY easy to over cut, and doing it by hand maybe gave me more control? I bought the reamer as I had about 5 barrels to do at different times, but renting one seems like the way to go. Good luck!
 

entoptics

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Jan 16, 2018
Messages
617
...The spare takeoff would be ideal IF the chamber were cut the same- but given it's a 700 takeoff there's zero correlation in chamber depth to the Savage. Still, could use it just to get a "feel" for it...

The spare is actually the OEM Savage barrel. But the same logic probably applies. It's unlikely to be cut the same as the current X-Caliber that I want to modify. Still, I can make a dummy round and practice getting it to the lands, before attempting it on the far more precious mid-lifespan X-caliber.

I'm also not after some precise throat length. The mag won't allow seating all the way past neck/shoulder, so my goal is to simply get a little more powder capacity, and have a little more room to confirm that this rifle is as insensitive to seating depth tuning as all my others. If I can hit pretty close to 0.15" that's fine. Even if I overshot 20 thou, I'd still be able to jam every bullet I've tried so far, inside mag length.

I think I might try this myself, so if there's any other suggestions, let em fly. I'm also interested in accuracy/fps win/loss/ties that people have seen from doing this or similar work.
 

elf

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Nov 26, 2017
Messages
321
I have two barrels, w, and a 7mm Rem Mag, which will be exclusively shooting ELD-M/X bullets (perhaps some other VLD t
hich are Savage prefits, that have throats considerably shorter than I'd like (0.15" - 0.19").



FYI, these are a 264WM
ypes, but nothing lighter than 143/175 gr). They both shoot pretty decent as is, but they come in right around SAAMI max length when 0.020" off the lands, so there's a heck of a lot of bullet below the neck/shoulder, and I have 3.5" of magazine to work with.

I've got access to a pretty solid lathe, and am pretty handy, but not sure I'd want to buy a reamer, then screw it up and be out a barrel and a reamer...

I don't have any smiths nearby, but since these are prefits, I assume costs would be somewhat lower if I were to send the barrels off to have it done? What's the "best guess" for what it would cost for a single barrel?
 

jimbires

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clearfield county , Pa

new2mud

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May 3, 2010
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Heart of TX
I did one by hand . it turned out good ,and it shoots well . I did a write up on another forum . I have a few of the bullet lengths wrong , but that's not important for seeing how it's done . if I were to do it again , I would buy the hornady seating depth tool , it would have saved me a bunch of time .


Nosler Reloading Forum • View topic - throating , the one I couldn't pass up part 2
Thanks for sharing this experience Jim. Gives hacks like me confidence in being able to do it at home!
 

tobnpr

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May 30, 2013
Messages
248
The spare is actually the OEM Savage barrel
****...where the hell did I pick up that it was a 700? Slippin' in my old age lol...
Actually, I'm thinking it could be useful as more than just practice.
Do you have a depth mike? Check go gauge protrusion on both barrels. They should be within .125-.130. Could do it with a caliper stem also keeping it square to the gauge.

Cut the throat to where you want it on the take-off, adjust for any slight difference in the above number. You should end up within a couple of thousandths with the uni-throater set by the take-off. That's plenty close enough... hell, you'll probably be increasing a couple thou every hundred rounds anyway.

In theory...:)
 

jrock

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Mar 12, 2014
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Idaho
If you have a lathe, I'd buy a regular throating reamer and go for it. They aren't much money and if you use it twice, it pays over renting. If you have a dummy round, its super easy to insert in the chamber until the bullet contacts the lands and then measure off the back of the case to the barrel tenon. Cut in until the measurement matches an empty case and then cut the jump you want. You just need to create a datum to work off of. Lots of ways to do that.
 

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