How to Increase Your Rifle Throat Length With a Chamber Uni Throating Reamer

parshal

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@T-nos28, I wouldn't do this if you already have a great shooting load. This is done when you want more room in the case to add more powder to find a better load.

 

T-nos28

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@T-nos28, I wouldn't do this if you already have a great shooting load. This is done when you want more room in the case to add more powder to find a better load.
Right now I am shooting the nosler ABLR 168 but I am wanting to switch to the 195 Berger EOL being I’m about to run out of the 168s and can’t find any. I have already purchased two 500 ct boxes of the 195s and from what I can best tell just by eye it looks as though the 195 seated optimally I’m around about the 3.750 COAL and right now with my chamber the way it is just touching I’m at 3.618 3.620 COAL. I was about to start working a load up with the 195 and N570 untill I found the video on the Uni throater. I understand the fact that if I seat a bullet out further it opens up room in the case for powder and increases the amount of powder that will fit in the case lowers the pressure with the same charge and ends up with a higher velocity. What I’m confused on is if this is done like Ryan said he lost 60 FPS on his load and if a chamber was throated say .100 to .150 longer how much velocity can one actually gain from this from say a 195 seated at 3.620 compared to a 195 seated at the 3.750. And also with both bullets seat at 3.620 and 3.750 and both with exact same charge of said powder the 3.620 is going to be a higer pressure but a slower velocity in that scenario correct? I’m no gun smith but I am intelligent and I have no doubt I am capable of throating my rifle and if I’m switching to the 195 I feel it would be worth it if the velocity gain is enough. With the info I have provided what do you feel is a reasonable expectation in velocity gain from my factory throat to useing the Uni throater and seating the bullets optimally
@T-nos28, I wouldn't do this if you already have a great shooting load. This is done when you want more room in the case to add more powder to find a better load.
 

Spreedizzle

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@T-nos28 another thing to consider......you didn’t mention if your rifle is stock or a custom. I say this, as almost all factory 28N’s have a 1:9” barrel, which is not enough twist to stabilize the 195’s.
 

T-nos28

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@T-nos28 another thing to consider......you didn’t mention if your rifle is stock or a custom. I say this, as almost all factory 28N’s have a 1:9” barrel, which is not enough twist to stabilize the 195’s.
Mine is a factory Fierce CT rival with 1-8.5
 

Spreedizzle

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Mine is a factory Fierce CT rival with 1-8.5
Good stuff. With an 8.5, you may or may not be able to stabilize it based on your elevation. I’m guessing that you are out west and at a decent elevation based on your desire to shoot the 195. If in question, you can hop on Berger’s site and plug in your ballistics and environmental conditions on their stability calculator.
 

T-nos28

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Mine is a factory Fierce CT rival with 1-8.5
Berger twist rate calculator says with a velocity of 2900 at my elevation and average temp is where the bullet becomes stable number it is giving me is 1.51 I should be able to shoot that bullet atleast that fast with combination
 

Jidaho

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I have not. I am not sure you will see a lot from throating a SAAMI 300WM. It's problem is not really from the throat length as far as where the ogive is going to contact the lands. It's problem is more related to the fact that it essentially has no freebore but it is a very sloppy chamber. With the slop and the lead angle it ends up allowing a 215 Berger to be seated out quite a bit. That is not something you can fix with a throater. I am not going to say you would see zero benefit but I am not sure I would mess with it. Having said that if I were building a 300 WM I would use a custom reamer for sure. The 10 twist I feel is optimal.
Can I ask what is the area just before the riflings after the freebore called is this what people refer to as being in the lands? If so have you noticed it is allot tighter in a Christensen barrel vs. Remington barrels?
I have not. I am not sure you will see a lot from throating a SAAMI 300WM. It's problem is not really from the throat length as far as where the ogive is going to contact the lands. It's problem is more related to the fact that it essentially has no freebore but it is a very sloppy chamber. With the slop and the lead angle it ends up allowing a 215 Berger to be seated out quite a bit. That is not something you can fix with a throater. I am not going to say you would see zero benefit but I am not sure I would mess with it. Having said that if I were building a 300 WM I would use a custom reamer for sure. The 10 twist I feel is so
I think the 215 gr Berger Hybrid in the Ridgeline sits really good. I can load them in my Ridgeline to the lands if I wanted to and still be seated in the neck about perfectly. See this post. I suppose you could get a few thou more out of the throat. https://www.longrangeonly.com/forum/threads/300-win-mag-215-gr-berger-n570.6809/post-55278

I would consider extending the throat if I wanted to run something like the 245 gr Berger EOL.
So do you think the freebore on a Christensen barrel is allot tighter than most the Remingtons out there? I’d like to see the reamer print they use.
 

Ladd

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Can I ask what is the area just before the riflings after the freebore called is this what people refer to as being in the lands? If so have you noticed it is allot tighter in a Christensen barrel vs. Remington barrels?


So do you think the freebore on a Christensen barrel is allot tighter than most the Remingtons out there? I’d like to see the reamer print they use.
With respect to the question directed at me, the chamber in a Christensen Arms Ridgeline is SAAMI spec and no different than other SAAMI spec chamber. The reamer is then identical to other SAAMI spec reamers.
 

FURMAN

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Can I ask what is the area just before the riflings after the freebore called is this what people refer to as being in the lands? If so have you noticed it is allot tighter in a Christensen barrel vs. Remington barrels?


So do you think the freebore on a Christensen barrel is allot tighter than most the Remingtons out there? I’d like to see the reamer print they use.
Ladd answered the second half. The area between the freebore and max rifling is tapered between the two dimensions. It’s called the leade.
 

md99cobra

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Tagged for later reference.


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hokiepride44

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@FURMAN Does this tool work with both .308 bolt face and mag bolt face cartridges or do you have to get a different bushing for each?

I’m going to order one for a 7 rem mag, just wondering if I need to specify that or if the bushing that comes with it will work.
 

FURMAN

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It’s caliber specific only, not cartridge so bolt face doesn’t matter.
 

md99cobra

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I used one of these on the throat of a 260AI and my best advice is to take it slow and check often. I overdid mine by a bit pretty quick. It still shoots good but I’d like to have that .010” back.


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